Innovations and Technologies in Construction: Selected Papers of BUILDINTECH BIT 2020 [1st ed.] 9783030546519, 9783030546526

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Lecture Notes in Civil Engineering

Sergey Vasil’yevich Klyuev Valeriy Stanislavovich Lesovik Nikolay Ivanovich Vatin Editors

Innovations and Technologies in Construction Selected Papers of BUILDINTECH BIT 2020

Lecture Notes in Civil Engineering Volume 95

Series Editors Marco di Prisco, Politecnico di Milano, Milano, Italy Sheng-Hong Chen, School of Water Resources and Hydropower Engineering, Wuhan University, Wuhan, China Ioannis Vayas, Institute of Steel Structures, National Technical University of Athens, Athens, Greece Sanjay Kumar Shukla, School of Engineering, Edith Cowan University, Joondalup, WA, Australia Anuj Sharma, Iowa State University, Ames, IA, USA Nagesh Kumar, Department of Civil Engineering, Indian Institute of Science Bangalore, Bengaluru, Karnataka, India Chien Ming Wang, School of Civil Engineering, The University of Queensland, Brisbane, QLD, Australia

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Sergey Vasil’yevich Klyuev Valeriy Stanislavovich Lesovik Nikolay Ivanovich Vatin •

•

Editors

Innovations and Technologies in Construction Selected Papers of BUILDINTECH BIT 2020

123

Editors Sergey Vasil’yevich Klyuev Belgorod State Technological University Belgorod, Russia

Valeriy Stanislavovich Lesovik Belgorod State Technological University Belgorod, Russia

Nikolay Ivanovich Vatin Peter the Great St. Petersburg Polytechnic University St. Petersburg, Russia

ISSN 2366-2557 ISSN 2366-2565 (electronic) Lecture Notes in Civil Engineering ISBN 978-3-030-54651-9 ISBN 978-3-030-54652-6 (eBook) https://doi.org/10.1007/978-3-030-54652-6 © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 This work is subject to copyright. All rights are solely and exclusively licensed by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Switzerland AG The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland

Preface

The International Scientific Conference “BUILDINTECH BIT 2020. INNOVATIONS AND TECHNOLOGIES IN CONSTRUCTION” is held from October 8 to 9, 2020, on the basis of Federal State Budgetary Educational Institution of Higher Education, Belgorod State Technological University named after V.G. Shukhov. BUILDINTECH BIT is an annual conference. The work of the conference is aimed at providing an opportunity for scientists, graduate students and representatives of the construction industry to generalize the recent achievements resulting in the field of industrial and civil construction (design, organization of all types of work, construction materials, etc.), discussing promising directions for the construction industry development and establishing useful partner relationships for future interaction. The conference is held on numerous topics: Session 1. Building Materials Session 2. Building Constructions, Industrial and Civil Construction Session 3. Structural Mechanics and Theory of Structures. Four hundred and twenty participants from 30 regions of the Russian Federation and 19 participants from 7 countries of the near and far abroad (China, Iraq, Kazakhstan, Tajikistan, Ukraine, Uzbekistan and Vietnam) were registered for the conference in 2020. The important problems of Building Constructions, Building Materials, Industrial and Civil Construction and Structural Mechanics and Theory of Structures (from ideas and projects to immediate implementation) are raised, and the ways of their solution and optimization are suggested in the reports presented in frameworks of these topics. Many reports were prepared as a benefit of the state support of science in the form of grants, federal target programs, resolutions of the Government of the Russian Federation and other programs. All articles were peer-reviewed by specialists with a degree. Fifty best scientific manuscripts corresponding to the profile of the conference and reflecting the results of theoretical and experimental studies of the authors are recommended for publication. v

vi

Preface

Annual holding of such conferences is planned to be organized on the main topics of the construction industry. Klyuev Sergey Vasil’yevich Lesovik Valeriy Stanislavovich Vatin Nikolay Ivanovich

Organization

Organizing Conference Committee Evtushenko E. I.

Uvarov V. A.

Lesovik V. S.

Doctor of Engineering Sciences (Advanced Doctor), Professor, Belgorod State Technological University named after V.G. Shukhov Doctor of Engineering Sciences (Advanced Doctor), Professor, Belgorod State Technological University named after V.G. Shukhov Doctor of Engineering Sciences (Advanced Doctor), Professor, Corresponding Member of RAASN, Belgorod State Technological University named after V.G. Shukhov

Scientific Conference Committee Amir Abdulrahman Ali Belloush (Rector) Ayzenshtadt A. M.

Vatin N. I.

Kovtun M. A. Kozhukhova M. I. Loganina V. I.

Doctor of Engineering, Anbar University, Iraq Funtius Institute, Morocco RF—Doctor of Chemical Sciences (Advanced Doctor), Professor, Northern (Arctic) Federal University named after M.V. Lomonosov RF—Doctor of Engineering Sciences (Advanced Doctor), Peter the Great St. Petersburg Polytechnic University Australia University of Wisconsin-Milwaukee, USA RF—Doctor of Engineering Sciences (Advanced Doctor), Professor, Penza State University of Architecture and Construction

vii

viii

Lukuttsova N. P.

Nenad Stoykovich Naumov A. E.

Elyan Issa Jamal Issa Salyamova K. D.

Sovann Chin Strokova V. V.

Suleymanova L. A.

Tabet Salem Al-Azab Fisher H. B. Hisham Almama Hussein Motawi (Vice-rector) Eknik Jürgen

Shakarna Mahmoud Husni Ibrahim

Organization

RF—Doctor of Engineering Sciences (Advanced Doctor), Professor, Bryansk State Engineering Technological University Nish Higher Technical School of Vocational Education, Serbia RF—Candidate of Engineering Sciences, Belgorod State Technological University named after V.G. Shukhov Al-Ahliyya Amman University, Jordan Uzbekistan: Doctor of Engineering Sciences (Advanced Doctor), Professor, Institute of Mechanics and Seismic Stability of Structures of the Academy of Sciences of the Republic of Uzbekistan Cambodia RF—Doctor of Engineering Sciences (Advanced Doctor), Professor, Belgorod State Technological University named after V.G. Shukhov RF—Doctor of Engineering Sciences (Advanced Doctor), Professor, Belgorod State Technological University named after V.G. Shukhov Yemen Bauhaus-University of Weimar, Germany Damascus University, Syria Damanhour University, Egypt Executive Director of a Swiss Company, Performance Selling Academy Zurich Area GmbH, Switzerland Palestine

All conference participants express deep gratitude to the Science team.

Contents

Statistical Analysis of the Frequency of Damage Accumulation in the Structure of Epoxy Composites Under Tensile Loads . . . . . . . . . T. A. Nizina, D. R. Nizin, and N. S. Kanaeva Mixed Binders with the Use of Volcanic Ash . . . . . . . . . . . . . . . . . . . . . L. H. Zagorodnyuk, A. E. Mestnikov, D. S. Makhortov, and Akhmed Akhmed Anis Akhmed

1 9

The Effect of Titanium Dioxide Sol Stabilizer on the Properties of Photocatalytic Composite Material . . . . . . . . . . . . . . . . . . . . . . . . . . . M. V. Antonenko, Y. N. Ogurtsova, V. V. Strokova, and E. N. Gubareva

16

Influence of Clinker Microstructure on Grinding Efficiency in the Presence of Grinding Intensifiers . . . . . . . . . . . . . . . . . . . . . . . . . L. D. Shahova, L. S. Schelokova, and E. S. Chernositova

23

Obtaining High-Quality Expanded Porous Gravel Based on Low-Expanding Stone-Like Clay . . . . . . . . . . . . . . . . . . . . . . . . . . . . H. N. Mammadov and A. A. Guvalov

30

Stress-Strain State of Normal Sections of Precast-Monolithic Reinforced Concrete Beams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. A. Kryuchkov, N. V. Frolov, and G. A. Smolyago

38

Low-Carbon Principles of Eco-Efficient Construction Development . . . . I. P. Avilova, A. E. Naumov, M. O. Krutilova, and D. D. Dakhova

45

Shungite Waste – An Effective Mineral Additive for Concrete Modification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. S. Estemesova, Z. N. Altaeva, and Zh. T. Aimenov

52

Concrete Chemicalization for Digital Printing: Control of Rheology and Structure Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V. A. Poluektova and N. A. Shapovalov

59

ix

x

Contents

Stabilization of the Clay Soil of the Increased Humidity for Road Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. I. Trautvain, A. E. Akimov, and V. A. Grichanikov

66

Progressive Destruction of Frame Buildings Made of Monolithic Reinforced Concrete . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. K. Ksenofontova

73

Increasing the Stability of the Polyimide Radiation-Protective Composite to the Effects of Atomic Oxygen . . . . . . . . . . . . . . . . . . . . . . N. I. Cherkashina, Z. V. Pavlenko, and N. V. Kashibadze

79

Reactivity of the Clay Component of Rocks at the Incomplete Stage of Mineral Formation to Lime During Autoclave Processing . . . . . . . . . A. N. Volodchenko and V. V. Nelyubova

86

Examination of the Safety of the Centrifuge Site of a Sugar Factory in the Belgorod Region in Order to Assess the Technical Condition of Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I. R. Serykh, E. V. Chernysheva, and A. N. Degtyar

92

Tape System for Damping Vibrations of Mesh Domes with a Central Mount for Seismic Impacts . . . . . . . . . . . . . . . . . . . . . . . 100 A. I. Shein and A. V. Chumanov Eco-Cement for 3D-Additive Technologies in Construction . . . . . . . . . . 108 V. S. Lesovik, A. N. Babaevsky, E. S. Glagolev, and A. A. Sheremet Research on the Possibility of Using Volcanic Sand of Kamchatka as a Component of a Composite Binder . . . . . . . . . . . . . . . . . . . . . . . . . 113 N. I. Alfimova, I. M. Shurakov, M. S. Ageeva, and N. I. Kozhukhova Innovative Approaches to Residential Development Using Large-Panel Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 R. G. Abakumov, M. A. Shchenyatskaya, I. V. Ursu, and M. I. Oberemok The Aspect of Color Optimization of the Mineral Repair Mixture for the Brickwork Restoration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124 V. E. Danilov, D. V. Ershkov, and A. M. Ayzenshtadt Concrete and Fiber-Reinforced Concrete in a Cage Made of Polymers Reinforced with Fibers . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131 L. A. Panchenko Wear Resistance of the Surface of the Structural Polyimide Composite Modified with Ceramic Corundum Coating . . . . . . . . . . . . . 137 R. N. Yastrebinsky, V. V. Sirota, and A. V. Yastrebinskaya Fiber Concrete on Greenest Cementitious Binders for Road Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143 R. S. Fediuk, A. V. Klyuev, Y. L. Liseitsev, and R. A. Timokhin

Contents

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Development of Composite Binders’ Compositions for Additive Technologies in Low-Rise Building Construction . . . . . . . . . . . . . . . . . . 150 E. S. Glagolev Crack Closure in a Cement Matrix Using Bacterial Precipitation of Calcium Carbonate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158 V. V. Strokova, U. N. Dukhanina, and D. A. Balitsky Stress Modelling of Composite Shallow Shells of Variable Structural Rigidity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165 S. V. Yakubovskaya and E. Yu. Ivanova Effective Driven Inclined Open Pile (IOP) . . . . . . . . . . . . . . . . . . . . . . . 172 A. E. Naumov, A. V. Shevchenko, A. V. Dolzhenko, and S. Yu. Pirieva Interaction of Potassium Oxide with Calcium Aluminate . . . . . . . . . . . . 179 A. O. Erygina and D. A. Mishin Influence of Polycarboxylate Superplasticizer and Mineral Additives of Various Nature on the Kinetics of Early Hardening Stages of Cement Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184 T. A. Nizina, A. S. Balykov, and D. I. Korovkin Increasing the Resistance of Building Materials with Bioactive Hybrid Coverage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191 M. I. Vasilenko, E. N. Goncharova, and Yu. K. Rubanov Features of Expertise in Wooden Housing Construction . . . . . . . . . . . . 198 S. I. Ovsyannikov, A. A. Suska, and V. M. Kashyna Surface Activity of the Fine Disperse Systems on the Basis of Construction Sands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206 M. V. Morozova, M. V. Akulova, and M. A. Frolova Optimization of the Structure of Flat Metal Tube Trusses . . . . . . . . . . . 213 V. A. Zinkova Composites on the Base of Industrial Waste with Biocidal Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219 Yu. K. Rubanov, Yu. E. Tokach, M. I. Vasilenko, and E. A. Belovodsky Assessment of the Durability of Coatings Based on Sol Silicate Paint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227 A. M. Gridchin, V. I. Loganina, E. B. Mazhitov, and A. N. Ryapukhin The Role of the Structure and Texture of the Gypsum Matrix in the Formation of Composite Materials . . . . . . . . . . . . . . . . . . . . . . . . 233 V. G. Klimenko

xii

Contents

Probabilistic Tornado Hazard Criterion for the Nuclear Facilities Siting Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239 G. P. Barulin and F. F. Bryukhan On the Issue of Designing Structures of Composite Binders . . . . . . . . . . 246 R. V. Lesovik, M. S. Ageeva, A. A. Matyukhina, and E. V. Fomina Composite Binders Based on Dust of Electric Filters . . . . . . . . . . . . . . . 253 L. H. Zagorodnyuk, V. D. Ryzhikh, D. A. Sumskoy, and D. A. Sinebok Influence of Chloride-Containing Media on the Protective Properties of Concrete . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260 Viktoriya Konovalova The Effect of Latex and Nanocarbon Modifiers ON the Properties of High-Strength Gypsum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266 L. Yu. Matveeva, M. V. Mokrova, A. V. Yastrebinskaya, and A. S. Edamenko Smalt Based on The Broken Colored Container Glasses . . . . . . . . . . . . 274 N. I. Bondarenko, D. O. Bondarenko, and K. A. Valuiskikh Possible Criterion for Evaluating the Compatibility of Components in the Building Mixtures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280 A. M. Ayzenshtadt, A. A. Shinkaruk, and M. A. Frolova Influence of Modified Bituminous Binders on the Properties of Stone Mastic Asphalt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287 D. A. Kuznetsov, A. V. Kurlykina, A. O. Shiryaev, and D. P. Litovchenko Physico-Chemical Properties of Fuel Ashes as Factor of Interaction with Cationic Bitumen Emulsion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294 A. Yu. Markov, V. V. Strokova, I. Yu. Markova, and M. A. Stepanenko The Study of Bitumen with Stabilizing Additives for SMA by Infrared Spectroscopy Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301 Dmitry Yastremsky, Tatiana Abaidullina, and Petr Chepur Composite Binder on the Basis of Concrete Scrap . . . . . . . . . . . . . . . . . 307 R. V. Lesovik, N. M. Tolypina, Ahmed Anees AlAni, and Al-bo-ali-wathiq Saeed Jasim Properties and Microstructure of Gypsum Stone with Synthetic and Protein Foaming Agents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313 N. P. Lukuttsova, A. A. Pykin, S. N. Golovin, and E. G. Artamonova The Effect of Separate Input of the Mineralizer on the Whiteness and Strength Characteristics of White Cement . . . . . . . . . . . . . . . . . . . 318 S. V. Kovalev, D. A. Mishin, and E. V. Neverova

Contents

xiii

Influence of Compatibilizator on the Operational and Technological Properties of Thermoplastic Composites Filled with Fine Barley Straw . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325 A. M. Kuzmin Remote Method for Predicting Damage to Cement Concrete Pavements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333 A. A. Fotiadi, S. A. Gnezdilova, and I. S. Strekha Author Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341

Statistical Analysis of the Frequency of Damage Accumulation in the Structure of Epoxy Composites Under Tensile Loads T. A. Nizina(&)

, D. R. Nizin

, and N. S. Kanaeva

National Research Mordovia State University, Saransk, Russia [email protected]

Abstract. Statistical analysis of the frequency of damage accumulation in the structure of epoxy polymer samples subjected to tensile loads was performed. Samples of polymers produced on the basis of epoxy modified binder Etal-247 cured with hardener Etal-45M, which is a mixture of aromatic and aliphatic dior polyamines, were chosen as the object of research. The main criterion for determining the coordinates of “critical” points was the results obtained using the author’s method for estimating changes in the fractality index based on the use of the least coverage method. The values of tensile stresses and relative elongations registered with high reading frequency (0.01 s) were used as input data. The levels of “critical” states corresponded to the values of fractality indices less than 0.5. The levels of accumulated damage were revealed with the excess leading to sample destruction. It has been established that in order to obtain the most objective results in the study of the damage accumulation kinetics, it is advisable to analyze not a single “most representative” sample, but a number of samples of the studied structure. Keywords: Epoxy polymers
Deformation curves
Damage accumulation Stress increase
Fractal analysis
Minimal coverage method




1 Introduction The active recent introduction in the practice of scientific research of modern testing equipment which is a high-precision system for collecting and recording experimental data, leads to the accumulation of big data volumes, and their processing and analysis requires the use of special techniques. In particular, when testing composite materials both for compression [1, 2] and tension [3, 4], data is registered with a frequency of 0.01 s. which makes it possible to obtain data volumes containing, on average, from 1.5 to 150 thousand lines for each sample depending on the loading speed and sample strength indicators. Processing the obtained data arrays, including using fractal calculus methods, provides important information about the deformation process, as well as allows developing methods for assessing quantitative values of the “critical” points of the process of loading composite materials subjected to mechanical loads which, no doubt, is an important material science challenge.

© The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 1–8, 2021. https://doi.org/10.1007/978-3-030-54652-6_1

2

T. A. Nizina et al.

A characteristic feature of polymer composite materials is a complex multi-level structure which leads to significant differences in the nature of the destruction of various polymer types [5, 6]. In addition, the presence of pores and primary defects in polymer composites can lead to significant differences in both the integral strength and deformation indicators, and the nature of the process of damage accumulation under mechanical loads even within the same series of samples of the studied composition. It is the structural heterogeneity of composite building materials that even at relatively low levels of mechanical stress leads to formation of weakened zones, which later cause loosening and destruction of composites. In this case, the fracture process is of a discrete-continuous nature that develops over time and is characterized by the occurrence of multiple origination, development, and aggregation of various kinds of defects until the appearance of main cracks leading to the sample destruction [7–10]. In the author’s studies [1–4], an algorithm based on the use of the fractal analysis of time series obtained with a high frequency of readings was proposed for analyzing the loading process of various composites subjected to mechanical loads. It allows quantitative determination of the coordinates of the “critical” points in the deformation curves indicating the appearance of certain “difficulties” (bifurcation points) in the composite structure. To determine the change in the values of fractality indices which make it possible to identify the “critical” stress and strain levels during loading of building composites, it is proposed to use the least coverage method described in [11, 12] and which is the most optimal even for large time series. Moreover, upon the analysis of the accumulated results of such studies, an important scientific task is to both determine the coordinates of the “critical” points of the deformation curves of individual samples, and also to analyze their relative position and distribution within a series of samples of the same structure in order to identify similarities and differences in the behavior of materials subjected to mechanical loads, taking into account their structural heterogeneity, the presence of hidden defects and other factors. In this paper, using the example of ten samples of the same structure, we analyze statistical indicators of the damage accumulation process leading to the composite destruction.

2 Methods and Materials As the object of study herein, we selected a polymer obtained on the basis of a modified Etal-247 epoxy resin (TU 2257-247-18826195-07), cured by Etal-45M hardener (TU2257-045-18826195-01) which is a mixture of aromatic and aliphatic di- or polyamines. Technical characteristics of Etal-247 resin: mass fraction of epoxy groups – not less than 21.4–22.8%; Brookfield viscosity at 25 °C – 650–750 cP. The AGS–X series tensile testing machine with TRAPEZIUM X software was used for mechanical tensile testing of polymer composite structures. The frequency of registering stress and strain values was 0.01 s. The tests were carried out on samples “eights” (type 2) in accordance with GOST 11262-2017 (ISO 527-2:2012) “Plastics. Tensile Stress Test” at a temperature of 23 ± 2 °C and relative air humidity of 50 ± 5%. The tensile testing machine clamp movement speed was 2 mm/min.

Statistical Analysis of the Frequency of Damage Accumulation

3

The methodology for determining the integral index of the fractal dimension of the deformation curve of polymeric materials and the coordinates of the “critical” points during loading of polymeric materials is described in [3, 4]. When developing the technique, we proceeded from the assumption that each step on the deformation curve is associated with finding the set of all structural elements of the system in one of two states – failure or operating state. It is assumed that the failed structural elements are not restored, and transitions in the system are possible only from the previous state to the next one (condition of process irreversibility) [3, 4]. To determine fractality index l when analyzing the deformation curve of polymer composites, we used the sequence m of embedded partitions where m ¼ 2n , where n ¼ 0; 1; 2; 3; 4 Each partition consisted of 2n intervals containing 24n experimental points. For each partition, xm ¼ ½a ¼ to \ t1 \ . . . \ tm ¼ b depending on step (d ¼ ðb  aÞ=mÞ, the amplitude variation Vf ðdÞ was calculated using equation [11, 12]: V f ð dÞ ¼

Xm i¼1

Ki ðdÞ;

ð1Þ

where Ki ðdÞ was defined as the difference between the maximum and minimum increase in tensile stress in the time interval [ti1 ; ti ]. In this case, point characterizes the beginning of the deformation process, point corresponds to the level of achievement of the maximum stresses by the sample. Coefficient b of regression equation logðVf ðdÞÞ ¼ ao þ b  logðdÞ determined using the least squares method, was used to determine the fractality index and the minimum coverage dimension: l ¼ b; Dl ¼ 1 þ l:

ð2Þ

3 Results and Discussion We illustrate the application of the developed technique by the example of one of the samples (No. 1) of the studied structure (Fig. 1). The analysis of the graphical dependence in Fig. 1b shows that the section of the deformation curve before the level of maximum stresses (dashed red line) is characterized by discrete acts of the increase and decrease in stresses. A sharp decrease in stress jumps is observed in the descending branch of the deformation curve increasing only near the fracture point. To determine the coordinates of “critical” points of the deformation curves of polymer samples, we studied the previous time interval corresponding to 16 ð24 Þ experimental points, i.e. 0.16 s. Graphical dependence of the change in the fractality index of sample No. 1 depending on the level of relative elongation under tension is shown in Fig. 1c. The coordinates of “critical” points corresponding to the lowest levels of fractality indices are highlighted in this figure by red (No. 1, 2) and yellow

4

T. A. Nizina et al.

a)

b)

c)

Fig. 1. Deformation curve (a), change in the increase of stress (b) and fractality index (c) of the epoxy polymer sample No. 1 an depending on the relative elongation under tension

(No. 3–15) circles. For convenience of visual analysis, the first ten most “critical” points were plotted on the initial deformation curve (Fig. 1a). Let us analyze the loading process of 10 samples of the studied structure under the tensile loads, with their deformation curves shown in Fig. 2. Dashed lines in this figure show the average levels of maximum stress and relative elongation under tension ðrstr: ¼ 37:38 MPa; estr: ¼ 7:24%) calculated taking into account the statistical analysis of the data. The analysis of Fig. 2 shows that the deformation curve of sample

Statistical Analysis of the Frequency of Damage Accumulation

5

No. 4 is characterized by higher deformation characteristics at break, almost two times higher than the similar values of other samples; the general character of the «re» curves for other samples is similar. No. 6 was chosen as the most representative curve of the ten samples studied, according to the correspondence of its main indicators to average values.

Fig. 2. Deformation curves of epoxy composite samples under tension

According to the fractality index l calculation results for the ten samples studied, it was found that the distribution curve is characterized by the normal law (Fig. 3). Main statistical indicators of the analyzed series are shown in Table 1. It is shown that the values of the accumulated damage frequencies corresponding to the achievement of the maximum tensile stress levels by the samples vary for the studied samples in the range from 5.10 to 7.16%. From the analysis of time series, it is known [11, 12] that the higher the value of l, the more stable the series. If l \ 0:5 the series is interpreted as a “trend” (a period of sharp up or down movement which usually indicates the occurrence of a “critical” state in the system under study); if l [ 0:5 the series is interpreted as a “flat” (a period of relative calm). To analyze the kinetics of damage accumulation in the studied samples, graphical dependencies were built that reflect the frequency of a decrease in the fractality index below the level of 0.5. In this case, the number of accumulated damage was separated both from the level of relative elongations (Fig. 4) and tensile stresses.

6

T. A. Nizina et al.

Fig. 3. Summary curve and histograms of the deformation curve fractality index distribution for epoxy composite samples Table 1. Statistical analysis of changes in the deformation curve fractality index distribution for epoxy composite samples Statistical indicators Epoxy 1 Arithmetic average 0.601 Median 0.603 Standard deviation 0.063 6.03 Accumulated damage frequency, %

sample number 2 3 4 0.600 0.594 0.600 0.603 0.596 0.603 0.061 0.062 0.062 5.56 7.16 6.07

5 0.603 0.604 0.064 5.88

6 0.601 0.603 0.063 6.06

7 0.603 0.604 0.062 5.10

8 0.605 0.607 0.062 5.19

9 0.599 0.600 0.062 5.64

10 0.604 0.607 0.061 5.15

According to the results obtained, it was found that the analysis of the damage accumulation kinetics for only one selected sample (in this case, No. 6) shows a slightly different dynamics from the averaged indicators. Depending on the test sample, a certain change in the rate of damage accumulation occurs depending on the level of strength and deformation indicators achieved by the samples during loading which leads to the need to take into account statistical variability of the results.

Statistical Analysis of the Frequency of Damage Accumulation

7

Fig. 4. Histograms of damage accumulation in epoxy composite samples at elongation (data are marked with a red line for sample No. 6; black indicates average values)

4 Conclusion The analysis of the frequency of damage accumulation in the epoxy polymer structure subjected to tensile load showed that the proposed approach can be successfully used to identify “critical” levels of loading and deformability that cause the greatest number of structural defects. Moreover, to obtain the most objective results, it is advisable to analyze not a single “most representative” sample, but all samples of the series under study.

5 Acknowledgement This work was supported by the RFBR grant No. 18-08-01050.

References 1. Selyaev, V.P., Nizina, T.A., Balykov, A.S., Nizin, D.R., Balbalin, A.V.: Fractal analysis of deformation curves of fiberreinforced fine-grained concretes under compression. PNRPU Mech. Bull. 1, 129–146 (2016) 2. Nizina, T.A., Balykov, A.S., Nizin, D.R., Korovkin, D.I.: Using fractal analysis methods in studying mechanisms of deformation and destruction of nano-modified cement concretes. Int. J. Nanotechnol. 16, 484–495 (2019) 3. Nizina, T.A., Selyaev, V.P., Nizin, D.R., Balykov, A.S., Korovkin, D.I., Kanaeva, N.S.: Application of fractal analysis methods in the study of mechanisms of deformation and fracture of composite building materials. IOP Conf. Ser.: Mater. Sci. Eng. 456, 012058 (2018)

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4. Nizina, T.A., Nizin, D.R., Kanaeva, N.S., Kuznetsov, N.M., Artamonov, D.A.: Applying the fractal analysis methods for the Study of the mechanisms of deformation and destruction of polymeric material samples affected by tensile stresses. Key Eng. Mater. 799, 217–223 (2019) 5. Khozin, V.G.: Strengthening of Epoxy Polymers. The Printing House (2004) 6. Startsev, O.V., Lebedev, M.P., Slavin, A.V., Noev, I.I.: Mechanisms of inhomogeneous polymer weathering. Dokl. Phys. Chem. 483(1), 145–150 (2018). https://doi.org/10.1134/ S0012501618120023 7. Ivanova, V.S., Balankin, A.S., Bunin, I.J., Oksogoev, A.A.: Synergetics and Fractals in Science of Materials. Nauka, Moscow (1994) 8. Zaitsev, Y.V.: Modelling of Deformation and Strength of the Concrete by Methods Fracture Mechanics. Moscow State Open University Press (1995) 9. Chernyshov, E.M., D’yachenko, E.I., Makeev, A.I.: Heterogeneity of structure and resistance to destruction of conglomerate building composites: issues of material science generalization and theory development, Voronezh (2012) 10. Travush, V.I., Selyaev, V.P., Selyaev, P.V., Kechutkina, E.L.: On the possible quantum nature of the deformation and fracture of composites. Indu. civ. Const. 9, 94–101 (2016) 11. Dubovikov, M.M., Starchenko, N.S.: Variation index and its applications to analysis of fractal structures. Sci. Almanac Gordon 1, 1–30 (2003) 12. Dubovikov, M.M., Starchenko, N.S., Dubovikov, M.S.: Dimension of the minimal cover and fractal analysis of time series. Phys. A 339, 591–608 (2004)

Mixed Binders with the Use of Volcanic Ash L. H. Zagorodnyuk1(&) , A. E. Mestnikov2 , D. S. Makhortov1 and Akhmed Akhmed Anis Akhmed3 1

,

Belgorod State Technological University Named After V.G. Shukhov, Belgorod, Russia [email protected] 2 M. K. Ammosov North-Eastern Federal University, Yakutsk, Russia 3 University of Baghdad, Baghdad, Iraq

Abstract. The most promising direction in modern science and construction is the creation of new effective mixed binders with specified properties. In recent years, there has been a significant increase in interest in the use of natural and technogenic products as components of mixed binders, the use of which is promising and relevant. This article presents the results of research on the production of mixed binders using volcanic ash from the Kenzhensky Deposit of the Kabardino-Balkar Republic in a vibrating mill, and the features of their grinding are established. Mixed binders were obtained at different ratios of cement and volcanic ash. The features of grinding and microstructure processes are studied, and the technological and physical and mechanical properties of the obtained binders are determined. The combined activation of mixed binders based on cement and volcanic ash in amount of 10% increases the compressive strength by 23%, and when using 20% of ash increases the strength by 22%, with significant savings of Portland cement up to 20%. The results obtained indicate the influence of the granulometric composition of mineral filler and cement in mixed binders on the formation of their physical and mechanical indicators. Keywords: Mixed binders
Portland cement
Volcanic ash
Granulometry Microstructure
Strength of cement stone




1 Introduction In the construction industry, new types of cements used for making construction composites for various purposes are appearing every year. New cements provide construction products and structures with special properties, increasing their strength and durability [1–4]. These binders include mixed cements obtained on the basis of Portland cements and mineral additives in the form of powders. A wide variety of mineral powders of natural origin, as well as technogenic products (slags, ash, slime, etc.) are used as mineral additives [5–8]. Among active mineral additives, a special place is occupied by additives of volcanic origin. Volcanic rocks are pyroclastic rocks that consist of small detrital products of volcanic outbursts and tiny pulverized lava particles bonded together. By chemical composition, volcanic rocks consist mainly of silica and alumina (70 … 90%), they contain a small amount of CaO and MgO (2… © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 9–15, 2021. https://doi.org/10.1007/978-3-030-54652-6_2

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4%), alkalis Na2O and K2O (3…8%) and hydrate water removed during calcination (5…10%). According to x-ray phase analysis, they are a mixture of amorphous glass (50 … 80%) and some silicates and aluminates, as well as hydrates in the crystalline state, in addition, they contain various impurities. The density of volcanic rocks is in the range of 2300 … 2600 kg/m3; bulk density 1200 … 2000 kg/m3.

2 Methods and Materials To analyze the distribution of particles of materials: Portland cement, volcanic ash and mixed binders by size, a laser analyzer Analysette 22 Nano Tec plus was used. The microstructure of the samples was studied using a high-resolution scanning electron microscope TESCAN MIRA 3 LMU. Physical and mechanical properties of mixed binders were determined in accordance with regulatory requirements.

3 Results and Discussions To obtain mixed binders, we used cement CEM I 42.5 N (GOST 31108) of JSC “Belgorod cement” and volcanic ash from the Kenzhensky Deposit of the KabardinoBalkar Republic, the chemical composition and physical properties are shown in Table 1 and Table 2. Table 1. Chemical composition of volcanic ash Chemical composition, wt% SiO2

Al2O3

Fe2O3 (total)

P2O5

CaO

MgO

K2O

Na2O

SO3 (total)

59.6 ± 0.3 15.0 ± 0.2 3.6 ± 0.1 0.2 ± 0.1 6.3 ± 0.1 3.3 ± 0.1 1.6 ± 0.1 4.4 ± 0.2 0.1 ± 0.1

Table 2. Physical properties of volcanic ash Indicator Value 3 2340 Real density, kg/m Average density, kg/m3 1650 Porosity, % 30 Water absorption by mass, % 16 Softening coefficient 0.72

The mineralogical analysis of the average sample of volcanic ash showed the presence of the following minerals (Table 3).

Mixed Binders with the Use of Volcanic Ash

11

Table 3. Mineralogical composition of volcanic ash № Minerals

№ Minerals

1 2 3 4 5 6

Content, % Magnetite 1.145 Pyrrhotite 0.017 Limonite 0.032 Ilmenite 0.115 Biotite 0.025 Zircon 0.027

9 10 11 12 13 14

7 8

Sillimanite 0.002 Garnet 0.031

Kyanite Tourmaline Epidote Amphibole Apatite Quartz

15 Feldspar 16 Volcanic glass

Content, % 0.009 0.096 0.225 1.008 0.002 6.425 18.684 34.458

№ Minerals 17 18 19 20 21 22

Carbonate Biotite Volcanic ash Zeolites Silicified debris Effusions with glass mass 23 Muscovite mica Sum

Content, % 15.841 0.980 4.031 6.364 5.494 2.587 0.000 100.000

The specific shape and surface morphology of the studied volcanic ash is related to the peculiarities of its formation [9, 10]. The ash is represented by a polydisperse distribution of particles of sizes from 1 to 350 l, having different configurations and rough surfaces specific surface area, which determines the high grinding capacity of volcanic ash. The granulometric analysis. This circumstance contributes to the creation of a high of volcanic ash performed on the MicroSiser 201 installation is shown in Fig. 1. The distribution curve of volcanic ash particles by size shows their distribution from 1 to 250 l. Attention is drawn to the presence of fine fractions in the range from 0.3 to 0.07 l, which will have a significant impact on the course of interaction reactions and filling the pore space of the composite.

Fig. 1. Distribution of volcanic ash particles by size

To obtain mixed binders, a grinding unit was used - a whirling jet mill WJM. The use of this mill allowed obtaining effective composite binders with the specified properties [11–13].

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L. H. Zagorodnyuk et al. Table 4. Physical and mechanical characteristics of mixed binders

№ Amount of ash,%

Ssp. NG

Without grinding

s.,

The

+increase, - -

m2 /

compressive

decrease in

kg

strength limit strength at the

367 25.5

№ Amount of ash,%

Ssp. NG

With grinding

s.,

The

+increase, - -

m2/

compressive

decrease in

kg

strength limit strength at the

at the age,

age of 28

at the age,

age of 28

days in MPa

days relative

days in MPa

days relative

14

to the

14

to the

28

28

composition

composition

without ash,

without ash,

%

%

1

0

2

10

376 27.77 59.50 81.98 +113.48

54.14 72.24 100

1p

2p 10

0

689 27.0

699 33.40 75.98 99.87 +112.42

70.75 88.84 100

3

20

376 30.06 52.24 70.30 −97.31

3p 20

689 36.31 68.65 89.89 +101.18

4

30

371 32.86 48.25 65.43 −90.57

4p 30

692 41.42 62.92 78.62 −88.50

5

40

374 35.83 34.36 57.24 −79.23

5p 40

696 45.00 44.99 69.39 −78.62

6

50

374 42.00 29.13 55.06 −76.22

6p 50

691 54.00 3763

6533

−73.76

Mixtures of compositions 1-6 and 1p-6p (Table 4) were prepared with different doses of volcanic tuff: 10, 20, 30, 40 and 50%. Mixtures of compositions 1–6 were prepared without grinding (by manual mixing), while the average specific surface area of the mixtures was 374 m2/kg. Compositions 1p-6p were loaded into a vibrating mill and ground for 20 min. As a result of joint grinding in a vibrating mill, the specific surface area of the mixtures was 693 m2/kg at average. And mixed binders with 20% ash content meet the strength of the additive-free cement, allowing saving up to 20% of expensive Portland cement. Thus, activation of mixed binders with volcanic ash in an amount of 10% increases the compressive strength by 23%, and when using 20% of the ash increases the strength by 22%, with significant savings of Portland cement up to 20%. The granulometric composition of the obtained mixed binders with a volcanic ash content of 10 and 20% was studied using the AnalyssetteNanoTecplus device (Table 5). Analyzing the curves of the granulometric composition of mixed binders 2 and 2p, it should be noted that the granulometric composition of mixed binder 2 is in the range of grain sizes from 1…100 l, which is determined by a significant proportion of Portland cement. Considering the granulometric composition curves of mixed binders 3 and 3p, it is noted that the composition of manual mixing is also included in the range of grain sizes 1 … 100 l, and volcanic ash in the amount of 20% is evenly distributed in the volume of Portland cement. It should be noted that in all mixed binders, volcanic ash, having a high specific surface area, is evenly distributed in the volume of binder grains and will affect the formation of the micro-and macrostructure of the cement stone.

Mixed Binders with the Use of Volcanic Ash

13

Table 5. Granulometric composition of Portland cement and mixed binders obtained by mechanical mixing and grinding in a vibrating mill Dosage of volcanic ash, %

without grinding

Type of grinding grinding in a vibrating mill

Without additive

10

20

To determine the physical and mechanical parameters of mixed binders, samples were formed - cubes of 3  3  3 cm in size, which were stored under normal conditions and tested at the age of 14 and 28 days (Table 5). The obtained results indicate a positive influence of the granulometric composition of mineral filler in mixed binders on the formation of their physical and mechanical parameters. Electronic and microscopic studies of Portland cement stones and activated Portland cement show that the fine fraction of Portland cement grains contributes to the formation of a denser structure than the sample of the original cement. The obtained data confirm that the fine fraction contributes to the active increase in the strength of the cement stone and participates in the creation of the final strength.

Fig. 2. Microstructure of non-crushed mixture of Portland cement and volcanic ash with a dosage of 10% at the age of 28 days of hardening

Fig. 3. Microstructure of mixture of Portland cement and volcanic ash crushed in a vibrating mill with a dosage of 10% at the age of 28 days of hardening

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Fig. 4. Microstructure of non-crushed mixture of Portland cement and volcanic ash with a dosage of 20% at the age of 28 days of hardening

Fig. 5. Microstructure of mixture of Portland cement and volcanic ash crushed in a vibrating mill with a dosage of 20% at the age of 28 days of hardening

The microstructure of the inactivated mixture is characterized by an uneven structure, with dense areas of the secondary hydrosilicate structure and separate areas of the loose structure marked throughout the sample volume (Fig. 2). The microstructure of the activated mixed binder sample is characterized by high uniformity (Fig. 3), products of pozzolanic reactions between ash particles and cement hydration products are formed on the surfaces of secondary hydrosilicate structures, which is consistent with the opinion [14, 15], which contributes to strengthening the bonds between cement hydration products and ash, and, therefore, increases the strength of cement stone. The microstructures of the inactive (Fig. 4) and activated (Fig. 5) mixed binder with volcanic ash (20%) have an uneven structure, differently oriented dense sections of the secondary hydrosilicate structure and separate layered sections of the loose structure (Fig. 4). The microstructure of the activated mixed binder sample is highly uniform (Fig. 5). As the space between the ash particles and the cement hydration products is filled, strong bonds are gradually formed, which leads to an increase in strength and durability [16].

4 Conclusion The performed research confirmed that the strength of cement stones obtained from mixed binders based on cement and volcanic ash depends more on the content of fractions in these cements with sizes from 3 to 30 l, as well as the presence of highly dispersed mineral filler. The combined use of mixed binders by grinding cement with volcanic ash in amount of 10% increases the compressive strength by 23%, and when using 20% of ash increases the strength by 22%, with significant savings of Portland cement up to 20%. The obtained results indicate a significant influence of the granulometric composition of mineral filler and cement in mixed binders on the formation of

Mixed Binders with the Use of Volcanic Ash

15

their physical and mechanical parameters, as well as the feasibility of using volcanic ash as a mineral component of mixed binders. Acknowledgements. The work is realized with the financial support of the RFBR as part of the scientific project № 18-29-24113

References 1. Ageeeva, M.S., Sopin, D.M., Ginzburg, A.V., Kalashnikov, N.V., Lesovik, G.A.: Development of composite binders for filling mixes. Bull. BSTU Named After V.G. Shukhov, 4, 43–47 (2013) 2. Lesovik, V.S., Zagorodnyuk, L.H., Tolmacheva, M.M., Smolikov, A.A., Shekina, A.Y., Shakarna, M.H.I.: Structure-formation of contact layers of composite materials. Life Sci. J. 11, 948–953 (2014) 3. Chernysheva, N.V., Shatalova, S.V., Evsyukova, A.S.: Fisher Hans-Bertram: features of the selection of the rational structure of the compositional gips binder. Constr. Mater. Prod. 1(2), 45–52 (2018). https://doi.org/10.34031/2618-7183-2018-1-2-45-52 4. Anikanova, L.A.: Wall materials based on a composite polymer-mineral binder. Bull. Tomsk State Univ. Archit. Constr. 6, 127–133 (2017) 5. Zagorodnyuk, L.H., Sumskoy, D.A., Chepenko, A.S.: Features of hydration processes of highly dispersed binders. Bull. BSTU Named After V.G. Shukhov, 12, 105–113 (2018) 6. Stroiteleva, E.A.: Fine-grained concrete with mineral additives. Des. Dev. Reg. Railw. Netw. 6, 58–62 (2018) 7. Kuprina, A.A., Lesovik, V.S., Zagorodnyuk, L.H., Elistratkin, M.Y.: Anisotropy of materials properties of natural and man-triggered origin. Res. J. Appl. Sci. 9, 816–819 (2014) 8. Demyanova, V.S., Kalashnikov, V.I., Borisov, A.A.: On the use of dispersed fillers in cement systems. Hous. Constr. 1, 17–18 (1999) 9. Turriziani, R., Corradini, G.: High silica pozzolanic materials. Ind. Ital. Cem. 31(10), 493– 498 (1961) 10. Costa, U., Massazza, F.: Factors affecting the reaction with lime of Pozzolanas (Italy). In: The Sixth International Congress on the Chemistry of Cement (Cements and Their Properties), vol. 3, pp. 222–227 (1976) 11. Zagorodnyuk, L.H., Lesovik, V.S., Shamshurov, A.V., Belikov, D.A.: Composite binders on the basis of the organic and mineral modifier for the dry repair mixtures. Bull. BSTU Named After V.G. Shukhov, 5, 25–31 (2014) 12. Sumskoy, D.A.: Thermal insulation mortar on the basis of the composite binder. Bull. Voronezh State Univ. Eng. Technol. 80(2), 283–289 (2018) 13. Forest, J., Demoulian, E.: Assesing the activity of fly ash and pozzolanas. Rev. Mater. Constr. Trav. Publ. 577, 312–317 (1963) 14. Guilaume, L.: L`activite pouzzolanique des cendres volantes dans les ciments portland et les ciments au laitier. Silic. Inds. 28(6), 297–300 (1963) 15. Venuat, M.: Ciments aux cendres volantes, influence de la proportion de cendre sur les proprietes des ciments. Rev. Mater. Constr. Trav. Publ. 565, 271–279 (1962) 16. Chatterjee, M.K., Lahiri, D.: Pozzolanic activity in relation to specific surface of some artificial pozzolanas. Trans. Indian Ceram. Soc. 26(3), 65–74 (1967)

The Effect of Titanium Dioxide Sol Stabilizer on the Properties of Photocatalytic Composite Material M. V. Antonenko

, Y. N. Ogurtsova(&) and E. N. Gubareva

, V. V. Strokova

,

Belgorod State Technological University named after V.G. Shukhov, Belgorod, Russia [email protected]

Abstract. This study aimed to establish the effect of a hydrolysis catalyst and a stabilizer of a hydrated titanium dioxide sol, such as nitric acid, in the synthesis of the photocatalytic composite material (PCM) of the SiO2–TiO2 system on its physicochemical characteristics. It was found that among the analyzed two types of photocatalytic composite materials (with and without nitric acid) having a similar chemical composition it is preferable to use material without nitric acid as a photocatalytic additive. It has higher photocatalytic activity, as it contains a significant amount of anatase-modified titanium dioxide with a developed surface, including nanosized particles. In the composition of PCM (without nitric acid), the presence of agglomerates of spherical particles of titanium dioxide is noted. In this case, the surface of diatomite is uniformly coated with titanium compounds. The structure of titanium-containing neoplasms in the composition of FCMN (with nitric acid) is significantly different. It has the form of a film deposited on diatomite particles. As a result, the surface of the PCMN is much less developed. Keywords: Photocatalysis
Sol-gel
Anatase
Diatomite Composition
Structure
Photocatalytic activity


Nitric acid


1 Introduction Anatase-modified titanium dioxide is known for its photocatalytic activity. In the photocatalysts preparation, the titanium dioxide applying to silica substrates to increase the efficiency of photocatalysis processes in various materials and media [1, 2]. For building materials science, the use of photocatalytic composite materials (PCM) of the SiO2–TiO2 system has significant potential for the implementation of surface selfcleaning and air purification processes, which is also due to high chemical affinity with the main components of building composites [3–6, 13]. The widespread introduction of PCM in the production of building materials and the erection of structures is currently limited by insufficient scientific groundwork in the field of their synthesis and principles of rational use.

© The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 16–22, 2021. https://doi.org/10.1007/978-3-030-54652-6_3

The Effect of Titanium Dioxide Sol Stabilizer

17

Oxide composites of the SiO2–TiO2 system are obtained in various ways, including catalytic hydrolysis, grafting of titanium alkoxides onto silica surface, coprecipitation, impregnation, chemical vapor deposition, and hydrolysis under hydrothermal conditions [7]. One of the simplest and easiest to manage is sol-gel synthesis [8]. The result of sol-gel synthesis – the phase composition and particle size of PCM – is influenced by the composition and ratio of reagents, including hydrolysis catalysts and stabilizers of titanium dioxide sol. For example, the use of certain acids accelerates hydrolysis, slows down polycondensation – the formation of TiO2•nH2O, increases the aggregative stability of a disperse system, and prevents aggregation and intergrowth of particles [9]. This study aimed to establish the effect of nitric acid – a hydrolysis catalyst and a stabilizer of a sol of hydrated titanium dioxide – in the synthesis of the photocatalytic composite material of the SiO2 – TiO2 system on its physicochemical characteristics.

2 Methods and Materials The PCM synthesis of the SiO2–TiO2 system was carried out by the sol-gel method. As a precursor for obtaining TiO2 sol, tetrabutoxytitanium Ti(C4H9O)4 was used (OOO PROMCHIMPERM, Russian Federation). Tetrabutoxytitanium was dissolved with a 95% solution of ethyl alcohol, into which nitric acid was previously introduced, with a mass ratio of tetra butoxy titanium: ethyl alcohol: nitric acid – 1:6.9: 0.09. For comparison, a sol without nitric acid was prepared. Then, the obtained sol of titanium hydroxide was poured into a powder of finely dispersed diatomite Diasil (specific surface Ssp = 1.39 m2/g, particle size 0.15–120 lm) (Diamix, Ulyanovsk Region, Russian Federation) with a mass ratio of tetra butoxy titanium: diatomite powder 2.6: 1. The flask was tightly closed, and the mixture was stirred on a magnetic stirrer for two hours. The resulting material was dried at a temperature of 100 °C for 10 h and then subjected to calcination at a temperature of 550 °C for 2 h. In the future, we denote the PCMN material obtained in the presence of nitric acid and the control PCM. The formation of the composite material occurs due to heterogeneous adhesive coagulation, which is facilitated by the difference in the charges of TiO2 sol particles (positive charge) and the surface of diatomite particles (negative charge). As a result, titanium dioxide particles are distributed on the surface of silicon dioxide particles [10]. The synthesized materials PCM and PCMN studied the composition, structural features, and photocatalytic activity. The determination of mineral and chemical compositions was carried out using: ARL 9900 WorkStation X-ray fluorescence spectrometer (Thermo Fisher Scientific); ARL X’TRA X-ray diffractometer (Cu anode) (Thermo Fisher Scientific); IR-Fourier spectrometer VERTEX 70 (Bruker). The features of the microstructure and elemental composition of the surface of the materials were investigated using a TESCAN MIRA 3 LMU (Tescan) high-resolution scanning electron microscope. Granulometric analysis of materials was carried out using a laser analyzer of particle sizes ANALYSETTE 22 NanoTec Plus (Fritsch), the measuring range of which is 0.01–2100 lm. The photocatalytic activity of materials under the influence of ultraviolet radiation was evaluated by the bleaching of the organic dye [11]. The method consists in applying to the surface of the test sample a solution of the organic dye rhodamine B (concentration 4 • 10−4 mol/l), followed by determining the

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M. V. Antonenko et al.

color change of the dye after 4 and 26 h of exposure to ultraviolet radiation (UV-A, 1.1 ± 0.1 W/m2). The color change was estimated from the Lab color space (coordinate a). Colorimetric parameters were determined at five points of the sample: four points at the corners of the sample, one point in the middle.

3 Results and Discussions The chemical composition of the synthesized PCM and PCMN powders is predominantly represented by the oxides SiO2 (more than 50%) and TiO2 (more than 30%) (Table 1). For PCMN, the SiO2/TiO2 ratio is slightly shifted toward SiO2. Table 1. The chemical composition of the studied materials Raw materials The content of oxides, mass% SiO2 TiO2 Al2O3 Fe2O3 MgO Na2O K2O CaO SO3 Other PCM 55.53 38.13 2.62 1.18 0.61 0.59 0.51 0.21 0.28 0.34 58.15 35.37 2.82 1.11 0.62 0.54 0.53 0.25 0.23 0.36 PCMN

The diffraction patterns of PCM and PCMN (Fig. 1) contain peaks of two crystalline phases: anatase and quartz. No significant difference in phase composition was observed between the two samples studied. The presence of an amorphous phase is noted, which can be attributed to opal silica of diatomite. The intensity of the quartz peak and the content of the amorphous phase are slightly higher for the PCMN sample. This fact may indirectly indicate insufficient coating of the surface of the diatomite powder with TiO2 crystals.

Fig. 1. Diffraction patterns of synthesized materials

The Effect of Titanium Dioxide Sol Stabilizer

19

The PCM IR-spectra of various compositions contain peaks characteristic of both diatomite and titanium dioxide (Fig. 2) [12]. In the left part of the spectra, a peak zone is observed that is characteristic of the hydroxyl group of both adsorbed water molecules and the surface layer of SiO2 and TiO2. Peaks responsible for symmetric (800– 810 cm−1) and asymmetric (1045–1100 cm−1) stretching vibrations of the tetrahedral SiO44− fragment is also observed. The Ti–O–Ti bond vibrations are present in a wide absorption range of 400–900 cm−1 with peaks characteristic of anatase at about 540 cm−1, 660 cm−1, and 740 cm−1. Due to the low content of titanium dioxide and the presence of a wide range of vibrations of the Si–O–Si bond (900–1250 cm−1), a peak in the vibration of the Si–O–Ti bond (900–975 cm−1) is not observed. When comparing the two spectral objects, the ratio of the intensities of the peaks of Si–O–Si and Ti–O–Ti can be noted that PCMN has a lower titanium dioxide content recorded by IR-spectroscopy.

Fig. 2. IR-spectra of synthesized materials

An analysis of the elemental composition and surface microstructure features of PCM and PCMN (Fig. 3a, b) shows that titanium-containing neoplasms partially cover diatomite particles. In the composition of PCM (Fig. 3a), the presence of agglomerates of spherical particles of titanium dioxide with a size of 50–100 nm is noted. Its deposition on the surface of diatomite is selective, anatase accumulations are observed on particles with a developed amorphized surface. Neoplasms of titanium dioxide do not cover crystallized particles of diatomite with a smooth surface. The structure of titanium-containing neoplasms in the composition of PCMN (Fig. 3b) is significantly different. It has the form of a film deposited on diatomite particles that cracked during sample preparation. As a result, the surface of PCMN is significantly less developed, which can adversely affect photocatalytic activity. Granulometric analysis shows (Fig. 4) that PCM contains particles with sizes of 0.01 lm, 0.09–106.9 lm, and a peak of 31.53 lm. The smallest of the presented particle ranges are conglomerates of formed TiO2, as well as partially destroyed conglomerates of SiO2. PCMN has an increase in the proportion of large-sized particles

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M. V. Antonenko et al.

а

b Fig. 3. The microstructure of the synthesized materials: a – PCM, b – PCMN

(0.1–174.1 lm, maximum 51.37 lm). This result suggests some enlargement of particles as a result of sol-gel synthesis. For evaluating the photocatalytic activity of the synthesized PCM and PCMN materials, tablets were prepared where white Portland cement CEM I 52.5 R manufactured by Adana Cimento (Turkey) was used as a binder. The PCM content (PCMN) is 2.5% by weight of cement. PCM has a more significant photocatalytic activity after 4 and 26 h of ultraviolet irradiation compared to PCMN (Fig. 5). This result is due to a more uniform coating of the surface of diatomite with nanosized titanium dioxide of anatase modification, a more developed surface. Removal of rhodamine B from the surface of the PCMN sample is slow. This process may be due to the structural feature of the titanium dioxide neoplasms, in particular, their film form, which significantly reduces the specific active surface for photocatalytic reactions.

The Effect of Titanium Dioxide Sol Stabilizer

21

Removal of rhodamine B (%)

70

Weight content (%)

7 6

PCM

5

PCMN

4

3 2

1 0 0.01

60 50

PCM PCMN

40 30 20 10 0

1 Particle size (μm)

100

Fig. 4. Granulometric composition of the synthesized materials

4 26 UV exposure time (h) Fig. 5. Photocatalytic activity of synthesized materials

4 Conclusion It was found that among the analyzed two types of photocatalytic composite materials (PCM and PCMN) with a similar chemical composition, the use of a material without a catalyst/stabilizer, nitric acid, is preferable as a photocatalytic additive. It has higher photocatalytic activity, as it contains a significant amount of anatase-modified titanium dioxide with a developed surface, including nanosized particles. In the composition of PCM, the presence of agglomerates of spherical particles of titanium dioxide is noted. In this case, the surface of diatomite is uniformly coated with titanium compounds. The structure of titanium-containing neoplasms in the composition of PCMN is significantly different and has the form of a film deposited on diatomite particles that cracked during sample preparation. As a result, the surface of PCMN is significantly less developed. The photocatalytic activity of PCMN (the rate of removal of rhodamine B from the surface of the sample) is lower due to the structural features of titanium dioxide neoplasms, in particular, their film form, which significantly reduces the specific active surface for photocatalytic reactions. Acknowledgments. The research was performed with a financial support of Russian Science Foundation (project No. 19-19-00263) using the equipment of the Center for High Technologies of BSTU named after V.G. Shukhov.

References 1. Antonenko, M., Ogurtsova, Yu., Strokova, V., Gubareva, E.: Photocatalytic active selfcleaning cement-based materials. Compositions, properties, application. Bull. BSTU Named After V.G. Shukhov, 3, 16–25 (2020)

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2. Wang, D., Hou, P., Zhang, L., Xie, N., Yang, P., Cheng, X.: Photocatalytic activities and chemically-bonded mechanism of SiO2@TiO2 nanocomposites coated cement-based materials. Mater. Res. Bull. 102, 262–268 (2018) 3. Lanka, S., Alexandrova, E., Kozhukhova, M., Hasan, M.S., Nosonovsky, M., Sobolev, K.: Tribological and wetting properties of TiO2 based hydrophobic coatings for ceramics. J. Tribol. 141(10), 101301 (2019) 4. Klyuev, S.V., Klyuev, A.V., Shorstova, E.S.: The micro silicon additive effects on the finegrassed concrete properties for 3-d additive technologies. Mater. Sci. Forum 974, 131–135 (2019) 5. Fediuk, R.S., Lesovik, V.S., Mochalov, A.V., Otsokov, K.A., Lashina, I.V., Timokhin, R.A.: Composite binders for concrete of protective structures. Mag. Civ. Eng. 82(6), 208–218 (2018) 6. Manzhilevskaya, S.E.: Organizational and economic problems of ecological safety in construction. Constr. Mater. Prod. 2(4), 73–78 (2019) 7. Pal, A., Jana, T.K., Chatterjee, K.: Silica supported TiO2 nanostructures for highly efficient photocatalytic application under visible light irradiation. Mater. Res. Bull. 76, 353–357 (2016) 8. Gubareva, E.N., Baskakov, P.S., Strokova, V.V., Labuzova, M.V.: Features of the structure of sols of titanium dioxide and morphology of the films based on them. Bull. Saint Petersburg State Inst. Technol. (Tech. Univ.) 48(74), 78–83 (2019) 9. Ivicheva, S.N., Kargin, Y.F., Kutsev, S.V., Shvorneva, L.I., Yurkov, G.Y.: Influence of anions stabilizing the sols in synthesis of powders of highly dispersed titanium dioxide and three-dimensional nanocomposites based on SiO2/TiO2. Phys. Solid State 55(5), 1111–1119 (2013) 10. Murashkevich, A.N., Alisienok, O.A., Zharskii, I.M.: Physicochemical and photocatalytic properties of nanosized titanium dioxide deposited on silicon dioxide microspheres. Kinet. Catal. 52(6), 809–816 (2011) 11. Guo, M.-Z., Maury-Ramirez, A., Poon, C.S.: Self-cleaning ability of titanium dioxide clear paint coated architectural mortar and its potential in field application. J. Clean. Prod. 112, 3583–3588 (2016) 12. Firas, J.A.-M.: Detection of random laser action from silica xerogel matrices containing rhodamine 610 dye and titanium dioxide nanoparticles. Adv. Mater. Phys. Chem. 2, 110– 115 (2012) 13. Klyuev, S.V., Klyuev, A.V., Shorstova, E.S.: Fiber concrete for 3-d additive technologies. Mater. Sci. Forum 974, 367–372 (2019)

Influence of Clinker Microstructure on Grinding Efficiency in the Presence of Grinding Intensifiers L. D. Shahova1 , L. S. Schelokova2 and E. S. Chernositova2(&)

,

LLC «Polyplast Novomoskovsk», Novomoskovsk, Russia Belgorod State Technological University named after V.G. Shukhov, Belgorod, Russia [email protected] 1

2

Abstract. Grinding processes in cement production technology are quite energy-intensive. The mechanism of action of surfactants on the course of the clinker grinding process has not been fully studied. According to the theory of P. A. Rebinder, surfactants change the mechanical properties of solids in the process of dispersion of materials. At the same time, the destruction of clinker grains must comply with the basic laws of physical and chemical mechanics of destruction of polymineral rocks. The results of the study of the grinding capacity of clinker grains show that their mechanical properties are determined by the size, shape, composition, spatial orientation and physical properties of the main phases. The paper presents the results of a study of the influence of the microstructure of Portland cement clinker on the efficiency of grinding in the presence of triethanolamine. It is shown that the grinding kinetics depends primarily on the characteristics of the clinker microstructure. The presence of surfactants accelerates grinding at the last stage by reducing the agglomeration forces. Keywords: The microstructure of the clinker efficiency
Triethanolamine


The rebinder effect
Grinding

1 Introduction The action mechanism of surfactants and increasing the efficiency of grinding mineral powders have been repeatedly studied and discussed. In some works, the action mechanism of surfactants is explained from the point of view of the Rebinder theory (Rebinder effect) [1, 2], in other works, the effect of surfactants is reduced only to a decrease in the aggregation of particles and sticking to the metal surfaces of grinding aggregates [3, 4]. Due to differences in research conditions and a large number of influencing factors in the interpretation of the mechanism of the medium action in dispersion, there are currently significant differences. On the one hand, according to the theory of P.A. Rebinder, surfactants change the mechanical properties of solids in the process of dispersion of materials. In this case, the structural features of the clinker should have a © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 23–29, 2021. https://doi.org/10.1007/978-3-030-54652-6_4

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L. D. Shahova et al.

significant impact on the dispersion process itself and specific energy consumption. On the other hand, the destruction of clinker grains must comply with the basic laws of physical and chemical mechanics of destruction of polymineral solids [5]. The results of numerous studies evaluating the grinding capacity of clinker grains show that their mechanical properties are determined by the size, shape, composition, spatial orientation and physical properties of the main phases, which makes experimental studies difficult [6, 7]. The aim of this work was to identify the influence of the clinker microstructure on the grinding efficiency in the presence of a grinding intensifier.

2 Methods and Materials Clinkers of the two companies were selected as the source clinkers. Petrographic analysis of clinkers was performed under the NU 2 microscope of Carl Zeiss Jena. Triethanolamine (TEA) at a dosage of 0.03% was used as a grinding intensifier. Numerous experiments on the study of the kinetics of dispersion of mineral rocks show that grinding in laboratory mills can predict the evolution of particle sizes. Therefore, the grinding of clinkers was carried out together with natural gypsum stone (5 wt%) in a laboratory ball mill for 30 min. The fineness of grinding was estimated by the residue on sieves with cells of 80 and 45 microns and the specific surface area by Blane. The fluidity of cement powder was determined by the method of the scientific and technical center of LLC Polyplast Novomoskovsk [8], the essence of which is to determine the material that passed through a sieve with a cell of 500 microns at shaking mechanically the sample on the Hagermann table. The strength of cements was tested on cement pastes in small samples.

3 Results and Discussions To study visually the features of the clinker microstructure in reflected light, polished sections were made, and the actual mineralogical composition was calculated. Optical microscopic examination was performed to study the features of the microstructure: the number and size of alite and belite crystals, amorphous phase. Micrographs were examined using various magnifications. Micrographs of the structure are shown in Fig. 1, the actual composition is shown in Table 1. Clinker 1 is characterized by the presence of large alite crystals (40–70 microns), sometimes individual crystals coalesce to form irregular conglomerates. Belite crystals are represented by two types: large grains up to 20–40 microns of elongated shape (dendritic structure) and small grains (15–25 microns) with ragged edges. Porosity is low. Clinker 2 is represented by fine-grained grains of alite and belite (10–30 microns). Alite crystals have clear edges, and belite grains are represented by the rounded shape of small crystals (5–15 microns). Porosity is high.

Influence of Clinker Microstructure on Grinding Efficiency

a)

25

b)

Fig. 1. Microstructure of clinkers: a) clinker 1; b) clinker 2 Table 1. The actual mineralogical composition of the clinkers Sample

Crystalline Amorphous phase, % (C3A + C4AF) Porosity,% phases C3S, % C2S, % Clinker 1 56.9 20.1 23.0 15 Clinker 2 56.1 29.1 14.8 29

Thus, with an equal content of alite, the content of belite and the amorphous phase in clinkers differs by 1.5 times. The kinetics of grinding on complete residues on sieves with a cell of 80 and 45 microns is shown in Fig. 2. As it can be seen on Fig. 2 the rate of dispersion of clinkers differs: – fine-grained clinker 2 is crushed faster; – the influence of TEA is observed only at the last stages of grinding; – the presence of TEA shifts the particle size to smaller diameters, but does not affect the shape of the curve.

a)

b)

Fig. 2. Kinetics of clinker dispersion by total residues on sieves with cells of 80 and 45 microns: a) clinker 1; b) clinker 2

26

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The results of the study of the fineness of grinding of cements based on two clinkers and the fluidity of cement are presented in Table 2 and Fig. 3.

Table 2. Fineness of grinding and fluidity of clinker-based cements Indicators of the fineness and fluidity

Clinker 1 Referent

Compressive strength, MPa

Residue on sieve with a cell of 80 microns, wt% Residue on sieve with a cell of 45 microns, wt% Blane specific surface area, m2/kg Fluidity (weight passed through the sieve 500 microns), %

Clinker 2 Referent

8

With TEA 4

6

With TEA 2

11.9

9.6

9.2

6.2

301 35.8

306 71

298 58.6

307 83.8

100 Compressive strength, MPa, at the age of 2 days Compressive strength, MPa, at the age of 7 days Compressive strength, MPa, at the age of 28 days

80

60 40 20 0 referent

with ТEА

clinker 1

referent

Samples

with ТEА

clinker 2

Fig. 3. The strength of samples of cement stone on the basis of clinkers

The obtained values of fineness of grinding indicate differences in the grinding process of two clinkers with significant differences in microstructure. Differences in the strength characteristics of clinker 2 relative to clinker 1 can be attributed to the presence of a higher content of the belite phase in clinker 2 and a small amount of tricalcium aluminate, which is responsible for the speed of strength gain at an early age. The presence of TEA slightly reduces the strength in the first period of hardening, but increases the strength by 28 days, which is quite consistent with the literature data. According to the theory of destruction of the academician V.E. Panin’s school [5] the destruction of a clinker particle as a multi-level system should be considered at various scale levels: micro -, meso- and macro (Fig. 4).

Influence of Clinker Microstructure on Grinding Efficiency

27

Fig. 4. Stages of dispersion of the polymineral structure of a clinker granule

Grinding along the course of the ball mill is accompanied by increasing resistance of the material. First, the cracks pass through large pores, as the porosity of the clinker is 17–26%. Further, up to the specific surface of 150–170 m2/kg, the grinding is carried out along the boundaries of the phase section (macrolevel). After 250 m2/kg, the grinding resistance begins to grow sharply, and the destruction occurs already by defects in the structure of crystals (mesolevel) and individual large crystals (microlevel) [9]. For the third stage of destruction of polymineral bodies (S  250 m2/g) sticking and aggregation of fine cement particles are characteristic; at the same time, the share of friction work increases, which is less effective than grinding by impact and crushing. At this stage of grinding, the role of the phase composition of the clinker and the influence of the presence of surfactants are particularly clearly felt. At the macro level, the predominant mechanism of destruction of the clinker granule is “intergranular sliding”. The strength of the amorphous intermediate phase is significantly lower than the strength of the only crystalline phases – alite and belite, so at the first stage, the destruction goes through the pores and the intermediate phase. It is known that disturbed internal phase boundaries and crystal defects created under stress play a fundamental role in the origin of plastic shifts at the mesoscopic scale level, and the physical processes of the origin of localized shifts at interfaces have a common physical nature, despite the huge variety of types of inclusions, grain structures, “coverage – base material” combinations, etc. As the crystals of the main silicate phases in the studied clinkers have different sizes and morphology, the kinetic grinding curves indicate a more intensive destruction of clinker 2. At the last stage, according to Rebinder’s theory, we should expect the effect of the TEA impact, which should penetrate into the mouth of the crack due to the diffusion of matter molecules along the freshly split border and reduce the strength of the crystal. Especially, this effect should be reflected in the dispersion of clinker 1, characterized by the presence of large alite crystals. The problem is the implementation of conditions for the penetration of surfactant molecules into microcracks, the size of which does not exceed the size of the surfactant molecule. In the mining industry it is known that the adsorption effect of lowering the strength of rocks increases with decreasing strain rate or increasing time of impregnation of the rock with surfactant solution [10].

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a)

b)

Fig. 5. Internal state of the mill surface and grinding bodies after clinker grinding: without TEA (a) and with TEA (b)

However, in a ball mill, the crack propagation rates in a solid material are very high and at such speeds, the surfactant molecules are not able to diffuse quickly to the top of the crack. This conclusion is confirmed by the results of modeling the crack propagation velocity [11], which is 11,500 km/h along the cleavage of surfaces of the alite mineral, which is almost ten times higher than the speed of sound in the air. The rate of wetting the surface of solids with various liquids reaches only from 1 µm/s to 10 µm/s (36 km/h), depending on the conditions [12]. Therefore, a number of studies have not revealed the Rebinder effect on the speed of clinker grinding in cement mills [13, 14].

4 Conclusion Numerous results of repeated own experiments, as well as data from technical literature show that the amount of work spent on grinding clinkers with different microstructures of silicate phases in the presence of surfactants does not change significantly: the fineness of grinding remains approximately equal. Only the rheological properties of the powder change, which are determined by the adhesion forces between the particles [15–18]. According to the results in Table 2 it is seen that in the presence of TEA, the fluidity of the cement powder increases sharply. This is due to a decrease in the surface polarity of the crushed particles and the surface energy, which prevents aggregation of small particles (coating), eliminates the problem of material sticking to the balls and hunch plates of the mills (Fig. 5) and increases the speed of material movement through the mill and circulation in the cross section. Acknowledgment. This work was realized in the framework of the Program of flagship university development on the base of the Belgorod State Technological University named after V G Shukhov, using equipment of High Technology Center at BSTU named after V G Shukhov.

Influence of Clinker Microstructure on Grinding Efficiency

29

References 1. Shchukin, E.D.: Influence of the active medium on the mechanical stability and damage of the solid surface. Bull. Moscow Univ. 53(1), 50–72 (2012) 2. Pertsov, N.I., Traskin, V.Y.: Rebinder Effect in nature. Advances in colloid chemistry and physical and chemical mechanics. Science, Moscow, pp. 155–165 (1992) 3. Sohoni, S., Sridhar, R., Mandal, G.: The effect of grinding aids on the fine grinding of limestone, quartz and Portland-cement clinker. Powder Technol. 67(3), 277–286 (1991) 4. Scheibe, W., Hoffman, B., Dombrowe, H.: Einige Probleme des Einsatzer von Mahlhifsmitteln in der Zementindustrie (Some problems of the use of grinding aids in the cement industry), Communicated by Tamas, F.D. Cem. Concr. Res. 4(1074), 289–298 (1973) 5. Panin, V.E.: Physical mesomechanics – a new paradigm at the junction of physics and mechanics of a deformable solid. Phys. Mesomech. 6(4), 9–36 (2003) 6. Hills, L.M.: Clinker microstructure and grindabillity: updated literature review, SN2967, Portland Cement Association, Skokie. Illinois, USA, p. 344 (2007) 7. Burak, K., Bulentet, A.: An effect of porosity and related interstitial phase morphology difference on the grindability of clinkers. Mater. Struct. 43, 179–193 (2010) 8. Shahova, L.D., Markova, S.V., Cherkasov, R.A.: Improving the efficiency of the cement grinding process by intensifiers of Polyplast Novomoskovsk LLC. Constr. Mater. Prod. (Ukraine) 2, 16–19 (2012) 9. Pashchenko, A.A. (ed.): Theory of Cement. Budivelnik, Kiev (1991) 10. Kusov, N.F., Edelshtein, O.A., Shobolova, L.P.: Application of adsorption-active media for reducing the resistance of rocks to destruction. In: Physical and chemical mechanics and lyophilicity of dispersed systems. Naukova Dumka, Kiev, Ukraine, pp. 41–46 (1986) 11. Weibel, M., Mishra, R.M.: Grinding aids increase the productive and cost-effectiveness of cement production. https://www.google.com/search?q=Grinding+aids+increase. Accessed 10 May 2020 12. Blake, T.D.: The physics of moving wetting lines. J. Colloid Interface Sci. 299(1), 1–13 (2006) 13. Deckers, M., Stettner, W.: Die Wirkung von Mahlhilfsmitteln unter besonderer Berucksictigung der Muhlenbedingungen (Effect of grinding aids with special consideration of the conditions). Aufbereitung-Technik 10, 545–550 (1979) 14. Mishra, R.K., Heinz, H., Muller, T., Zimmermann, J., Flatt, R.J.: Understanding the effectiveness of polycarboxylates as grinding aids. Am. Concr. Inst. Symp. Ser. 288, 235– 251 (2012) 15. Shahova, L.D., Chernositova, E.S., Denisova, J.V.: Flowability of cement powder. IOP Conf. Series: Mater. Sci. Eng. 327, 032049 (2018) 16. Shahova, L.D., Chernositova, E.S., Denisova J.V.: Investigation of the effect of technological additives on the rheological properties of cement powder. Bull. BSTU Named After V. G. Shukhov, 10, 123–128 (2017) 17. Shahova, L.D., Chernositova, E.S., Denisova, J.V.: Flowability and durability of cement containing technological additives during grinding process. AIME. AER-Adv. Eng. Res. 133, 162–167 (2017) 18. Elistratkin, MYu., Minakov, S.V., Shatalova, S.V.: Composite binding mineral additive influence on the plastisizer efficiency. Constr. Mater. Prod. 2(2), 10–16 (2019)

Obtaining High-Quality Expanded Porous Gravel Based on Low-Expanding Stone-Like Clay H. N. Mammadov1

and A. A. Guvalov2(&)

1

Azerbaijan Republic Ministry of Emergency Situations Research and Design Institute of Building Materials named after S.A. Dadashov, Baku, Azerbaijan 2 Azerbaijan University of Architecture and Construction, Baku, Azerbaijan [email protected]

Abstract. The present paper deals with the obtaining of high-quality keramzit aggregate on the base of low-expanding stone-like hydromicaceous clay. The developed technology allows to widen raw stuff base of producing aggregates for lightweight concretes and to improve their physico-mechanical properties. It has been revealed from investigations that the composition of stone-like clay does not contain sufficient quantity of gas-generating substances which are the main factor of developed pore formation on expansion. For this reason the influence of various pore-forming additives on the expansibility of the said clay was studied. Simutaneously investigations into expansibility of stone-like lowexpanding clay depending on expansion condition were being performed. It has been found out that clay expansibility and physico-mechanical properties of the obtained aggregate depend on preliminary thermal treatment temperature, temperature and duration of expansion. Using porous gravel of density brand 300– 700, dense sand and plasticizing additives, lightweight concrete of 850– 1800 kg/m3 in density and strength of 3.4–42.0 MPa has been produced and using porous gravel, dense sand without plasticizing additives lightweight concrete with density of 1150–1170 kg/m3 and strength of 10.0–35.0 MPa has been obtained. Keywords: Clay
Expansion
Temperature
Density
Strength
Keramzit Lightweight concrete




1 Introduction One of the principal ways of increasing construction efficiency is the reduction in building structures mass without loss of their bearing capacities and other performance characteristics. The use of lightweight concrete lowers material expenditures by 1.5– 2.5 times as compared to ordinary heavy concrete of the same strength class [1–5]. The manufacturing and utilization of products and structures from lightweight concretes made with the use of artificial porous aggregates are one of the most efficient ways of resolving these problems [1, 2, 5]. To produce high-efficient lightweight concrete a qualitatively new lightweight aggregate of keramzit type is required which possesses desirable physico-mechanical © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 30–37, 2021. https://doi.org/10.1007/978-3-030-54652-6_5

Obtaining High-Quality Expanded Porous Gravel

31

properties. In the last few years the majority of keramzit producing plants have been employing low-grade raw stuff because of lack of well-expanding clay. Introduction of various correcting additives in the batch composition brings about improvement in expansibility of argillaceous materials [7–10]. Well-expanding argillaceous raw stuff is absent on the territory of the Azerbaijan Republic while there are huge natural stores of low-expanding stone-like clay on the Sumqaitchay deposit. It is impossible to obtain keramzit gravel with improved physicomechanical properties by processing them using existing methods. Due to this situation the development of scientific basis and technology for manufacturing lightweight and high-strength porous aggregates for heat-insulating, heat insulating structural and structural lightweight concretes from low-expanding stonelike clays of the Sumgaitchay deposit is an important and topical problem facing artificial porous aggregate industry. The objectives of the present researches are to reveal the possibility and establish the basic mechanisms governing the regulation of porous structure and phase composition of aggregates on the base of low-expanding stone-like clay as well as to develop production technology for porous aggregates having predetermined physicomechanical properties [11].

2 Methods and Materials When conducting experimental investigations and performing industrial checks stonelike low-expanding hydromicaceous clay of the Sumgaitchay deposit was used. The experimental investigations were conducted in three stages: at the first stage a batch was prepared and raw granules were made, at the second stage mass expansion kinetics and formation of aggregate structure were studied, at the third stage physicomechanical properties of an artificial porous aggregate being obtained were explored. The industrial tests were carried out and technological parameters of porous gravel production were specified on the technological line for lightweight aggregate manufacturing in the town of Sumgait. The clay is dense, stone-like, hardly water-absorbing, of medium plasticity, its plasticity number is 17–23, sintering temperature is 1000 °C. Its granulometric composition is characterized by homogeneity, argillaceous fraction is 70–85%. By its expansion coefficient (K = 1, 15) the clay is between low-expanding and nonexpanding clays.

3 Results and Discussions In the investigations into expansion kinetics of a mass on the base of the Sumgaitchay clay specimens in the form of small cylinders of 16 mm in diameter and height as well as granules on a laboratory plate granulator with fractions of 5–10 mm in dimensions were made from a specially prepared batch using correcting additives. Structural changes in the stone-like clay start after the action of temperature of 100 °C, before 100 °C drying process occurs, other changes are not observed. As seen

32

H. N. Mammadov and A. A. Guvalov

Dilatation,%

from Fig. 1, volumetric dilatation of 0.6–0.7% takes place in the 100–700 °C range. Then when temperature is over 750 °C, shrinkage occurs and liquid phase begins to appear. Maximum shrinkage is marked at 1000 °C, in this period the formation of gaseous phase is necessary to provide expansion and appearance of porous structure in granules.

1 0.5 0

-0.5 50

250

450 650 Temperature, 0C

850

1050

-1 Shrinkage, %

-1.5 -2 -2.5 -3 -3.5

Fig. 1. Structural changes of the Sumgaitchay stone-like clay depending on heating temperature

The amount of gas-generating substances is insufficient in chemical composition of this clay and, therefore, expansion process does not take place on heating - for this it is required to introduce a gas-forming additive into the composition of masses and this is the principal task of causing expansion process of granules made from stone-like lowexpanding clay. To achieve this, it is necessary to dry and remove physically bound water from the composition, to disturb the primary structure of stone-like clay, to introduce gas-generating additives into the composition and simultaneously disperse the clay with the additives. Following this the powdered mass must be granulated and raw granules must be obtained. After obtaining raw granules from the powder liquid additives can be introduced. Simultaneous grinding provides uniform distribution of a gas-generating agent throughout the volume which on expanding allows to produce a homogeneous porous structure evenly distributed through the whole of a granule [12]. During granulation of the powder the primary porous structure is formed, the remaining part of pores is detected on expanding. After drying the porosity of raw granules is 30–31%. The investigation results are demonstrated in Figs. 2 and 3. The study of expansion kinetics of the specimens prepared from low-expanding stone-like hidromicaceous clay showed that, as expansion temperature rises from 1000 °C to 1100 °C, no pore formation is observed in the specimens without additives. Porosity does not change and is 30–31%. With increase in expansion temperature over 1100 °C little amount of gases evolves from the clay composition (Fig. 2). Porous structure starts forming together with volumetric dilatation of the specimens. At 1125 °C

Obtaining High-Quality Expanded Porous Gravel

33

100

Porosity, %

80 60 40 20 0 1000

1-without additives 2-with the addition of 3% spent gumbrin 3- with the addition of 1% alkaline waste 1050

1100 1150 Swelling temperature, 0C

1200

Fig. 2. Porosity changes of swelling Sumgaitchay clay samples depending on swelling temperature

2

Density, g/sm3

1.6 1.2 0.8 0.4 0 1000

1050

1100

1150

1200

Swelling temperature, 0C 1-without additives 2-with the addition of 3% spent gumbrin 3- with the addition of 1% alkaline waste Fig. 3. Density changes of swelling Sumgaitchay clay samples depending on swelling temperature

porosity goes up and is 34–35%. In this case density is equal to 1.62 g/cm3 (Fig. 2). With further elevation of temperature to 1170 °C an increase in the density of the specimens takes place. Maximum expansion is noticed. Porosity in this case is 44% (Fig. 2). With

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H. N. Mammadov and A. A. Guvalov

increase in porosity density begins to fall. The density of the expanded specimens drops only to 1.44 g/cm3 (Fig. 3). When expansion temperature rises to 1200 °C fusion occurs on the specimens’ surface and porosity of the specimens diminishes, falling to 35–38%. With the aim of increasing expansibility of this clay gas-generating additives were used. The investigation results have shown that with the introduction of 3% of used gumbrine or 1.0% of alkaline waste into the batch composition (Fig. 2) the nature of the curves changes sharply in porosity. Intense development of porosity starts at a temperature of 1025–1030 °C. With further rise in expansion temperature to 1150 °C the development of porous structure goes on. The attained porosity of the expanded specimens reaches 85%. With increase in porosity a drop in the density of the expanded specimens occurs and its maximum is attained. The density goes down to 0.32–0.34 g/cm3 (Fig. 3). The investigation results have demonstrated that to provide formation of porous structure through the whole volume of granules and to avoid cracking as well as to enhance thermal resistance of raw granules they must be preliminarily heated to a temperature below the beginning of the burn-out of gas-generating additives [13]. The results of the investigation into the influence of preliminary thermal treatment temperature on expansibility of the Sumgaitchay stone-like clay are given in Fig. 4.

Density of grains, g/sm3

0.8 0.7 0.6 0.5 0.4 0.3 0.2

200

300

400

500

600

700

800

Preliminary thermal treatment temperature, 0C 1-alkaline waste 1%

2- used gumbrine 3%

Fig. 4. The influence of a preliminary thermal treatment temperature on the density of the specimens made from masses based on the Sumgaitchay clay with additives

It can be seen from Fig. 4 that a temperature of preliminary thermal treatment of a mass on the base of the Sumgaitchay stone-like clay in the range between 250 °C and 300 °C allows to obtain an aggregate of 0.32–0.34 g/cm3 by density.

Obtaining High-Quality Expanded Porous Gravel

35

An increase in a preliminary thermal treatment temperature to 400–500 °C leads to a rise in density of the expanded granules from 0.32 g/cm3 to 0.37–0.45 g/cm3 and with increase in a preliminary thermal treatment temperature to 600–700 °C the nature of the curves changes noticeably and the density of the expanded granules goes up to 0.60–0.64 g/cm3. The investigation into the influence of expansion duration on the development of porous structure shows that sintering and deformation in granules both with additives and without them occur within 3–4 min and the start of gas liberation is observed already after the lapse of the said time. The expansion of the granules made using 3.0% of used gumbrine ends in the course of 6–7 min. Intense pore formation in the granules begins after the fourth minute since their coming into the calcination zone. Porous structure development continues for 6 min. With increase in expansion duration to 8 min no change in density is noticed. This displays that gas liberation has been completed and pore dimensions do not widen. With further increase in expansion duration in the calcination zone to 10–12 min a rise in the density of the expanded granules and a change in pore shape on the surface layer are detected. Optimum porous structure develops when calcination goes for 6–7 min. Structure elements are represented by fine grained vitreous substance pierced with amorphized dark grey material. The latter differs from the main vitreous mass by its high light refraction index. Pores are of various shapes, mostly they are irregularly spherical, their diameter is between 5–8 mcm and 0.3 mm. Thus, the investigation results demonstrate the necessity of performance of the following procedures in order to use stone-like hydromicaceous low-expanding clay as the basic raw stuff: to destroy the primary natural structure of the clay, to remove physically bound water from the clay composition, to introduce optimum amount of gas-generating additives into the composition of masses, to prepare raw granules and expand them under optimum expansion conditions. The investigation results are implemented on the technological line for lightweight aggregate production in the town of Sumgait. Table 1 contains the physico-mechanical characteristics of the lightweight aggregate expanded on the technological line of the plant.

Table 1. Physico-mechanical characteristics of the lightweight aggregate made from stone-like low-expanding clay (industrial test) No Aggregate characteristics 1 2 3 4 5

Aggregate brand by bulk density 300 400 500 600 2.46 2.46 2.48 2.48 Density, g/cm3 Bulk density, kg/cm3 270– 380– 420– 570– 300 400 480 600 Compression strength in cylinder, MPa 1.0–1.4 1.7–2.2 2.3–2.8 3.5–4.0 Average value of gravel grain shape coefficient 1.1 1.0 1.0 1.0 Content of cleft grains in gravel, % by mass 6–8 4–5 5–7 4–6

36

H. N. Mammadov and A. A. Guvalov

The industrial investigation results show that the physico-mechanical characteristics of the lightweight aggregate obtained from stone-like hydromicaceous lowexpanding clays comply with the acting standard requirements in all respects.

4 Conclusion The lightweight aggregate are recommended as a coarse aggregate for producing lightweight concretes as well as heat-insulating and sound-insulating fillings. With the use of the obtained aggregates optimum compositions of lightweight concrete were selected. Dense sand was taken as a fine aggregate. The results of the investigation into selection of lightweight concrete compositions and their physicomechanical characteristics are given in Table 1. Using porous gravel of density brand 300–700, dense sand and plasticizing additives, lightweight concrete of 850–1800 kg/m3 in density and strength of 3.4– 42.0 MPa has been produced and using porous gravel, dense sand without plasticizing additives lightweight concrete with density of 1150–1170 kg/m3 and strength of 10.0– 35.0 MPa has been obtained.

References 1. Rogovoy, M.I.: Technology of artificial porous aggregates and ceramics. Ekolit, p. 320 (2011) 2. Mammadov, H., Suleymanova, İ., Bahadur, T.: An artificial lightweight aqqreqate based on non-ferrous metallurgy slags. Int. J. Adv. Eng. Res. Sci. 5(10), 115–120 (2018). https://doi. org/10.22161/ijaers.5.10.16 3. Alfimova, N.I., Pirieva, SYu., Gudov, D.V., Shurakov, I.M., Korbut, E.E.: Optimization of receptural-technological parameters of manufacture of cellular concrete mixture. Constr. Mater. Prod. 1(2), 30–36 (2018) 4. Davidyuk, A.N.: Lightweight concretes made using glass granulates - future of spaceenclosing structures, concrete and reinforced concrete, (1), 2–4 (2016) 5. Bazhenov, Yu.M., Korolev, E.A.: Space enclosing structures using concretes with low heat conduction. Fundamentals of the Theory, Calculation Methods in Process Designing. M., ASV, p. 320 (2008) 6. Yarmakovskiy, V.N., Semchenkov, A.S.: Structural lightweight concretes of new modifications in resource-saving construction systems of buildings. Acad. Archit. Build. 3, 31–38 (2010) 7. Antonenko, L.V., Bigildeeva, G.M.: Use of TPS slags for the Keramzit production. Scient Techn. Ref. Inf., Ser. “Industry of Ceramic Wall Mater. and Porous Aggregates”. M., VNIIESM, pp. 1–6 (1980) 8. Babenishev, V.I.: Reduction in volumetric density of keramzit by introducing coke-andbenzene production waste. J. Build. Mater. 10, 12 (1977) 9. Zavadsky, V.F., Onitsenko, A.I., Oznobukhin, Yu.I., Okun F.I.: Manufacturing Keramzit gravel using oil slurry addition. Ref. Inf. series “Industry of ceramic Wall Materials and Porous Aggregates”. M., VNIIESM, p. 2 (1981) 10. Knigina, G.I., Panova, V.F., Tatsky, L.N.: Study of iron-containing waste in loamy keramzit production. Build. Mater. 7, 9–11 (1980)

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11. Mamedov, G.N., Mirzoyev, M.M.: Porous gravel based on various slags and low-expanding stone-like clays, high-strength lightweight concretes on their base. In: Proceedings of the 3rd All-Russian Conference on Concrete and Reinforced Concrete, vol. 5, pp. 291–299 (2014) 12. Mamedov, G.N.: High-strength artificial porous aggregates, Baku, p. 222 (2000) 13. Mamedov, G.N.: Efficient use of alkali-containing waste of production association “Azerneftyanadzhag” in manufacturing artificial porous aggregates. Izvestiya High. Tech. Educ. Inst. Azerbaijan Baku 5, 83–88 (2001)

Stress-Strain State of Normal Sections of Precast-Monolithic Reinforced Concrete Beams A. A. Kryuchkov

, N. V. Frolov(&)

, and G. A. Smolyago

Belgorod State Technological University named after V.G. Shukhov, Belgorod, Russia [email protected], [email protected]

Abstract. The paper is devoted to theoretical and experimental studies of the stress-strain state of normal sections of precast-monolithic reinforced concrete beams. It is noted that at present there is a significant increase in interest in methods for calculating reinforced concrete structures taking into account nonlinear diagrams of concrete deformation. This is due both to the occurrence of reliable experimental data on the parameters of such a diagram, and to the widespread use of computational techniques. At the same time, despite the fact that numerous studies were conducted on studying the force resistance of reinforced concrete bending elements of composite sections and the development of methods of their calculation considerable success has been achieved, the tasks associated with the analytical evaluation of the stress-strain state of normal sections of precast-monolithic concrete beams have been remained unsolved. In this regard, a refined calculation method has been developed that allows determining the parameters of the stress-strain state at all stages of loading. For its justification, special experimental studies of samples of precast-monolithic reinforced concrete beams were conducted. The results of control tests are described and their brief analysis is made. Numerical studies on the convergence of theoretical and experimental data were carried out. The accuracy of the developed calculation method is estimated. Keywords: Precast-monolithic reinforced concrete beam
Stress-strain state Section
Strength




1 Introduction The main feature of the current stage of development of the theory of reinforced concrete is the transition from the power to the deformation model for calculating reinforced concrete structures [1]. One of the most important elements of this model is the actual deformation diagrams of structural materials [2]. The use of idealized material deformation diagrams (for example, Prandtl or threeline) gives an acceptable result when determining the strength of normal sections of reinforced concrete elements, but has insufficient accuracy when evaluating their stressstrain state at other loading stages. Therefore the use of this type of diagram is justified only in engineering methods of calculation [3]. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 38–44, 2021. https://doi.org/10.1007/978-3-030-54652-6_6

Stress-Strain State of Normal Sections

39

The most reliable way to evaluate the stress-strain state of both individual normal sections and reinforced concrete structures in general is to use the approach using complete nonlinear deformation diagrams (primarily concrete diagrams) [4]. At the same time, it is worth noting that the development and use of these diagrams is almost impossible without the use of software and computing systems and the organization of iterative counting [5]. The rather numerous studies dedicated to the study of force resistance of reinforced concrete bending elements of composite sections [6–14] and in the development of methods of their calculation considerable success is achieved, but problems associated with the analytical evaluation of the stress-strain state of normal sections of precastmonolithic concrete beams have been remained unsolved. In this regard, the paper aims to develop and substantiate experimentally a method for calculating the stress-strain state of normal sections of precast-monolithic reinforced concrete beams, taking into account actual concrete deformation diagrams.

2 Methods 2.1

Calculation Procedure

The calculated diagram of concrete deformation is shown in Fig. 1.

Fig. 1. The calculated diagram of concrete deformation

Currently, many dependencies are proposed for the analytical description of the nonlinear relationship between stresses and deformations of the concrete diagram. The most convenient of them from the point of view of calculations is the dependence in the form of a power-law polynomial: rb ¼ Rb

n X k¼1

 ak

eb ebR

k

;

where: ak are some physical constants; k are positive numbers.

ð1Þ

40

A. A. Kryuchkov et al.

The same relationship is described with the work of stretched concrete to stresses in the concrete equal to wbt Rbt . Thus, at developing a method for calculating the stress-strain state of normal sections, the following assumptions and working hypotheses are used: • the section whose stress-strain state corresponds to the average state of the block between cracks is taken for calculation; • deformations in the section under consideration are distributed according to the flat cross-section hypothesis; • the relationship between stresses and deformations of concrete is described by a polynomial with integer exponents (1); • operation of stretched concrete after reaching the maximum tensile deformations of concrete ebt;u ¼ 2Rbt =Eb is described by a rectangular diagram with an ordinate wbt Rbt ; • the relationship between stresses and deformations of reinforced steel is described by a piecewise linear diagram, the parameters of which are accepted according to experimental data or recommendations. To determine the relationship between the stress-strain states of the composite section without cracks and external forces according to Fig. 2 let us write down the following equations: Z rb dA þ

m X

Z rb ydA þ A

rsi Asi ¼ 0;

ð2Þ

rsi ysi Asi  M ¼ 0;

ð3Þ

i¼1

A m X i¼1

Fig. 2. Stress-strain state of the calculated section.

Stress-Strain State of Normal Sections

41

where: rb are stresses in an elementary site in “precast” or “monolithic” concrete with the area dAb, located at a distance equal to y from the lower edge of the section; rsi, Asi and ysi is stresses in the i-th reinforcing bar, the area of its cross-section and the distance from the lower edge of the cross-section of the structure to the center of gravity of the specified area; M is the external bending moment. The calculation method includes the coefficient b equal to: • at bm =b  1 b ¼ bm ¼ bm =b the monolithic section does not extend beyond the rectangular section; • at bm =b [ 1 b ¼ 1; bm ¼ bm =b the monolithic section goes beyond the crosssection. By varying the values h, hc , b, bm we can describe any of the layouts suggested in Fig. 3.

Fig. 3. Possible layouts of composite sections.

Then the solution of Eqs. (4) and (5) can be presented in general form: "  kþ1   kþ1  n n X X 1 ak e1  vk1 þ 1 ak e1  vk2 þ 1 Rbc  Rbc b e1  e2 kþ1 ebR kþ1 ebR k¼1 k¼1 #   n m X X bk ek1 þ 1  vk3 þ 1 þ Rbm bM rsi lsi ¼ 0; þ wbt Rbt ðv4  e2 Þ þ kþ1 ebR i¼1 k¼1 (

 kþ2   kþ1  n n X X ak e1  vk1 þ 2 ak e1  vk1 þ 1 e  R bc 2 kþ2 ebR kþ1 ebR ð e1  e2 Þ2 k¼1 k¼1 "    # n n k þ 2 k þ 2 k þ 1 k þ 1 X ak X ak e1  v2 e1  v2 Rbc b  Rbc e2 kþ2 ebR kþ1 ebR k¼1 k¼1 "    # n n X X bk ek1 þ 2  vk3 þ 2 bk ek1 þ 1  vk3 þ 1 þ Rbm bM  e2 kþ2 ebR kþ1 ebR k¼1 k¼1  X m w Rbt þ bt ðv4  e2 Þ2 þ rsi lsi nsi  m ¼ 0; 2 i¼1 1

ð4Þ

Rbc

M where lsi ¼ Abhsi , m ¼ bh 2.

ð5Þ

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Let us introduce the values of the parameters v1 , v2 , v3 and v4 according to Table 1. Table 1. Parameter values of vi . Case of crack formation 1 2

Initial conditions e2  ebtu e2 [ ebtu

v1

v2

v3

v4

Notes

e2 ebtu

ec ec

ec ec

ec ebtu

3

e2 [ ebtu

ebtu

ebtu

ebtu

ebtu

No cracks Cracks only in precast concrete Cracks in precast and monolithic concrete

2.2

Methods of Experimental Research

For the physical experiment, experimental samples were made in the form of conventional (SB series) and precast-monolithic (SM series) reinforced concrete beams with a rectangular cross-section of 100  200 mm with a calculated span, as well as precast–monolithic beams (SM-KMA series), in the monolithic part of which the aggregate – quartzite sandstone was used. In the remaining beams, granite rubble was used as a large aggregate. The design of experimental samples and reinforcement schemes are shown in Fig. 4.

Fig. 4. Design of experimental samples.

The general view of the tests is shown in Fig. 5.

Stress-Strain State of Normal Sections

43

Fig. 5. General view of reinforced concrete beams tests.

3 Results and Discussion In the course of experimental studies, data were obtained on the stress-strain state of normal sections of experimental samples. In the course of numerical studies, the comparison of experimental and calculated data obtained taking into account the actual dimensions of the beams and the characteristics of concrete and steel reinforcement was provided. After calculation, we obtained all parameters of stress-strain state of sections on which graphics “momentcurvature” were made (e.g. Fig. 6). After application of data of physical experiment on the same graphic a statistical comparison of the received data was carried out.

Fig. 6. Dependence M  @, kNm–m−1 of beam 18SM4-2.

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The results of comparing experimental data and theoretical data obtained on the basis of the developed methodology indicate a fairly good match.

4 Conclusions Comparison of theoretical and experimental data showed their satisfactory convergence; in this regard, the developed calculation method allows evaluating the stressstrain state of normal sections of precast-monolithic reinforced concrete beams at all stages of their loading up to the exhaustion of strength, including extreme states.

References 1. Romashko, V.: The generalized model of reinforced concrete elements and structures deformation. Int. Sci. J. 1(3), 84–86 (2016) 2. Karpenko, N., Eryshev, V., Rimshin, V.: The limiting values of moments and deformations ratio in strength calculations using specified material diagrams. IOP Conf. Ser. Mater. Sci. Eng. 463(3), 032024 (2018) 3. Bondarenko, V., Kolchunov, V.: Settlementmodels of Power Resistance of Reinforced Concrete. ASV Publ, Moscow (2004) 4. Belyaev, A., Nesvetaev, G., Mailyan, D.: Calculation of three-layer bent reinforced concrete elements considering fully transformed concrete deformation diagrams. In: MATEC Web of Conferences, vol. 106, p. 04022 (2017) 5. Kryuchkov, A., Zhdanov, A.: Approach to an estimation deformability of bending concrete elements based on iterative calculation method. Bull. Belgorod State Technol. Univ. named after V.G. Shukhov, 2(1), 73–76 (2017) 6. Chithra, R., Thenmozhi, R., Hareesh, M.: Bending behavior, deformability and strength analysis of prefabricated cage reinforced composite beams. Constr. Build. Mater. 38, 482– 490 (2013) 7. Klueva, N., Kolchunov, V., Rypakov, D., Bukhtiyarova, A.: Durability and deformability of precast-cast-in-place frameworks for residential buildings with low material consumption at beyond-design-basis impacts. Ind. Civ. Eng. 1(1), 5–9 (2015) 8. Mohamed, F., Lamiaa, K.: Flexural behavior of large scale semi-precast reinforced concrete T-beams made of natural and recycled aggregate concrete. Eng. Struct. 198, 109525 (2019) 9. Halicka, A.: Influence new-to-old concrete interface qualities on the behaviour of support zones of composite concrete beams. Constr. Build. Mater. 25(10), 4072–4078 (2011) 10. Mitasov, V., Koyankin, A.: Work of a disk combined and monolithic overlapping. News of higher educational institutions. Construction 3(663), 103–109 (2014) 11. Nedviga, E., Vinogradova, N.: Systems of prefabricated monolithic slabs. Constr. Unique Build. Struct. 4(43), 87–102 (2016) 12. Seljaev, V., Tsyganov, V., Utkin, I.: Combined prefabricated monolithic slabs on the basis of non-formwork prestressed reinforced concrete beams. Build. Mater. Prod. 1(3), 5–11 (2012) 13. Travush, V., Krylov, S., Konin, D., Krylov, A.: Ultimate state of the support zone of reinforced concrete beams. Mag. Civ. Eng. 83(7), 165–174 (2018) 14. Vatin, N., Velichkin, V., Kozinetc, G., Korsun, V., Rybakov, V., Zhuvak, O.: Precastmonolithic reinforced concrete beam-slabs technology with claydit blocks. Constr. Unique Build. Struct. 70(7), 43–59 (2018)

Low-Carbon Principles of Eco-Efficient Construction Development I. P. Avilova(&)

, A. E. Naumov , M. O. Krutilova and D. D. Dakhova

,

Belgorod State Technological University named after V.G. Shukhov, Belgorod, Russia [email protected]

Abstract. One of the most exigent problems of the modern construction industry is lack of sustainability. This ultimate issue of the construction industry is exacerbated by the absence of an effective and transparent regulation tool, which provides clear understanding of necessity of designing more ecologically conscious and low-carbon construction solutions. GHG emissions in construction industry cover a significant part of industrial GHG emissions and are expected to consistently increase. Therefore, the conversion of the subject and results of the study to algorithms, tools and institute for managing and regulating carbon impact in the process of creating civil construction objects from the point of effective management of green construction and extended environmental responsibility of the developer is justified, promising and contains significant research potential. The key aspects of the proposed eco-friendly comparative analysis based on alternative design concepts of building realization of given consumer characteristics and functional purpose, performed in traditional and with using of the green structural and technological solutions are presented in the article. Keywords: Low-carbon construction
Eco-efficient construction development
Carbon impact
Green building

1 Introduction The development of the construction industry market in regard to environmental conservation is an urgent multidisciplinary task, which involves an improvement and analysis of used and promising methods of pricing building products, a search for new eco-oriented solutions in construction, which in turn implies a transition to green (including low-carbon) construction. In this regard, the proposal of a scientifically based reliable, universal and scalable methodology for quantitative analysis and cost estimation of environmental impact while creating construction products and an effective tool for organizational and economic stimulation of low-carbon construction would stimulate the planning and implementation of measures to improve the environmental safety of capital construction projects at all stages of its life cycle [1–3]. The impact of greenhouse gas (GHG) emissions in the construction industry on the environment is receiving increasing attention both from the construction industry and © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 45–51, 2021. https://doi.org/10.1007/978-3-030-54652-6_7

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the government, which recognize that emissions from the construction sector constitute a significant part of the harm done to the environment: in fact, the construction of buildings and their operation account for up to 30% per annum global greenhouse gas emissions (including vehicles) [4]. GHG emissions occur at all stages of the building’s life cycle and are divided into indirect emissions (during the construction, reconstruction or overhaul, as well as at the stage of the end of the building’s life), and direct emissions associated with maintaining an object of capital construction in a state of functional and operational suitability. Direct and indirect carbon emissions throughout the building’s life cycle can vary significantly depending on the type and purpose of the building, in this regard, international studies indicate that the percentage of embodied carbon during the life cycle ranges from 20% to 80% (civil buildings) [5, 6]. Also, many researchers notice that the energy consumption at the construction stage of the facility, closely related to carbon emissions in current construction technologies, occupy a significant share in the total energy consumption of the building’s life cycle and make up to 60%. On the other hand, taking into account the modern toughened requirements for sustainability and energy efficiency of objects of capital construction imposed by technical regulations, a trend towards decrease in a rate of direct emissions has been gaining momentum along with the increasing the quantity and quality of innovations in this field [7]. The reduction in the percentage of direct GHG emissions, increasing the percentage of indirect ones, shifts the focus of research towards the study of scientifically based and practically effective strategies, institutions and tools for reducing carbon impact at the construction stage.

2 Methods and Materials Full-scale implementation of the concept of low-carbon development in construction involves managing the environmental safety of buildings and structures in all of its life cycles associated with the creation of objects of capital construction - from optimizing the structural spatial concepts at the pre-design and design stages, to rationalizing organizational and technological strategies at the construction production stage [8]. Modern building information modeling (BIM) technologies make it possible to optimize plenty of engineering concepts in construction with minimal efforts of designer, achieving effectiveness according to a number of quantitative criteria, including acceptable criteria related to minimizing the impact on the environment, reduction of the energy consumption in the construction and installation works, in building materials production and operation of machines and mechanisms; increase the degree of recycling of materials, etc. [9]. The criteria are combined by the authors under the general organizational and economic assessment of the effectiveness of architectural, structural, organizational and technological solutions of the project, which has an environmental and economic focus, determined by the analysis and quantitative consideration of the carbon impact on the environment in the construction of a capital construction object and the production of related building materials. The methodological basis of the proposed eco-friendly comparative analysis is the informational accounting of resource components

Low-Carbon Principles of Eco-Efficient Construction Development

47

associated with the construction process, and, based on it, objective and cross-checked mechanism for quantifying the low-carbon level construction project used in a comparative analysis of design options [10] (Fig. 1). Criteria

Building’s life cycle stages Pre-design and design

Construction

Maintenance

End of the building’s life

Carbon impact (CI) Ability to influence on the CI Variability of tools of influence on the CI low

high

Fig. 1. Conceptual resource schema of construction life cycles

The carbon impact assessment in physical terms directly characterizes the degree of environmental safety of alternative engineering solutions and needs to be transformed into a comparative cost estimate added to the previously estimated construction cost [11]. An algorithm for such a transformation is the conditional environmental taxation tool (EcoT) of the project, alternatively implemented by the compared engineering solutions. EkoT, being a tool that objectively evaluates environmental safety of construction, is also an effective governmental regulatory mechanism that allows an additional project assessment, taking into account the degree of applying green materials and solutions offered by the regional market and the regional specifics of the construction industry. The most effective and transparent algorithm for the formation of such an estimate is the margin estimate, obtained from the available boundary data on the estimated construction costs (ECCmax and ECCmin) and the brought carbon impact (CO2max and CO2min) of construction projects of a similar orientation implemented or being implemented in the region. Local authorities are given the opportunity to adjust the amount of tax on a quarterly published multiplier K, which allows to selectively assess and regulate the degree of economic interest of developers in the application of green technologies by branches and types of construction products being created [12].

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3 Results and Discussions The algorithm of civil construction eco-development from a low-carbon perspective includes an automated assessment of the resource use of the compared engineering solutions, carbon impact of the construction industry, their transformation into the universal amount of the conditional environmental tax imposed by state authorities on the object of capital construction, engineering solutions of which are not effective enough from the standpoint of environmental safety (Fig. 2). In this way, a flexible instrument of organizational and economic motivation for regional construction communities to actively and purposefully green the construction and support the production and application of green technologies is created, understood and acceptable by market participants and universally applicable by the regulator [13].

Fig. 2. The algorithm for choosing the most eco-friendly construction project

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The direction of practical use of the obtained research results is characterized by complexity and multi-level [14]. At the micro level, it is proposed to conduct an environmental and economic analysis of the applied design solutions in construction, the selection of the least environmentally hazardous options for the practical implementation of specific construction projects. At the meso level, environmental monitoring, analysis and effective management of urban planning policies implemented at the level of municipal and federal entities aimed at minimizing the environmental damage caused by the regional construction complex should be carried out. At the macro level, it is planned to collect, analyze, systematize statistical indicators of environmental damage caused by the construction industry as a whole, adjust federal investment programs in construction on this basis, and introduce design and estimate documentation into practical use of the institute of environmental safety audit [15]. It is proposed to introduce the concept of builder’s extended responsibility (green developers) similarly to the existing extended producer responsibility [16]. The key aspect of the effectiveness of green developers, according to the authors, is their active involvement in the implementation of construction projects financed from budgetary funds, and therefore, with the initial less preferred economical offer to the bid price coming from green developers, it is advisable to introduce the institution of green certification of the developer and the formation on its basis of tender preferences that increase their competitiveness. The rational use of instruments for issuing and regulating tender preferences will allow executive authorities to establish and regulate the degree of involvement of the state construction order in the development of regional green construction [17]. An example of the proposed by the author concept of the appointment of tender preferences to green developers, built on their green certification, is shown in Table 1. Table 1. The concept of tender preferences in the effective functioning of the institution of green certification of developers as a tool to increase tender competitiveness Green certificate of the developer A

% EcoT to the total cost of construction products used by the developer 0–10

B

11–25

C

26–99

Tender preferences

Priority receive of large orders, maximum share in the evaluation of tender documentation Advantages in receiving large orders, high proportion in the evaluation of tender documentation General order placement process, minimum weight in the evaluation of tender documentation

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4 Conclusion The algorithm of civil construction eco-development from a low-carbon perspective considered in the work allows to optimize structural, space-planning decisions and technological solutions of buildings and structures. An effective environmental audit in investment and construction activities should be based on popularization of green lowcarbon solutions, supported by a transparent and effective methodology for valuation of carbon impact caused by construction industry. Thus, the conversion of the subject and results of the study to algorithms, tools and institutes for managing and regulating carbon impact in the process of creating civil construction objects from the point of effective management of green construction and extended environmental responsibility of the developer is justified, promising and contains significant research potential. It makes construction industry more eco-friendly and will be an effective supplement to the practice of green design and developer’s certification established in the country and the world. Acknowledgments. The work is realized in the framework of the implementation of a comprehensive project to create high-tech production “Development of new methods and tools for management of property in the budget sector and their implementation in the software package of the information-analytical system for centralized management of property owned by the constituent entities of the Russian Federation, municipalities, as well as state property companies” (agreement No. 074-11-2018-026 of 07/11/2018), with the financial support of Ministry of Science and Higher Education of the Russian Federation.

References 1. Ilyichev, V., Kolchunov, V., Bakaeva, N., Emelianov, S.: Principles of urban areas reconstruction ensuring safety and comfortable living conditions. IOP Conf. Ser.: Mater. Sci. Eng. 463(3), 032011 (2018) 2. Avilova, I., Naumov, A., Krutilova, M.: Methodology of cost-effective eco-directed structural design. Int. Multidiscip. Sci. GeoConf. SGEM 53, 255–261 (2017) 3. Bashmakov, I.: Costs and benefits of low-carbon economy and society transformation in Russia - 2050 Perspective. Center for Energy Efficiency (CENEf), Moscow (2014) 4. Lopez-Pena, A., Perez-Arriaga, I., Linares, P.: Renewables vs. energy efficiency: the cost of carbon emissions reduction in Spain. Energy Policy 50, 659–668 (2012) 5. Abakumov, R.G., Avilova, I.P., Abakumova, M.M.: Problem and effectiveness assessment statement of the reproduction at the regional level housing. Bull. BSTU named after V. G. Shukhov 3(5), 110–128 (2018) 6. Bakaeva, N.V., Vorobyov, S.A., Chernyaeva, I.V.: Application of biosphere compatibility indicator for assessment of the effectiveness of environmental protection methods. IOP Conf. Ser.: Mater. Sci. and Eng. 262, 012193 (2017) 7. Tsai, W.-H., Yang, C.-H., Huang, C.-T., Yen-Ying, W.: The impact of the carbon tax policy on green building strategy. J. Environ. Plan. Manag. 60(8), 1–27 (2016) 8. Heinonen, J., Saynajoki, A., Junnila, S.: A longitudinal study on the carbon emissions of a new residential development. Sustainability 3(12), 1170–1189 (2011)

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9. Bakaeva, N.V., Chernyaeva, I.V., Vorobyev, S.A.: Evaluation of the performance of biosphere compatible city functions in modern residential areas. J. Appl. Eng. Sci. 15(4), 447–454 (2017) 10. Ilyichev, V., Emelyanov, S., Kolchunov, V., Bakaeva, N.: About the dynamic model formation of the urban livelihood system compatible with the biosphere. Appl. Mech. Mater. 725–726, 1224–1230 (2015) 11. Avilova, I.P., Krutilova, M.O.: Methodology of ecooriented assessment of constructive schemes of cast in-situ RC framework in civil engineering. IOP Conf. Ser.: Earth Environ. Sci. 3, 012127 (2018) 12. Oberemok, M., Naumov, A., Schenyatskaya, M.: Qualitative analysis of view characteristics of residential property. Bull. BSTU named after V. G. Shukhov, 4(3), 44–51 (2019) 13. Golub, A., Lugovoy, O., Potashnikov, V.: Quantifying barriers to decarbonization of the Russian economy: real options analysis of investment risks in low-carbon technologies. Clim. Policy 19(6), 716–724 (2019) 14. Benuzh, A.A., Orenburova, E.N.: Standardization of green building technologies for environment design. MATEC Web Conf. 86, 05014 (2016) 15. Zharikov, I.S., Laketich, A., Laketich, N.: Impact of concrete quality works on concrete strength of monolithic constructions. Constr. Mater. Prod. 1(1), 51–58 (2018) 16. Naumov, A.E., Koshlich, Yu., Oberemok, M.I., Belousov, A.: Comparative analyzes for increasing the energy efficiency of civil constructions. In: 19th International Multidisciplinary Scientific GeoConference SGEM 2019 Conference Proceedings, pp. 277–284 (2019) 17. Grebenik, A., Koshlich, Yu., Abakumov, R.G., Shchenyatskaya, M.A.: Improvement of techniques for energy saving management on the principle of sustainable development. In: 19th International Multidisciplinary Scientific GeoConference SGEM 2019 Conference Proceedings, pp. 301–308 (2019)

Shungite Waste – An Effective Mineral Additive for Concrete Modification A. S. Estemesova1

, Z. N. Altaeva2

, and Zh. T. Aimenov3(&)

1

2 3

KazACA, Almaty, Kazakhstan Satbayev University, Almaty, Kazakhstan M. Auezov SKSU, Shymkent, Kazakhstan [email protected]

Abstract. This article is devoted to the research of shungite waste generated in the process of extraction and technological operations. Despite the rich raw material base of the mining industry, there is no market for domestic modifying additives based on local raw materials. Shungite waste expands the range of mineral additives and provides qualitatively new properties to concrete and reinforced concrete products and structures. The paper is also considers the research of shungite waste as a modifying mineral additive of concrete. Its influence on the main characteristics of concrete is studied and the features of processes occurring in the hardening silicate system “cement - dispersed shungite particles” are shown, which provide an increase in the strength of concrete and reduce the duration of its heat and humidity treatment. The features of dispersed particles of a mineral additive from shungite waste in hardening silicate systems are shown, which consist in the fact that the surface of the mineral filler particles is subject to hydration, which contributes to the production of concrete and mortar with improved physical and mechanical characteristics. Amorphism of SiO2 particles in the mineral filler creates foci of formation of crystals of hydroaluminates and calcium hydrosilicates. Keywords: Shungite
Concrete Hydration of cement stone


Mineral additive
Strength of concrete


1 Introduction In construction materials science, technologies related to the development of new methods for obtaining effective nano-modifying additives that allow to regulate directly the properties of composites based on mineral and organic binders are being intensively developed [1–4]. The analysis of the issue shows that carbon nanoparticles are the most acceptable for increasing the strength and other performance properties of concretes, solutions, and polymers [5–8]. The use of mineral raw materials and mining waste in fine state as aggregates of traditional concretes is difficult due to a significant increase in cement consumption. However, in new-generation concretes, the use of fine-dispersed production waste as a © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 52–58, 2021. https://doi.org/10.1007/978-3-030-54652-6_8

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mineral additive with the addition of a superplasticizer helps to reduce the consumption of cement and the net cost of concrete [9, 10]. Prerequisites for the use of shungite as a mineral additive in concretes are its unique properties due to the nanostructure and composition of a variety of carbon-silicic shale with a special form of natural carbon and silica [11–13], significant waste during its extraction and the need for their processing due to dust emission, which worsens the environmental situation in the region of its production, as well as a sufficient raw material base. The estimated reserves of the Shungite Deposit only in the Almaty region (Kazakhstan) are 620 million tons [14, 15]. Therefore, the ecological and nanostructural potential of shungite, realized as an effective mineral additive in concrete, is promising and long-term. In the development and saturation of the construction market with modifying mineral additives, it seems promising to use shungite waste as modifiers in concrete [16–19].

2 Methods and Materials As a mineral additive of concrete, shungite waste was used under the brand “Taurite” of the mining company “Koksu”. Taurite is a fine material with a size of 0–1 mm and up to 20 microns, which is based on the processes of mechanical activation and enrichment at a temperature of 400 to 600 °C. Properties of TS-A shale taurite are shown in Table 1. Table 1. Main properties of TS-A shale taurite Indicators Values Mass fraction of silicon dioxide (SiO2), % 84.93 Content of water-soluble substances, % 0.63 pH of aqueous suspension 7.36 Bulk density, kg/m3 695 Humidity, % 2

The properties of the mineral additive “TS-D-A” with grain sizes of 5 microns are shown in Table 2. Table 2. Main properties of the TS-D-A shale taurite Indicators Values Mass fraction of silicon dioxide (SiO2), % 79.51 Content of water-soluble substances, % 0.75 pH of aqueous suspension 8.3 Bulk density, kg/m3 504 Humidity, % 0.7

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Portland cement and all samples of cement stone were examined by a complex of physical and chemical analysis methods: x-ray phase and differential thermal. Radiographs were obtained using a DRON-3M diffractometer with a copper anticathode in the angle range of 4–64°. Samples in the form of fine-ground powder were pressed into a plexiglass cell. Thermograms were taken on a Q-1500D derivatograph from 10 to 1000 °C with a temperature rise rate of 100 °C per minute.

3 Results and Discussions Reducing the water demand of cement composite materials with mineral additives is achieved by the complex use of mineral additives with a superplasticizer, which has a significant water-reducing effect. Table 3 shows the composition of concretes with mineral additives of taurite and polietilen-naphthalenesulfonate additive of Kratasol brand. Table 3. Concrete compositions with the mineral additive taurite № of composition

Cement

Rubble

Sand

1 2 3 4 5

380 380 380 380 380

990 990 990 990 990

875 875 875 875 875

Mineral additive “TS-A” – 19 19 – –

Mineral additive “TS-D-A” – – – 11.4 11.4

Super plasticizer Kratasol – – 3.8 – 3.8

W/C

0.58 0.63 0.56 0.68 0.65

The samples were solidified at room temperature for a day and after being formed, one series of concrete cube samples was solidified for 3, 7, 14, 28 days under normal humidity conditions, and the second series of concrete cube samples after forming was placed in a heat and humidity treatment chamber (70 °C) after two hours. Analysis of Table 3 data shows that the use of mineral additives, depending on their composition and content, affects the W/C ratio of the concrete mixture, namely: coarse-grained additives without plasticizer require water consumption in the range of 239 l/m3–243 l/m3, with a superplasticizer on average 201 l/m3. The effect of plasticization with different amounts of introduced mineral and plasticizing additives differs: concrete mix № 1 for 60 min from grade on the mobility of PK5 decreased to PK3; concrete mix № 2 from PK5 to PK4; concrete mix № 3 did not show changes in mobility during the same time; concrete mix № 4 from PK5 to PK4; concrete mix № 5 from PK5 to PK4. The diluting effect of the superplasticizer “Kratasol” allows reducing significantly the amount of mixing water and obtaining high-strength concretes with a given mobility of the concrete mix.

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55

The research results on concrete compressive strength are shown in Table 4. Table 4. Strength of concrete with mineral additive taurite and superplasticizer Kratasol in different conditions of hardening Numbers of W/C Workability Limit of compressive strength, compositions MPA Hardening in the Normalconditions of humidity hardening, day HHTC, day OK, cm 3 7 28 12 h 1 28 1 0.58 20 13.2 19.8 32.9 10.6 22.5 33.4 2 0.63 22 14.1 20.2 33.7 13.2 23.7 34.2 3 0.56 23 15.9 25.4 40.8 14.8 23.8 41.4 4 0.68 22 17.5 26.9 41.3 14.4 25.7 41.8 5 0.65 23 18.2 28.6 42.7 14.8 29.0 41.6

From the data given in Table 4, it can be seen that the greatest strength of concrete was shown by compositions № 3, № 4 and № 5, containing the mineral additives TS-A and TS-D-A and the superplasticizer “Kratasol”. The increase in strength of compositions № 2–5, which hardened in normal humidity conditions, in comparison with the control composition on 3rd day is from 6.7 to 30.7%, on 7th day from 2.02 to 44.4%, on 28th day 2.5–30%. The increase in the strength of concrete compositions № 2–5 during heat and humidity treatment in comparison with the control composition in 12 h is from 24.5 to 39.6%, in 1 day from 5.3 to 29.9%, in 28 days 2.4–25%. Studies of processes occurring in the cement-mineral additive system show that mineral additives have a significant effect on the phase composition of hardening systems. Thus, the microstructure of the solidified solution at the age of 3 days in natural conditions showed that the particles of the mineral additive had been already exposed to the alkaline components of the cement dough at the initial stage of hydration of the hardening silicate system. As a result of this effect, we can say that the surface of the particles of the mineral additive is also hydrated, while the thickness of the hydration layer is 1 … 5 microns. The hydrated part of the grains forms a “border” around them, without separating from the remaining main part. In some cases, the intermediate cementing phase, on the contrary, penetrates into the grain structure of the mineral component. Figures 1 and 2 show the obtained x-ray diffractograms of compositions after 28 days of natural hardening based on cement and mineral additives “TS-A”, “TS-D-A”. Analyzing the curves of 28 day hardening with “TS-A” (Fig. 1) and with “TS-DA” (Fig. 2), it should be noted that the diffractograms preserved the mineral lines of the original Portland cement: tricalcium silicate C3S, bicalcium silicate b-C2S, C3A, and also there is quartz and hydration products: Ca(OH)2; CaCO3 and ettringite.

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Fig. 1. Diffractogram of cement stone with mineral additive “TS-A”

Fig. 2. Diffractogram of cement stone with mineral additive “TS-D-A”

The differential-thermal endoeffect at 120 °C is connected with the dehydration of ettringite, and the endoeffect at 520 °C with the dehydration of Ca(OH)2. A sign of the hydration reaction in the system is the presence of a 4.92Å line belonging to portlandite Ca(OH)2. The latter always accompanies the process of cement hydration, hydrolysis of Portland cement clinker minerals (calcium silicates). The occurrence of the line 5.6 Å is due to ettringite C3A
3CaSO4
32H2O, which is usually formed in the early stages of hydration of Portland cement.

4 Conclusion The features of dispersed particles of a mineral additive from shungite waste in hardening silicate systems are shown, which consist in the fact that the surface of the mineral filler particles is subject to hydration, which contributes to the production of concrete and mortar with improved physical and mechanical characteristics. Amorphism of SiO2 particles in the mineral filler creates foci of formation of crystals of hydroaluminates and calcium hydrosilicates. The influence of mineral additives on the rate of hydration processes of hardening of silicate systems was studied and established. The main products of hydration of modified mixtures are ettringite, portlandite and gel-like silicate phase. It is established that in the presence of mineral additives,

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57

interdependent aluminosilicate and polymer phases are formed and additives “TS-A”, “TS-D-A” are inhibitors of structure formation.

References 1. Sakharov, G.P.: On the short-term perspective of nanotechnologies in the production of building materials and products. Technol. Concr. 5, 13–15 (2009) 2. Klyuev, S.V., Klyuev, A.V., Shorstova, E.S.: Fiber concrete for 3-d additive technologies. Mater. Sci. Forum 974, 367–372 (2019) 3. Klyuev, S.V., Klyuev, A.V., Shorstova, E.S.: The micro silicon additive effects on the finegrassed concrete properties for 3-d additive technologies. Mater. Sci. Forum 974, 131–135 (2019) 4. Bazhenov, Yu.M., Demyanova, V.S., Kalashnikov, V.I.: Modified High-Quality Concrete. Scientific edn. p. 368. Publishing house of the Association of Construction Universities, Moscow (2006) 5. Khavari-Khorasani, G., Murchison, D.G.: The nature of carbonaceous matter in the Karelian shungite. Chem. Geol. 26, 165–182 (1979) 6. Mosin, O.V., Ignatov, I.: Application of natural fullerene-containing mineral shungite in construction and construction technologies. Nanotechnol. Constr. Sci. Online J. Moscow: CST “Nano-Construction”, 4(6), 22–34 (2012) 7. Karpikov, E.G., Lukuttsova, N.P., Soboleva, G.N., Golovin, S.N., Cherenkova, Y.: Effect of microfillers based on natural wollastonite on the properties of fine-grained concrete. Constr. Mater. Prod. 2(6), 20–28 (2019) 8. Izotov, V.S., Sokolova, Y.: Mechanism of action of SP on melamine and naphthalene basis. Int. J. Appl. Fundam. Res. 1, 109–121 (2013) 9. Kovalevski, V.V., Buseck, P.R., Cowley, J.M.: Comparison of carbon in shungite rocks to other natural carbons: an X-ray and TEM study. Carbon 39(2), 243–256 (2001) 10. Mosin, O.V., Ignatov, I.: Structural properties and composition of fullerene containing mineral shungite. Nano- i microsystemnaja technika. 1, 12–20 (2013) 11. Chernousov, D.I.: Application of asphalt binder with shungite in the construction of road surfaces: abstract of dis. … Candidate of Engineering Sciences. Voronezh, p. 19 (2011) 12. Cascarini de Torre, L.E., Fertitta, A.E., Flores, E.S., Llanos, J.L., Bottani, E.J.: Characterization of shungite by physical adsorption of gases. J. Argent. Chem. Soc. 92(4– 6), 51–58 (2004) 13. Kwiecinska, B., Pusz, S., Krzesinska, M., Pilawa, B.: Physical properties of shungite. Int. J. Coal Geol. 71, 455–461 (2007) 14. Zhurinov, M.Zh., Baeshov, A.B., Zhumabay, I.M., Serikbaev, B.A., Salaeva, Z.P.: Investigation of sorption properties of Koksu shungites: collection of scientific papers. Kentau, pp. 6–12 (2006) 15. Yestemessova, A.S., Yesselbayeva, A.G., Yestemessova, S.M.: Shungite waste of mining production in modified concretes regional case stady. Int. J. Chem. Sci. 16–26 (2017) 16. Rafienko, V.A. Technology of processing shungite rocks. M.: GEOS, p. 214 (2008)

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17. Kalinin, Yu.K.: Carbon-containing shungite rocks and their practical use: Autoref. of Dis. Doct. of Engineering Sciences. Moscow, p. 50 (2002) 18. Lukuttsova, N.P., Pykin, A.A., Degtyarev, E.V., Shirko, S.V.: Structure and properties of cement stone and concrete with the addition of a UKN-modifie. Cem. Appl. 3, 119–121 (2012) 19. Kalinin, Yu.K., Kalinina, AI., Skorobogatova, G.A.: Karelian shungites for new building materials, in chemical synthesis, gas treatment, water treatment and medicine. Publishing House of UNC SPbSU, SPb, p. 219 (2008)

Concrete Chemicalization for Digital Printing: Control of Rheology and Structure Formation V. A. Poluektova(&)

and N. A. Shapovalov(&)

Belgorod State Technological University named after V.G. Shukhov, Belgorod, Russia [email protected], [email protected]

Abstract. The stages of evolution of rheological properties and structure formation of concrete in digital printing conditions with layer-by-layer application of material and in the absence of formwork are considered. A solution to the problems of each stage of the evolution of rheology is proposed by concrete chemicalization, which is a fine-grained composite based on two active substances: a mineral binder and a polymer binder. The chemical additives present in concrete are represented by a complex of phloroglucinfurfural oligomers and polymer molecules of polyvinyl alcohol. It was found that the phloroglucinfurfural super plasticizer not only reduces the maximum dynamic shear stress, but also increases the area of the hysteresis loop, which characterizes the structure of the system and the speed of its recovery after destruction. It is proved that polymer molecules lead to an increase in the elastic-plastic strength of the layer. The interaction between the system components of both the dispersed phase (polyvinyl acetate, cement, sand) and the dispersion medium (phloroglucinfurfural oligomers, polyvinyl alcohol molecules) does not lead to undesirable side effects; on the contrary, there is a positive synergy effect when additives act on the rheology and structure formation of concrete. Keywords: 3D concrete
Chemical additives Structure formation
Plastic strength


Rheology
Hysteresis loop


1 Introduction The growth of interest in construction digital printing is due to many factors: increasing the level of production automation, speeding up the process of building structures, improving product quality, reducing production waste, etc. At the same time, concrete has been and remains one of the main building materials with prospects for use in innovative technologies [1–3]. The method of digital printing with concrete, due to a scientific interdisciplinary approach in the development of additive technologies, may be, on the one hand, more profitable and effective for the construction of unique buildings and structures, and on the other hand – for the construction of economical housing for typical projects, than traditional methods of construction. A special feature of construction printing is the layer-by-layer application of the material and the absence of formwork during the construction of buildings and structures. This determines one of the main problems of innovative technology – the © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 59–65, 2021. https://doi.org/10.1007/978-3-030-54652-6_9

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problem of the evolution of rheological properties and structure formation of concrete for printing.

2 Methods and Materials According to the classical ideas of Bingham and Shvedov, the rheological properties of plastic bodies (structured liquids) are characterized by two constants: the yield strength Pт and the plastic viscosity ηпл. It is more convenient to monitor the change in the maximum dynamic shear stress s0 and the maximum shear stress Pm. The value of s0 was determined using a rotational viscometer “Reotest-2” with coaxial cylinders. The rotation speed of the working cylinder was changed from 0.33 s−1 to 146 s−1. In the course of research, the relationship between the values of the shear stress s and the shear rate c_ was determined. Based on the results obtained, rheological curves were constructed. For large values of the shear rate, the dependence s ¼ f ð_cÞ is easily approximated by a straight line. The segment on the shear stress axis is equal to the maximum dynamic shear stress s0. The plastic viscosity of ηпл was defined as the tangent of the inclination angle of the straight line to the axis of the shear rate. Determination of the plastic strength Pm was performed using a conical plastometer developed by P.A. Rebinder. The following materials were selected as the main components of concrete for digital printing: 1. Mineral binder – portland cement CEM I 42.5 and CEM II/A-SH 32.5 with a specific surface area of 2856 and 1400 cm2/g according to GOST 31108-2003. 2. Fine aggregate – sand, Mk = 2.0  2.5 according to GOST 8736-2014. 3. Polymer binder – dispersion of polyvinyl acetate (PVA) with a dispersed phase content of 51%, stabilized at the polymerization stage with polyvinyl alcohol (PVAl) according to GOST 18992-80. 4. Phloroglucinfurfural super plasticizer – a modifier with a high plasticizing and water-reducing ability for mineral and polymer mineral dispersions. Synthesis of the modifier in the form of a 20% aqueous solution was performed according to the method presented in the patent [4]. Fine-grained polymer-cement concrete for 3D printing was obtained by first mixing dry components (Portland cement: sand as 1: 2.5) for 3–4 min. The liquid components were mixed separately: the synthesized modifier was dosed from 0 to 0.3% of the dry substance by weight of cement and introduced into the water of the compound. Then, a polymer binder was added to the solution, which was also dosed on a dry substance, while the amount of water contained in the polymer dispersion was necessarily taken into account when calculating the mixing water. When using a redispersible polymer powder, the technology of dry building mixes was developed [5].

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3 Results and Discussions The change in the rheological properties of concrete during digital printing is illustrated in Fig. 1. The entire process can be divided into 4 stages that characterize the evolution of changes in the yield strength from the properties of concrete. The direction of printing with concrete (layer deposition) is schematically shown from right to left. In this case, the hardening process is performed in the opposite direction, from left to right, from the fresh concrete mix extruded from the print head, presented in light gray tones, to the hardened concrete of a dark gray color.

Fig. 1. Stages in the evolution of yield strength relative to the properties of concrete for printing

From stage 1 (pumping) to stage 2 (deposition), the concrete is subjected to strong mechanical stress. The first stage is a period of fresh concrete during which the applied shear stress must reduce the yield strength or at least the Pт must remain constant during mixing, pumping and extrusion. Extrusion is the beginning of stage 2 of layer deposition. Concrete at the second stage goes into a state of rest, and the formation of a coagulation structure begins. The dotted line in Fig. 1 shows the required reduction of the yield strength with subsequent acceleration of the structure formation of the material, which is possible only with the chemicalization of concrete. When introducing chemical additives (modifiers), you can get a material with expressed thixotropic properties. Stage 2 shows a transition period when the yield strength increases over time due to a thixotropic increase in the strength of the coagulation structure, followed by a transition to the coagulation-crystallization structure (stage 3) and a rapid set of early strength (stage 4). The beginning of stage 4 characterizes the critical point, after which there should be a sharp increase in the yield strength exponentially. The proposed evolution of the rheological properties of concrete is consistent with the research presented in [6–10], and is due to the need to withstand the weight of an increasing number of subsequent layers. According to research [11], the material structure must support at least 150 cm of construction layers. The yield strength at the first stage depends on the cement hydration reactions and corresponds to the induction period of cement hardening [12], which can be extended

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by the slowing effect of super plasticizers. Low yield strength of concrete is necessary for good performance of the 3D printer [13, 14] and will depend on the type of super plasticizer and its dosage. The mechanism of action of the super plasticizer involves, first of all, the adsorption of its molecules on cement and aggregate particles. As a result of adsorption modification of the phase interface, the SP disperses particles and controls the coagulation process, and as a result, the rheological properties of highly concentrated dispersions. After the induction period of concrete hardening, the SP dramatically increases the strength gain stage. 3.1

Effect of a Phloroglucinfurfural Super Plasticizer on the Yield Strength and Area of the Hysteresis Loop of Cement Systems

The effectiveness of using phloroglucinfurfural oligomers as a modifier for producing concrete mixtures for digital printing is due not only to a reduction in the yield strength, but also to the size of the hysteresis loop area, which characterizes the degree of structuring of the system and the speed of its recovery after destruction. Complete rheological curves of modified CEM I suspensions showed that the phloroglucinfurfural SP when introduced up to 0.1% of the cement mass leads to an increase in the area of the hysteresis loop, while at high concentrations the loop area decreases. SP strongly plasticizes the system to the values of s0 almost equal to zero at a dosage of 0.3%. When modifying portland cements of the second type of CEM II with a content of up to 20% of mineral fillers, a more significant influence of the SP on the area of the hysteresis loop was found (Fig. 2a). Analyzing the obtained dependences, we can conclude that the phloroglucinfurfural SP when introduced up to 0.2% of the cement weight CEM II/A-SH 32.5 leads to an increase in the area of the hysteresis loop, which indicates a rapid recovery of the coagulation structure in the thixotropic system at rest. The maximum dynamic shear stress obtained when the rheological curve is directly removed in the absence of a SP is equal to 80 Pa, and when 0.1% of the SP is introduced, it is equal to 132 Pa, 0.2% – 115 Pa, and only more than 0.3% leads to a decrease in the rate of structure formation less than the control system. At the same time, it should be noted that s0, during the reverse course at these concentrations, tends to zero, the ηпл decreases to 0.4 Pa∙s, remaining constant afterwards, i.e., the modification leads the system to a state with expressed thixotropic properties. The yield strength of the mixture after extrusion must be sufficient to withstand the load of subsequent layers, that is, the material must have good plastic strength. The time interval between the two applied layers, on the one hand, should be long enough to provide the necessary strength, but on the other hand – small to ensure a strong bond (adhesion) between the layers. Comparing these two constraints leads to the paradox of optimizing print speed. A material with the required properties can be obtained, in our opinion, by creating a composite material based on two active substances: a mineral binder and a polymer binder. The simplest way to produce polymer-cement systems is to use waterdispersion polymers (for example, dispersion of polyvinyl acetate stabilized with polyvinyl alcohol), which allows preserving the advantages of the classical technology

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Fig. 2. Complete rheological curves of CEM II/A-SH 32.5 with a phloroglucinfurfural superplasticizer (1 - 0%; 2 - 0.1%; 3 - 0.2%, 4 - 0.3%): a - change in the hysteresis loop from the SP concentration; b - change of s0 from the SP concentration.

of concrete preparation and does not require thermal or heat-wet processing of the material or other special conditions of hardening. The strength of the adhesive seam increases more than 4 times with the introduction of polyvinyl acetate dispersion [4]. To identify the role of polymer additives in the origin of the concrete structure and the manifestation of thixotropic properties of the composite material, the influence of PVA and PVAl on the kinetics of structure formation was studied. 3.2

Kinetics of Plastic Strength of Polymer-Cement Systems

Measurement of rheological properties of modified highly concentrated polymercement systems with a reduced W/C content by a rotary viscometer is difficult due to the high yield strength and viscosity of materials for 3D printing. According to [15], the yield strength for printing concrete on industrial printers should be within 270  590 Pa, and the plastic viscosity should be 21.1  38.7 Pa∙s. Studies on the Rebinder plastometer allowed estimating the duration of dispersion in the plastic state and the plastic strength of the structure by the value of the maximum shear stress Pm. This value is conditional, because instead of the flow when the cone is submerged in the system, a crumpling stress develops. Figure 3 shows the regularities of growth of plastic strength of polymer-cement mixtures over time from the concentration of PVA and PVAl. From the moment of interaction of cement with water, two parallel processes of coagulation and condensation-crystallization structure formation begin to occur. The analysis of the obtained results showed that in the first minutes after closing, the process of forming a coagulation structure begins (the plastic strength is small), which can be easily destroyed without consequences for the final strength of the stone. Increasing the rest time of the system leads to an increase in elastic-plastic strength.

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Fig. 3. Kinetics of plastic strength of cement systems on the amount of polymer 1-0%; 2-0.15% PVAl; 3-0.3% PVAl; 4-0.15% PVA; 5-0.3% PVA.

During the first 2–2.5 h, the plastic strength of polymer-cement systems increases faster by 2 times (curve 5) than in the control system. However, it should be noted that the subsequent formation of the crystallization structure is more intense in the cement system (curve 1).

4 Conclusion The concrete required for digital printing must be a fine-grained composite based on two active components: a mineral binder and a polymer binder. The solution to the problems of each stage of the evolution of the rheological properties of concrete is possible by the chemicalization of concrete. It should be taken into account that the mechanism of action of the additive complex is very sensitive to their chemical interaction or adsorption behavior (competition) on the surface of particles of dispersed systems. The interaction between the system components of both the dispersed phase (PVA polymer, cement) and the dispersion medium (SP oligomers and PVAl polymers) does not lead to undesirable side effects, but on the contrary, the synergistic effect of the studied chemical additives on the rheology and structure formation of concrete for printing is shown. Acknowledgements. This work was realized in the framework of the Program of flagship university development on the base of the Belgorod State Technological University named after V.G. Shukhov, using equipment of High Technology Center at BSTU named after V.G. Shukhov.

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References 1. Elistratkin, M.Y., Lesovik, V.S., Alfimova, N.I., Shurakov, I.M.: On the question of mix composition selection for construction 3D printing. Mater. Sci. Forum 945, 218–225 (2019) 2. Denisova, Y.: Additive technology in construction. Constr. Mater. Prod. 1(3), 33–42 (2018) 3. Tianrong, Y., Qiaoling, L.: 3D printing cement-based material and preparation method thereof. Pat. CN104891891A (2015) 4. Poluektova, V.A., Shapovalov, N.A., Chernikov, R.O., Yevtushenko, E.I.: Modified polymer-cement composite material for 3D printing. Pat. RU2661970 (2018) 5. Poluektova, V.A., Kozhanova, E.P.: Improvement of dry mix mortar production technology for 3D printing. Addit. Fabr. Technol. 1(1), 14–23 (2019) 6. Marchon, D., Kawashima, S., Bessaies-Bey, H., Mantellato, S., Ng, S.: Hydration and rheology control of concrete for digital fabrication: potential admixtures and cement chemistry. Cem. Concr. Res. 112, 96–110 (2018) 7. Lootens, D., Jousset, P., Martinie, L., Roussel, N., Flatt, R.J.: Yield stress during setting of cement pastes from penetration tests. Cem. Concr. Res. 39, 401–408 (2009) 8. Flatt, R.J., Larosa, D., Roussel, N.: Linking yield stress measurements: spread test versus Viskomat. Cem. Concr. Res. 36, 99–109 (2006) 9. Lecompte, T., Perrot, A.: Non-linear modeling of yield stress increase due to SCC structural build-up at rest. Cem. Concr. Res. 92, 92–97 (2017) 10. Bellotto, M.: Cement paste prior to setting: a rheological approach. Cem. Concr. Res. 52, 161–168 (2013) 11. Wangler, T., Lloret, E., Reiter, L., Hack, N., Gramazio, F., Kohler, M., Bernhard, M., Dillenburger, B., Buchli, J., Roussel, N., Flatt, R.: Digital concrete: opportunities and challenges. RILEM Tech. Lett. 1, 67–75 (2016) 12. Mantellato, S.: Flow Loss in Superplasticized cement pastes. Doctoral dissertation. ETH Zurich (2017) 13. Choi, M., Roussel, N., Kim, Y., Kim, J.: Lubrication layer properties during concrete pumping. Cem. Concr. Res. 45, 69–78 (2013) 14. Feys, D., Khayat, K.H., Khatib, R.: How do concrete rheology, tribology, flow rate and pipe radius influence pumping pressure. Cem. Concr. Compos 66, 38–46 (2016) 15. Buswell, R.A., Leal de Silva, W.R., Jones, S.Z., Dirrenberger, J.: 3D printing using concrete extrusion: a roadmap for research. Cem. Concr. Res. 112, 37–49 (2018) 16. Klyuev, S.V., Klyuev, A.V., Shorstova, E.S.: The micro silicon additive effects on the finegrassed concrete properties for 3-D additive technologies. Mater. Sci. Forum 974, 131–135 (2019) 17. Klyuev, S.V., Klyuev, A.V., Shorstova, E.S.: Fiber concrete for 3-D additive technologies. Mater. Sci. Forum 974, 367–372 (2019)

Stabilization of the Clay Soil of the Increased Humidity for Road Construction A. I. Trautvain(&)

, A. E. Akimov

, and V. A. Grichanikov

Belgorod State Technological University named after V.G. Shukhov, Belgorod, Russia [email protected] Abstract. In the work, the influence of stabilizing additive «Baustab» (produced by the Scientific and Production Enterprise «Plant of Innovative Industrial Equipment») on the change in humidity, water-holding capacity of soil with increased humidity was studied. We also studied changes in the maximum density and optimal moisture content of the modified soil using the example of light sandy loam. It has been established that the use of the additive slightly affects the change in soil moisture over time. Despite this, «Baustab» - added soil becomes denser, more viscous, partially aggregated, and no water separation is observed. A study of the water retention capacity of the percentage of stabilizing additives «Baustab» showed an increase in this indicator compared with soil without additives in the range from 3 to 7%. In addition, the use of additives in the soil composition increased its compaction and mobility even at low humidity of the modified soil. The effect of water on compaction of modified soil is also negligible. Such soil is likely to be subject to minimal subsidence and loss of strength characteristics in the autumn-spring period. Keywords: Soil stabilization
«Baustab» stabilizing additive produced by the Scientific and Production Enterprise «Plant of Innovative Industrial Equipment”
Water-holding capacity
Maximum density
Optimal humidity

1 Introduction The development of compositions based on soil with inorganic binders (cement, lime, fly ash, etc.) and organic binders (bitumen, bitumen emulsions, tar, polymer resins, etc.) are involved in many scientific schools [1–8]. However, the strengthening of soils with binders of various nature does not always contribute to the production of a material with specified physical and mechanical characteristics. This is due to the fact that the soil of the subgrade of the road perceives not only the load from vehicles and overlying structural layers of pavement, but also perceives the effects of weather and climate factors. Water penetrating into the pores and the process of alternating freezing and thawing have the greatest effect on the subgrade soil [1–3, 8–11]. Therefore, when strengthening soils, it is necessary to increase not only their strength characteristics, but also to change the water-repellent effect through the use of stabilizers. Long-term studies in various countries of the world have shown that increasing the water resistance of clay soils is possible through the use of surface-active substances © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 66–72, 2021. https://doi.org/10.1007/978-3-030-54652-6_10

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(surfactants). When using surfactants, you can reduce the need for binders, improve the physicomechanical characteristics of clay soils and make them suitable for use in construction work []. Recently, a number of companies have been actively promoting various new calcium-based additives to stabilize subgrade soils. The mechanism of action of these commercially available additives is not always known, and their patented chemical composition makes it difficult to predict their effectiveness [12–21].

2 Methods and Materials As soil, use light sandy loam in the Belgorod region. The name of the soil was determined by the test results on indicators: the number of plasticity and particle size distribution according to the state general educational standard 25100-2011. Humidity at the rolling boundary WP (17.4%), humidity at the yield strength WT (26.86%), and the plasticity number IP (9.46) were determined according to state educational standard 5180-2015. In order for the subgrade to be stable and free from subsidence, the soil must be compacted at optimum humidity to maximum density. This indicator is determined according to the state general educational standard 22733-2016. The maximum density of the initial soil was qmax = 1.82 g/cm3 with its optimum moisture content Wopt = 15.15%. The water holding capacity of the soil was determined according to the state general educational standard GOST 5802-86. As a stabilizing additive was used «Baustab» produced by the Scientific and Production Enterprise «Plant of Innovative Industrial Equipment». This additive has been specially formulated to stabilize soils from tunneling with high humidity. In this regard, such soil was not suitable for transportation and further use in construction. The additive is a milk-white powder, the passage of soil particles through a sieve of 0.071 mm is more than 95%. The chemical composition of the additive was carried out using an X-ray fluorescence spectrometer. It is worth noting that this composition is not accurate, since the powder contained compounds that were not determined during the study. However, the main component of the supplement is calcium oxide (more than 93%).

3 Results and Discussions At the first stage of the work, the change in soil moisture was investigated when an additive was added to the soil with increased humidity in the amount of 3 and 6% by weight of the dry soil skeleton. In the work we used soil with a humidity of 50, 100 and 150% above the optimum. So, in the latter case, the soil was a mobile mixture; its moisture content exceeded the moisture content at the yield point. The research results are presented in Fig. 1. From the presented results it is seen that the use of the additive slightly affects the change in soil moisture over time. When 3% stabilizing additive “Baustab” is added to the soil moistened 50% above the optimum humidity, its moisture content decreases from 18.7% to 16.5%. The change was 2.2% within an hour. Soil moistened 100%

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31 29 Moisture W, %

27 25

23 21 19 17 15 0

10

20

30

40

50

60

Over time T, min

Fig. 1. Change in soil moisture over time

above the optimum moisture, with the introduction of 3% additives showed a total drop in moisture by 1.8%. When the soil is moistened by 150%, a drop in humidity of 1.5% is observed in the first 15 min. The total drop is 2.1%. Thus, the results obtained in terms of changes in humidity are similar to each other and do not depend on the degree of soil moisture. With the introduction of a 6% additive by weight of a dry soil skeleton moistened by 50%, a drop in humidity during the hour by 2.9% is observed. Soil moistened 100% with the same amount of stabilizing additive showed a smooth drop in humidity from 23.0 to 21.0%, which amounted to 2.0%. With an increase in the degree of soil moistening by 150%, the total drop in humidity during the hour is 1.3% - from 28.6 to 27.3%. I would like to note that a further drop in humidity over 23 h is insignificant and amounts to 0.8; 0.6; and 0.5% for soil moistened at 50, 100 and 150% above the optimum value, respectively. Thus, the change in soil moisture with the introduction of various amounts of additives was 1–3%. This change is possibly associated only with the evaporation of water from the surface of the modified soil while mixing the soil with the additive. Despite the results obtained, the soil with the addition of Baustab acquired a dense consistency, became more viscous, partially aggregated, water separation was not observed. The sorption ability of the additive could be visually observed in the first 10 min after its introduction into the soil. It can be concluded that the additive attracts and retains on itself the excess water located between the particles of the soil, like a sponge, that is, physically and chemically binds water. This process may be associated with the presence of hydrophilic groups, which make the additive hygroscopic. Physically-chemically bound water plays an important role in the compaction of the soil of the subgrade, since it is a plasticizer, weakens the intermolecular bonds of soil particles. The presence of free fluid in the capillaries of the soil creates additional stresses in the structure of the soil and reduces the possibility of high-quality compaction.

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Water retention ability. V, %

Next, a study was conducted of the effect of the additive on the water retention capacity of soil moistened with 150% of optimal moisture. The evaluation was carried out by adding additives to the moistened soil in the amount of 1, 3, 6, 9 and 12% by weight of the dry soil skeleton. Water retention capacity is shown in Fig. 2.

100 99 98 97 96 95 94.66 94 93 92 91.42 91 90 0

98.38

97.9 96.22

95.71

2

4

6

8

10

12

14

Amount of stabilizing additive Q, %

Fig. 2. The dependence of the water retention ability on the percentage of stabilizing additives «Baustab»

Studies have shown an increase in this indicator compared with soil without additives by 3.2; 4.3; 4.8; 6.5; and 6.9%, respectively. According to the graph shown in Fig. 1, I want to note the “jump” of this indicator from 91.42% to 94.66% with the addition of only 1% «Baustab» to the ground. This indicator can positively affect the strength of cement-reinforced soil in the presence of the «Baustab» modifier. That is, the additive helps to retain a sufficient amount of water for the normal hardening of the cement binder. The third stage of the study was to determine the maximum density and optimal humidity at various percentages stabilizing additives of the «Baustab» to the mass of the studied soil (3, 6, 9%). The graph of the dependence of the change in the density of the skeleton of the soil on moisture is shown in Table 1. This indicator is one of the most important in road construction and requires special attention. This is due to the fact that in order to ensure the stability of the subgrade and prevent precipitation, the soil must be compacted at optimum humidity to maximum density. According to the graph (Table 1), the maximum soil density with the addition of 3% «Baustab» is qmax = 1.61 g/cm3 at its optimum moisture content Wopt = 9.2%. With the addition of 6% «Baustab» - qmax = 1.59 g/cm3 and is achieved with its optimum humidity Wopt = 7.0%; at 9% «Baustab» qmax = 1.59 g/cm3 with humidity Wopt = 5.5%. Tests to determine the maximum density and optimal soil moisture in a percentage ratio of 3, 6 and 9% «Baustab» to the mass of the tested soil showed a

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Table 1. Dependence of soil density on its moisture content with various amounts of additive «Baustab» Amount of 0% Humidity, % 9,23 11,34 13,45 15,15 16,69

stabilizing additive 3% Density, Humidity, % g/cm3 1,56 6,5 1,64 7,83 1,73 9,21 1,82 10,98 1,8 12,72

Density, g/cm3 1,54 1,6 1,61 1,61 1,5

6% Humidity, % 6,01 6,99 8,55 9,66 11,55

Density, g/cm3 1,56 1,59 1,59 1,58 1,58

9% Humidity, % 5,53 6,1 7,13 9,67 11,93

Density, g/cm3 1,59 1,59 1,59 1,57 1,55

decrease in optimal moisture by 6% or more relative to the original soil. Moreover, the maximum density, regardless of the amount of additive, decreased by 0.2 g/cm3 and averaged 1.6 g/cm3. Based on this, the introduction of additives in the soil leads to a decrease in soil compaction. However, it is worth paying attention to the fact that the use of additives in the composition of the soil can reduce the effect of water on soil compaction, that is, the dependence graph is less extreme. Soil containing 9% «Baustab» at low humidity (5.5%) acquires a maximum density (1.59 g/cm3) and retains it with a further increase in the amount of water. Such soil loses its density only when the soil is moistened more than 10%. The introduction of a smaller amount additive of the «Baustab» (3 and 6%) into the initial soil only slightly changes the above research results. So, the graphs of changes in the maximum density as a result of increasing soil moisture using 3 and 6% «Baustab» have a slightly more “convex” appearance, compared with soil containing 9% modifier. But the effect of the water component on soil compaction is also negligible. Based on this, it follows that the density of the soil of the subgrade modified with «Baustab» will be minimally affected by water relative to the original. This will have a positive effect on its disintegration during the unfavorable autumn-spring period of operation of the highway. Such soil is likely to be subject to minimal precipitation and loss of strength characteristics. Analysis of changes in the optimum soil moisture with the introduction of various amounts of additives shows that to obtain the maximum density, the source soil needs a significantly larger amount of water (about 15%), compared with «Baustab» modified soil (5.5 to 9.2% water is required per depending on the amount of modifier). The water component of the soil increases the mobility of the particles of the system, increasing their compaction. Upon reaching a certain amount of water, the density of the soil decreases, that is, its excess leads to a break in the bonds between the grains of the soil, the space between which is filled with water. The use of additives in the composition of the soil helps to obtain a system with high compaction, and, consequently, mobility even at low humidity of the modified soil. Moreover, the resulting soil does not lose the maximum density achieved over a wide range of changes in the amount of water in the system.

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4 Conclusion Tests of the «Baustab» stabilizing additive showed the feasibility of its use in strengthening soils for road construction, in particular, as a stabilizer for waterlogged soil. In the work we used soil with a humidity of 50%, 100% and 150% above the optimum. The change in soil moisture with the introduction of various amounts of additives was 1–3%. This change is possibly associated only with the evaporation of water from the surface of the modified soil while mixing the soil with the additive. Despite the results obtained, the soil with the addition of «Baustab» acquired a dense consistency, became more viscous, partially aggregated, water separation was not observed. Based on this, we can conclude that the additive attracts and retains excess water located between the particles of the soil, like a sponge, that is, physically and chemically binds water. Studies of the dependence of water holding capacity on the percentage of stabilizing additives «Baustab» showed an increase in this indicator compared to soil without additives in the range from 3 to 7%, respectively. I would like to note a “jump” of this indicator from 91.42% to 94.66% with the addition of only 1% «Baustab» to the ground. An increase in the water holding capacity of the soil in the presence of the «Baustab» modifier can positively affect the strength of the cement-reinforced soil. That is, the additive will help to retain a sufficient amount of water for the normal hardening of the cement binder. Tests to determine the maximum density and optimum soil moisture in the percentage ratio of 3, 6 and 9% Baustab to the mass of the soil tested showed a decrease in optimal humidity by 6% or more relative to the original soil. Moreover, the maximum density, regardless of the amount of additive, decreased by 0.2 g/cm3 and averaged 1.6 g/cm3. Based on this, the introduction of additives in the soil leads to a decrease in soil compaction. However, it is worth paying attention to the fact that the use of additives in the composition of the soil can reduce the effect of water on soil compaction. The use of additives in the composition of the soil helps to obtain a system with a maximum density even at low humidity of the modified soil. Moreover, the resulting soil does not lose the maximum density achieved over a wide range of changes in the amount of water in the system. This will have a positive effect on its disintegration during the unfavorable autumn-spring period of operation of the highway. Such soil is likely to be subject to minimal subsidence and loss of strength characteristics. Acknowledgements. This work was realized in the framework of the Program of flagship university development on the base of the Belgorod State Technological University named after V G Shukhov, using equipment of High Technology Center at BSTU named after V G Shukhov.

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References 1. Obuzor, G.N., Kinuthia, J.M., Robinson, R.B.: Soil stabilisation with lime-activated-GGBS —A mitigation to flooding effects on road structural layers/embankments constructed on floodplains. Eng. Geol. 151, 112–119 (2012) 2. Manso, J.M., et al.: The use of ladle furnace slag in soil stabilization. Constr. Build. Mater. 40, 126–134 (2013) 3. Trautvain, A.I., Akimov, A.E., Chernogil, V.B.: Study of physical and mechanical characteristics of various types of soil strengthened by clinker waste. Constr. Mater. Prod. 1 (3), 43–50 (2018) 4. Trautvain, A.I., Akimov, A.E., Yakovlev, E.A., Chernogil, V.B., Lukashuk, A.G.: Evaluation of the effectiveness of the use of stabilizers of the Chimston series in soils reinforced with inorganic binders. Bull. BSTU Named After V.G. Shukhov 12, 6–13 (2017) 5. Ortega-López, V., et al.: The long-term accelerated expansion of various ladle-furnace basic slags and their soil-stabilization applications. Constr. Build. Mater. 68, 455–464 (2014) 6. Kolias, S., Kasselouri-Rigopoulou, V., Karahalios, A.: Stabilisation of clayey soils with high calcium fly ash and cement. Cement Concr. Compos. 27(2), 301–313 (2005) 7. Yong, R.N., Ouhadi, V.R.: Experimental study on instability of bases on natural and lime/cement-stabilized clayey soils. Appl. Clay Sci. 35(3–4), 238–249 (2007) 8. Miller, G.A., Azad, S.: Influence of soil type on stabilization with cement kiln dust. Constr. Build. Mater. 14(2), 89–97 (2000) 9. Kavak, A., Akyarlı, A.: A field application for lime stabilization. Environ. Geol. 51(6), 987– 997 (2007) 10. Trautvain, A.I., Akimov, A.E., Yakovlev, E.A., Chernogil, V.B., Lukashuk, A.G.: Evaluation of the effectiveness of the use of stabilizers of the “chim-hundred” series in soils reinforced with inorganic binders. Bull. BSTU Named After V.G. Shukhov 12, 6–13 (2017). https://doi.org/10.12737/article_5a27cb7c733e24.73795944 11. Bell, F.G.: Lime stabilization of clay minerals and soils. Eng. Geol. 42(4), 223–237 (1996) 12. Harichane, K., et al.: Use of natural pozzolana and lime for stabilization of cohesive soils. Geotech. Geol. Eng. 29(5), 759–769 (2011) 13. Tang, A.M., Vu, M.N., Cui, Y.J.: Effects of the maximum soil aggregates size and cyclic wetting–drying on the stiffness of a lime-treated clayey soil. Géotechnique 61(5), 421–429 (2011) 14. Amadi, A.A., Okeiyi, A.: Use of quick and hydrated lime in stabilization of lateritic soil: comparative analysis of laboratory data. Int. J. Geo-Eng. 8(1), 3 (2017) 15. Al-Taie, A., et al.: Volumetric behavior and soil water characteristic curve of untreated and lime-stabilized reactive clay. Int. J. Geomech. 19(2), 04018192 (2019) 16. Jafer, H.M., et al.: Development of a new ternary blended cementitious binder produced from waste materials for use in soft soil stabilization. J. Clean. Prod. 172, 516–528 (2018) 17. Coudert, E., et al.: Use of alkali activated high-calcium fly ash binder for kaolin clay soil stabilisation: physicochemical evolution. Constr. Build. Mater. 201, 539–552 (2019) 18. Chemeda, Y.C., Deneele, D., Ouvrard, G.: Short-term lime solution-kaolinite interfacial chemistry and its effect on long-term pozzolanic activity. Appl. Clay Sci. 161, 419–426 (2018) 19. Salimi, M., Ghorbani, A.: Mechanical and compressibility characteristics of a soft clay stabilized by slag-based mixtures and geopolymers. Appl. Clay Sci. 184, 105390 (2020) 20. Boardman, D.I., Glendinning, S., Rogers, C.D.F.: Development of stabilisation and solidification in lime–clay mixes. Geotechnique 51(6), 533–543 (2001) 21. Trautvain, A., Akimov, A., Yakovlev, E.: Improvement of properties of the argillaceous soils when using additives “Chimston” in combination with inorganic astringent. Mater. Sci. Forum 945, 136–140 (2019)

Progressive Destruction of Frame Buildings Made of Monolithic Reinforced Concrete T. K. Ksenofontova(&) Russian State Agrarian University-Moscow Timiryazev Agricultural Academy, Moscow, Russia [email protected]

Abstract. The design of multi-storey buildings is currently carried out with mandatory verification of their progressive destruction. Progressive destruction is the process of rapid sequential destruction of load-bearing structures due to the destruction of any element of the building or part of it. Different factors can be the causes of local destruction: an explosion of household gas, terrorist acts, the impact of vehicles on the supporting structures of the building, the impact of wind loads that exceed the amount accepted in the project, and so on. The article investigates possible scenarios for the occurrence of a progressive destruction due to a car hitting one of the columns along the perimeter of a multi-storey frame building. Options were considered for a car hitting a row column located in the middle of the building, as well as a car hitting one of the corner columns. It was found that the impact of a car hitting an ordinary column leads to its destruction, as well as the destruction of the building ceiling above the first floor. The most dangerous option is the car hitting the corner column. A hit to the corner column causes the corner of the building to collapse globally. Keywords: Progressive destruction
Local destruction of structures
Crack resistance
The emergence of stresses in the rebar
Equal to the yield strength

1 Introduction The calculation of multi-storey buildings for progressive destruction has recently been paid considerable attention to [1–10, 16]. With progressive destruction, large deformations of structures occur, in which significant plastic deformations occur in the concrete, as well as in dangerous sections, the rebar works at stresses equal to the yield strength [2, 11, 12], or it breaks down. In this case, there is often a situation when the destruction of cross sections occurs when a number of through cracks are formed, and the stress in the rebar does not reach the yield point. Different causes of local destruction have different effects on the occurrence of progressive building destructions [13]. Therefore, the design must take into account the impact of each of them.

© The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 73–78, 2021. https://doi.org/10.1007/978-3-030-54652-6_11

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2 Methods and Materials This article examines the impact of local destruction of buildings from the impact of a car hitting and examines the most dangerous scenarios of destruction. Calculations were performed using the finite element method in a quasi-static setting [14], taking into account the physical non-linearity of materials, concrete and rebar, using the software package “LIRA-SAPR 2019”. For the study, a multi-storey frame building with smooth floors without crossbars was adopted, the design scheme of which is shown in Fig. 1, and in Fig. 2 – the floor plan. The model of P.L. Pasternak with two bed coefficients implemented in LIRASAPR was used for the ground base.

Fig. 1. The building design scheme

The thickness of the building floors was 200 mm, and the cross-section of the columns was 500  500 mm. The concrete class B30 was adopted, and for working longitudinal rebar - class A500C. The calculation for a progressive destruction is made in two stages. Initially, in LIRA-SAPR 2019, the problem was solved in a linear setting based on the effect of design loads: the actual weight of the structures and the operational load. The purpose of the solution was to determine the rebar of floors and columns of the building. Then, with the known rebar, the calculation was made for the standard loads from the own weight of the vehicle, operating loads and impact. The quasi-static impact value was determined according to the norms [14]. The second stage of the calculation took into account the physical nonlinearity of concrete and rebar operation in accordance with the deformation diagrams ϭ–e, shown in Fig. 3. The most dangerous option when a vehicle collides with a frame building is to hit the car in any of the columns. The calculation considered the impact of both trucks and cars in the columns of the first floor. In this case, the impact force depends on the speed of movement and is distributed according to [14] both in the direction of movement of the car and in the direction perpendicular to the movement. Thus, for expressways, the impact forces are 1000 kN and 500 kN, respectively; for conventional highways – 750 kN and 375 kN; for conventional roads −500 kN and 250 kN; territories near buildings

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Fig. 2. Scheme of building floors and impact of the car on the 1st floor columns

Fig. 3. Deformation diagrams ϭ–e for concrete (a) and rebar (b)

for cars −50 kN and 25 kN, for trucks −150 kN and 75 kN. The specified values of the impact force from the impact of vehicles should be distributed along the length of the columns, starting from the height h specified in [14], depending on the type of vehicle. Loads from the impact of cars hitting were applied to the columns of the building located along the outer contour. An intermediate column was selected at the intersection of axes 1-D, as well as columns in the corners of the building at the intersection of axes 2 - A and 1-F (Fig. 2). In this case, it was taken into account that for columns on the right side of the road, the impact of the car can be applied along the two-letter axes (direction a), or along the numeric axes (direction b).

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3 Results and Discussions When calculating the progressive destruction of the building from the impact of vehicles, we studied the movements that occur in the building floors, the possibility of the occurrence and spread of cracks, the emergence of flow stresses in the longitudinal rebar and through cracks, which would indicate the occurrence of zones of destruction in the floors. Firstly, the impact of cars on the intermediate column at the intersection of the 1–D axes was considered. As expected, with such an impact, the greatest displacement occurs in the floor covering of the first floor in the impact zone. When the impact force is equal to 1000 kN, the greatest amount of displacement in this floor covering reaches up to 45 cm. According to the height of the building closer to the upper floors, the impact of the hit on the ceiling is gradually leveled. The influence of the type of vehicle and speed of movement on the degree of impact on the building when the car is hit was also studied. Table 1 shows the values of movements in the floor covering of the first floor from these factors. Table 1. Movement in the floor covering above the first floor, mm Speed performance Expressways Usual roads Area around the buildings

Cars 426 358 307

Trucks 447 378 325

% of variation 4.7 5.3 5.5

As it can be seen from Table 1, the type of vehicle has little effect on the degree of impact from the impact of cars. The maximum variation when cars and trucks are exposed to an ordinary column does not exceed 5.5%. However, the speed of the car has a significant impact. The impact of a car moving at high speed (expressways) differs from the impact of cars that move around buildings at a slower speed by about 21%. In the study of the occurrence of zones of formation of cracks and zones of destruction of floors, cracks that occurred in the floors under operating loads before the car hit were taken into account. During operation, cracks mainly occur in the upper part of the floors near the columns. After the car hit column 1-D, these zones significantly increased, and in the floor covering above the first floor there were zones of destruction, where the stress in the rebar reached the yield point (Fig. 4). When the car hits the corner columns on the axes 2–A and 1-A, it was found that the direction of the impact (Fig. 2, directions a and b) has very little effect on the calculation results. Therefore, in the future, only one of the directions was considered. The impact of a car hit in column 2-A leads to significantly less consequences than the hit in column 1-F. Therefore, the analysis of the impact of a car hitting a corner column was mainly performed only for column 1-F. Calculations showed that the impact of a truck hit in the corner column 1-F is a more dangerous option than the hit in the row column 2-A. So, if as a result of the car hit in column 2-A in the floor covering of the

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Fig. 4. Zones of cracks and rebar fluidity in the floor covering of the first floor of the building: a – top of the floor covering: b – bottom of the floor covering

first floor only crack zones increased, as well as there were flow zones of rebar, then when the car hits the corner column 1-F, a complete collapse of the corner of the building on all floors on a significant area of floor covering occurs.

4 Conclusion As calculations showed, when a car hits the columns along the perimeter of a frame building, local destruction may occur, resulting in extensive areas of cracks and rebar fluidity in the floor coverings, and a progressive destruction of part of the building may occur. The emergence of rebar fluidity, which occurs when a car hits an ordinary column 1-D, creates the prerequisites for a situation in which a progressive destruction may occur, but it is also possible that a scenario in which there is no global destruction of the building. This is possible due to the redistribution of forces between the loadbearing structural elements, as well as due to the plastic properties of the rebar [13, 15].

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In this case, during the reconstruction of the building, it is possible to restore the directly affected column and floor covering above the first floor. A particularly dangerous option is the car hitting in the corner column, which can lead to a complete progressive destruction of its corner section.

References 1. Almazov, V.O.: Prevention of progressive destruction. Monograph. MGSU, ISA, Moscow, Russian Federation (2006) 2. Almazov, V.O., Khoi, K.Z.: Dynamics of progressive destruction of monolithic multi-storey frames. Monograph. DIA Publishing House, Moscow, Russian Federation (2013) 3. Perelmuter, A.V.: Progressive collapse and design methodology. Earthquake engineering. Saf. Struct. 6(6), 15–18 (2004) 4. Shapiro, G.I., Guryev, V.V., Eisman, Yu. A.: Method of calculation of monolithic residential buildings for stability against progressive. MNIITEP, Moscow, Russian Federation (2004) 5. Klyuev, S.V., Klyuev, A.V., Shorstova, E.S.: The micro silicon additive effects on the finegrassed concrete properties for 3-D additive technologies. Mater. Sci. Forum 974, 131–135 (2019) 6. Zhang, W.: Design of multi-storey and high-rise reinforced concrete structures. ASV Publishing House, Moscow, Russian Federation (2010) 7. Peifu, X., Fu, S., Van, S., Xiao, Z.: Design of modern high-rise buildings. ASV Publishing House, Moscow, Russian Federation (2008) 8. Gilmor, J.R., Virdi, K.S.: Numerical modelling of the progressive collapse of a framed structure as a result of impact or explosion. In: 2nd International Ph.D. Symposium in Civil Engineering, Budapest (1998) 9. Protection of buildings and structures from progressive collapse, SP 385.1325800.2018. StandardInform, Moscow, Russian Federation (2018) 10. Klyuev, S.V., Klyuev, A.V., Khezhev, T.A., Pucharenko, Y.: Technogenic sands as effective filler for fine-grained fibre concrete. J. Phys: Conf. Ser. 1118, 012020 (2018) 11. Rastorguev, B.S., Mutoka, K.N.: Deforming structures of ceilings of frame buildings after the sudden destruction of one column. Earthquake engineering. Saf. Struct. 1(6), 12–15 (2006) 12. UFC 4-023-03: Design of buildings to resist progressive collapse. Department of Defense (DoD) (2003). 176 p. 13. Tamrazyan, A.G.: Resource of survivability – the main criterion for decisions of high-rise buildings. Hous. Constr. 1(12), 15–18 (2010) 14. Buildings and structures. Special effects, SP 296.1325800.2017. StandardInform, Moscow, Russian Federation (2017) 15. Kolchunov, V.I., Androsova, N.B., Klyuyeva, N.V., Bukhtiyarova, A.S.: Survivability of buildings and structures under non-design impacts, Scientific edn. Publishing House DIA, Moscow, Russian Federation (2014) 16. Klyuev, S.V., Shlychkov, D.I., Muravyov, K.A., Ksenofontova, T.K.: Optimal design of building structures. Int. J. Adv. Sci. Technol. 29(5), 2577–2583 (2020)

Increasing the Stability of the Polyimide Radiation-Protective Composite to the Effects of Atomic Oxygen N. I. Cherkashina(&)

, Z. V. Pavlenko

, and N. V. Kashibadze

Belgorod State Technological University named after V.G. Shukhov, Belgorod, Russia [email protected]

Abstract. The paper presents data on increasing the resistance to atomic oxygen of a polymer composite based on polyimide and tungsten oxide WO2 by adding crystalline silicon. As an additive to the composite, finely dispersed crystalline silicon of the KR-00 grade 40 lm with a specific surface area of 5 m2/g was used. Tests simulating the effect of atomic oxygen on composites in space were carried out by treating polyimide composites with oxygen plasma. The energy of atoms and oxygen molecules reached 35 eV. Composites of optimal composition with a content of 65 wt% WO2 were tested. The data on the mass loss of composites after treatment with oxygen plasma are presented, and the microstructure of the surface of the composites is studied. The introduction of an additive of crystalline silicon in an amount of 1 wt% allows reducing the mass loss of the composite under the influence of an oxygen plasma flow by 31.6%. Keywords: Polymer composite


Filler
Tungsten oxide
Crystalline silicon

1 Introduction Currently, various types of polymers and composites based on them are widely used in construction. Modern synthetic composites are successfully used in the design and decoration of buildings and structures along with metal, concrete, wood, glass [1, 2]. In some cases, polymers act as analogues of traditional building materials, but sometimes the unique properties of synthetic composites make them indispensable, especially in the nuclear industry as radiation-protective materials [3–7]. With the development of astronautics, polymers and materials based on them became used in the manufacture of spacecraft. The use of lighter materials, compared with traditional metal, allows reduce the mass of radiation-protective materials with the same thickness of protection [8–12]. However, the use of materials in space requires additional studies related to the study of the effects of the space environment on the functional properties of structures made of these materials. The following negative cosmic factors affecting polymers are known: deep vacuum, radiation conditions, impact of meteorite particles, impact of incident atomic oxygen, extreme temperatures from −170 to +200 °C, etc. [13, 14]. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 79–85, 2021. https://doi.org/10.1007/978-3-030-54652-6_12

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The combined effect of these factors leads to the destruction of the polymer structure, the destruction of molecules, including their further crosslinking and recombination [15]. In this case, the properties of the polymer are significantly deteriorated. Atomic oxygen is one of the most negative cosmic factors in Earth orbit (altitude from 350 to 800 km above sea level). The incident flow of atomic oxygen carries particles off the surface of the polymers, causing enormous damage to the surface properties without affecting the deeper layers of the polymer [16–18]. Siliconcontaining substances are promising for protection against atomic oxygen. The interaction of silicon with highly reactive oxygen in space allows you to create a protective layer that prevents further penetration of oxygen particles into the polymer and thereby protecting it. This paper presents data on the study of a polyimide composite with tungsten (IV) oxide to the effects of atomic oxygen by adding crystalline silicon in an amount of 1%. Evaluation of the effectiveness of the use of this additive.

2 Methods and Materials As a binder for the polymer composite used thermoplastic polyimide grade PI-PR-20 manufactured by JSC Institute of Plastics named after G.S. Petrov, Moscow, Russia. The polyimide was a compression powder with a particle size of from 0.1 to 250 lm. To impart radiation protective properties necessary for use in space, the polyimide was filled with tungsten oxide WO2. WO2 was a black powder with a particle size of 0.1 to 25 lm. 65 wt% filler was used to create highly filled composites. As an additive (1 wt%) To the composite, finely dispersed crystalline silicon of the KR-00 grade 40 lm (manufacturer PPM Uralatomizatsiya LLC) with a specific surface of 5 m2/g was used. The mixing of all components (polyimide, WO2, crystalline silicon) in the required percentage ratio was carried out in a jet vortex mill for 30 min. The synthesis of highly filled composites was carried out by the hot method pressing the resulting mixture at a specific pressure of 80 MPa in a steel mold with constant heating and holding at a temperature of 350–360 °C. The crystal structure of the materials was investigated using X-ray diffraction (ARL X’TRA, ThermoTechno) with a CuKa source in the range of angles 4–56°(2h). For scanning electron microscopy, a TESCAN MIRA 3 LMU field emission electron microscope (TESCAN, Czech Republic) was used. Tests simulating the effect of atomic oxygen on composites in space were carried out by treating polyimide composites with oxygen plasma. Oxygen plasma was formed in a magnetoplasmodynamic accelerator. The pressure in the chamber was about 10−3 Pa, while the energy of atoms and oxygen molecules reached 35 eV.

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3 Results and Discussions The X-ray powder diffraction pattern of the used silicon additive is shown in Fig. 1. Using X-ray diffraction, it was found that the additive powder used has a pronounced crystalline structure (Fig. 1): intense reflections corresponding to cubic Si are recorded on the diffractogram (ICDD-ICPDS card No. 27-1402). The X-ray diffraction spectra (Fig. 1) clearly show peaks at 2h angles of 28.5°, 44.8°, characteristic of the (111), (220) silicon planes, respectively.

Fig. 1. X-ray powder diffraction pattern of used silicon

Figure 2 shows SEM images of the surface of a silicon powder at various magnifications. Particles are mainly in the form of cubic crystals whose sizes range from 0.5 to 2 microns. In addition, the presence of quasispherical particles with sizes of 100– 300 nm is noticeable in SEM images (Fig. 2).

Fig. 2. SEM image of the surface of the silicon additive

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To assess the effect of the addition of finely divided silicon powder on the resistance of the radiation-protective polyimide composite to the flow of oxygen plasma, two samples were prepared: 1 composition - polyimide: 35 wt%, WO2: 65 wt%. 2 composition - polyimide: 34 wt%, WO2: 65 wt%, silicon powder - 1 wt%. The samples were subjected to oxygen plasma treatment for 100 min., the fluence of oxygen atoms was 5 ∙ 1019 cm−1. Since the energy of oxygen atoms reached 35 eV, and in space the flow of incident particles of atomic oxygen has a much lower energy of 5 eV, the equivalent fluence was calculated for an energy of 5 eV. It amounted to 2 ∙ 1017 cm−2 ∙ s −1. An analysis of the quantitative characterization of the ablation of a polyimide composite with and without silicon under the influence of a free flow of oxygen plasma was estimated by the mass erosion coefficient Rm: Rm ¼ Dm/S/Fm

ð1Þ

where Dm is the mass loss, S is the area over which the mass loss is measured, Fm is the equivalent fluence. Table 1 presents the results of the specific mass loss and erosion coefficients of the polyimide radiation-protective composite with and without silicon. Table 1. Specific mass loss and erosion coefficients of composites Composite without Si with Si 42.6 Dm/S, 10−4 ∙ g/cm2 62.3 Rm, 10−21 g/atom O 31.1 21.3

Analysis of the data in Table 1 showed that the introduction of an additive of crystalline silicon in an amount of 1 wt%, can significantly reduce the mass loss of the composite when exposed to an oxygen plasma stream by 31.6%. Increasing the resistance of the composite to atomic oxygen upon administration crystalline silicon can be explained by the effect of self-healing intermolecular structure of the polymer. This effect is based on the possibility of capturing atomic oxygen particles by the interaction of Si and O with the formation of amorphous silica, filling micro-cracks and structural defects that arise in the polymer layer. The resulting SiO2 (silica) is resistant to oxidation and protects the polymer matrix from thermal degradation processes. To confirm this theory, studies were made on an electron scanning microscope. Figure 3a shows a SEM image of the surface of the original radiation protective composite before treatment with oxygen plasma. Particles of WO2 (light region) 1–4 lm in size are coated with thermoplastic polyimide (dark region).

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Fig. 3. SEM image of the surface of the polyimide composite before (a) and after treatment with oxygen plasma (b)

Also visible in the figure are smaller (lighter) particles of about 0.5 microns in size, which can be attributed to crystalline silicon (Fig. 3a). Figure 3b shows a fragment of a polymer composite after treatment with oxygen plasma. The dark region is a polymer (polyimide). It is noticeable that on top of the composite there is an increase in a new substance (highlighted in red in the figure).

Fig. 4. The results of x-ray dispersion microanalysis of the obtained compound

The energy dispersive analysis (Fig. 4) of the dense substance formed showed that, as expected, the compound consists of oxygen and silicon atoms. Thus, during the transition of Si to SiO2 (silica), the molar volume increases by almost 2 times, which leads to the “healing” of microdefects of the polymer structure resulting from the impact of incident atomic oxygen.

4 Conclusion The possibility of introducing an additive of finely dispersed silicon into a polyimide radiation-protective composite has been established. The introduction of an additive of crystalline silicon in an amount of 1 wt%, allows to reduce the mass loss of the composite when exposed to an oxygen plasma stream by 31.6%. The resulting silica is

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not subject to further oxidation, thereby protecting the polyimide matrix from oxidation and thermal degradation. Thus, the introduced fine silicon powder serves as a “trap” for trapping atomic oxygen. Acknowledgements. The work was supported by a project of the Russian Science Foundation (№19-19-00316) using equipment of High Technology Center at BSTU named after V G Shukhov.

References 1. Abramyan, S.G., Polyakov, V.G., Oganesyan, O.V.: External translucent coatings device with the use of glassprofite and composite materials. Constr. Mater. Prod. 2(4), 50–55 (2019) 2. Fetuhina, E.G., Sharova, N.V., Paraguzov, P.A.: Synthesis of moulded refractory products based on zeolite-bearing rocks and high-modulus silicates. Bull. BSTU named after V.G. Shukhov 2(12), 112–120 (2019) 3. Yastrebinsky, R.N., Bondarenko, G.G., Pavlenko, A.V.: Structural features of mineral crystalline phases and defectiveness of bismuth organo-siliconate crystals at high temperatures. Inorg. Mater.: Appl. Res. 5(9), 825–831 (2018) 4. Yastrebinsky, R.N.: Decrease gripping gamma–radiation scale composite neutron and protective material on the basis of the modified hydride of the titan with various content of atoms of bor. Probl. Atom. Sci. Technol. 4(110), 103–106 (2017) 5. Yastrebinsky, R.N., Pavlenko, V.I., Karnauhov, A.V.: Radiation resistance radiation– defensive the ferrous aggregates in the gamma fields. Probl. Atom. Sci. Technol. 2, 46–49 (2013) 6. Pavlenko, V.I., Yastrebinskii, R.N., Voronov, D.V.: Investigation of heavy radiation– shielding concrete after activation by fast neutrons and gamma radiation. J. Eng. Phys. Thermophys. 4(81), 686–691 (2008) 7. Pavlenko, V.I., Epifanovskii, I.S., Yastrebinskii, R.N., Kuprieva, O.V.: Thermoplastic constructional composite material for radiation protection. Inorg. Mater.: Appl. Res. 2(2), 47–52 (2011) 8. Yastrebinskii, R.N., Bondarenko, G.G., Pavlenko, V.I.: Radiation resistance of structural radiation-protective composite material based on magnetite matrix. Inorg. Materials: Appl. Res. 5(7), 718–723 (2016) 9. Pavlenko, V.I., Bondarenko, G.G., Yastrebinsky, R.N.: Attenuation of photon and neutron radiation using iron–magnetite–serpentinite radiation-protective composite. Inorg. Mater.: Appl. Res. 2(8), 275–278 (2017) 10. Yastrebinsky, R.N., Bondarenko, G.G., Pavlenko, V.I.: Radiation hardening of constructional cement–magnetite–serpentinite composite under gamma irradiation at increased dose. Inorg. Mater.: Appl. Res. 5(8), 691–695 (2017) 11. Yastrebinskii, R.N.: Attenuation of neutron and gamma radiation by a composite material based on modified titanium hydride with a varied boron content. Russ. Phys. J. 60(12), 2164–2168 (2018) 12. Pavlenko, V.I., Lipkanskij, V.M., Yastrebinskii, R.N.: Calculations of the passage of gamma-quanta through a polymer radiation-protective composite. J. Eng. Phys. Thermophys. 1(77), 11–14 (2004) 13. Zeynali1, O., Masti, D., Gandomkar, S.: Shielding protection of electronic circuits against radiation effects of space high energy particles. Adv. Appl. Sci. Res. 3, 446–451 (2012)

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14. Howard, J.W., Hardage, D.M.: Spacecraft Environments Interactions: Space Radiation and Its Effects on Electronic Systems, NASA/ TP-1999–209373 (1999). 36 p. 15. Ghosh, L., Fadhilah, M.H., Kinoshita, H., Ohmae, N.: Synergistic effect of hyperthermal atomic oxygen beam and vacuum ultraviolet radiation exposures on the mechanical degradation of high-modulus aramid fibers. Polymer 47(19), 6836–6842 (2006) 16. Samwel, S.W.: Low earth orbital atomic oxygen erosion effect on spacecraft materials. Space Res. J. 7, 1–13 (2014) 17. Shuvalov, V.A., Kochubei, G.S., Priimak, A.I., Pismennyi, N.I., Tokmak, N.A.: Changes of properties of the materials of spacecraft solar arrays under the action of atomic oxygen. Cosmic Res. 45, 294–304 (2007) 18. Tagawa, M., Yokota, K.: Atomic oxygen-induced polymer degradation phenomena in simulated LEO space environments: how do polymers react in a complicated space environment? Acta Astronaut. 62(2–3), 203–211 (2008)

Reactivity of the Clay Component of Rocks at the Incomplete Stage of Mineral Formation to Lime During Autoclave Processing A. N. Volodchenko(&)

and V. V. Nelyubova

Belgorod State Technological University named after V G Shukhov, Belgorod, Russia [email protected]

Abstract. High reactivity to lime in the conditions of autoclave processing of clay loam component of the Lebedinsky field, morillonite-hydro micaceousquartz clay and opoka clay, which belong to the rocks of the incomplete stage of mineral formation. The peculiarity of these deposits is the presence of thermodynamically unstable compounds, such as hydro mica, mixed-layer formations, and x-ray amorphous phase formed as a result of processes of disintegration of the crystal structure of the source minerals due to weathering processes. Such rocks make up the majority of clay deposits and are widely distributed on the territory of the Russian Federation and in many states of the world. According to the results of these kinetic studies the features of phase formation in the system “CaO–SiO2–Al2O3–H2O” on the basis of clay component of rocks at the incomplete stage of mineral formation are found out, consisting in the intensification of the synthesis of gel-like and crystalline cementing compounds, such as low-base and high-base calcium hydro silicates, alumina-containing tobermorite and hydrogranates. It is shown that due to the polymineral composition of the clay component, the synthesis of different new formations proceeds in different time periods, which reduces the number of microdefects and accelerates the formation of a cementing substance of a rational microstructure. The clay component of rocks at the incomplete stage of mineral formation can be used as a component of the raw material mixture to produce effective silicate materials using energy-saving technology. Keywords: Clay rocks
Clay component Interaction kinetics
Reactivity


Lime
Autoclave processing


1 Introduction Currently, the urgent task is to expand the raw material base of autoclave silicate materials, for which lime and quartz sand are used as traditional raw materials, which provide the synthesis of new formations in the “CaO–SiO2–H2O” system [1, 2]. One of the promising raw materials is polymineral clay rocks, which are widely distributed both on the territory of the Russian Federation and in many countries of the world [3– 6]. The synthesis of new formations in silicate materials based on polymineral clay rocks occurs in the “CaO–SiO2–Al2O3–H2O” system, which forms a more complex © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 86–91, 2021. https://doi.org/10.1007/978-3-030-54652-6_13

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composition of the cementing substance. This increases the physical and mechanical properties of silicate materials and reduces energy costs for production, which allows obtaining a wide range of autoclave building materials [7–9]. Clay rocks are formed by weathering of igneous and metamorphic rocks. At the final stage of weathering, depending on the conditions, kaolinite or montmorillonite clays are formed. However, most of the clay rocks are represented by deposits formed during the intermediate stages of weathering and they are related to as rocks of the incomplete stage of mineral formation. These rocks differ in the disordered crystal structure of the source minerals, which increases their thermodynamic instability and, consequently, their reactivity [10]. One of the important factors in the intensification of the production of silicate materials is the rate of interaction of lime with the components of clay rocks and, accordingly, the rate of synthesis of new formations. This determines the criteria for the effectiveness of product manufacturing technology. The clay component has the highest reactivity, which is determined by the high dispersion of clay minerals and their layered structure [11]. The aim of this work is to study the reactivity of clay rocks of various deposits to lime in hydrothermal conditions.

2 Methods and Materials The reactivity of the clay component of rocks at the incomplete stage of mineral formation was evaluated using the kinetics of CaO absorption under autoclave processing. In research the fraction with particle size less than 0.005 mm, obtained by elutriation of clay deposits of KMA was used: loam of the Lebedinsky field, morillonite-hydro micaceous-quartz clay and opoka clay. By chemical composition, these rocks are classified as acidic with a high content of free silica (Table 1). The clay component of the studied rocks is represented by hydro mica (reflexes 10.00; 4.84–5.00; 3.32 Å), mixed–layer minerals, x–ray amorphous phase, fine-disperse quartz (reflexes 4.27; 3.34; 2.455 Å), imperfect structure with kaolinite (reflexes 7.138; 3.56 Å) and montmorillonite (reflexes 14,347 – 14.36; 4,484-4,493; 2.55 Å) (Fig. 1). Opoka clay also contains amorphous silica - opal. Table 1. Chemical composition of clay rocks Rock Opoka clay Morillonite-hydro micaceous-quartz Loam of the Lebedinsky field

Al2O3 Fe2O3 TiO2 CaO MgO Na2O K2O p. Amount m.a. 72,64 11,87 4,38 0,81 0,62 0,78 0,24 1,70 6,02 99,06 64,67 12,05 4,56 0,86 4,62 1,11 0,72 1,75 7,80 98,14

SiO2

66,97 12,75 5,33

0,92 4,38 1,20

0,44

1,60 6,34 99,93

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Fig. 1. Radiographs of clay rocks: 1 - opoka clay; 2 - morillonite-hydro micaceous-quartz; 3 loam of the Lebedinsky field

In experiments, CaO of the “XCH” brand was used, pre-burned at 1000 °C. Samples were pressed from clay-lime mixtures and subjected to autoclave processing at different times. The amount of absorbed CaO was calculated from the difference between the total content of calcium oxide in the raw material mixture and free one, i.e., not react after autoclaving.

3 Results and Discussion On the basis of the clay component of the loam of the Lebedinsky field, morillonitehydro micaceous-quartz clay and opoka clay, clay-lime mixtures were prepared, from which samples were obtained by semi-dry pressing. The lime content was 0.84 g/g of clay, which corresponds to the maximum absorption of CaO (30 mEq/g of clay) by monomineral clays – kaolinite and montmorillonite [11]. The kinetics of CaO absorption by the clay component was studied under autoclave processing at 160 °C (Fig. 2). The nature of lime absorption by the clay component of the studied rocks, as well as by monomineral clays, indicates that this process is most intensive in the first 20– 30 min of hydrothermal treatment. This is due to the reaction occurring mainly in the kinetic region. With an increase in the number of new formations, the interaction process moves to the diffusion region. At the same time, the rate of CaO absorption slows down and then remains constant. Montmorillonite, which has a three-layer structure, interacts more actively with calcium oxide than kaolinite, which consists of two-layer packages. The absorption kinetics of calcium oxide in the clay component of the loam of the Lebedinsky field, morillonite-hydro micaceous-quartz clay and opoka clay indicates a higher reactivity in comparison with kaolinite and montmorillonite (see Fig. 1). This is due to the presence of minerals in the intermediate stage of weathering. Hydro mica formed in the second stage of weathering of rocks, like montmorillonite, relates to three-layer minerals. In mixed-layer minerals, the multi-layer structure alternates between disordered layers of

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Fig. 2. Kinetics of CaO absorption of the clay component of rocks: 1 - kaolinite; 2 montmorillonite; 3 - loam of the Lebedinsky field; 4 - morillonite-hydro micaceous-quartz; 5 opoka clay

silicates and aluminum silicates. The degree of structural disorder of such minerals is significantly higher than the initial rocks and products of the final stage of weathering (monomineral clays). This causes the thermodynamic instability of rocks in the incomplete stage of weathering and, consequently, their high reactivity. The reaction of lime with clay minerals occurs in the “CaO–SiO2–Al2O3–H2O” system. In the interaction of lime and kaolinite in conditions of autoclave processing hydrogranates and slight crystallizing hydro silicates of calcium are synthesized. Montmorillonite clay promotes the formation of mostly low essential calcium hydro silicates and hydrogranates. This specificity of phase formation is associated with the different structure and composition of clay minerals [11, 12]. The presence of an incomplete stage of mineral formation in clay rocks of thermodynamically unstable clay minerals, x-ray amorphous phase, and fine-dispersed quartz determines not only the high reactivity of the studied raw materials, but also the synthesis of different types of new formations. A feature of phase formation in the system based on the studied raw materials is the intensification of the synthesis of both gel-like and crystalline cementing compounds, such as low-base and high-base calcium hydro silicates, tobermorite and hydrogranates. Well crystallized tobermorite formations in traditional lime-sand materials are synthesized under conditions of long-term isothermal aging in an autoclave. In raw materials mixtures based on the studied clay raw materials, due to the high reactivity of rock-forming minerals, the phase formation time is significantly reduced.

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Fig. 3. New formations based on the clay component of rocks at the incomplete stage of mineral formation, SEM, 6000: a – loam of the Lebedinsky field; b – opoka clay

After 3 h of autoclave processing at 160 °C, the formation of tobermorite is observed in the new formations (Fig. 3). Due to aluminum, which is a part of clay minerals, it is possible to form aluminumcontaining tobermorite, as it is known that silicon ions in the structure of the tobermorite crystal lattice can be replaced by aluminum ions [13–15]. The crystalline phases are a micro-filler in the submicrocrystalline weight of low-essential calcium hydro silicates, optimizing the composition of the cementing substance. The polymineral and polydispersed composition of the system and, accordingly, the different degree of activity of rock-forming minerals leads to the synthesis of various reaction products in different time periods. This reduces the number of microdefects that appear as a result of crystallization pressure, accelerates the synthesis and formation of a cementing substance of a rational microstructure.

4 Conclusions Thus, a high reactivity to lime in the conditions of autoclave processing of clay loam component of the Lebedinsky field, morillonite-hydro micaceous-quartz clay and opoka clay, which belong to the rocks of the incomplete stage of formation. The peculiarity of these rocks is the presence of thermodynamically unstable compounds, such as hydro mica, mixed-layer formations, and x-ray-amorphous phase formed as a result of the disintegration of the crystalline structure of the source minerals due to exogenous weathering processes. The specificity of phase formation in the “CaO– SiO2–Al2O3–H2O” system based on the clay component of rocks at the incomplete stage of mineral formation is to intensify the synthesis of gel-like and crystalline cementing compounds, such as low-base and high-base calcium hydro silicates, tobermorite and hydrogranates. It is also possible to replace aluminum ions in the structure of the tobermorite crystal lattice with silicon ions to form aluminumcontaining tobermorite. The different degree of activity of rock-forming minerals leads to the fact that the synthesis of different types of new formations occurs in different

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periods of time. This reduces the number of microdefects resulting from crystallization pressure, accelerates the formation of a cementing substance of a rational microstructure. The clay component of rocks at the incomplete stage of mineral formation can be used as a component of the raw material mixture to produce effective silicate materials using energy-saving technology. Acknowledgements. This work was realized in the framework of the Program of flagship university development on the base of the Belgorod State Technological University named after V G Shukhov, using equipment of High Technology Center at BSTU named after V G Shukhov.

References 1. Hvostenkov, S.I.: On the chemistry of the interaction process in the Ca(OH)2–SiO2–H2O system under hydrothermal synthesis conditions. Build. Mater. 5, 76–81 (2008) 2. Klimesch, D., Ray, A.: Evaluation of phases in a hydrothermally treated CaO–SiO2–H2O system. J. Therm. Anal. Calorim. 70(3), 995–1003 (2002) 3. Lesovik, V.S., Volodchenko, A.A., Svinarev, A.A., Kalashnikov, N.V., Rjapuhin, N.V.: Reducing energy intensity of production of non autoclave wall materials. World Appl. Sci. J. 31(9), 1601–1606 (2014) 4. Lesovik, V.S.: Geonics (geomimetics). Examples of application in building materials science, Belgorod (2014) 5. Volodchenko, A.A., Lesovik, V.S., Volodchenko, A.N., Zagorodnjuk, L.H.: Improving the efficiency of wall materials for «green» building through the use of aluminosilicate raw materials. Int. J. Appl. Eng. Res. 10(24), 45142–45149 (2015) 6. Alfimova, N.I., Pirieva, S.Yu., Gudov, D.V., Shurakov, I.M., Korbut, E.E.: Optimization of receptural-technological parameters of manufacture of cellular concrete mixture. Constr. Mater. Prod. 1(2), 30–36 (2018) 7. Volodchenko, A.N., Lukutsova, N.P., Prasolova, E.O., Lesovik, V.S., Kuprina, A.A.: Sandclay raw materials for silicate materials production. Adv. Environ. Biol. 8(10), 949–955 (2014) 8. Lesovik, V.S., Leshchev, S.I., Ageeva, M.S., Alfimova, N.I.: Zeolite-containing terra-silicea as a component of composite binders. Mater. Sci. Forum 974, 136–141 (2019) 9. Volodchenko, A.N.: Aluminosilicate raws material for produce autoclave finishing materials. Bull. BSTU Named After V.G. Shukhov 2, 172–177 (2017) 10. Volodchenko, A.N., Strokova, V.V.: Development of scientific bases for production of silicate autoclave materials using clay raw materials. Build. Mater. 9, 25–31 (2018) 11. Lesovik, V.S.: Improving the efficiency of production of building materials taking into account the genesis of rocks. Publisher ASV (2006) 12. Volodchenko, A.N.: Monomineralic clay interaction with calcium hydroxide under hydrothermal conditions. In: The Proceedings of World, vol. 30, pp. 35–38 (2012) 13. Fedin, A.A.: Scientific and technical fundamentals of the production and use of silicate cellular concrete. Publisher GASIS (2002) 14. Matsui, K., Ogawa, A., Kikuma, J., Tsunashima, M., Ishikawa, T., Matsuno, S.: In situ timeresolved X-ray diffraction of tobermorite formation process under hydrothermal condition: influence of reactive Al compound. Powder Diffr. 26(2), 134–137 (2011) 15. Carlos, A., Craig, D., Fullen, M.: Hydrothermal synthesis of hydrogarnet and tobermorite at 175 °C from kaolinite and metakaolinite in the CaO–Al2O3–SiO2–H2O system: a comparative study. Appl. Clay Sci. 43(2), 228–237 (2009)

Examination of the Safety of the Centrifuge Site of a Sugar Factory in the Belgorod Region in Order to Assess the Technical Condition of Structures I. R. Serykh(&)

, E. V. Chernysheva

, and A. N. Degtyar

Belgorod State Technological University named after V.G. Shukhov, Belgorod, Russia [email protected]

Abstract. The structure integrity is affected equally adversely by both the defects revealed as a result of builders and designers’ negligence and those that appeared during operation, even to a greater extent. During the survey violations of the integrity of bearing and enclosing structures are detected, which can lead to emergency situations. Unfortunately, not all types of damage can be detected with the naked eye. The detected defects make it possible to predict the behavior of structures during their operation and allow determining the suitability of the entire building structure for further use. The object of the survey is a centrifuge platform at the sugar factory of the Belgorod region. The non-implementation of previously recommended measures and the ongoing process of corrosion and deformation destruction of building structures caused doubt about the safety of certain structural components of the platform, which ultimately led to the conduct of these surveys. Keywords: Defects structures


Damages
Building wear
Corrosion
Reliability of

1 Introduction During the buildings construction and operation, structural elements can be damaged, which should be identified in time, as well as proper measures should be taken to eliminate the damages in order to guarantee the reliability, durability, safety and survivability of the building [1–10]. During the survey violations of the integrity of bearing and enclosing structures are detected, which can lead to emergency situations [11, 12]. Unfortunately, not all types of damage can be detected with the naked eye. Moreover, it is often very difficult to identify technical discrepancies without special expertise. The detected defects make it possible to predict the behavior of structures during their operation and allow determining the suitability of the entire building structure for further use. The results of the expertise determine specific measures to eliminate errors and inconsistencies made during construction, as well as identify the defects that the object acquired after substantial completion. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 92–99, 2021. https://doi.org/10.1007/978-3-030-54652-6_14

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The structure integrity is affected equally adversely by both the defects revealed as a result of builders and designers’ negligence and those that appeared during operation, even to a greater extent. Any defects carry a risk of varying severity. The defects of the first group lead to a threat of collapse, deformation, loss of the frame integrity and as a result - an emergency. The second group allows the structure to remain intact, but the load-bearing capacity is reduced. The result is that the facility cannot be used for its intended purpose. With the third group of defects the building remains intact and exploitable, but its maintenance requires extra repair costs. In order to prevent them from growing into a more dangerous group, periodic inspection of such building structures should be carried out and measures should be taken timely to eliminate defects. According to the results of the survey, depending on the extent of damage the degree of reduction in the load-bearing capacity of structural elements is detected, then the possibility of its restoration is determined. If the extent of damage is minor (less than 5%), further use of the facility is allowed; if it is weak (up to 15%), the facility needs repair and reinforcement of damaged structures; if it is average (up to 25%), major overhaul and reinforcement are required; if it is severe (up to 50%) – major repairs must be accompanied by a replacement of certain construction components. The facilities, the load-bearing capacity of which decreased by more than 50%, are subject to dismantling, since further safe operation is not possible due to the risk of collapse. The object of the survey is a centrifuge platform at the sugar factory of the Belgorod region that was put into service in 1962. It included seven centrifuges of the first product, three centrifuges of the second product and five centrifuges of the third product. The facility was operated continuously until the end of January, 2006. In the same year partial overhaul was carried out at the factory and the coating was reconstructed. However, the non-implementation of previously recommended measures and the ongoing process of corrosion and deformation destruction of building structures caused doubt about the safety of certain structural components of the platform, which ultimately led to the conduct of these surveys. Thus, the reason for the survey was the non-compliance of the structures with the requirements of normal operation of the building and their physical deterioration. The purpose of the building survey is to determine the technical condition of reinforced concrete and metal building structures of the centrifuge platform of the sugar factory main building to identify defects and develop recommendations for the factory repair in order to ensure its safe and long-term operation.

2 Methods and Materials The choice of methods for restoring operational qualities and reconstructing damaged parts of the centrifuge platform is determined by a qualitative assessment of their technical condition based on scientific diagnostics. The diagnostics allows studying and identifying the signs and causes of damage, as well as developing ways and means for their analysis and evaluation. In this case it is necessary to rely on the standard values and acceptable deviations of technical condition parameters.

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To reveal the actual conditions of the structures service, as well as the factors determining the destruction, the diagnostics of damages involved determination of the properties of the materials used, the specific features of their manufacturing, installation and operation of the building structures, as well as external and technological influences on them. The following methods were used to assess physical deterioration and corrosion of building structures: – method of visual determination of physical deterioration of the centrifuge platform structures by external signs; – method of instrumental assessment of centrifuge platform structures condition with the use of diagnostic devices – method of engineering analysis of diagnostic data in order to draw conclusions about the technical condition of buildings and measures for their maintenance, restoration, improvement and repair. The survey included: – field survey of building structures by inspection, measurements and special instrumental methods; – determination of structural materials properties and the quality of joints; – clarification of actual loads, impacts and operating conditions with registration of dimensional drawings and diagrams, lists of defects and other necessary materials. The work on evaluating the technical condition of building structures involved verification calculations taking into account the defects and damages detected during the survey, the actual properties of materials, predicted loads, impacts and operating conditions. These calculations allow finding ways to use the reserves of load-bearing capacity of reinforced concrete and metal structures on the basis of theoretical and experimental studies of structures, taking into account their actual operation, updated data on the design scheme, loads and strength characteristics of materials. The program of works for the expertise of technical condition of the structures of the sugar factory centrifuge platform included: 1. Analysis of project, executive and operational documentation. 2. On-site inspection of building structures and components. – external inspection of all structural components of the site; – internal inspection of load-bearing structures; – assessment of the technical condition of building structures. 3. Instrumental survey of platform structures. – determination of durability and condition of materials with the use of nondestructive testing methods, sampling and laboratory testing; – measurements of temperature and humidity and operational parameters of heat and dust release of the environment in case of non-compliance with the design operating mode and lack of data on the actual mode.

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4. Verification calculations of load-bearing structures taking into account the detected defects and damages. 5. Determining the causes of damage. 6. Making conclusions based on the results of surveys of the structures technical condition, development of recommendations for their operation.

3 Results and Discussions During the field surveys of the centrifuge platform structures the conditions of their operation, types, degree and nature of adverse effects, defects and damages were studied. Examination of metal beams under the technological equipment showed that, judging by their physical deterioration, they had been in a fairly aggressive environment (Fig. 1). Basically, the components of building steel structures were operated in the open air for a long time without proper care for them. There are traces of old paint in some places. In fact, all the surfaces of steel structures were covered with a bedded layer of rust and ulcerative corrosion, so the geometric characteristics of the sections of rolled profiles were lower than the design values. The quality of the metal frame welding also prompted questions: incompleteness of the welds, slag inclusions, nonwelding, interruption of the welding seam, abrupt transitions from the main metal to the surfaced one and drips.

Fig. 1. Condition of metal structures of the centrifuge platform

When examining reinforced concrete beams, in a number of cases the destruction of the tensile zone of the concrete in combination with reinforcement uncovering and corrosion was revealed (Fig. 2). As for the other beams, the protective layer of concrete was detached in a tensile zone, which was accompanied by exposing the longitudinal principal reinforcement. The thickness of the protective layer in the areas of damage was 0–4 mm instead of 25 mm according to the requirements of the project and current standards. The reinforcement corrosion was observed only on the lower surface and did not exceed 0.2 mm. The beams had vertical cracks. Spots of gray and dark colors were observed on the entire surface of the beams, which indicate the formation of mold due to excessive humidity in the area.

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Fig. 2. Condition of reinforced concrete structures of the centrifuge platform

The monolithic reinforced concrete sections were in a dilapidated state. The concrete of the tensile zone was completely destroyed (Fig. 2), the principal reinforcement was uncovered and had traces of deep corrosion, which, as in the case of reinforced concrete beams, was the result of dampening of building structures and insufficient size of the protective layer of concrete, the impact of vibration loads, as well as poor-quality dismantling of previously installed equipment. To predict the durability of steel and reinforced concrete structures, it is important to know both the speed and the nature of corrosion damage. For metal structures local corrosion is particularly dangerous, since it causes stress concentration in addition to weakening of cross section, which in turn increases the probability of brittle steel destruction and, consequently, the probability of an emergency state of structural components under planned loads after the reconstruction. The most dangerous damage to monolithic reinforced concrete floors is the corrosion of reinforcement with the concrete cover peeling. The process of such corrosion destruction is as follows. If the protective layer is insufficient or not dense, there is relatively free access of oxygen to the reinforcement. As a result, it corrodes, especially in places of humidification. Reinforcement corrosion products (rust) by volume are 2–3 times more than steel. They force aside the concrete and cracks form in the protective layer. The corrosion process becomes more intense, the cracks in concrete open, the protective layer peels off and crumbles and the reinforcement is exposed. The presence of process vapors in the air contributes to the development of corrosion processes. Such corrosion damages to reinforced concrete structures are dangerous for several reasons. First of all, due to corrosion the cross-section area is reduced and it takes much less effort. Besides, stresses are concentrated in places of corrosive cavities and intergranular cracks, the reinforcement reduces its strength characteristics, loses plasticity. Its destruction is characterized by a brittle rupture. Finally, when cracking and, especially, peeling off the concrete protective layer, its adhesion to the reinforcement is violated, which can lead to the destruction of the structure because of its pulling. As a result of monitoring the durability of concrete with the use of field nondestructive methods, it was found out that the durability of concrete was reduced by 30– 35% in places of leaching out, which depended on the degree of damage. Selective uncoverings showed that corrosion of concrete structures reinforcement occurs, as a rule, from the lower (tensile) surface (zone). In some places the degree of damage to beams and monolithic sections reaches 90% of the surface. In places where

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the protective layer of concrete is detached, the depth of reinforcement corrosion is 0.5–6 mm, which is a quite significant damage. When assessing the technical condition of the centrifuge platform structures, the nature, degree of development and danger of defects and damages, the possibility of their further development, the actual load-bearing capacity and safety of structural components, their predicted durability, the degree of responsibility of individual elements in the structural scheme of the building, the scope of physical and moral wear of building structures, as well as a number of other factors, were taken into account. For this purpose the structural design of the building was analyzed, the loads and impacts before and after reconstruction were evaluated taking into account the operating conditions, the impact of dynamic loads associated with the action of centrifuges, the necessary physical and mechanical properties of materials were checked, checking static and structural calculations were carries out. The calculations related to metal structures showed that their durability was insufficient at the existing level of corrosion damage. Intensively developing corrosion processes led to a decrease in the cross-section area and collapse of damaged sections. Physical depreciation of metal beams is in the range of 70–75%, which excludes their further operation. In other words, the technical condition of metal structures with corrosion damage should be considered unsatisfactory, the existing reserves of loadbearing capacity are completely exhausted. Thus, the beams should be dismantled. The calculation related to reinforced concrete beams showed that, despite the relatively large areas of corrosion damage to the reinforcement, their durability is sufficient. However, the existing corrosion processes will continue to develop intensively, which will lead to a further decrease in the reinforcement cross-section area and the collapse of damaged sections. Physical depreciation of reinforced concrete beams is in the range of 50–55%, which allows them to be used, but only after reinforcing. Depending on the degree of destruction the technical condition of damaged ironconcrete beams, with some exceptions, is satisfactory. Calculations related to the reinforced concrete monolithic sections showed complete exhaustion of load-bearing capacity, so it was proposed to dismantle them and replace them with a lightweight floor covering on profiled flooring. Other defects and damages of building structures and components that are detected during field surveys do not significantly affect their durability, reinforcement and crack resistance, but they worsen other operational qualities and must be eliminated. The technical condition of such structures should be considered satisfactory and in need of optional minor maintenance. In general taking into account the volume and risk of defects and damage, the degree of physical and moral wear of structures and a number of other factors, the loadbearing structures of the sugar factory centrifuge platform can be considered unsatisfactory – for metal structures, quite satisfactory – for reinforced concrete structures, and the building – suitable for further operation after reconstruction.

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4 Conclusions As a result, the survey showed that the existing damage occurred due to the long-term influence of a highly aggressive environment associated with the specifics of the technological processes organized in the premises of the sugar factory’s centrifuge platform under investigation. All damages are of a corrosive nature, the causes of which are constant soaking of building structures with aggressive technological liquids spilled from containers, malfunction of the shut-off valves, as well as violations of the climatic regime of the area. Therefore, to prevent further destruction of the building structures it is necessary to exclude them from operation process. The total wear and tear of the building is 80% and its technical condition was assessed as unsatisfactory. Most of the bearing structures of the sugar factory’s centrifuge platform are not fully operational and need restoration or improvement of their operating conditions. It is recommended to remove some of the reinforced concrete beams placed under the centrifuge platform. As for the other beams, the option of their reinforcement with metal angles and batten plates of strip steel is suggested. Before reinforcing it is recommended to restore the concrete beams to the design value by pretreating the uncovered reinforcement steel with a rust penetrating solvent. The metal structures of the centrifuge platform and the destroyed monolithic sections of the floor should be removed with their subsequent replacement. The analysis of defects that were detected during the survey indicates that most of them are dangerous and can cause damage to some building structures independently or in combination with other defects. Therefore, normal operation of the facility for its intended purpose without restrictions is possible only after the implementation of all recommendations for their elimination and restoration of damaged load-bearing components. Acknowledgements. This work was realized in the framework of the Program of flagship university development on the base of the Belgorod State Technological University named after V G Shukhov, using equipment of High Technology Center at BSTU named after V G Shukhov.

References 1. Travush, V.I., Kolchunov, V.I., Klyueva, N.V.: Some directions of development of the theory of vitality of structural systems of buildings and structures. Ind. Civ. Eng. 3, 4–11 (2015) 2. Mirsayapov, I.T., Tamrazyan, A.G.: To the development of scientific foundations of the theory of endurance of reinforced concrete structures. Ind. Civ. Eng. 1, 50–56 (2017) 3. Shutova, M.N., Evtushenko, S.I.: Calculating residual building life using probabilistic methods and graph theory. Constr. Mater. Prod. 2(5), 5–12 (2019) 4. Klyueva, N.V., Kolchunov, V.I., Gubanova, M.S.: Strength criterion of loaded and corrosion damaged concrete at flat stressed state. Hous. Constr. 5, 22–27 (2016) 5. Kolchunov, V.I., Klyueva, N.V., Androsova, N.B., Buxtiyarova, A.S.: Living Capacity of Buildings and Structures Under Beyond Design Basis Impacts: Monograph, p. 209. DIA Publishing House, Moscow (2014)

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6. Mirsayapov, I.T., Tamrazyan, A.G.: To calculation of reinforced concrete structures for endurance. Ind. Civ. Eng. 11, 19–23 (2016) 7. Chernysheva, E.V., Serykh, I.R., Statinov, V.V., Chernysheva, A.S.: Actual problems of industrial safety. In: Zbornik radova: visoka tehnička škola strukovnih studija, Niš, Serbia, pp. 164–165, December 2016 8. Degtyar, A.N., Serykh, I.R., Panchenko, L.A., Chernysheva, E.V.: Residual life of structures of buildings and structures. Bull. BSTU named after V.G. Shukhov 10, 94–97 (2017) 9. Serykh, I.R., Chernysheva, E.V., Degtyar, A.N., Chernositova, E.S., Chernysheva, A.S.: Industrial safety examination of the building of the VZhS Shebekinsky chemical plant in order to assess the technical condition of structures. Bull. BSTU named after V.G. Shukhov 9, 55–61 (2018) 10. Degtyar, A.N., Serykh, I.R., Chernysheva, E.V., Panchenko, L.A.: Examination of industrial safety of the pump tank farm building of the Belgorod region in order to assess its residual life. In: Safety in Construction: Materials III International Science-Practice Conference, St. Petersburg, 23–24 November 2017, pp. 41–45. Izd-vo Spbgasu, St. Petersburg (2017) 11. Alferov, D.L.: Causes of buildings and structures accidents. Tech. Superv. 6(79), 78–81 (2013) 12. Lapina, A.P., Ponomarenko, A.V., Shenczova, K.V., Kotesova, A.A.: Analysis of the causes of accidents at different stages of the life cycle of the construction object. Constr. Mater. Prod. 2(2), 17–22 (2019)

Tape System for Damping Vibrations of Mesh Domes with a Central Mount for Seismic Impacts A. I. Shein

and A. V. Chumanov(&)

Penza State University of Architecture and Construction, Penza, Russia [email protected]

Abstract. This article describes a tape system for damping vibrations of mesh domes with central reference points during seismic impacts. Based on the forms of the locator’s own vibrations at low frequencies, the effective location of the vibration dampener was selected. A program for dynamic calculation of dometype mechanical systems based on the method of central differences has been developed. A mathematical model of a mechanical system with a vibration dampener based on the differential equation of vibrations taking into account the tension forces of the belts and the resistance to unwinding of the belts in inertial coils. A series of numerical experiments has been carried out, which has shown the high efficiency of the tape vibration damping system. With this arrangement of the dampener and the accepted model of vibration damping, the most significant parameter of damping is the force of the beginning of unwinding of the coils. Analysis of the graphs presented above shows that it is the parameter N that provides the greatest damping effect. In this example, for a locator with an outer ring radius r = 10 m, the maximum decrease in the oscillation amplitude (by 40–50%) gives the parameter value N = 900 N at b = 750 kg/s. Keywords: Tape system
Vibration damper
Dynamic calculation vibrations
Seismic load
Damping
Inertia coil


Dome

1 Introduction Vibration damping is one of the most important tasks of designing buildings and structures that are subject to such natural influences as seismic and pulsating wind. Currently, various types of dampers have been developed and optimized, of which the most common are Tuned Mass-Damper [1–3], Tuned Mass Column Damper [4, 5], used mainly for high-rise buildings. Vibration damping can also be achieved using composite polymer materials [6], friction vibration dampers [7], roller systems [8], etc. In [9, 10], new methods of damping vibrations of various structures were studied: frame frames using plastic overlays on frame elements, as well as steel towers using reactive vibration dampers. In [11], a new method for dampening the vibrations of locator elements from an air shock wave using a tape system was proposed. Locators are structurally related to cyclic symmetric carrier systems. The study of eigenvalue forms of cyclically symmetrical dome-type structures has shown that at low frequencies corresponding to the first two eigenvalue frequencies, bending (the first © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 100–107, 2021. https://doi.org/10.1007/978-3-030-54652-6_15

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form of vibrations) and torsional forms of deformations (the second form of vibrations) occur. In this case, the bending occurs along the axis in the direction of which the stiffness of the mechanical locator system is the smallest. For torsion forms of deformations, rotation occurs relative to the Central axis of symmetry of the dome structure, or the locator structure. This article discusses the operation of a tape system for dampening locator vibrations in seismically dangerous areas, i.e. under seismic influence. To increase the elastic modulus of the belts, we use their reinforcement with oriented glass fibers (fiberglass). They have as a filler long glass fibers laid naturally in separate strands, which gives the fiberglass high strength, and the tapes-high longitudinal stiffness and increased strength. In addition, the elastic modulus of the belts can be significantly increased using continuous high-strength and high-modulus boron fibers in the polyester tape matrix, or carbon fiber based on continuous high-strength and highmodulus carbon fibers. They are also characterized by low density, high strength, high modulus of elasticity, vibration resistance.

2 Methods and Materials 2.1

Description of the Extinguisher

Seismic effects are characterized by vibrational movements of the ground, creating kinematic excitation of vibrations of the studied dome. This circumstance required adjustment of the basic scheme of operation of the dome vibration dampener. When modeling the operation of the vibration dampener on the impact of an air wave, described in the article [11], it was assumed that it was activated after changing the direction of movement of the points of attachment of the belts in the section of the maximum diameter. The application of the principle of operation of the tape system in the form of two mutually perpendicular, diametrically located lines of maximum radius, used in [11], showed that due to the high frequency of seismic vibrations, the mechanism for stopping the unwinding of the tape is not an effective method of damping (there was no noticeable decrease in the amplitude of vibrations on the oscillation charts). Therefore, in this work, firstly, applied and studied tape system with Central locking strips (Fig. 1), and secondly made the transfer to another algorithm of the tape system: the algorithm that provides the damped oscillations In the places of fastening tape equipped with reels, the unwinding of which is carried out when the forces of the tension belts some specific values. When unwinding the tape in the coils, there are forces of resistance to movement, proportional to the speed of unwinding. We assume that when the distance between the points of attachment of the tape increases, the mechanism of unwinding the tape does not start working until the force in the tape reaches a certain value N. In order for the process of quenching vibrations to begin immediately, it is necessary to install pre-tensioners in the inertia coils, designed to wind the tape and stretch it until the longitudinal force in the tape takes the value of N. During the unwinding of the tape, a force of resistance to unwinding occurs in the coil, proportional to the speed of change in the distance between the opposite points of attachment of the tape (proportionality coefficient b).

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Fig. 1. Scheme of installation of tapes and coils

2.2

Building a Numerical Experiment

The finite element method was used in the numerical experiment. The movement of the mechanical dome-tape-coil system was described by a differential equation of the form: € þ BU_ þ KU ¼ PðtÞ; MU

ð1Þ

M – the diagonal mass matrix; U – the displacement vector; B – the damping matrix (matrix of the resistance movement); K – the stiffness matrix of the system; P(t) is the vector of nodal loads equal to the product of the acceleration value for a given accelerogram (Fig. 2) of the earthquake by the mass of the corresponding node.

Fig. 2. Accelerogram of the 1976 earthquake in Gazli

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When determining the movements of the dome nodes at each time the method of Central differences was used: € t ¼ Ut þ Dt  2
Ut þ UiDt ; U ðDtÞ2

Ui þ Dt  UiDt ; U_ t ¼ 2Dt

ð2–3Þ

Ut þ Dt - moving to the next moment in time, m; Utt - moving at a given time, m; UtDt - moving to the previous time, m; Dt - time step, s In the case of known initial conditions Ut ¼ 0; UtDt ¼ 0

ð4–5Þ

we determine the movement in subsequent moments of time: "

Ut þ Dt

#1 " # B M
ðUtDt  2Ut Þ B
UiDt ¼ þ
Pt  K
Ut  þ ð6Þ 2
ðDtÞ ðDtÞ2 2
ðDtÞ ðDtÞ2 M

The conditions for entering the vibration dampener into the calculation are as follows: If

li þ 1  li [ 0

then

  li þ 1  li Pi ¼ PðtÞi  N þ b
Dt

The accelerogram of the 1976 earthquake in Gazli (Uzbekistan) was used as a model of seismic impact (Fig. 2).

3 Results and Discussions To conduct numerical experiments, a program for dynamic calculation of the dome system for seismic impact “Dynamics of the structure’s dome” has been developed, which implements the above algorithm. Below is a series of vibration damping graphs with point movements in the direction of acceleration of the calculated accelerogram, compiled for a locator with a radius of the outer ring of 10 m at different forces of the beginning of unwinding of tapes and coefficients of resistance to the unwinding movement. Damping of the dome vibrations is implemented on a fairly wide range of tension parameters and coefficients of resistance to movement. In this example, for a locator with an outer ring radius r = 10 m, the maximum reduction in the vibration amplitude (by 40–50%) is realized at the values of the unwinding force parameter N = 900 N and the value of the coefficient of resistance to movement b = 750 kg/s (Figs. 3, 4, 5, 6 and 7).

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Fig. 3. N = 1200 N, b = 750 kg/s

Fig. 4. N = 900 N, b = 750 kg/s

Tape System for Damping Vibrations of Mesh Domes

Fig. 5. N = 600 N, b = 750 kg/s

Fig. 6. N = 600 N, b = 1500 kg/s

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Fig. 7. N = 600 N, b = 3000 kg/s

4 Conclusions The results of the calculation showed a high efficiency of the vibration damping system in the form of a belt structure with a central belt attachment and damping coils. With this arrangement of the dampener and the accepted model of vibration damping, the most significant parameter of damping is the force of the beginning of unwinding of the coils. Analysis of the graphs presented above shows that it is the parameter N that provides the greatest damping effect. In this example, for a locator with an outer ring radius r = 10 m, the maximum decrease in the oscillation amplitude (by 40–50%) gives the parameter value N = 900 N at b = 750 kg/s. If you increase the rigidity of the entire structure to create a similar level of damping, the parameters N and b must be increased.

References 1. Marano, G.C., Greco, R., Trentadue, F., Chiaia, B.: Constrained reliability-based optimization of linear tuned mass dampers for seismic control. Int. J. Solids Struct. 44, 7370–7388 (2007) 2. Owji, H.R., Shirazi, A.H.N., Sarvestani, H.H.: A comparison between a new semi-active tuned mass damper and an active tuned mass damper. Proc. Eng. 14, 2779–2787 (2011) 3. Etedali, S., Rakhshani, H.: Optimum design of tuned mass dampers using multi-objective cuckoo search for buildings under seismic excitations. Alexandria Eng. J. 57, 3205–3218 (2018) 4. Adam, C., Di Matteo, A., Furtmüller, T., Pirrotta, A.: Earthquake excited base-isolated structures protected by tuned liquid column dampers: design approach and experimental verification. Proc. Eng. 199, 1574–1579 (2017)

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5. Altay, O., Nolteernsting, F., Stemmler, S., Abel, D., Klinkel, S.: Investigations on the performance of a novel semi-active tuned liquid column damper. Proc. Eng. 199, 1580–1585 (2017) 6. Lasowicz, N., Jankowski, R.: Investigation of behaviour of metal structures with polymer dampers under dynamic loads. Proc. Eng. 199, 2832–2837 (2017) 7. Seong, J.Y., Min, K.W.: An analytical approach for design of a structure equipped with friction dampers. Proc. Eng. 14, 1245–1251 (2011) 8. Burtseva, O.A., Tkachev, A.N., Chipko, S.A.: Roller seismic impact oscillation neutralization system for high-rise buildings. Proc. Eng. 129, 259–265 (2015) 9. Shein, A.I., Chumanov, A.V.: Constructive methods of vibrations damping of buildings and structures. In: Modelling and Mechanics of Structures, vol. 6 (2017). http://mechanicspguas. ru/Plone/nomera-zhurnala/no8/matematicheskoe-modelirovanie-chislennye-metody-i-kompleksy-programm/6.6/at_download/file 10. Shein, A.I., Chumanov, A.V.: Numerical experiments on the damping of vibrations of vertical rod by reactive dampers. In: Modelling and Mechanics of Structures, vol. 8 (2018). http://mechanicspguas.ru/Plone/nomera-zhurnala/no8/matematicheskoe-modelirovanie-chislennye-metody-i-kompleksy-programm/8.2/at_download/file 11. Shein, A.I., Chumanov, A.V.: Inertial pre-tensioning polyester-tape vibration damping system of cyclically symmetric dome-type structures. In: Modelling and Mechanics of Structures, vol. 10 (2019). http://mechanicspguas.ru/Plone/nomera-zhurnala/no8/matematicheskoe-mode lirovanie-chislennye-metody-i-kompleksy-programm/10.1/at_download/file

Eco-Cement for 3D-Additive Technologies in Construction V. S. Lesovik

, A. N. Babaevsky , E. S. Glagolev and A. A. Sheremet(&)

,

Belgorod State Technological University named after V.G. Shukhov, Belgorod, Russia [email protected] Abstract. Modern construction technologies develop mainly through the use of new materials and minor changes in the construction of buildings. This paper presents the advantages of using 3D-additive technologies in construction: increasing the speed of construction, cutting production costs, energy efficiency, sustainable use of secondary construction resources and advanced materials, great variety of space-planning and architectural solutions. This line of research confirms the relevance of the selected problem. Requirements to composite binders with the predefined set of properties and structural and functional organization are specified. The criteria of selecting the composites’ formulas for using them in 3D printing technologies are formulated. The findings of prism strength and energy-efficiency studies of composite binders on the basis of ecocement are presented. To meet a number of technical, technological and economic requirements to a concrete on the basis of composite binders for 3Dadditive technologies in construction, the application of a set of modifying additives and eco-cement is needed. Keywords: 3D-additive technologies
Geonics Geomimetics
Eco-cement
Composite binders


Construction


1 Introduction At present, in order to increase the level of building industry’s development, it is necessary to implement innovative methods in solving many problems [1–6]. Additive technologies or additive manufacturing are nowadays one of the most rapidly developing areas in science. The switch to transdisciplinary research, which holds the leading positions nowadays, including such area as geonics (geomimetics), is a mainstay of designing and creating composite materials for additive technologies [2]. Advantages of 3D-printing technology: – increasing the speed of construction (reducing time for constructing buildings by 50–70%); – cutting production costs (up to 50%); – energy efficiency; – sustainable use of secondary construction resources and advanced materials; – great variety of space-planning and architectural solutions [7]. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 108–112, 2021. https://doi.org/10.1007/978-3-030-54652-6_16

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To implement the opportunities of 3D-additive technologies in various spheres of construction, one of the most challenging and complicated problems is creating the multi-component, multilayered, energy-efficient and durable composite binders with the predefined set of properties and structural and functional organization [8–10]. The conventional cement is a very power-intensive material to produce, and, due to the continuous increase of energy resources cost with the increase of their consumption, the topicality of using eco-cement takes on greater and greater importance [11–13].

2 Methods and Materials Taking into account the production technology of a new energy-efficient composite binder on the basis of eco-cement for 3D-additive technologies, an experimental procedure was developed and implemented. The mixed grinding of the clinker component with weight content 30–50%, superplasticizers and a mineral hydroactive admixture – screenings of quartzitic sandstone crushing and granulated blast furnace slag – was performed. The alteration of raw mix composition influences the power consumption and specific surface increment at grinding. Various phase components of the raw mix have different effective ranges of specific surface, achieved by various mechanical activation methods, as well as different optimal values of hydraulic activity. The chemical composition of components, used for preparing the raw charge, is presented in Table 1. Table 1. The chemical composition of components № 1 2 3 4 5 6 7

Component Slag of NLMK Slag of KMZ Slag of OEMK Slag of OMZ Slag of Serov MZ Slag of Ilyich MMZ KT-1

SiO2 40.6 40.52 23.3 22.0 35.55 38.8 20.09

AI2O3 6.52 8.46 4.1 – 12.88 7.0 6.23

Fe2O3 – – 15.1 – – – 4.56

CaO MgO FeO MnO 41.94 10.27 0.44 0.05 39.75 7.73 0.23 0.5 38.8 8.1 – – 55.4 6.5 0.2 1.5 43.17 4.74 0.52 0.53 46.9 5.2 0.24 0.1 65.6 1.65 – –

T1O2 – 0.19 – – 0.91 0.32 –

The raw charge mix was prepared in accordance with experimental conditions and with the predefined increment of weight content. The experiment with each mix was carried out until achieving the specific surface value no less than 4000 cm2/g. For the research the composite binder samples with mineral admixtures content of 70, 50 and 30% respectively were prepared. Portland cement PZ-500D0 was taken as a test sample. In the experiment a ball mill with capacity 15 kgph and raw materials up to 2 mm were used.

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3 Results and Discussion At synthesizing a composite binder the milling time was taken into account, and the consumption of electric energy for milling was calculated by computational method. The synthesis was carried out until achieving the specific surface no less than 4000 cm2/g (Bleine), which is the minimal boundary of mineral admixtures activation. After that, the indicated values were determined in relation to the samples’ weight and their specific surface, as a key factor of laboratory studies at the experiment was reducing the grinding energy at obtaining high dispersion ability. The primary results are summarized in Table 2. Table 2. Results of the experimental samples’ integrated tests Sample Milling time (min)

Electric energy (watthour)

Specific surface (Bleine)

1A 1B 1C 2A 2B 2C ЗA ЗB 3C 4A 4B 4C 5A 5B 5C 6A 6B 6C 0 test

45

2250

4185

20

1000

10

Weight of charge in milling (g)

Specific energy consumption (W/cm2/g)

W/C

Cone slump (mm)

577

3900

0.54

4405

427

2340

0.23

500

5793

125

4000

0.09

110

5500

4745

1375

4000

1.16

40

2000

4165

581

3440

0.48

40

2000

4530

526

3800

0.44

0.396 0.396 0.396 0.396 0.396 0.396 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4

114 113 112.6 113 112.9 112.5 112.2 112.1 112.1 112.2 112.3 112.5 113.8 113.5 113.9 114.8 114.2 114 112.6

2980

Energy consumption (W/h/kg)

At gauging the composite binder samples, water-cement ratio (W/C) was determined by the cone slump (CS), the values of which are presented in Table 2. The prism strength tests of bending and compressive strength were carried out at 2-days and 28days age of the samples.

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The prism strength tests of experimental samples were performed according to GOST 30744-2001. Test results are presented in Table 3.

Table 3. Results of prism strength tests Sample Energy consumption (W/h/kg)

Specific energy consumption, (W/cm2/g)

1A 1B 1C 2A 2B 2C ЗA ЗB 3C 4A 4B 4C 5A 5B 5C 6A 6B 6C 0 test

577

0.54

427

0.23

125

0.09

1375

1.16

581

0.48

526

0.44

Strength 2-day (kgf/cm2) Bending Compressive 22 59 36 122 50.5 194 16.5 36.3 33 103 48 195 19.5 52 31 112 49.8 164 8 5 9 9 47.5 145 22 62 35 115 49.5 193 24 60 35.5 125 50 211 58.5 236

Strength 28-day (kgf/cm2) Bending Compressive 76.5 365 84.5 448 85 423 78.5 248 83.5 381 81.5 419 31.5 75 55 200 67 279 34.5 97 49 157 66.5 345 76 437 81.5 426 81 487 78 379 77 485 84.5 521 74 361

As a result of the strength tests, the formulas of a composite binder on the basis of eco-cement were designed, equal to Portland cement PZ-500D0 GOST 31108-2003 in its technical characteristics, which would allow using this composite binder similarly to Portland cement in a wide range of construction industry areas. So, the application of eco-cement is relevant for using 3D-additive technologies in construction and for 3D-printing of complex-shaped products, where the high values of energy-efficiency and strength gain are required.

4 Conclusion The requirements to composites for additive manufacturing technologies in construction industry are very high, due to application of an unconventional concrete 3Dprinting technology. Much attention is given to power consumption economy and the maximum strength of composite binders. To meet a number of technical, technological

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and economic requirements to a concrete on the basis of composite binders for 3Dadditive technologies in construction, the application of a set of modifying additives and eco-cement is needed. Acknowledgements. This work was realized in the framework of the Program of flagship university development on the base of the Belgorod State Technological University named after V. G. Shukhov, using equipment of High Technology Center at BSTU named after V. G. Shukhov.

References 1. Lesovik, V.S.: Geonics (Geomimetics). Examples of Implementation in Building Materials Science. Monograph. BSTU Publishing Office, Belgorod (2016) 2. Lesovik, V.S., Pershina, I.L., Degtyarev, D.A.: The role of architectural geonics in creating an architectural space. IOP Conf. Ser.: Mater. Sci. Eng. 463, 1–7 (2018) 3. Klyuev, S.V., Klyuev, A.V., Shorstova, E.S.: The micro silicon additive effects on the finegrassed concrete properties for 3-D additive technologies. Mater. Sci. Forum 974, 131–135 (2019) 4. Klyuev, S.V., Klyuev, A.V., Shorstova, E.S.: Fiber concrete for 3-D additive technologies. Mater. Sci. Forum 974, 367–372 (2019) 5. Elistratkin, M.Y., Glagolev, E.S., Absimetov, M.V., Voronov, V.V.: Composite binder for structural cellular concrete. Mater. Sci. Forum 945, 53–58 (2019) 6. Fediuk, R., Pak, A., Kuzmin, D.: Fine-grained concrete of composite binder. IOP Conf. Ser.: Mater. Sci. Eng. 262(1), 012025 (2017) 7. Denisova, Y.: Additive technologies in construction. Constr. Mater. Prod. 1(3), 33–42 (2018) 8. Klyuev, S.V., Klyuev, A.V., Khezhev, T.A., Pucharenko, Y.: Technogenic sands as effective filler for fine-grained fibre concrete. J. Phys: Conf. Ser. 1118, 012020 (2018) 9. Babaevsky, A.N., Romanovich, A.A., Glagolev, E.S.: Methods to improve efficiency of production technology of the innovative composite cementing materials. IOP Conf. Ser.: Mater. Sci. Eng. 327, 032009 (2017) 10. Elistratkin, M.Y., Lesovik, V.S., Alfimova, N.I., Shurakov, I.M.: On the question of mix composition selection for construction 3D printing. Mater. Sci. Forum MSF 945, 218–225 (2018) 11. Lesovik, V.S., Alfimova, N.I., Trunov, P.V.: Reduction of energy consumption in manufacturing the fine ground cement. Res. J. Appl. Sci. 9(11), 745–748 (2014) 12. Zagorodnyuk, L.H., Okuneva, G.L.: Analysis of the quality of mixing of dry building mixes in various mixing devices by statistical method. Bull. BSTU Named After V.G. Shukhov 5, 209–214 (2014) 13. Zagorodnyuk, L.H.: Dry Thermal Insulation Mixtures on Composite Binders. Monograph. BSTU Publishing Office, Belgorod (2014)

Research on the Possibility of Using Volcanic Sand of Kamchatka as a Component of a Composite Binder N. I. Alfimova1,2(&) , I. M. Shurakov1 , M. S. Ageeva1 and N. I. Kozhukhova1 1

,

Belgorod State Technological University named after V.G. Shukhov, Belgorod, Russia [email protected] 2 National Research Tomsk State University, Tomsk, Russia

Abstract. Composite binders with the use of raw materials of various genesis as a siliceous component are a promising material, as their application allows solving a number of significant problems, in particular, to expand the raw material base for regions where there is no natural raw material; to reduce the load on the environment by using raw materials stored in heaps and reducing the clinker component; and to obtain materials with unique properties. The results of research aimed at studying the possibility of using the volcanic sand of Kamchatka from the Klyuchevskoy volcano (the lower waterfall of the Krutenkaya River) as a component of composite binders are presented. Based on the fact that the main obstacle to the extensive application of composite binders are significant energy costs associated with its production by grinding, the possibility of using not only the sand itself, but also its silt fraction was considered. For this purpose, the material composition, morphology and granulometry of volcanic raw materials and its silt fraction were studied. Based on the obtained results, conclusions are made about the feasibility of using the studied raw materials as a component of composite binders and the possibility of additional reduction of energy consumption for their production due to the use of a silt fraction. Keywords: Composite binders


Volcanic sand
Energy saving
Grinding

1 Introduction Nowadays composite binders (CB) differ in a wide range of assortment due to the variety and combination of components that can be included in their composition. The main components of CB, such as binders of low water demand (BLWD) and fineground cements (FGC), are Portland cement or Portland cement clinker and silica component, as well as a complex of chemical additives. At the moment, there is an experience of using a large amount of both rocks and technogenic raw materials as a siliceous component, which has not been used yet [1–12]. In the production of composite binders, the control of its production by ultra-fine grinding is required special attention. This is primarily due to the processes occurring during grinding and, in particular, the conversion of mineral raw materials to a © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 113–117, 2021. https://doi.org/10.1007/978-3-030-54652-6_17

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chemically active state [5, 6], which determines the special properties of composites made on the basis of CB, as well as expands the scope of their use in the production of special purpose products [4, 7–12]. It should be noted that when considering the possibility of using a particular siliceous raw material as a component of a composite binder, it is necessary to apply a systematic approach aimed at studying its qualitative characteristics (material composition, granulometry, specific surface area, etc.), and also one should take into account the possibility of increasing its potential through the use of mechanical activation. In order to identify the possibility of using volcanic sand of the Kamchatka Peninsula as a component of composite binders, complex research of its qualitative characteristics was conducted.

2 Methods and Materials The particle surface morphology was analyzed using a high-resolution scanning electron microscope TESCAN MIRA 3 LMU, including an X-MAX 50 Oxford Instruments NanoAnalysis energy-dispersed spectrometer. The specific surface area was measured using a multifunctional device PSKH-12. The raw material was ground in a vibrating laboratory mill. The quality coefficient of siliceous components (Sc) as a component of composite binders was determined by the methodology developed at the Department of Structural Materials Science of Products and Structures of BSTU named after V. G. Shukhov [13]. Kamchatka volcanic sand of volcano Klyuchevskoy (lower waterfall of the Krutenkaya River) was the object of the study.

3 Results and Discussions As everyone knows, the main limiting factor in the widespread use of composite binders is the significant energy costs associated with grinding. One of the ways to solve this problem is the use of mineral components that initially characterized by a larger specific surface area. In this regard, it is advisable to consider the possibility of using not only the products of volcanic activity themselves, but also their silt fraction separately as a component of the CB. The objects of research were the volcanic raw materials of the Klyuchevskoy volcano (the lower waterfall of the Krutenkaya River), which is located on the Eastern part of the Kamchatka Peninsula and is the highest active volcano on the Eurasian continent. Visually, this raw material is a fine material of dark gray to black color with a true density of 2780 kg/m3 and a grain size modulus of 0.78. The characteristics of the volcanic raw material and its silt fraction are presented in Table 1. The results of determining the material composition showed that the main compounds in both cases are silicon and aluminum oxides (Table 2).

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Table 1. Characteristics of volcanic raw materials and their dusty fraction Type of raw material depending on the fractions

Volcanic raw material Silt fraction

Indicators Bulk density, kg/m3 1500 –

Specific surface area, m2/kg

Average weight size of particles

73.3 125.5

29.6 17.6

Table 2. Chemical composition of volcanic raw materials Type of raw material depending on the fractions Volcanic raw material Silt fraction

Content, weight % SiO2 Al2O3 CaO Fe2O3 MgO Na2O TiO2 K2O

P2O5 MnO R2O

50.58 21.98 8.23 7.34

4.96

4.55

0.884 0.846 0.191 0.135 0.304

50.64 21.98 8.32 7.28

4.69

4.62

0.91

0.86

0.192 0.134 0.374

Fig. 1. Morphology of volcanic sand particles (a) and silt fraction (b)

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weight per volume

The research of the microstructure of the raw material and its silt fraction allowed finding out that it is represented by particles that do not differ from each other in texture and structural characteristics of the surface and grain morphology (Fig. 1). The particles are grains of various shapes with obvious traces of corrosion, which contributes to the formation of sufficiently developed surfaces (Fig. 1). In addition, unevenness, cracks and deepening are often filled with shatter material up to 40–50 microns in size. The presence of small fragments is associated with the fragmentation of larger particles as a result of collisions of grains with each other under the action of the current, surf, and waves. This fine material can act as an active component of the resulting composite binder, or as centers of crystallization. At high magnification, the roughness of the particle surface and significant roughness are clearly visible (Fig. 1, b, d). Analysis of the granulometry of the researched raw material showed that its silt fraction has a more expressed polyfractional composition, therefore, its use as a component of a composite binder can have a positive effect on the microstructure of cement stone due to the possibility of forming a denser spatial packing of particles (Fig. 2). 14 12 10 8 6 4 2 0

particle size, μм volcanic sand

silt fraction

Fig. 2. Granulometric composition of volcanic sand and silt fraction

Analysis of the results of the quality coefficient of volcanic sand (1.12) and its silt fraction (1.2) showed that the second one has higher values of this indicator, which is due to its qualitative characteristics and, in particular, a more developed surface and polydisperse granulometric composition.

4 Conclusion Consequently, based on the complex research of volcanic sand of Kamchatka and its silt fraction, it can be concluded that they are promising raw materials for the production of composite binders, meanwhile the silt fraction does not differ from the large

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one in material composition, having a large specific surface area and polydisperse distribution of particles, which is more promising from the position of reducing energy consumption for grinding. Acknowledgments. This work was realized in the framework of the Program of flagship university development on the base of the Belgorod State Technological University named after V G Shukhov, using equipment of High Technology Center at BSTU named after V G Shukhov.

References 1. Elistratkin, M.Yu., Minakov, S.V., Shatalova, S.V.: Composite binding mineral additive influence on the plasticizer efficiency. Constr. Mater. Prod. 2(2), 10–16 (2019 2. Sobolev, K., Flores-Vivian, I., Pradoto, R.G.K., Kozhukhova, M., Potapov, V.: The effect of natural SiO2 nanoparticles on the performance of Portland cement based materials. In: 2nd International Workshop on Durability and Sustainability of Concrete Structures, DSCS, 6–7 June 2018, Russian Federation, vol. 2018-June, Issue SP 326, American Concrete Institute, ACI Special Publication, Moscow (2018) 3. Sobolev, K., Flores-Vivian, I., Pradoto, R.G.K., Kozhukhova, M., Potapov, V.: The effect of natural SiO2 nanoparticles on the performance of Portland cement based materials, vol. 326, pp. 14.1–14.10, Special Publication (2018). https://doi.org/10.1007/s11709-017-0438-2 4. Klyuev, S.V., Klyuev, A.V., Khezhev, T.A., Pucharenko, Y.: Technogenic sands as effective filler for fine-grained fibre concrete. J. Phys: Conf. Ser. 1118, 012020 (2018) 5. Alfimova, N.I., Kalatozi, V.V., Karatsupa, S.V., Vishnevskaya, Y.Yu., Sheychenko, M.S.: Mechanical activation as a method of increasing efficiency of using raw materials of various genesis in construction material science. Bull. BSTU named after V.G. Shukhov 6, 85–89 (2016) 6. Lesovik, V.S., Alfimova, N.I., Trunov, P.V.: Reduction of energy consumption in manufacturing the fine ground cement. Res. J. Appl. Sci. 9(11), 745–748 (2014) 7. Lesovik, V.S., Absimetov, M.V., Elistratkin, M.Yu., Pospelova, M.A., Shatalova, S.V.: For the study of peculiarities of structure formation of composite binders for non-autoclaved aerated concrete. Constr. Mater. Prod. 2(3) 41–47 (2019) 8. Zagorodnyuk, L., Lesovik, V.S., Sumskoy, D.A.: Thermal insulation solutions of the reduced density. Constr. Mater. Prod. 1(1), 40–50 (2018) 9. Elistratkin, M.Yu., Kozhukhova, M.I., Pospelova, M.A., Semernin, E.O.: Regards study of feature consolidation of building structures produced by additive technologies. Addit. Fab. Technol. 1(1), 5–13 (2019) 10. Poluektova, V.A., Kozhanova, E.P.: Improvement of dry mix mortar production technology for 3D printing. Addit. Fabr. Technol. 1(1), 14–23 (2019) 11. Klyuev, S.V., Klyuev, A.V., Shorstova, E.S.: The micro silicon additive effects on the finegrassed concrete properties for 3-D additive technologies. Mater. Sci. Forum 974, 131–135 (2019) 12. Klyuev, S.V., Klyuev, A.V., Shorstova, E.S.: Fiber concrete for 3-D additive technologies. Mater. Sci. Forum 974, 367–372 (2019) 13. Lesovik, R.V., Zhernovsky, I.V.: The choice of silica-containing component of composite binders. Constr. Mater. 8, 78–79 (2008)

Innovative Approaches to Residential Development Using Large-Panel Elements R. G. Abakumov(&)

, M. A. Shchenyatskaya and M. I. Oberemok

, I. V. Ursu

,

Belgorod State Technological University named after V.G. Shukhov, Belgorod, Russia [email protected]

Abstract. The article is devoted to the application of innovative trends in residential development using large-panel elements. The relevance of this study is determined by the increasing requirements for the efficiency of large-panel housing construction. The main innovations related to the application of monolithic joint; hinge joints of reinforced concrete elements without using welded joints; space-planning solutions of sections of large-panel houses with longitudinal bearing L-shaped walls; structural layout of panel housing with the first floor frame construction; combinations of large-panel elements and various acoustic and thermal insulation materials; 3D printers for optimization of factory processes for the manufacture of printed non-standard structural elements; BIMtechnologies for monitoring the technical condition and quality control of seams in large-panel buildings. The article presents an analysis of advantages of using innovative approaches to development of large-panel reinforced concrete construction of residential buildings and also provides their brief overview. The article offers an original integrative approach to increase the efficiency of largepanel housing construction, taking into account the conditions for applying a set of innovative achievements in the field of construction, which will allow to achieve the goals of providing the population with affordable and comfortable housing. Keywords: Large-panel construction
Innovative construction technologies Innovations
Spatial planning and architectural solutions
Technology for connecting elements
BIM technologies
3D printing




1 Introduction Large-panel residential construction is considered very conservative within the framework of technologies and architectural solutions, which is largely due to the “slowness” of large-panel elements production and the sufficient economic efficiency of outdated construction technologies. Panel residential construction is developing quite intensively these days as an economic sector and meets the housing needs of a wide range of people. The service life of most modern panel houses is 100 years. Like any other technology, large-panel residential construction requires updating and developing innovative approaches based on new engineering, planning and design solutions. The © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 118–123, 2021. https://doi.org/10.1007/978-3-030-54652-6_18

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quality indicators of the new large-panel series have significantly improved compared to Soviet houses. The main task of this research is to find and describe innovative approaches to development of large-panel housing construction, based on new technologies, materials, architectural and design solutions.

2 Methods and Materials Innovative development of residential construction from large-panel elements is a basis for evolutionary progress, but it is hindered by the economic interests of stakeholders in housing construction projects and the production of building materials. Innovative areas of residential construction development are associated with prospective and costeffective technologies within the life-cycle in the field of improving of construction and installation works, architectural and design solutions, energy efficiency, the implementation of new technological methods of production of building materials and structures using information modeling. Modern innovative research and development of construction are characterized by the following areas: sustainability and energy efficiency of buildings and structures; green buildings; construction waste recycling; production of building materials with programmable characteristics; robotization of construction and installation works; information modeling of new architectural and design solutions, etc. Foreign science is more focused on innovations in the field of construction technology and manufacture.

3 Results and Discussions There are some problems of innovative development of large-panel residential construction: related obstacles to technology transfer; lack of understanding by stakeholders of the potential benefits of implementation of construction innovations; underdeveloped estimates of economic impacts of integrated innovations in the development of large-panel residential construction; the lack of interest of the innovation recipient in the distribution and declaration; limited vision of the innovation’s types of large-panel construction; lack of understanding of the cross-effects of innovations due to the division of processes; low consumer demand for high-quality construction products due to the high price; the general predominance of supply and demand for the “economy housing” category; the continuity of the “quality”, “high price” and “innovation” categories. One of the innovative approaches to development of large-panel residential construction is the use of modern solutions of erection joint that can increase the service life of residential buildings up to 150 years. Let’s consider the main ways on improving the erection joint of large-panel elements. 1. The use of a monolithic joint is one of the ways of development of large-panel housing construction. A lot of work is underway to develop and test the structures of the joint of floor slabs with wall elements for high-rise large-panel residential

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buildings. The use of this design option for erection joint of large-panel elements allows not only to increase the bearing capacity of the joint, but also to reduce the risks of defects that occur during the installation of this type of building structures. Such application of the platform joint will allow the use of concrete wall panels and floor panels with different physical and strength indicators. This design solution allows you to produce multistoried large-panel objects (up to 25 floors). Figure 1 presents an example of a structural joint diagram.

1-the lower wall panel of a residential building; 2-the overlap panel; 3 - connecting reinforcement in panels; 4-embedded reinforcement; 5-concrete poured to connect joints; 6-contact seam; 7-upper wall panel of a residential building Fig. 1. Example of a structural diagram of the junction of erection joint of large-panel elements

2. An effective innovation is the use of loop joints of reinforced concrete elements without using welded joints. Reduced labor costs for loop connections up to 48% compared to welded ones. Minimization of the volume of monolithic works during the installation of buildings is exclusively for the sealing of butt joints. The volume of sealing joints in large-panel buildings is 2–2.5 times less in comparison with frame and prefabricated-monolithic buildings. Figure 2 shows examples of options for loop connections of reinforced concrete elements without using welded joints.

Fig. 2. Examples of options for loop connections of reinforced concrete elements without using welded joints

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The comparison of costs (Table 1) with different options for connecting largepanel products allows us to confirm the economic efficiency of innovative developments of erection joint of large-panel elements. Table 1. Costs for product connection options, rubles/kub.m of total area Name of work and labor costs

Welded option 500/100%

Loop option 4 elements 570/ + 14%

The cost of embedded parts installed in precast concrete products at the manufacturer’s factory Labor costs Total

3 elements 530/ + 6%

77/100% 577/100%

52/ – 33% 622/ + 8%

52/ – 33% 582/ + 1%

Option with hard links 407/ – 19%

63/ – 18% 470/ – 19%

3. Application of new structural schemes of housing construction from large-panel elements. Offers of space-planning solutions for sections of a large-panel residential building with L-shaped longitudinal load-bearing walls guarantee the spatial rigidity of the entire building (Fig. 2). The use of L-shaped panels will ensure the safety of construction of residential buildings up to 16 stories high (with a floor height of 3.3 m), which becomes an attractive option for all stakeholders. The use of these proposals will create a unified model of housing construction from large-panel elements, which will allow to apply various planning solutions and plastic solutions of facades, therefore it will increase the attractiveness of housing for consumers. The perspective solution for large-panel houses is the construction of a panel building on a frame platform supported by columns or pilasters with a height of the first floor of at least 4 m. The first floors of buildings facing transport or pedestrian streets must have a supporting frame structure along the street axis for organizing entrances to the building in any longitudinal step. It allows to organize the placement of public areas on the first floors of large-panel buildings. 4. Solving the problems of reduced sound insulation and thermal insulation of largepanel elements for housing construction. Each structural element of external wall panels contributes to the balance of the heat system, which is accounted during developing energy efficiency projects for wall enclosing structures. Many studies and proposals are aimed at the use and combination of large-panel elements and various sound insulation materials. The most effective of them are the soundabsorbing material “Tekhnoplast” and partition system “ASOTAS”. To design effective sound-absorbing structural elements for large-panel construction it is necessary to have a technology for regulating the characteristics of sound-proof layers. This will allow you to get the most effective wall panels and design elements with pre-set parameters. Reducing the energy cost of maintaining new houses by 25%, compared to standard indicators, will allow residents to save up to a quarter of their heating costs. 5. The most reasonable innovative solution is the transition to the technology of manufacturing building structures through the use of construction 3D printers,

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which will not only optimize the factory processes for the production of printed structural elements, but also will increase the variety of products produced by varying changes in the internal part of the element. This technology has significant advantages: minimum number of service staff; reduced possibility of occurrence of dangerous situations related to labor protection on the construction site; minimization of the number of inconsistent actions and the time and resources; reduction of the bad influence on the environment by reducing waste and unused residues; bulk structure has increased solidity; high production speed of construction. However, 3D printing technologies are due to the small size of printed products, which contributes to the deviation from large-panel construction towards the use of panels with a height of 1.5 m. This decision may negatively affect the speed of work on the construction of the walls of a panel building. But it will have a positive impact on the problem of transportation of printed panels. 6. Application of BIM technology in monitoring the technical condition and quality control of seams of large-panel buildings. Use of BIM-technology allows to reduce risks during the construction and installation work, which minimizes simple construction equipment and accessories. A key application of this technology type is the construction of a BIM model for control and monitor the state of joints and seams of panel elements which will optimize the quality of work as well as prevent the possibility of joint deformations. The main problem of destructibility of large-panel buildings is poor-quality execution of butt joints of panel elements. To track deformation changes and predict possible cracks in the butt elements of panel housing construction, it is possible to use load cells that will transmit data on changes in deformation to a computer, which will process the information and output data to a 3D model of the building.

4 Conclusion Using the integration of innovative approaches to residential development using largepanel elements (monolithic joint; hinge joints of reinforced concrete elements without the use of welded joints; space-planning decisions of sections of large-panel houses with longitudinal bearing L-shaped walls; structural diagrams and panel housing with the first floor frame construction; a combination of panel elements and various acoustic and thermal insulation materials; building 3D printers for the manufacture of nonstandard panels; BIM technologies for monitoring the technical condition and quality control of seams of large-panel buildings), it is possible to optimize panel construction and provide the population with affordable and comfortable housing. Large-panel housing construction is very promising for production in the field of residential construction. However, it is necessary to radically change its technology by switching to the innovative way of development, which will allow this type of housing construction to be the most popular among existing ones.

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Acknowledgments. This work was realized in the framework of the Program of flagship university development on the base of the Belgorod State Technological University named after V G Shukhov, using equipment of High Technology Center at BSTU n.a. V G Shukhov.

References 1. Abakumov, R.G., Avilova, I.P., Ursu, I.V., Kapustina, E.O.: Methodical toolkit of managing reproduction of the fixed assets of an organization. J. Soc. Sci. 10, 1449 (2015) 2. Abakumov, R.G., Naumov, A.E., Zobova, A.G.: Advantages, tools and efficiency of implementation of information modeling technologies in construction. Bull. BSTU named after V.G. Shukhov (5), 171–181 (2017) 3. Abakumov, R.G., Naumov, A.E.: Building information model: advantages, tools and adoption efficiency. IOP Conf. Ser.: Mater. Sci. Eng. 11(6), 1–12 (2017) 4. Dolzhenko, A.V., Naumov, A.E., Shevchenko, A.E.: Bearing capacity and rigidity of short plastic-concrete-tubal vertical columns under transverse load. IOP Conf. Ser.: Mater. Sci. Eng. (327), 042024 (2018) 5. Abdrazakov, F.K., Pomorova, A.V., Shchenyatskaya, M.A., Litvishko, O.V.: Organizational partnership for building, reconstruction and capital overhaul of hydrotechnical structures. Int. Bus. Manag. 9, 1163–1168 (2015) 6. Kara, K.A., Dolzhenko, A.V., Zharikov, I.S.: Influence of processing factors over concrete strength. IOP Conf. Ser.: Mater. Sci. Eng. (327), 032027 (2018) 7. Klyuev, S.V., Bratanovskiy, S.N., Trukhanov, S.V., Manukyan, H.A.: Strengthening of concrete structures with composite based on carbon fiber. J. Comput. Theor. Nanosci. 16(7), 2810–2814 (2019) 8. Klyuev, S.V., Abakarov, A.J., Lesovik, R.V., Muravyov, K.A., Tatlyev, R.Dz.: Optimal engineering of rod spatial construction. J. Comput. Theor. Nanosci. 16(1), 200–203 (2019) 9. Naumov, A.E., Koshlich, Yu., Oberemok, M.I., Belousov, A.: Comparative analyzes for increasing the energy efficiency of civil constructions. In: 19th International Multidisciplinary Scientific GeoConference SGEM 2019 Conference Proceedings, pp. 277–284, Sofia (2019) 10. Oberemok, M.I., Naumov, A.E., Shchenyatskaya, M.A.: Qualitative analysis of view characteristics of residential property. Bull. BSTU named after V.G. Shukhov 3(4), 44–51 (2019) 11. Klyuev, S.V., Klyuev, A.V., Shorstova, E.S.: The micro silicon additive effects on the finegrassed concrete properties for 3-D additive technologies. Mater. Sci. Forum 974, 131–135 (2019) 12. Zharikov, I.S., Laketic, A., Luketich, N.: Influence of the quality of concrete work on the strength of concrete monolithic structures. Constr. Mater. Prod. 1(1), 51–58 (2018)

The Aspect of Color Optimization of the Mineral Repair Mixture for the Brickwork Restoration V. E. Danilov(&)

, D. V. Ershkov

, and A. M. Ayzenshtadt

Northern (Arctic), Federal University named after M.V Lomonosov, Arkhangelsk, Russia [email protected]

Abstract. The paper presents the testing of the optimization method of the composition of repair compound to a historic brick to compensate its losses, consisting in a step-by-step selection of mineral raw materials which ensure color identity and affinity of structures. Ceramic filled bricks of 1859 and 1786 were used as samples. Their color characteristics in the CIE L*a*b* system are studied. It was found that the cement-sand repair compositions prepared at the first stage of the study with the addition of modern bricks in the form of crumbs and powder do not correspond in their color characteristics to historical bricks. To eliminate the color difference, in the second stage various experimental techniques were used to increase the values of chromatic components a* and b* (increasing the fineness of fillers grinding, removing cement milk from the surface of samples of repair compositions), and various pigments were introduced into the repair mixture. As a result of this adjustment, it was possible to obtain repair mix compositions that correspond to the ranges of historical bricks in all three color characteristics. Keywords: Repair compositions
Color characteristics
Coloristics
Ceramic bricks
Brickwork

1 Introduction The best way to prolong the life of extant architectural monuments is to recreate the composition of the brickwork or plaster solution of the monument during restoration based on the analysis of old samples [1, 2]. The compressive strength of many ancient lime-cement solutions reaches large values, sometimes up to 70–80 kgf/cm2 [3]. But it is very difficult to provide such physical and mechanical properties with the solution prepared today for brickwork restoration [4, 5]. Therefore, a more rational approach is based on replacing damaged sections of the structure with modern materials with properties as identical as possible to the materials of the old brickwork. However, the use of different types of materials is fraught with the occurrence of cracks and breaking the bonds of the common array. Differences in the physical and mechanical characteristics of old and new materials, their thermal expansion coefficients, and elastic modulus become more important the larger the volume of the restoration is. Selection of materials not only with similar © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 124–130, 2021. https://doi.org/10.1007/978-3-030-54652-6_19

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strength properties, but also with identical temperature-deformation and physicalmechanical characteristics is the main task of a brick building restorer [6–8]. In work [8, 9], experimental studies were conducted of brickwork samples reinforced in areas with recess (i.e., those where indents and nests were made for the device of new brickwork) with ligation from the old one. For brickwork, both samples of modern M75 and historical bricks were used, as well as cement-sand solution with the addition of lime as a plasticizer. The results showed that the solidness of the brickwork in the areas of the recess is low enough, and for its restoration, it is recommended to inject a solution into the brickwork seams under pressure. Monolithic character of brickwork in areas with recess can be further improved by bringing the system “historical brick-cement-sand solution-modern brick” to the state of compatibility with the use of the law “affinity of structures” [10, 11], providing the closest physical characteristics to the elements of the system. Another compatibility factor is the possibility of spontaneous maximum splicing of the surface of the contacting phases. This is provided by the van der Waals interaction followed by an adhesive effect. The method that allows solving this problem is based on the OWRK model (comparison of free surfaces energy) [12, 13]. A special approach is necessary when preparing a repair solution for historical bricks in order to make up for losses, chipping, filling cracks. In this case, the primary task, in our opinion, is to obtain a cement-sand solution, whose color matches the color of the original brick. At the same time, the use of organic dyes is not desirable, because they are usually temporary, under the influence of external factors (solar radiation, humidity, atmospheric and anthropogenic influences), they quickly change not only color, but also physical and chemical, and in particular adhesive characteristics [14]. The solution in this situation is step-by-step selection of mineral raw materials for the preparation of the repair composition, which will primarily provide identity colors (first phase) and secondly, the affinity of structures by physical and thermodynamic compatibility (second stage). This paper presents the results of testing the first stage of the above theoretical approach to optimize the composition of the repair mix for brickwork.

2 Methods and Materials The object of research is a filled ceramic brick of wall brickwork of the building of the Children’s Music School No. 1 of the Barents region in Arkhangelsk. It is established that the brick samples are 161 years old (1859 year of manufacture) and 234 years old (1786 year of manufacture). In the future, these bricks are encrypted as HB1859 and HB1786 (Fig. 1). According to preliminary tests, the HB1859 brick has an average compressive strength of 7.63 MPa and 0.08 MPa for bending, which corresponds to the M75 brick brand. The following raw materials were used to prepare the repair mix (for sealing cracks, chips and making up for brick losses). Portland cement (C) of the M-500 brand was used as a binder. Quartz-containing polymineral river sand (S) from the Krasnoflotsky-Zapad field with a grain size modulus of Mk = 1.93 with initial density of 2.65 g/cm3 was used as a filler for

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Fig. 1. Photos of historical bricks: a – HB1859; b – HB1786

manufacturing samples of repair compositions. As a filler, brick crumbs (BC) were used, obtained by crushing a brick of ceramic ordinary filled single KR-rpo250  120  65/1NF/150/2,0/50 produced in accordance with GOST 530-2012. The brick is made by plastic molding, has a density of 1640 kg/m3, maximum compressive strength of 15.0 MPa and 2.8 MPa at bending, water absorption of 14.5%. As a black pigment, carbon nanotubes (CNT) of the Taunit series produced by Nanotechcenter LLC in Tambov were used. Fine quartz sand (QS) obtained by mechanical activation of polymineral quartz was used as a blue pigment. At the first stage of the research, 4 compositions of the repair mixture (RC) were prepared (the content of raw components is indicated as a percentage by weight): 1. 2. 3. 4.

Control composition – RC0 (C 25%, S 75%); Composition with replacement of 25% S by BC – RC25 (C 25%, S 50%, BC 25%); Composition with replacement of 50% S by BC – RC50 (C 25%, S 25%, BC 50%); Composition with replacement of 75% S by BC – RC75 (C 25%, BC 75%);

At the second stage of the research, 4 color-corrected components of the repair mixture were prepared: 1. Composition with replacement of 25% S by fine ground BC – RC25F (C 25%, S 50%, fine ground BC 25%); 2. Composition with replacement of 25% S by BC and adding 0.2% CNT – RC25C (C 25%, S 50%, BC 25%, CNT 0.2%). 3. Composition with replacement of 75% S by fine ground BC – RC75F (C 25%, fine ground BC 75%); 4. Composition with replacement of 75% S by50% fine ground BC + 25% QS, and also adding 0.2% CNT – RC50FC25QS (C 25%, QS 25%, fine ground BC 50%, CNT 0.2%). Color coordinates of historical bricks, mineral raw materials and finished repair compounds were determined using the x-Rite 964 spectrophotometer in the international CIE L*a*b* system.

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3 Results and Discussions The color coordinates of restored materials, raw materials for production and readymade repair compounds in the international CIE L*a*b* system are shown in Table 1. In the CIE L*a*b* color space, the brightness value is separated from the value of the chromatic component of the color (tone, saturation). The brightness is set by the coordinate L (varies from 0 to 100, that is, from the darkest to the lightest), the chromatic component is set by two Cartesian coordinates a and b. The first indicates the position of the color in the range from green to red, the second – from blue to yellow. Table 1. Color coordinates of restored materials, raw materials for production and ready-made repair compositions in the CIE L*a*b* system. Sample

Color coordinates in the CIE L*a*b* system L* a* b* Restored materials HB1859 58.37 ± 5.95 +20.25 ± 2.73 +26.84 ± 1.07 HB1786 51.26 ± 3.61 +13.39 ± 2.28 +11.35 ± 2.58 Raw materials for the repair compositions C 60.59 ± 0.77 −0.29 ± 0.08 +7.18 ± 0.20 BC 54.93 ± 2.49 +25.02 ± 2.21 +29.23 ± 2.55 QS 62.58 ± 3.24 −0.40 ± 0.46 −0.79 ± 1.53 Repair compositions (upper face) RC0 73.45 ± 1.95 +0.17 ± 0.26 +8.03 ± 0.63 RC25 65.36 ± 4.38 +5.24 ± 0.75 +10.13 ± 1.33 RC50 65.75 ± 4.54 +8.00 ± 1.02 +11.54 ± 1.31 RC75 61.45 ± 2.25 +12.09 ± 0.95 +15.39 ± 1.46 Repair compositions (side face) RC0 63.30 ± 0.78 +0.22 ± 0.18 +8.23 ± 0.36 RC25 58.40 ± 5.61 +6.05 ± 1.17 +11.80 ± 2.28 RC50 54.77 ± 2.09 +9.87 ± 0.43 +15.03 ± 0.19 RC75 51.09 ± 5.41 +14.37 ± 2.28 +19.21 ± 1.28 RC0* 60.16 ± 1.35 +0.75 ± 0.08 +9.64 ± 0.29 RC25* 56.79 ± 2.79 +6.64 ± 0.24 +12.84 ± 0.57 RC50* 54.15 ± 3.13 +11.16 ± 0.44 +15.72 ± 0.14 RC75* 51.82 ± 0.86 +16.21 ± 1.73 +19.17 ± 1.62 RC25F 53.95 ± 0.15 +8.57 ± 0.25 +13.48 ± 0.31 RC25C 52.14 ± 1.77 +9.26 ± 0.19 +13.71 ± 0.55 RC75F 53.46 ± 0.71 +16.76 ± 1.88 +19.53 ± 0.99 RC50FC25QS 55.58 ± 0.79 +6.88 ± 1.16 +8.58 ± 0.92 * - after removing the cement milk from the sample face

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According to Table 1, all three bricks (new and historical) differ from each other in color, especially HB1786. This fact is more clearly shown in Fig. 2, which shows its color ranges in the form of rectangles for each brick. The obtained samples of repair compounds were measured both from the top and from the side, as cement milk was present on the upper face. After cleaning the samples from the cement milk, L* decreases, and the components a* and b* increase slightly. It is noted that when adding BC to repair compositions, as well as increasing the fineness of the grinding of this filler, the chromatic components of repair compositions grow linearly. When CNT is added, the value of the L* coordinate is expected to decrease (in preliminary experiments, the linear dependence of the brightness for RC on the amount of black pigment L* = −20.63
CCNT + 56.84 in the range of CNT concentrations 0.1–1%), and the a* coordinate unexpectedly increases. Adding QS leads to an increase in L*, 25% QS completely neutralizing the effect of adding 0.2% CNT black pigment. In addition, quartz powder leads to a sharp decrease in the chromatic components of the repair composition, in our case, the desired decrease in b* (to obtain a RC close to HB1786) and the undesired decrease in a*.

Fig. 2. Color coordinates of bricks and repair compositions: a – lightness of L* and a*; b – chromatic components

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Thus, it is possible to obtain a RC entering the ranges of HB1786 on the basis of further adjustment of the RC25C by increasing a* or RC50* by reducing b*, while to obtain a RC entering the ranges of HB1859, it is necessary to increase the chromatic components of the RC75F.

4 Conclusion The selection of mineral raw materials for the preparation of repair composition for brickwork should include two independent stages. These stages should be associated with the selection of raw materials that ensure the proximity (identity) of the values of color indicators according to the international CIE L*a*b* system and the physical and chemical characteristics of the materials being compared. The above results allow drawing a conclusion about the applicability of the proposed color system and a method for optimizing the composition of the repair mix for brickwork. The influence of individual components of the repair mixture on its color characteristics is established. A two-step adjustment of the composition allows approaching the repair mix, which is close in all three color characteristics to the ranges of historical bricks. Acknowledgements. The study was funded by state assignment, project No. 0793-2020-0005.

References 1. Belanovskaya, E.V.: Restoration and Basics of Restoration of Stone Monuments of Architecture. ASV Publishing House, Moscow (2013) 2. Perunov, A.S.: Evaluation of the stress state of structures, restored historical brick buildings with the use of high-strength materials for cleaning. Bull. MSUCE 1, 122–126 (2009) 3. Evseev, E.: Evolution of construction technologies in the context of the history of architecture of the XIX century: restoration aspect. World Art: Bull. Int. Inst. Antiq. 3(15), 86–92 (2016) 4. Lukyanova, A.O., Bokareva, E.N.: Technologies of restoration of brickwork. Electron. Sci. Pract. J. Youth Sci. Bull. 12(37), 279–283 (2018) 5. Khanukaev, R.S.: To the question about the quality of plastering work in the restoration of historic buildings. Indu. Civ. Constr. 5, 33–35 (2003) 6. Podyapolsky, S.S., Bessonov, G.B., Belyaev, L.A., Postnikova, T.M.: Restoration of architectural monuments: textbook for universities. Under the general editorship of S.S. Podyapolsky, pp. 149–152. Stroyizdat, Moscow (1988) 7. Serikova, L.S., Lapunova, K.A.: Technologies of restoration of bricklaying. Sci. Almanac 4– 3(42), 85–88 (2018) 8. Subbotin, O.S.: Features of using building materials in the restoration of architectural and town-planning heritage. Constr. Mater. Prod. 2(3), 85–89 (2019) 9. Ishchuk, M.K., Ishchuk, E.M., Frolova, I.G.: Joint work of the old and new masonry on the sites with recess. Indu. Civ. Constr. 1, 28–30 (2014) 10. Lesovik, V.S., Zagorodnyuk, L.H., Belikov, D.A., Shchekina, A.Yu., Kuprina, A.A.: Effective dry mixes for repair and restoration work. Constr. Mater. 7, 82–85 (2014)

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11. Elistratkin, M.Yu., Minakova, A.V., Jamil, A.N., Kukovitsky, V.V., Issa Jamal Issa Eleyan Composite binders for finishing compositions. Constr. Mater. Prod. 1(2), 37–44 (2018) 12. Danilov, V.E., Strokova, V.V., Ayzenshtadt, A.M.: Role of dispersion and polarization effects in the formation of a wood-mineral composite based on fine-dispersed components. Phys. Chem. Mater. Process. 4, 50–56 (2018) 13. Danilov, V.E., Ayzenshtadt, A.M., Frolova, M.A., Tutygin, A.S.: Change in surface energy a criterion for optimizing the composition of a cementless composite binder. Mater. Sci. 2, 39–44 (2018) 14. Tarasova, G.I.: The development of compositions of silicate-based paints thermalizing conveyor-washing sediment – waste of the sugar industry. Constr. Mater. Prod. 1(1), 21–31 (2018)

Concrete and Fiber-Reinforced Concrete in a Cage Made of Polymers Reinforced with Fibers L. A. Panchenko(&) Belgorod State Technological University named after V.G. Shukhov, Belgorod, Russia [email protected] Abstract. Experimental studies have shown that in steel pipes filled with concrete, there is a rather weak coupling between the concrete and the cage. This is due to the significant difference in the Poisson ratio of steel and concrete, which causes the concrete to separate from the pipe when both materials experience longitudinal deformation, as well as the fact that the shrinkage of the concrete leads to delamination at the contact boundary of the two materials under any loading. As a result, pipe-concrete elements may fail due to steel yield or concrete crushing. This disadvantage is overcome by the use of polymers reinforced with fibers (FRP), that is, the device of a fiberglass or carbon-plastic cage. Increasing the strength of concrete is achieved by fiber reinforcement (glass, carbon or other fibers). Cage out of FRP exhibits elastic properties up to the failure. An overview of the results of experimental studies of concrete specimens FRP cage, including the experiments conducted by the author. The stress and strain formulas based on them can be used to reliability the estimate of the designed structures. Keywords: Concrete in the cage fibers
Fiber-reinforced concrete


Polymers reinforced with glass and carbon

1 Introduction Pipe-concrete columns are widely used, in particular, in tall structures. This rational constructive solution allows to reduce the consumption of concrete and steel, in connection with decreased weight and reduced labor costs [1]. Experimental studies have shown that in steel pipes filled with concrete, there is a rather weak coupling between the concrete and the cage. There are two reasons for this phenomenon. First, concrete in a large range of stresses has a Poisson’s ratio lower than that of steel, so that the concrete separates from the pipe when both materials experience longitudinal deformation. Secondly, the shrinkage of concrete leads to delamination at the contact boundary of the two materials under any loading. As a result, failure of pipe-concrete elements is caused by certain factors (steel yield, concrete crushing).

© The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 131–136, 2021. https://doi.org/10.1007/978-3-030-54652-6_20

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This disadvantage is overcome by the use of polymers reinforced with fibers (FRP), that is, the device of a fiberglass or carbon-plastic cage. Increasing the strength of concrete is achieved by fiber reinforcement (glass, carbon or other fibers) [2]. A special effect is achieved in the design of pipes made of fiberglass. The pressing stresses created by the steel pipe are limited by the yield strength of the steel. The fiberglass cage shows elastic properties up to destruction. Polyvinyl chloride and Acrylonitrile butadiene styrene pipes were among the first to be tested. In [3], an attempt is made to give an acceptable “stress-strain” diagram of concrete bounded by a fiber-reinforced polymer pipe. In [4], the results of testing concrete columns in a saw cage are also considered. The content of glass fibers varied from 1 to 6 percent. The influence of their strength and rigidity on the strength of concrete is established. It increased with increasing rigidity of the cage. In work [5] it is shown: for concrete limited by pipe from FRP, original models incompatible with variants of spiral steel reinforcement are necessary. The model for concrete columns bounded by composite strips is noteworthy [6]. The study of the layered structure of pipe from FRP filled with concrete is considered in [7]. Polymers reinforced with glass and carbon fibers were used, and the number of layers was one, three, or five. Limit stresses and deformations increased with increasing number of FRP layers. Concrete in a pipe made of a polymer reinforced with carbon fibers showed higher strength than in a pipe made of a polymer with glass fibers. In the latter case, however, higher deformability was observed. Similar studies were carried out under cyclic loading [8]. Glass fibers were laid in 5, 10 and 14 layers. The form of destruction of the samples was similar to that of monotonous loading, and the change in rigidity was not so significant compared to concrete in a steel cage.

2 Methods and Materials This brief overview of the results of experimental studies of concrete in a pipe from FRP allows us to make theoretical generalizations. The pipe boundary restrains the transverse expansion of concrete under uniaxial compression loading. The cage puts the concrete in a state of three-axis compression. Reducing shear stress and, as a result, increasing of the probability of crack suppression in the concrete core increases the strength of the structure. The stress-strain state of such structures is considered in [9]. According to the Mender’s theory [10], the stress in bounded concrete is calculated by the formula rbc ¼ by

rbc a x ; a þ xa  1

ð1Þ

Concrete and Fiber-Reinforced Concrete

a ¼

133

Ebo ðEbo  Ebs Þ

ð2Þ

ebc ; ebc

ð3Þ

x ¼

where Ebo and Ebs are module of bounded concrete under compression, namely: tangential (initial) module of elasticity and intersecting module at limit strain ebc . For the values of the strength limit of a bounded concrete and the corresponding strain, simple dependencies can be used [11]:
 rcom t rbc ¼ rbo 1 þ 4:1 ; Drbo

ð4Þ

Ecom t ; Drbo

ð5Þ

ebc ¼ 0:002 þ 0:001

where rbo - the strength paint of bound concrete; rcom – the tensile strength point of a composite with a thickness t around a concrete core with a diameter D; Ecom – the elastic module of the composite in the tangential direction. Theoretical studies [12] have received experimental confirmation. Concrete columns in a cage from polymer with glass or carbon fibers have a higher strength, viscosity and potential energy of deformation than the same kind of structures without a cage. For concrete cylinders in a fiberglass cage, the stress-strain curve is usually bilinear [13]. At an early stage of loading, the Poisson ratio of concrete is less than the Poisson ratio of the pipe material, so that the FRP-pipe does not create a boundary effect on the concrete core. In this regard, the angle of inclination of the first section of the diagram is the same as for bound concrete. In the future, the longitudinal strain increases so much that the lateral expansion of the concrete becomes greater than in the FRP-pipe. Radial pressure appears on the concrete surface. In this case, the concrete experiences a three-axis stress state. The second section of the diagram has a much smaller angle than the first section. The intersection point of the two linear branches of the diagram indicates, in essence, the initial damage to the concrete core in the cage. For fiberglass pipes filled with concrete, the increase in the limit axial strain ranges from 660–1100%, while carbon-polymer pipes exhibit a lower axial strain (300– 790%). Fiberglass pipes are destroyed as a result of the rupture of the specimen ruling at the end and the wedge-shaped crack propagation in a certain zone. Pipes with carbon fibers are destroyed simultaneously with the concrete core to form conical surfaces.

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3 Results and Discussions The author conducted experimental studies on specimens made of fine-grained concrete in the form of short cylinders with a length-to-diameter ratio equal to 3. A saw FRPpipe with a thickness of 1, 2 and 3 mm was used as a cage. The load was applied through a rubber gasket over the core area. Strains were measured using cells placed along the height of the cylinder in the longitudinal and transverse directions. Their registration was carried out on the basis of SIIT. Experiments have shown that the axial strain increases with increasing pipe thickness. It turned out to be 1.5–2.4 times greater than the strain of the bound concrete cylinder. The destruction of the pipe went along a line oriented on specimen ruling. The idea of concrete in the cage has spread to the bended elements of buildings and structures. In [14], we consider a beam on two articulated supports with a symmetrical load in the form of two concentrated forces, that is, having a region of pure bending. The cage is a square-section pipe made of a fiber composite (Fig. 1, a), and the core is a fiber concrete. a

b

c

Fig. 1. Stresses in bended element from fiber-reinforced concrete in a cage: a – cross-section; b – stresses diagram in fiber-reinforced concrete; c – stresses diagram in cage

An approximate representation is used based on a simplified assumption of the shape of the normal stress diagram in the stretched concrete zone after the formation of cracks (Fig. 1, b), when the fibers are stretched or extended through the cracks in the entire stretched area. rfbc – stress in the compressed zone; rfbu – tensile strength point after cracking, in the case of fiber exit from the matrix, calculated by the formula [15]: rfbu ¼ a Vm rbu þ bsVf

l ; d

ð6Þ

where Vm and Vf – are the volume fractions of the concrete (matrix) and fiber; l and d  are the length and diameter of the fiber; rbu – is the tensile strength point of the concrete; s – is the average binding stress; a and b – are the empirical constants. Figure 1, c shows the stress diagram in the cage, the material of which with the module Ecom follows Hooke’s law until destruction. Based on the flat section hypothesis, we have:

Concrete and Fiber-Reinforced Concrete

r1 ¼ rfbc

Ecom ; Efb0

r2 ¼ rfbc

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Ecom a  y : Efb0 y

PTo determine the unknown y and rfbc the equilibrium equations are used: 0; M ¼ 0; that is

ð7Þ P


 1 Ecom a  y 1 rfbc ay þ rfbc d a þ ð a  yÞ 2 2 Efb0 y   Ecom 1  rfbc d a þ y ¼ 0; 2 Efb0

X ¼

rfbu aða  yÞ 


 1 1 Ecom a  y 1 rfbu aða  yÞ2 þ rfbc ay2 þ rfbc d að a  y Þ þ ð a  y Þ 2 2 3 3 Efb0 y   Ecom a  y 1 2 ay þ y þ rfbc ¼ M; 3 Efb0 y

ð8Þ

ð9Þ

where M - is the bending moment in the cross-section of the beam. When writing formulas (8) and (9) due to the fact that a  d, simplifications are adopted that do not significantly affect the accuracy of the calculation. If the stresses rfbc or r2 exceed their permissible values, the fiber reinforcement should be adjusted for the core or the cage, respectively. The above calculation does not provide for a significant influence on the stress state of tangential stresses from transverse forces. When calculating the second limit state, the reduced rigidity Bred is represented as follows: Bred ¼

h io 1 n Efb0 ða  2dÞ4 þ Ecom a4  ða  2dÞ4 : 12

ð10Þ

This formula is also used when calculating statically indeterminate beams. The variational optimization problem of the considered design can be implemented on the basis of the energy criterion [16, 17]. Variable parameters include the thickness of the cage and the modules of the materials used.

4 Conclusion Pipe, concrete and fibers in columns and beams form rational structures that reduce the consumption of concrete and pipe material, reduce weight and labor costs. In comparison with steel pipes, cages made of polymers reinforced with fibers exhibit elastic properties and provide extending stresses up to failure [18]. The presented stress and strain formulas for concrete and fiber-reinforced concrete in the cage in the designated structural elements can be used to assess the reliability of the designed structures.

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Acknowledgements. This work was realized in the framework of the Program of flagship university development on the base of the Belgorod State Technological University named after V G Shukhov, using equipment of High Technology Center at BSTU named after V G Shukhov.

References 1. Rimshin, V., Truntov, P.: An integrated approach to the use of composite materials for the restoration of reinforced concrete structures. In: E3S Web of Conferences on Innovative Technologies in Environmental Science and Education (ITESE-2019), vol. 135, p. 03068 (2019) 2. Nelyubova, V.V., Babayev, V.B., Alfimova, N.I., Usikov, S.A., Masanin, O.O.: Improving the efficiency of fibre concrete production. Constr. Mater. Prod. 2(2), 4–9 (2019) 3. Grace, N.F., Abdel-Sayed, G., Ragheb, W.F.: Strengthening of concrete beams using innovative ductile fiber - reinforced polymer fabric. ACI Struct. J. 5, 692–700 (2002) 4. Harris, H.G., Somboonsong, W., Frank, K.K.: New ductile hybrid FRP reinforcement bar for concrete structures. J. Compos. Constr. 1, 28–37 (1998) 5. Saman, M.: Concrete-filled FRP tubes, 42 p. Ph.D. thesis, University of Central Florida (1997) 6. Monti, G., Spoestra, M.R.: Fiber-section analysis of RC bridge piers retrofitted with FRP jackets Structures Congress XV. In: Building to Last, pp. 884–888, ASCE, Portland (1997) 7. Miller, M.A.: FRP prepares as external reinforcement for concrete cylinders: research report, 92 p. University of Bethlehem (1994) 8. Mirmiran, A., Shahamy, M.: Behavior of concrete columns confined by fiber composites. J. Struct. Eng. ASCE 123(5), 583–590 (1997) 9. Yuriev, A.G.: Stress-strain state of pipe-concrete elements. Bull. Belglass 5(2), 460–463 (2000) 10. Mander, J.B.: Observed stress-strain behavior of confined concrete. J. Struct. Eng. ASCE 114(8), 1827–1849 (1998) 11. Richard, F.E., Brandtzaeg, A., Bown, R.L.: A study of failure of concrete under combined compressive stresses, vol. 190, no. 72, University of Illinois Bulletin, Illinois (1998) 12. Dolzhenko, A.V., Naumov, A.V., Shevchenko, A.V., Stoykovich, N.: Numerical studies of the stress-strain state of a plastic-tube concrete centrally compressed short rod. Bull. BSTU named after V.G. Shukhov 10, 23–32 (2018) 13. Saafi, M., Toutanji, H.A., Zongjin, Li.: Behavior of concrete columns confined with fiber reinforced polymer tubes. ACI Mater. J. 4, 500–509 (1999) 14. Panchenko, L.A., Serykh, I.R., Yuriev, A.G.: Stresses in pipe-reinforced concrete bending elements. Int. Res. J. 3(34), 110–111 (2015) 15. Panchenko, L.A.: Building Structures with Fiber Composites, 183 p. Publishing house of V. G. Shukhov BSTU, Belgorod (2013) 16. Yuriev, A.G.: Variational principles of construction mechanics, 90 p. Publishing house of Belgtasm, Belgorod (2002) 17. Yuriev, A.G., Panchenko, L.A., Naumov, A.E.: A variational statement of problem for the case of dispersely and discretely reinforced material. Int. J. Pharm. Technol. 8(3), 15361– 15369 (2016) 18. Karpikov, E.G., Lukuttsova, N.P., Soboleva, G.N., Golovin, S.N., Cherenkova, Y.: Effect of microfillers based on natural wollastonite on the properties of fine-grained concrete. Constr. Mater. Prod. 2(6), 20–28 (2019)

Wear Resistance of the Surface of the Structural Polyimide Composite Modified with Ceramic Corundum Coating R. N. Yastrebinsky(&) , V. V. Sirota and A. V. Yastrebinskaya

,

Belgorod State Technological University named after V.G Shukhov, Belgorod, Russia [email protected]

Abstract. In this paper, we consider the results of studies of the wear resistance of the surface of a highly filled polymer-carbon composite based on a polyimide matrix modified with a-Al2O3 ceramic corundum corundum layer. To increase the wear resistance of the composite, a layer of ceramic corundum coating based on aAl2O3 is applied to the surface of a filled, reinforced polymidic matrix by detonation gas-thermal spraying. The coating has a high degree of adhesion to the surface of the polyimide matrix. The thickness of the corundum coating layer is 200 lm. The results of studies of the wear resistance of the surface of a highly filled polymer-carbon composite based on a polyimide matrix modified with aAl2O3 ceramic corundum corundum layer are considered. It is shown that filling a polyimide composite with modified tungsten dioxide and applying a corundum coating significantly increases its wear resistance. The brittle-plastic fracture mechanism of the polymer composite coated with a-Al2O3 ceramic corundum coating was established, the filler was chipped, and the polymer retained plastic deformation. According to tribological studies, due to the presence of a corundum layer on the polymer surface, no signs of wear are observed. Keywords: Polyimide composite
Tungsten dioxide
Corundum coating
Wear resistance
Erosion wear
Fracture mechanism
Friction coefficient

1 Introduction The use of polymer composite materials in various industries, including construction, is due to their high performance characteristics, often not inferior, and in some cases superior to the properties of metal and concrete building structures. Building structures on cement binders can play the role of supporting skeletons, and polymers - the role of facing materials [1–3]. Designing polymer composites is often a complex and demanding process that requires an understanding of the manufacturing technology of composite building structures and its components [4–7]. The necessary properties of structural polymers are determined by the chemical nature of the polymer binder matrix, the type and concentration of the dispersed filler, and also modifying surface materials [8–11]. One of these characteristics is the corrosion and chemical resistance of polymer composites, manufacturability (ease of © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 137–142, 2021. https://doi.org/10.1007/978-3-030-54652-6_21

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preparation and processing), radiation resistance and radiation protective properties (due to the possibility of a high degree of filling of the polymer matrix with various high-density dispersed materials), as well as the wear resistance of the surface of modified filled polymers [12, 13]. In this regard, in this paper, we consider the results of studies of the wear resistance of the surface of a highly filled polymer-carbon composite based on a polyimide matrix modified with a-Al2O3 ceramic corundum corundum layer.

2 Methods and Materials For research, we used a polymer composite based on a polyimide matrix filled with modified tungsten dioxide (60 wt%) and reinforced with carbon fabric [14–16]. To increase the wear resistance of the composite, a layer of ceramic corundum coating based on a-Al2O3 is applied to the surface of a filled, reinforced polymidic matrix by detonation gas-thermal spraying. The coating has a high degree of adhesion to the surface of the polyimide matrix. The thickness of the corundum coating layer is 200 lm. The microhardness of the corundum coating was evaluated using a Hi-end Nexus 4000 class automatic microhardness meter in the load range from HV1 to HV50 using Vickers, Knoop, and Brinell indenters. The fingerprint of the microhardness meter intender was evaluated using an integrated electronic digital microscope with a precision sensor. The erosion resistance of the samples was studied at 25 °C in accordance with ASTM G76-02 «Standard Test Method for Conducting Erosion Tests by Solid Particle Impingement Using Gas Jets» using the Air Jet Erosion Testing Machine TR-471–400. The test time for all samples was 1 h, the consumption of abrasive material was 2.2 g/min; corundum powder (Al2O3) with an average fraction of 50 lm was used as abrasive material. The air pressure was 0.35 bar. Erosion wear was calculated from the ratio of volume loss to feed rate of abrasive particles: ðm0  m1 Þ
S q

ð1Þ

where m0 - is the mass of the sample before the test; m1 - is the mass of the sample after the test; q - is the density of the sample (coating); S - is the speed of abrasive particles. The tribological characteristics of the modified polyimide composite (corundum coating wear) were carried out on an MTU-1 universal friction machine using a set of reference mass weights. The friction coefficient in the tribocouple was calculated by the formula: K ¼

Fd R0 Fn ¼ P Rk P

ð2Þ

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where Fd - is the interaction force of the contacting surfaces of the friction pair, P - is the calibration characteristic of the load force, Rk - is the average radius of the contact spot, R0 - is the distance from the rotation circle to the thrust pin, Fn - is the force acting on the elastic element. The value of the coefficient of friction is variable and depends on many factors. The technique of constructing calibration graphs before each measurement allows minimizing the influence of factors such as ambient temperature, pressure, etc.

3 Results and Discussions According to ten tests, the average microhardness of the polymer composite coated with a-Al2O3 ceramic corundum coating was 846 HV/0.2, and the interval of values was 806–902 HV/0.2. The image of the indenter print of a microhardness tester when measuring the microhardness of an Al2O3-based coating is shown in Fig. 1.

Fig. 1. Image of the indenter print of a microhardness tester when measuring the microhardness of an Al2O3 coating.

The test results of the developed materials for erosion wear showed that a pure polyimide composite has an erosion wear of 0,018 10−3 mm3/g. In this case, the central part of the erosion wear spot has a characteristic deepening of viscous-brittle fracture (Fig. 2a). The central part of the erosion wear spot of the polyimide composite with 60% wt. filling with tungsten dioxide has a characteristic deepening of fracture (Fig. 2b) with erosion wear of 0,081 10−3 mm3/g. The presence of shallow recesses throughout the area of influence indicates a fragile fracture mechanism, spalling of the filler. Evaluation of the erosion wear of a polymer composite coated with a-Al2O3 ceramic corundum coating indicates a brittle fracture mechanism under the influence of the flow of abrasive particles (Fig. 2c). The smoothed perimeter indicates the viscousbrittle nature of the destruction of the coating. Erosion wear is 0.034 10−3 mm3/g.

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Fig. 2. Image of the surface (Digital Video Microscope HIROX KH-7700 3D) of the polymer composite during erosion wear: a - pure polyimide composite; b - polyimide composite with 60% wt. filling with vol-fram dioxide; c - polymer composite coated with a-Al2O3 ceramic corundum coating.

According to the results of tribological studies in Fig. 3 and Fig. 4 shows photographs of the surface wear of a polyimide composite filled with modified tungsten dioxide (Fig. 3) and of a composite coated with a 200 lm thick a-Al2O3 ceramic corundum coating (Fig. 4), which indicate that at the same time on the surface a wear hole was formed on the pure composite, and no signs of wear were observed on the coated composite.

Fig. 3. Results of surface wear of a pure polyimide composite.

In Fig. 5 shows a graph of the change in the coefficient of friction for a polyimide composite coated with a-Al2O3 ceramic corundum coating with a thickness of 200 lm. Analyzing the graph of the dependence of the coefficient of friction on the time of wear, we can distinguish the following characteristic sections: 1 - plot grinding surface of the counterbody, which takes about several seconds; 2 - wear section of corundum coating lasting about 150 s; 3 - the area of wear of corundum coating, which lasts the longest time (about 250 s); 4 - a section characterized by a significant increase in the coefficient of friction, which indicates the wear of the coating and the friction of the counterbody on the polymer substrate.

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Fig. 4. Results of surface wear of a polyimide composite coated with a-Al2O3 ceramic corundum coating.

Fig. 5. Dynamics of changes in the coefficient of friction for a polyimide composite coated with a-Al2O3 ceramic corundum coating with a thickness of 200 lm.

4 Conclusion The erosive wear of the polymer composite coated with a-Al2O3 ceramic corundum coating showed the presence of many shallow depressions throughout the exposure area, which indicates a brittle-plastic fracture mechanism, spalling of the filler, and plastic deformation that holds its polymer. According to tribological studies, due to the presence of a corundum layer on the polymer surface, no signs of wear are observed. Acknowledgments. The work was supported by a project of the Russian Science Foundation (№19-19-00316).

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References 1. Sokolskay, M.K., Kolosova, A.S., Vitkalova, I.A., Torlova, A.S., Pikalov, E.S.: Binders for obtaining modern polymer composite materials. Fundam. Res. 10(2), 290–295 (2017) 2. Kolosova, A.S., Sokolskaya, M.K., Vitkalova, I.A., Torlova, A.S., Pikalov, E.S.: Fillers for the modification of modern polymer composite materials. Fundam. Res. 10(3), 459–465 (2017) 3. Kozhukhova, N.I., Strokova, V.V., Kozhukhova, M.I., Zhernovsky, I.V.: Structure formation in alkali activated aluminosilicate binding systems using natural raw materials with different crystallinity degree. Constr. Mater. Prod. 1(4), 38–43 (2018) 4. Cherkashina, N.I., Pavlenko, A.V.: Synthesis of polymer composite based on Polyimide and Bi12SiO20 Sillenite. Polymer Plast. Tech. Eng. 57, 1923–1931 (2018) 5. Pavlenko, V.I., Cherkashina, N.I.: Synthesis of hydrophobic filler for polymer composites. Int. J. Eng. Technol. 7, 493–495 (2018) 6. Yastrebinsky, R.N.: Distribution neutron and gamma of radiation in the protective composite with various content of atoms of boron. Probl. Atom. Sci. Technol. 5, 66–72 (2016) 7. Pavlenko, V.I., Edamenko, O.D., Cherkashina, N.I., Noskov, A.V.: Total energy losses of relativistic electrons passing through a polymer composite. J. Surf. Investig. X-ray, Synchrotron Neutron Tech. 8(2), 398–403 (2014). https://doi.org/10.1134/S102745101402 0402 8. Pavlenko, V.I., Zabolotny, V.T., Cherkashina, N.I., Edamenko, O.D.: Effect of vacuum ultraviolet on the surface properties of high-filled polymer composites. Inorg. Mater.: Appl. Res. 5(3), 219–223 (2014). https://doi.org/10.1134/S2075113314030137 9. Pavlenko, V.I., Cherkashina, N.I., Zaitsev, S.V.: Fabrication and characterization of nanocomposite films Al, Cu/Al and Cr/Al formed on polyimide substrate. Acta Astronaut. 160, 489–498 (2019) 10. Cherkashina, N.I., Pavlenko, V.I., Noskov, A.V.: Radiation shielding properties of polyimide composite materials. Radiat. Phys. Chem. 159, 111–117 (2019) 11. Yastrebinsky, R.N.: Attenuation of neutron and gamma radiation by a composite material based on modified titanium hydride with a varied boron content. Russ. Phys. J. 12(60), 2164–2168 (2018) 12. Rybiev, I.A.: Materials Science in Construction. Publishing Center Academy (2006) 13. Kochurov, D.V.: High-strength polymer composite materials. Int. Stud. Sci. Bull. (5). http:// eduherald.ru/ru/article/view?id=19200. Accessed 25 Nov 2019 14. Cherkashina, N.I., Pavlenko, A.V.: Modification of optical characteristics of a polymer composite material under irradiation. Tech. Phys. 63(4), 571–575 (2018). https://doi.org/10. 1134/S1063784218040072 15. Pavlenko, V.I., Bondarenko, G.G., Cherkashina, N.I.: Physicomechanical characteristics of composite based on polyimide matrix filled with tungsten oxide. Inorg. Mater.: Appl. Res. 11(2), 304–311 (2020). https://doi.org/10.1134/S2075113320020306 16. Cherkashina, N.I.: Stability of polymer composites with tungsten oxide against electron irradiation. Tech. Phys. 65(1), 107–113 (2020). https://doi.org/10.1134/S106378422001 0028

Fiber Concrete on Greenest Cementitious Binders for Road Construction R. S. Fediuk1(&)

, A. V. Klyuev2 , Y. L. Liseitsev1 and R. A. Timokhin1

,

1

2

Far Eastern Federal University, Vladivostok, Russia [email protected] Belgorod State Technological University named after V.G. Shukhov, Belgorod, Russia

Abstract. The urgent task of the construction industry at present is the search for durable building materials for pavement. Cement concrete in road construction is promising because of its durability and wear resistance. Fiber concrete compositions based on greenest cementitious binders with both steel and basalt fiber have been developed. The microstructure of composites, as well as the characteristics of static and dynamic strength, have been investigated. In the study of crack resistance upon impact stress of fiber reinforced concrete with various types of fibers, it has been found that optimization of the composite structure due to the introduction of fibers made it possible to increase the tensile strength of concrete (before the formation of the first crack) up to 9 times in comparison with the corresponding mixtures without fiber. The developed materials can be used for cement concrete road clothes, as well as for other special applications in the construction of unique buildings and structures. Keywords: Steel fibers
Fiber reinforced materials
Fiber-reinforced concrete
Cements
Mortar
Cement-based composites

1 Introduction Due to the low durability of asphalt concrete, effective cement concrete for paving is currently gaining particular importance. For these concretes, a special set of characteristics is needed - static compressive and tensile strength, impact strength, dynamic strength, crack resistance and workability [1–3]. The design of materials that can provide a set of these characteristics at a given level is possible only by using the latest achievements in building materials science and controlling the processes of structure formation using multicomponent systems [4–6]. At the same time, care for human life and health from the standpoint of the “manmaterial-environment” system should be taken into account even at the stage of production of materials. Reducing the consumption of clinker raw materials and energy consumption of the manufacture of materials, as well as the disposal of industrial waste are the most important steps on this path [2, 7, 8]. Thus, it seems appropriate to develop fiber-reinforced concrete taking into account the increase in their effectiveness by promising composite binders using local raw materials and production waste [9–15]. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 143–149, 2021. https://doi.org/10.1007/978-3-030-54652-6_22

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Objective: to develop effective dispersion-reinforced concrete on environmentally friendly composite binders for road structures. To achieve this objective, the following tasks have been solved: – study of the material composition, structure and qualitative characteristics of the starting materials; – development of greenest cementitious binders (GCB) based on Portland cement and polymineral additives; selection of the optimal composition and manufacturing parameters of the GCB, taking into account the provision of the required physical, mechanical and rheological characteristics of fiber concrete; – identification of the mechanism of structure formation of fiber concrete on the GCB; – static and dynamic strength characteristics of fiber concrete.

2 Methods and Materials Considering the fact that Primorsky Krai is one of the first places in the country for harvesting rice, the authors previously developed a technology to produce rice husk ash (RHA) [12], which involves the heat treatment of rice husk at a temperature of 800900 °C for 2 h. The sample consists of particles up to 60 lm in size, the surface of which repeats the relief of the grain membrane (Fig. 1).

Fig. 1. RHA microstructure

In addition to the synthesized RHA, the composition of the GCB included Portland cement CEM I 42.5N (Spasskcement, Russia), 7% of finely ground quartz sand (Razdolnenskoye deposit, Russia) and 8% of the screening of crushing limestone (Dlinnognogorskoye deposit, Russia). Considering that RHA is a hydrophilic material, the Pantarhit PC 160 superplasticizer (SP) (Betonchemie, Germany) has been used to reduce the water-cement ratio.

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The quartz sand (Razdolnenskoye deposit, Russia) has been used as aggregates. To create fiber-reinforced concrete, two types of fiber have been used, steel and basalt ones (Akstrimstroy, Russia). The microstructure of raw materials and synthesized composites has been studied using a MIRA TESCAN electron microscope (Brno, Czech Republic). Cubic and prismatic compressive strengths have been investigated on a hydraulic press using standard specimens. Tensile strength has been tested on a tensile testing machine. Based on the data obtained, the elastic modulus of concrete was calculated. Dynamic characteristics have been studied using a falling impactor (mass 10 kg, drop height 2 m) [16].

3 Results and Discussion Table 1 lists the developed compositions of fine-grained concrete using the methods of mathematical planning of the experiment. A study of the characteristics of an unreinforced composite revealed that the use of the GCB is more effective compared to traditional compositions due to compaction of the microstructure of the hardening composite, reduced overall porosity, reduced water demand of the mixture, and increased adhesion between the cement paste and aggregates. Table 1. Physicomechanical properties of the fine-grained concrete depending on the composition of the binder ID

1 2 3 4 5 6 7 8 9 Note:

Consumption of materials per 1 m3, kg CEM Fillers SP FA Water 702 452 11 646 508 15 582 572 18 652 502 11 606 548 15 631 523 18 601 553 11 695 459 18 631 523 15 Filler (Rice husk ash +

Cubic Prism strength, strength, MPa MPa 1020 235 71,2 53,9 1020 223 73,6 54,0 1020 201 70,4 53,6 1020 253 69,8 52,8 1020 231 82,6 65,2 1020 203 68,0 52,9 1020 251 72,9 54,1 1020 196 75,3 50,3 1020 221 71,2 53,8 ground quartz sand + crushing limestone)

Elaslic modulus, GPa 40,1 41,0 39,2 38,4 55,3 37,2 40,9 41,3 40,8

The high strength properties of the ID5 composition are ensured by the fact that, in contrast to the traditional cement paste (Fig. 2, a, b), the reduced content of voids and microcracks is observed in the composite obtained. Clearly distinguishable needle and plate-type new growths are observed that fill isometric and anisometric pores (Fig. 2, c, d).

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Fig. 2. Microstructure of new growths (age 28 days): pure cement paste (a, b) and cementitious paste on the GCB (ID 5) (c, d)

Based on the concrete matrix of composition ID5, a wide range of low-porous dispersed reinforced concrete of high density with a different percentage of fiber reinforcement has been developed (Fig. 3).

Fig. 3. The influence of the percentage of reinforcement with various types of fiber on the tensile strength (a) and elastic modulus (b) of fiber-reinforced concrete

It has been revealed that the nature of the effect of the amount of both basalt and steel fibers on the tensile strength and elastic modulus of fiber concrete is almost the same. In the study of crack resistance upon impact of fiber-reinforced concrete (Fig. 4) reinforced with various types of fibers, it has been found that optimization of the composite structure due to the introduction of fiber made it possible to increase the

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tensile strength of concrete (before the formation of the first crack) up to 9 times in comparison with the corresponding mixtures without fiber.

Fig. 4. Dependence of the number blows for the formation of the first crack (a) and for the failure of fiber concrete on the volume concentration of fiber (b)

Both steel and basalt fiber were effective in preventing the growth of microcracks and reducing the propagation of these cracks before the cracks joined to form macrocracks. Even after the formation of the first cracks, the specimen was able to withstand a large amount of impact load before it collapsed (Fig. 5). The final impact energy (before destruction) has increased significantly. This means that the developed fiber concrete has high impact strength and excellent potential for use as a structural material for pavement.

Fig. 5. Failure of samples without fiber (a) and with fiber (b)

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4 Conclusion In the course of the study, greenest compositions of fiber-reinforced concrete with steel and basalt fiber were developed, the study of which gave the following conclusions: 1. Fiber-concrete, developed based on greenest cementitious binders, are effective for the construction and operation of pavement. The relationship between the components of GCB, the content of fine aggregate and the processes of structure formation has been revealed, which allows to significantly increasing operational characteristics. 2. The regularities of the influence of prescription factors on the static and dynamic strength and fiber concrete are established. The optimal compositions were designed based on certain natural technogenic resources of the Primorsky Krai, which have high adhesion to the cement matrix. 3. It has been revealed that the nature of the effect of the amount of basalt and steel fibers on the tensile strength and elastic modulus of fiber concrete is almost the same. In the study of crack resistance upon impact of fiber reinforced concrete reinforced with various types of fibers, it has been found that optimization of the composite structure due to the introduction of fibers made it possible to increase the tensile strength of concrete (before the formation of the first crack) up to 9 times in comparison with the corresponding mixtures without fiber.

References 1. Klyuev, S.V., Khezhev, T.A., Pukharenko, Y.V., Klyuev, A.V.: Fiber concrete on the basis of composite binder and technogenic raw materials. Mater. Sci. Forum (2018). https://doi. org/10.4028/www.scientific.net/MSF.931.603 2. Abirami, T., Loganaganandan, M., Murali, G., Fediuk, R., Vickhram Sreekrishna, R., Vignesh, T., Januppriya, G., Karthikeyan, K.: Experimental research on impact response of novel steel fibrous concretes under falling mass impact. Constr. Build. Mater. (2019). https:// doi.org/10.1016/j.conbuildmat.2019.06.175 3. Fediuk, R., Smoliakov, A., Stoyushko, N. Increase in composite binder activity. IOP Conf. Ser.: Mater. Sci. Eng. (2016). https://doi.org/10.1088/1757-899X/156/1/012042 4. Fediuk, R., Pak, A., Kuzmin, D. Fine-grained concrete of composite binder. IOP Conf. Ser.: Mater. Sci. Eng. (2017). https://doi.org/10.1088/1757-899X/262/1/012025 5. Fediuk, R., Timokhin, R., Mochalov, A., Otsokov, K., Lashina, I.: Performance properties of high-density impermeable cementitious paste. J. Mater. Civ. Eng. 31 (2019). https://doi.org/ 10.1061/(ASCE)MT.1943-5533.0002633 6. Klyuev, S.V., Klyuev, A.V., Khezhev, T.A., Pukharenko, Y.V.: High-strength fine-grained fiber concrete with combined reinforcement by fiber. J. Eng. Appl. Sci. (2018). https://doi. org/10.3923/jeasci.2018.6407.6412 7. Klyuev, S.V., Klyuev, A.V., Khezhev, T.A., Pucharenko, Y.: Technogenic sands as effective filler for fine-grained fibre concrete. J. Phys: Conf. Ser. 1118, 012020 (2018) 8. Evelson, L., Lukuttsova, N.: Application of statistical and multi fractalmodels for parameters optimization of nano-modified concrete. Int. J. Appl. Eng. Res. 10(5), 12363–12370 (2015)

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9. Klyuev, S.V., Klyuev, A.V., Shorstova, E.S.: The micro silicon additive effects on the finegrassed concrete properties for 3-D additive technologies. Mater. Sci. Forum 974, 131–135 (2019) 10. Fediuk, R.S., Lesovik, V.S., Liseitsev, Y.L., Timokhin, R.A., Bituyev, A.V., Zaiakhanov, M.Y., Mochalov, A.V.: Composite binders for concretes with improved shock resistance. Mag. Civ. Eng. (2019). https://doi.org/10.18720/MCE.85.3 11. Fediuk, R.S., Cherneev, A.M.: Development of power supply devices for limitations of short circuit on the ship’s hull. IOP Conf. Ser.: Mater. Sci. Eng. (2016). https://doi.org/10.1088/ 1757-899X/124/1/012009 12. Fediuk, R.S., Smoliakov, A.K., Timokhin, R.A., Batarshin, V.O., Yevdokimova, Y.G. Using thermal power plants waste for building materials. IOP Conf. Ser.: Earth Environ. Sci. (2018). https://doi.org/10.1088/1755-1315/87/9/092010 13. Klyuev, S.V., Klyuev, A.V., Shorstova, E.S.: Fiber concrete for 3-D additive technologies. Mater. Sci. Forum 974, 367–372 (2019) 14. Strokova, V.V., Babaev, V.B., Markov, A.Yu., Sobolev, K.G., Nelyubova, V.V.: Comparative evaluation of road pavement structures using cement concrete. Constr. Mater. Prod. 2 (4), 56–63 (2019) 15. Nelyubova, V.V., Babayev, V.B., Alfimova, N.I., Usikov, S.A., Masanin, O.O.: Improving the efficiency of fibre concrete production. Constr. Mater. Prod. 2(2), 4–9 (2019) 16. ACI Committee 544: State-of-the-art report on fiber reinforced concrete reported by ACI Committee 544. ACI Struct. J. (2002)

Development of Composite Binders’ Compositions for Additive Technologies in Low-Rise Building Construction E. S. Glagolev(&) Belgorod State Technological University named after V.G. Shukhov, Belgorod, Russia [email protected]

Abstract. One of the new advanced technologies in low-rise buildings construction is 3D–printing technology, for development of which creating efficient materials with the required adjustable properties on the basis of hydration composite with micro-, ultra- and nanodispersed mineral admixtures and extenders in combination with hyper- and superplasticizers is necessary. The paper considers the opportunity of obtaining composite binders and quicksetting composite gypsum binders for this purpose. As an active mineral admixture in the binders the opoka marl was used, which demonstrates hydraulic activity at its interaction with Ca(OH)2 with forming low-basic hydrous calcium silicates and other formations. In the process of binders’ structurization with mineral admixtures Ca(OH)2 is fixed and excluded from the reaction. Hydrolysis of clinker minerals is catalyzed; simultaneously the amount of low-basic hydrous calcium silicates like CSH(B) is increased, which positively influences the properties of hardened binders. The findings of the carriedout research confirm the possibility and feasibility of using the OM as an active mineral admixture in compositions of CB and CGB, which would improve their performance characteristics in general, provide quick strength gain of binders at the initial setting time, except for the subsequent self-destruction of the structure due to crystallization pressure. Keywords: Composite binders
Composite gypsum binders admixtures
Opoka marl
Properties


Mineral

1 Introduction In recent decades both in Russia and abroad some innovative technologies of construction operations have come into use, including 3D-technologies (concrete 3Dprinting) in low-rise buildings construction, which can provide the implementation of almost any solution: reducing the time and cost for buildings’ construction due to no need for specialized equipment; possibility of quick and flexible changes in the project at its production stage; possibility and economic feasibility of small-quantity production; reducing losses and waste products, environmental friendliness; opportunities for simplifying logistics, reducing delivery time and volumes of materials in storage; creation of various architectural solutions etc. The theoretical basis for creating the © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 150–157, 2021. https://doi.org/10.1007/978-3-030-54652-6_23

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new-generation composites for 3D-printing is the fundamental premises of a new transdisciplinary science – geonics or geomimetics [1–9]. For implementing the opportunities of 3D-printing in various spheres of construction one of the most challenging and complicated problems is creating efficient composite materials and concrete mixes on their basis for various purposes and with required adjustable properties (quick setting time, high strength, uniformity and bonding strength between different layers), by using cost-efficient and widely available natural-balanced raw materials with account of their genesis. Especially effective for these purposes, in comparison with Portland cement, are the new-generation hydraulic binders – composite binders (CB) and quick-setting composite gypsum binders (CGB), obtaining of which is accompanied with using the complex compositions as components – Portland cement (PC), modifying active mineral admixtures (MA) and extenders of various genesis, gypsum binders and other types of admixtures [7–9]. The chemical activity of MA to PC is of particular importance. The amorphous phase of SiO2 in MA promotes fixation of Ca(OH)2, disengaged at the hydration of alite, and reduction of the hardening composition’s basicity with eliminating growth conditions for high-basic hydrated calcium aluminates and ettringite, and with formation of tobermorite-like low-basic slightly-soluble hydrous calcium silicates, which compact the microstructure and increase waterresistance and stability of composites. But, lack of the already carried-out research concerning the usefulness of such material and its influence on composite binders’ properties limits the opportunity of its wide application. Within the framework of implementing the Flagship University development program on the basis of BSTU named after V.G. Shukhov up to 2021, and with the purpose of expanding the range of available and cost-effective raw materials, the integrated research of obtaining efficient CB and CGB was carried out.

2 Methods and Materials As active mineral admixtures (AMA) the fine-ground opoka marl (OM) was used - a carbonate-siliceous rock, which can react with components of the binder and actively influence the physical and chemical processes in the hardening composition. The properties and structure of raw materials and hardened binders was studied by using high-precision instrumental research methods and standard procedures.

3 Results and Discussions To obtain the efficient CB and CGB for 3D-additive technologies, the principle of directed control over the production process at all its stages was taken as a basis: – – – –

using active mineral admixtures made of the natural or waste raw materials; implementing the mechano-chemical activation of binders’ components; designing the balanced compositions of efficient composite binders; using chemical modifiers and other methods.

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To obtain the efficient CB and CGB the well-graded components (Portland cement + finely-dispersed mineral admixture + gypsum GVVS-16) were mixed, and then for a short time ground in a laboratory vibratory mill. The mineral admixture – opoka marl – was preliminarily ground to the specific surface 500 m2/kg. The opoka marl (OM) is a carbonate-siliceous rock, which contains calcite – 35– 38%, mixed-layer clay formations – 10–20%, zeolites – 10−20%, opal – up to 15%. Some of the minerals in OM are amorphous or have defective crystal lattice, which predetermines their sorption and pozzolanic activity (Fig. 1).

Fig. 1. Microstructure of opoka marl, SEM

In the opoka marl’s composition, the most quantitatively prevailing oxides are SiO2, Al2O3, Fe2O3 and CaO, which in the finely-powdered form can interact with Ca (OH)2, forming insoluble compounds. The chemical composition of OM is presented in Table 1. Table 1. The chemical composition of the MA Type of admixture SiO2 Al2O3 Fe2O3 P2O5 TiO2 MgO CaO R2O SO3 ппп Opoka marl 34.92 4.61 6.31 0.21 – 1.02 30.52 0.12 0.37 21.9

During the research, the hydraulic activity of a fine-ground OM was experimentally determined. As it is known, the reaction activity of a mineral admixture is increased during grinding, due to the increase of crystalline structure defects and partial amorphization of the quartz particles surface layers, which promotes fixation of Ca(OH)2, disengaged at the hydration of alite with formation of slightly-soluble hydrous calcium silicates, like CSH(B), at ordinary temperature (Table 2).

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Table 2. Absorption activity of MA for CaO Type of admixture Specific surface, m2/kg Absorption activity for CaO (titration), mg/g Opoka marl (OM) 487 76.4

To provide the optimum experimental conditions of CGB hardening, according to the TS, in GCPB 21-31-62-89, the optimum ratio of the finely-dispersed opoka marl and Portland cement was set. As a result of the carried-out research the ratio between the finely-dispersed OM and PC – 1:0.5 was determined, which provides the optimum conditions of CGB hardening with reducing the concentration of Cao in solution (Table 3). Table 3. Alterations of CaO concentration in CGB water suspension № Materials, g

1 2

Concentration of CaO in solution, g/l, after: Gypsum PC OM 5 days 7 days 4 2.5 1.25 1.02 0.87 4 2.5 2.5 0.97 0.86

On the basis of the obtained findings the CGB formula was determined (% by weight): gypsum: cement: OM – 60:26.7:13.3. The properties of CB and CGB are influenced by the dispersity value of their components. In the previously conducted research of the CB particle-size distribution and [7–9] the significant shift of graphs was determined (in comparison with Portland cement) from the range of coarse particles (100 µm) to the range of finer particles (up to 60 µm), and the reduction of particles’ fractions in the range 3…6 µm with the increase in the range 0.06…0.5 µm, which indicates the increased dispersity, which promotes the compaction of the binders’ structure, optimizes their particle-size distribution, catalyzes their structure formation processes and, as a result, increases their strength. The findings of strength characteristics of CB and CGB, hardening in normal conditions, simulating the conditions of OM contact with clinker minerals and the processes of their interaction, are presented in Table 4.

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№ Composition, % Properties PC OM G-16 Syд. m2/kg SC % Setting time, initial/final min Rcomp, MPa, in time 7 days 28 days Without SP 1 100 – – 324 27 121/141 54.6 62.5 2 90 10 – 551 32 176/192 58.8 64.8 3 26.7 13.3 60 498 42 8/9 25.8 28.4 With SP 3 100 – – 324 18 28/160 64.2 76.0 4 90 10 – 551 23 15/168 75.3 79.3 5 26.7 13.3 60 498 34 16/18 27.2 29.3 Note: the CGB activity was determined on cube samples, 30  30  30 mm CB – with SP Muraplast FK 19 (0.1%); CGB – with SP SikaPlast 2135(0.3%)

The hydration activity of CB and CGB is provided by their high specific surface and mechano-activated surface layers of cement grains and fine fractions of OM, which determines their physical and mechanical performance. The optimum content of OM (10%) in the hardened CB provides strength increase by 1.3 times in comparison with hardened cement due to the increase of hydrate formations’ volume concentration and interaction of Ca(OH)2 with OM active components. To improve physical and mechanical properties of the binders, superplasticizers Muraplast FK 19 (0.1%) and SikaPlast 2135 (0.3%) of the binder’s mass were used, providing the possibility of adjusting their structure formation in the plastic stage and in the process of hardening. For the CB the efficiency of SP Muraplast FK 19 (0.1%) was determined, and for CGB - SP SikaPlast 2135 (0.3%) in reducing the water demand for the grout of normal consistency [7–11]. The admixtures were added with the gauging water (Table 4). As a result of the research it was found out that in CB samples with OM at adding SP Muraplast FK 19 with its deflocculating effect, the normal grout consistency is significantly reduced (by 28–31%), the initial setting time is accelerated (by 8 times) and the ultimate compressive strength is increased (up to 20% at the average) as compared to CB without SP. The presence of zeolite and opal in OM, along with calcite and mixed-layer clay formations, allows accelerating the process of mixes setting in the optimum time parameter. In the hardened CGB samples with OM and SP SikaPlast 2135 water demand is reduced by 19% with the slight increase of strength (by 5%), but due to the surface adsorption and the effect of intermolecular electrostatic repulsion and steric repulsion of CGB particles, as well as the simultaneous process of the polymer’s interaction with binder’s phases, the premature setting is inhibited by half.

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The integrated research of the hardened CB and CGB phase composition at the 28days age was carried out, which demonstrated that adding OM to the compositions of CB and CGB increased the hydration degree of clinker minerals – C3S (d = 2.76; 2.19…Å) and C2S (d = 2.78; 2.74; 2.19…Å), and reduced the amount of Ca(OH)2 – (d = 4.93; 3.11; 2.63; 1.93; 1.79; 1.69…A). As a result of Ca(OH)2 fixation and its exclusion from the reaction the hydrolysis of clinker minerals C3S и C2S is accelerated and their amount is considerably reduced as well. At the same time the amount of lowbasic hydrous calcium silicates like CSH(B) is increased, which positively influences the properties of hardened binders. Ettringite is virtually not discovered in X-ray patterns. The electronic microscopy findings confirm the stability of the formed CB and CGB structures at their early strength (Fig. 2). Heterogeneous composition of binders with the mineral admixture OM promotes synthesis of the stronger and more compact structure of composites with the distinguishable filling of intergranular space and pores.

a)

b) Fig. 2. Microstructure of the hardened CB (a) and CGB (в) with mineral admixture OM

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The crystallized formations are densely formed on the surface of OM particles, forming microstructure with no apparent defects, which increases the strength of hardened CB and CGB (Fig. 2).

4 Conclusions So, the findings of the carried-out research confirm the possibility and feasibility of using the OM as an active mineral admixture in compositions of CB and CGB, which would improve their performance characteristics in general, provide quick strength gain of binders at the initial setting time, except for the subsequent self-destruction of the structure due to crystallization pressure. The designed CB and CGB with mineral admixture OM can be recommended for using in production of efficient composite materials and concrete mixes on their basis for various purposes and with required adjustable properties (quick setting time, high strength) for implementing the opportunities of 3D-printing in low-rise buildings construction. Acknowledgements. This work was realized in the framework of the Program of flagship university development on the base of the Belgorod State Technological University named after V G Shukhov, using equipment of High Technology Center at BSTU named after V G Shukhov.

References 1. Kazlitina, O.V., Glagolev, E.S.: Geonika. Geommimetics is the theoretical basis for the development of fine concrete. In the collection: high technologies and innovations Electronic collection of reports of the International scientific and practical conference dedicated to the 65th anniversary of BSTU named after V.G. Shukhov, pp. 207–210 (2019) 2. Zagorodnjuk, L.H., Lesovik, V.S., Chernysheva, N.V., Voronov, V.V., Absimetov, M.V.: The objective prerequisites for transition to composite binders. Int. J. Pharm. Technol. 8(4), 22525–22537 (2016) 3. Elistratkin, M.Y., Lesovik, V.S., Alfimova, N.I., Shurakov, I.M.: On the question of mix composition selection for construction 3D printing. Mater. Sci. Forum 945, 218–225 (2018) 4. Elistratkin, M.Y., Ermolaeva, A.E., Belashova, A.N.: Additive technologies in construction production. In the collection: Science and innovations in construction. Collection of reports of the International scientific-practical conference (on the 165th birthday of V.G. Shukhov), pp. 369–372 (2018) 5. Denisova, Y.: Additive technology in construction. Constr. Mater. Prod. 1(3), 33–42 (2018) 6. Klyuev, S.V., Klyuev, A.V., Shorstova, E.S.: The micro silicon additive effects on the finegrassed concrete properties for 3-D additive technologies. Mater. Sci. Forum 974, 131–135 (2019) 7. Glagolev, E.S., Voronov, V.V.: The efficient composite binder for cast-in-situ aerated concrete. Bull. BSTU Named After V.G. Shukhov 79–84 (2016) 8. Elistratkin, M.Yu., Glagolev, E.S., Absimetov, M.V., Voronov, V.V.: Composite binder for structural cellular concrete. Mater. Sci. Forum 945(53) (2019)

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9. Chernysheva, N.V., Lesovik, V.S., Drebezgova, MYu., Shatalova, S.V., Alaskhanov, A.H.: Composite gypsum binders with silica-containing additives. IOP Conf. Ser.: Mater. Sci. Eng. 327(3), 032015 (2018) 10. Poluektova, V.A., Shapovalov, N.A., Novosadov, N.I.: Kinetics of heat release and hydration features of modified polymer-cement mixtures for 3D construction printing. Promising Mater. 3, 54–61 (2019) 11. Klyuev, S.V., Klyuev, A.V., Shorstova, E.S.: Fiber concrete for 3-D additive technologies. Mater. Sci. Forum 974, 367–372 (2019)

Crack Closure in a Cement Matrix Using Bacterial Precipitation of Calcium Carbonate V. V. Strokova

, U. N. Dukhanina(&)

, and D. A. Balitsky

Belgorod State Technological University named after V.G. Shukhov, Belgorod, Russia [email protected], {Duhanina777,DmitryBalitsky2020}@yandex.ru

Abstract. The article presents the analysis the degree of clogging of mechanically formed cracks by new growths induced as a result of the urease activity of bacteria in model solutions. Intensification of the induction of new formations depending on the type of bacterial culture is characterized by the formation of positive reliefs on the surface of the cement stone. The continuous fouling of the inner surface of the formed fault by crystals of various morphologies formed as a result of the enzyme activity of bacterial strains is visualized. The authors propose the method for calculating the area of an asymmetric fracture with different widths of the convergence of parts. The results of the intensification of precipitation of crystals are determined by the coefficient of crack closure. On the basis of comparative analysis of bacterial cultures by the intensity of continuity reattachment in the fracture zone, they were ranked according to the increase of efficiency of the following sequence: S. pasteurii ! B. pumilus ! B. megaterium ! L. sphaericus. Keywords: Self-healing inoculum

 Concrete  Calcium carbonate  Crack  Bacterial

1 Introduction Despite the great variety of existing methods and technological solutions for the restoration of concrete products during the formation of various kinds of micro-defects and cracks [1], one of the rather new, but promising areas is the use of carbonate biomineralization [2]. Bacterial sedimentation of lime stone in cement matrix leads to densification of the pore space and filling of the cracks with new growths, which, accordingly, leads to the restoration of the structure of the cement stone and the initial physical and mechanical properties of concrete products. A cement stone with restoration properties during its operation can be obtained by the introduction of a bacterial inoculum in the form of a solution or lyophilisate into mixing water or introduction of strains directly into cement before mixing with water [3, 4]. In order to eliminate the adverse effects of high pH values (13–14), bacteria are placed in carriers made of hydrogel [5], prepolymer [6], glass [7], or absorbed into porous carriers from pumice, zeolite [8], limestone [9], vermiculite [10]. The process of bacteria encapsulation is more complicated, but it allows the strains to be released only © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 158–164, 2021. https://doi.org/10.1007/978-3-030-54652-6_24

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when a crack appears in the cement matrix, activating at the opening point with natural access to moisture and ensuring the restoration processes of building material [11]. To eliminate cracks arising during the operation of products without first introduction of bacteria into the concrete mix, the most effective and technologically feasible method is local processing of crack opening points with a solution of bacterial inoculum and precursors [3]. Despite the well-known methods of bacteria introduction, the efficiency and prospects of carbonate biomineralization technologies for the restoration of building materials from concrete is practically assured, but it requires a rational choice of the type of bacterial cultures and precursors.

2 Methods and Materials As model samples of the study, the authors used cubes with a rib size of 10 mm with a WC/R (water-cement relation) of 0.4, molded using Portland cement of the CEM I 42.5 N brand and tap water. In order to achieve the standard values of strength, the samples were subjected to heat and humidity treatment according to the regime of 1.5 + 6 + 1.5 h at 60 °C. Further, the cubes were disinfected with ultraviolet radiation in order to exclude the influence of other microorganisms on the experimental results. In order to study the process of self-healing of cracks in a cement matrix, we used bacterial strains of the All-Russian Collection of Microorganisms of Institute of Biochemistry and Physiology of Microorganisms named after G.K. Scriabin RAS used in earlier studies: Lysinibacillus sphaericus (VKM B-509), Bacillus megaterium (VKM B-40), Bacillus pumilus (VKM B-23), Sporosarcina pasteurii (VKM B-513). The choice is based on the ability of bacteria to produce urease, the possibility of spore formation and the absence of pathogenicity. In order to stimulate the urease enzymatic activity of bacteria, CaCl2 and CH4N2O precursors were used. Calcium chloride was dissolved in distilled water, based on a proportion of 20 g/l, followed by autoclaving for 20 min at 120 °C. Granular urea was preliminarily sterilized in a dry oven at 100 °C for 20 min, followed by dissolution in distilled water with CaCl2 based on a proportion of 20 g/l. Optical microscopy studies were performed using a Lomo MSP-2 stereoscopic microscope option 3. Scanning electron microscopy was used to assess the changes in the cement stone microstructure and morphology of new growths using a TESCAN MIRA 3 LMU microscope with an X-MAX 50 Oxford Instruments NanoAnalysis energy dispersive spectrometer for electron probe micro-analysis with a Schottky high-brightness cathode. In the samples of cubes of cement stone, longitudinal asymmetric fractures are artificially obtained with the subsequent convergence of individual parts and, thus, the formation of cracks of different widths. In order to assess the intensity of crack closure by new growth induced by bacterial strains, the samples were incubated in sterile Petri dishes by contact wetting (placing 2/3 of the sample in a liquid) in a solution of CaCl2 and CH4N2O (15 ml) with a bacterial inoculum (2  108 CFU/ml). The solutions of precursors and strains were updated every 3 days in order to reactivate the enzymatic activity of bacteria within 28 days.

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To identify the possible effect of precursors on the crack closure processes by crystalline new growths, control samples were prepared without bacterial exposure, but kept in a solution of CaCl2 and CH4N2O under the same technological conditions. For the analysis of the degree of crack clogging, we measured the width of the crack before being placed in the analyzed solutions and zones of new growths that clogged in the crack and overlapped a slot (growth) along the surface of the cement stone sample. The border of the new growths was visually identified using optical microscopy by a characteristic larger crystalline structure compared to the bulk of the cement stone.

3 Results and Discussions After 28 days, the complete closure of cracks by crystalline new growths with their overlap is visualized in the sample of cubes placed in solution with bacterial strains: B. pumilus, B. megaterium and S. pasteurii. In the sample treated with L. sphaericus, this process is local in nature, i.e. closure is not observed throughout the crack. This fact may be due to insufficient urease activity of the bacterial culture, which is confirmed by previously performed studies on the intensity of the enzymatic activity of this strain. In the control sample, surface clarification and a slight change in the crack width are observed in the direction of reduction due to crystallization of the precursors on the inner surface of the fracture, but its complete closure is absent. The reattachment of the surface of cubes placed in a solution with a bacterial inoculum and precursors occurs in the thickness of the fracture and above its surface in that part of the sample that is above the liquid level. The wetting of the non-watered portion of the sample occurs due to capillary leakage. According to the assumption of a decrease in the capillary leakage rate as a result of internal closure of the crack by the induced L. sphaericus (VKM B-509) crystals, a zonal (incomplete) fracture was restored. The result of the intensification of crystal precipitation by bacteria is the formation of positive and negative forms of surface lay of the sample cubes. Thus in the zones of the highest concentration of induced new growths, bumps are formed, mainly above the crack surface, observed in samples incubated in a solution of precursors with bacteria B. pumilus and S. pasteurii, forming a positive surface lay. The hollow visually observed in the fracture zone of the samples during continuous (B. megaterium) or partial (L. sphaericus) closure of the crack form a negative lay of the outer surface of the cube. Due to the formation of asymmetric fractures in the samples, the geometrically uneven sides of the crack have different approach widths from a minimum value of 0.08 mm to a maximum value of 1.33 mm (Fig. 1, a). The fluctuations in the dimension of the width of convergence are insignificant, and therefore, they were not taken into account as a factor affecting the degree of crack closure. Taking into account the difficulty of the precise calculation of the area of crack growth by new growths and the need for a comparative analysis of the degree of restoration of cement stone using bacterial deposition of calcium carbonate, the average value of the crack opening width was calculated using four points (Fig. 1, a, b).

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According to the results of the control sample, it seems doubtful to calculate crack closure convergence, in connection with which, the average value of the thickness of the growth of the new growths on the two sides of the fracture is calculated. In order to assess the potential contribution of bacteria to the crystallogenesis of new growth, the crack area was calculated: S0 ¼ a  l; where: a – average crack closure width, mm; l – crack length, mm. For simple interpretation of the results and a comparative analysis of the degree of crystal precipitation in the fracture of the cube sample and on its surface between bacterial cultures, the coefficient of crack closure was calculated: S1 ; S0

K ¼

mm 1.4

1.33

1.2

1.21

a)

1.27

1 0.73

0.8

0.56

0.6

0.6

0.48 0.53

0.52 0.55

0.66 0.69

0.7

0.59

0.51

0.4 0.2 0 B. pumilus

B. megaterium

Maximum value, mm

Minimal value, mm

2

2

1.49

1.5

0.5

S. pasteurii

Control

Average value, mm

b)

mm 2.5

1

L. sphaericus

0.89 0.58

0.73

1.74 1.25 0.81 0.42

1.02

1.16

0.58 0.17 0.08 0.13

0 B. pumilus B. megaterium L. sphaericus Maximum value, mm Minimal value, mm

S. pasteurii Control Average value, mm

Fig. 1. Width value: a – of formed cracks, mm; b – of crack closure, mm

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where: S1 – the area of clogging of new growths in the crack zone (crack closure), mm2; S0 – initial value of the crack area, mm2. If the crack is not completely closed, the value of the coefficient is К < 1. With a complete clogging of the crack with new growths and its closure, К = 1. If the new growths completely clog the crack and grow on the surface of the sample, overlapping the width of the initial fault, then coefficient is К > 1. In the complete absence of any changes on the walls of the crack, К will be equal to 0, but this is almost impossible, since the processes that occur in the cement stone throughout the entire period of operation are accompanied by both continuing hydration of clinker minerals and the migration of soluble substances and bloom formation. Thus, with all other conditions being equal, we can assume that the higher the coefficient К, the higher the producing ability of the bacterial strain. The analysis of the producing activity of the studied bacterial strains and the degree of closure of the cracks showed that the maximum overgrowth of the fractures occurs when the bacterial strain S. pasteurii, is used, as evidenced by the value of the coefficient К, which significantly exceeds 1–2.32 (Table 1). During the use of strains of B. pumilus and B. megaterium, the initiation of crystallogenesis is carried out with the overlap of the crack, without the manifestation of crystallization in the marginal zones of the fracture, as evidenced by the values of K 1.38 and 1.37, respectively. The composition with bacteria L. sphaericus is characterized by less intense crystallization К is practically equal to 1 (1.05), i.e. healing of cracks occurs, but the appearance of new growths on the surface is not observed. In the sample of the control composition, the crack did not close, but there was a slight increase in the crystals on the walls of the crack, which was expressed in the value of К = 0.22.

Table 1. Rates of cement stone crack closure using various bacterial strains The initial value of the crack area, mm2 (S0)

The area of clogging of new growth in the crack zone, mm2 (S1)

9.28 9.90

4.92 12.57

6.77 17.23

9.65

5.31

5.60

1.05

9.20 10.08

6.35 5.95

14.72 1.31

2.32 0.22

The type of bacterial agent

Crack length, mm (l)

B. pumilus B. megaterium L. sphaericus S. pasteurii Control

Crack closure coefficient (К) 1.38 1.37

Based on the calculated data of the crack closure coefficient, the analyzed bacterial strains were ranked according to the increase the efficiency of initiation of crystallization of lime stone in the following sequence: S. pasteurii ! B. pumilus ! B. megaterium ! L. sphaericus.

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Scanning electron microscopy of the inner surface of the cement stone fracture showed the distribution of induced new growth over the surface (Fig. 2).

B. pumilus (VKМ B-23)

B. megaterium (VKМ B-40)

L. sphaericus (VKМ B-509)

S. pasteurii (VKМ В-513)

Control

Fig. 2. The microstructure of new growth induced by bacteria in the fracture

In micrographs, dense clogging of lime stone crystals over the entire fracture surface is visualized. New growths formed as a result of the enzymatic activity of bacterial cultures have different morphologies. The influence of technological conditions for the introduction of healing solutions, as well as external factors under which the intensification of carbonate biomineralization processes occurs on the mechanism of crack closure in cement stone requires further research.

4 Conclusion According to the study of the process of crack closure in a cement matrix by the method of bacterial deposition of calcium carbonate, the following results were obtained: 1. For a comparative analysis of the contribution of bacteria to the process of crystal precipitation and, as a result, clogging of cracks, it is proposed to use the coefficient of crack closure, calculated as the ratio of the area of clogging of new growths in the fracture zone to the initial value of its area. 2. Based on the calculated data of the crack closure coefficient, the analyzed bacterial strains were ranked according to the increase of the efficiency of initiation of crystallization of carbonate in the following sequence: S. pasteurii ! B. pumilus ! B. megaterium ! L. sphaericus. Acknowledgments. The reported study was funded by RFBR as a part of the research project No. 18-29-12011 using the equipment of the Center for High Technologies of BSTU named after V.G. Shukhov.

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References 1. Zharikov, I.S., Laketich, A., Laketich, N.: The influence of the quality of concrete work on the strength of concrete in monolithic structures. Constr. Mater. Prod. 1(1), 51–58 (2018) 2. Strokova, V.V., Vlasov, D.Yu., Frank-Kamenetskaya, O.V.: Microbial carbonate biomineralization as a tool of natural-like technologies in construction material science. Constr. Mater. 7, 66–72 (2019). https://doi.org/10.31659/0585-430X-2019-772-7-66-722 3. Strokova, V.V., Vlasov, D.Yu., Frank-Kamenetskaya, O.V., Dukhanina, U.N., Balitsky, D. A.: The use of microbial carbonate biomineralization in biotechnology the creation and restoration of building materials: analysis of the state and development prospects. Constr. Mater. 9, 83–103 (2019). https://doi.org/10.31659/0585-430X-2019-774-9-83-103 4. Chaurasia, L., Bisht, V., Singh, L.P.: A novel approach of biomineralization for improving microand macro-properties of concrete. Constr. Build. Mater. 195, 340–351 (2018). https:// doi.org/10.1016/j.conbuildmat.2018.11.031 5. Wang, J.Y., Snoeck, D., Van Vlierberghe, S., Verstraete, W., De Belie, N.: Application of hydrogel encapsulated carbonate precipitating bacteria for approaching a realistic selfhealing in concrete. Constr. Build. Mater. 68, 110–119 (2014). https://doi.org/10.1016/j. conbuildmat.2014.06.01.01 6. Bang, S.S., Galinat, J.K., Ramakrishnan, V.: Calcite precipitation induced by polyurethaneimmobilized Bacillus pasteurii. Enzym. Microb. Technol. 28(4–5), 404–409 (2001). https:// doi.org/10.1016/S0141-0229(00)00348-3 7. Tsangouri, E.: A decade of research on self-healing concrete. Sustain. Constr. Build. Mater. 21–36 (2018). https://doi.org/10.5772/intechopen.82525 8. Erofeev, V.T., Al Dulaimi, S.D.S.: Study of changes in the strength characteristics of cement composites depending on the concentration of bacteria in them and the age of the samples. Volga Sci. J. 3(47), 70–77 (2018) 9. Shaheen, N., Khushnood, R.A., Ud Din, S., Khalid, A.: Influence of bio-immobilized limestone powder on self-healing behavior of cementitious composites. IOP Conf. Ser.: Mater. Sci. Eng. 431 (2018). https://doi.org/10.1088/1757-899X/431/6/062002 10. Yoon, H.-S., Yang, K.-H., Lee, S.-S.: Evaluation of sulfuric acid resistance of biomimetic coating mortars for concrete surface protection. J. Korea Concr. Inst. 31, 61–68 (2019). https://doi.org/10.4334/JKCI.2019.31.1.061 11. Xu, H., Lian, J., Gao, M., Fu, D., Yan, Y.: Self-healing concrete using rubber particles to immobilize bacterial spores. Materials 12, 2313 (2019). https://doi.org/10.3390/ma12142313

Stress Modelling of Composite Shallow Shells of Variable Structural Rigidity S. V. Yakubovskaya(&)

and E. Yu. Ivanova

FSBEI of HE “Tyumen Industrial University”, Tyumen, Russia [email protected]

Abstract. The stress state of composite structures of variable structural rigidity is calculated. Composite structures are multilayer plates and shells. Layers of such structures are interconnected by bonds that allow slipping of one layer in relation to another. Such systems have high strength and rigidity. The solution to the problem of determining the stress-strain state of such structures will significantly reduce their material consumption, subject to (in relation to) their reliability and durability. The paper considers composite shells with layers of variable thickness. The parameters of the shell include: the dimensions of the shell in the plan, the thickness of the steel sheathing of the upper and lower layers, the initial thickness of the concrete layer at the borders, the amplitude of the change in the thickness of the middle concrete layer for a given law of change, the stiffness coefficient of shear bonds between the layers. The task of calculating composite shallow shells of variable structural stiffness for strength is to determine the stresses and strains at specific loads and evaluate them from the standpoint of reducing the material consumption of these structures. Keywords: Composite shells
Stresses layers


Strains
Stiffness of bonds between

1 Introduction The question of reducing the material consumption of structures, provided they are reliable and durable is the most important task of increasing the efficiency of construction production. This problem is solved by applying structures made of composite materials. At construction sites of oil and gas complexes, the chemical industry and nuclear energy, multilayer plates and shells are used. Layers of such structures are interconnected by bonds that allow slipping of one layer in relation to another. In this case, the connection between the finite elements (layers) has finite rigidity. Such systems have high strength and rigidity with a relatively low weight, good heat and sound insulation properties. The problem of calculating composite shallow shells with layers of variable thickness is that these structures have a number of features: the distribution of forces and stresses between layers depends on the seam stiffness; variable layer thickness complicates the solution of the task. The study of the stress state of composite shells has received significant development. Despite the large number of works [1–8], in which the stress-strain state of multilayer plates and shells are considered, the problems of calculating the composite shells of variable structural © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 165–171, 2021. https://doi.org/10.1007/978-3-030-54652-6_25

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stiffness in combination with the finite value of the stiffness of shear bonds between the layers are insufficiently studied and represent an urgent task of building mechanics.

2 Methods and Materials The object of study is a composite structure, which is a set of elastic shells of variable thickness, interconnected by elastic-yielding shear bonds (Fig. 1) [9]. In the transverse direction, the bonds are absolutely rigid. They prevent the removal or convergence of the layers relative to each other in thickness. In the longitudinal direction of the bond, shear forces are perceived, slippage is allowed between the layers.

Fig. 1. Physical model and diagram of the connections between the layers of a composite shallow shell

When solving the problems of bending composite shallow shells, we have a system of differential equations and boundary conditions that are implemented using variational, numerical, and other methods. As a result of the implementation of these methods, various systems of algebraic equations are obtained, the solution which represents some mathematical difficulties. Particularly complicated is the solution of the differential equations of composite plates and shallow shells due to the fact that the number of resolving equations and unknowns increases significantly. This in turn leads to a decrease in the stability of the system solution. In the presented work, the method of sequential elimination of residuals was applied to solve the problems of bending of composite shallow shells. The essence of the method is that a high order matrix is not resolved here. The system is resolved relatively to the unknown with deduction of one

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member of a row at each stage. Furthermore, the previous solution is refined using the resulting discrepancy. The system of differential equations is represented as: Lðwðx; yÞÞ ¼ qðx; yÞ;

ð1Þ

where L- is the differential operator; qðx; yÞ- uniformly distributed external load; wðx; yÞ- deflection of the shell. Approximate solution wðx; yÞ ¼

K X

ak wk ðx; yÞ;

ð2Þ

k¼1

where ak -unknown coefficients; wk ðx; yÞ-a system of linearly independent functions, satisfying the boundary conditions. Holding in (2) the first member of the series (k = 1) and substituting into the system of differential Eq. (1) we have L½a2 ; w2 ðx; yÞ ¼ qðx; yÞ  L½a1 ; w1 ðx; yÞ:

ð3Þ

Equation (3) is resolved relatively to a2 . Thus, we have: L½ak ; wk ðx; yÞ ¼ qðx; yÞ  L½

k1 X

am ; wm ðx; yÞ

ð4Þ

m¼0

The right side of the differential equation is the discrepancy that we have after defining ak1 k ¼ 1; a0 ¼ 0. When calculating a composite shallow shell with layers of variable thickness, a mathematical model was used [10]. A composite shallow shell of variable structural rigidity was considered, articulated on a contour and loaded with a uniformly distributed load. It is required to find deflections w, stress functions /i for the i-th layer and shear functions T i for the i-th seam. These functions were presented as wðx; yÞ ¼

K X

ak ; wk ðx; yÞ;

/i ðx; yÞ ¼

k¼1

K X

bik ; /ik ðx; yÞ;

k¼1

T i ðx; yÞ ¼

K X

dki ; Tki ðx; yÞ;

k¼1 npy i where ak ¼ wmn , bik ¼ /imn , dki ¼ Tmn - required coefficients; wk ðx; yÞ ¼ sin mpx a sin b , npy i mpx /k ðx; yÞ ¼ sin a sin b npy Tki ðx; yÞ ¼ sin mpx a sin b - a system of linearly independent functions satisfying the boundary conditions.

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Using methodology (4), we describe the system of differential equations and at each stage we determine the coefficients in the series of the desired functions w, /i ,T i . The thickness of the outer layers (steel sheathing) was assumed as a constant, and the change in the thickness of the middle concrete layer was adopted according to the following law: h2ðx;yÞ ¼ h0 þ

16f0 xða  xÞyðb  yÞ; a2 b2

where h0 - is the thickness of the shell along the contour, mm; f0 - the amplitude of the change in thickness, mm; a; b- shell dimensions of the plan, mm. The numerical implementation of the mathematical model [10] was performed when calculating a number of composite plates and shallow shells of variable structural rigidity. In particular, a three-layer composite shell articulated on a contour was considered. The calculation was carried out on a uniformly distributed load over the entire surface of the shell.

3 Results and Discussions The parameters of the three-layer composite shallow shell of variable structural stiffness were represented by the following values: shell dimensions of the plan −a  b ¼ 10000  10000ðmm  mmÞ; elastic modules of the 1st and 3rd steel layers, respectively E1 ¼ E3 ¼ 2:1
105 MPa; the elastic module of the middle concrete layer E2 ¼ 0:8
104 MPa; thickness of steel the layers h1 ¼ h3 ¼ 3 mm; shell thickness along the contour h2 ¼ h0 ¼ 200 mm; the amplitude of the thickness variation of the middle concrete layer f0 ¼ 300 mm. The value of the stiffness coefficient of shear bonds ðgÞ between layers varied from 0 to 20 N/mm3. Calculated parameters of the plate: dimensions of the shell of the plan -; elastic modules of the 1st and 3rd steel layers, respectively E1 ¼ E3 ¼ 2:1
105 MPa; the elastic modulus of the middle concrete layer E2 ¼ 0:8
104 MPa; thickness of the steel layers h1 ¼ h3 ¼ 3 mm; shell thickness along the contour h2 ¼ h0 ¼ 200 mm; the amplitude of the thickness variation of the middle concrete layer f0 ¼ 0 mm. External load - evenly distributed varies from 0 to q ¼ 0:005 MPa. In Figs. 2, 3 and 4 shows the calculated results. The dashed line indicates the results of calculating a three-layer composite shallow shell with layers of variable thickness (middle concrete layer), the solid line shows the results of calculating a composite three-layer plate with layers of constant thickness. The study of the magnitude of the deflection for two types of structures (shell and plate) is shown by what magnitude, depending on the load and stiffness of the shear bonds between the layers, it changes. So, the deflection w = 2 mm with bond stiffness of 20 N/mm3 is achieved for a composite plate with a load of q = 0.001 MPa, and for a composite shell with an average concrete layer of variable thickness with only a load of q = 0.005 MPa. This confirms that the shell bends significantly less than the plate. In

Stress Modelling of Composite Shallow Shells of Variable Structural Rigidity

Fig. 2. Dependence of the deflection change in the centre of the structure

Fig. 3. Distribution of stresses in the upper steel layer of the shells

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Fig. 4. Distribution of stresses in the middle concrete layer of the shells

Figs. 3 and 4 graphs of stress distribution in the upper and middle layers of a composite plate and composite shell (external load q ¼ 0:005 MPa. The value of maximum stresses in the plate is much higher than in the shell. In the upper steel layer at g ¼ 1 N/mm3, the stresses in the plate exceed the emerging stresses in the shell by almost 2.5 times, in the average concrete layer by 2 times.

4 Conclusion The presented results of calculations of composite shallow shells with layers of variable thickness allow for predicting the behaviour of the structure during operation and recommending their design parameters. The calculated stresses and strains at specifically given loads and parameters of such structures make it possible to evaluate them from the standpoint of reducing material consumption.

References 1. Grigorenko, Ya.M., Berenov, M.N.: Solving problems of the statics of shallow shells and plates with hinged and rigidly fixed opposite edges. Appl. Mech. 1, 30–38 (1990) 2. Yakubovskaya, S.V., Ivanova, E.Yu., Silnitskaya, N.Yu.: Selection of optimal parameters of the composite shallow shell with the anchor layer connection. J. Comput. Theoret. Nanosci. 16, 2756–2760 (2019)

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3. Ovchinnikov, I.G., Ratkin, V.V., Garibov, R.B.: Modelling the behaviour of a compressible reinforced concrete element reinforced by an external steel holder after exposure to an aggressive chlorine-containing medium. Univ. News Constr. 1, 9–12 (2017) 4. Kobelev, E.A.: Calculation of discretely supported shallow shells taking into account the resistance of torsion ribs. Innov. Invest. 11, 202–208 (2018) 5. Yuryev, A.G., Zinkova, V.A.: Ata El-Karim Soliman Truss design calculation. Constr. Mater. Prod. 2(1), 37–44 (2019) 6. Leontyev, V.V., Kondratova, E.V., Kolomiychenko, V.P.: Investigation of the stress condition of riveted joints by finite element method. Constr. Mater. Prod. 2(1), 32–36 (2019) 7. Klyuev, S.V., Abakarov, A.J., Lesovik, R.V., Muravyov, K.A., Tatlyev, R.Dz.: Optimal engineering of rod spatial construction. J. Comput. Theoret. Nanosci. 16(1), 200–203 (2019) 8. Klyuev, S.V., Bratanovskiy, S.N., Trukhanov, S.V., Manukyan, H.A.: Strengthening of concrete structures with composite based on carbon fiber. J. Comput. Theoret. Nanosci. 16 (7), 2810–2814 (2019) 9. Rzhanitsyn, A.R.: Compound rods and plates, p. 316. Moscow: Stroyizdat (1986) 10. Yakubovskaya, S.V.: Calculation of composite shallow shells with layers of variable thickness. Univ. News Constr. Archit. 2, 22–25 (1991)

Effective Driven Inclined Open Pile (IOP) A. E. Naumov1 1

, A. V. Shevchenko1 , A. V. Dolzhenko1(&) and S. Yu. Pirieva1,2

,

Belgorod State Technological University named after V.G. Shukhov, Belgorod, Russia [email protected] 2 National Research Tomsk State University, Tomsk, Russia

Abstract. Inclined open pile foundations are arranged in the case of large horizontal and pulling loads acting on the pile cluster. Such foundations are typical for buildings and structures of industrial use and tower type. The loadbearing capacity of such foundations depends significantly on the area of load transfer by the lower part of each cluster forming inclined open pile. This area depends on the geometric parameters of the pile and the divergence angle of the inclined open piles. The process of plunging inclined open piles is very laborintensive and it is not always possible to achieve the designing divergence angle of inclined open in the conditions of the construction site. The inhomogeneity of the ground conditions of the construction site and additional compaction of the soil around the submerged piles influence on ensuring the design divergence angle of piles during plunging. In this paper, the authors propose the use of a pile opener, which allows ensuring the design opening angle of inclined open piles that compacts the soil in the compressed zone between them. The authors conducted laboratory and mathematical studies simulating the process of plunging and diverging of inclined open piles with the use of a pile opener. The authors also determined the influence of the opening angle of inclined open piles on the load-bearing capacity of the pile foundation under vertical and horizontal loading. Keywords: Pile foundation
Inclined open pile
Pile opener
Static loading
Opening angle of inclined piles

1 Introduction The use of inclined piles as part of the grillage of buildings and structures that bear significant pulling and horizontal loads is quite common in modern construction practice [1–4]. Inclined piles are used when the resultant of all forces applied to the foundation deviates from the vertical by an angle of 5 to 15°, and at large angles of inclination, it becomes rational to use the so-called inclined open piles. Such foundations consist of two piles driven in the same plane at an angle to each other, the heads of which are connected together. The angle of inclination of such piles for the entire construction practice was from 15 to 45° and depended non-linearly on the specific conditions of the construction site. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 172–178, 2021. https://doi.org/10.1007/978-3-030-54652-6_26

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Studies of the operation of inclined piles under various forces are conducted around the world [5–10]. Collaboration of inclined open pile with the surrounding ground depends not only on engineering geological elements composing the building site, as well as such factors as the cross sectional shape of the piles, the angle of the elements and the angle of the bevel on their edge [11, 12]. In this regard, guaranteed provision of the inclination angle of the elements that make up the frame and gantry foundation is the most important factor affecting the reliability of this type of foundation.

2 Methods and Materials To ensure the design inclination of the inclined open piles, the authors previously proposed the use of the so-called pile opener, shown in Fig. 1. The pile opener is installed when diving between the points of the inclined open piles and ensures the accuracy of their divergence. However, when using a pile opener, the stress-strain state of the soil between the piles changes, the final density of which depends on the loadbearing capacity of the frame and gantry foundation.

Fig. 1. Scheme of frame and gantry foundation submerged using a pile opener

To study the operation of frame and gantry foundations using a pile opener when they are installed, it became necessary to obtain the dependencies of the depth of immersion and the value of horizontal movement on the angle of inclination of the piles and the angle of inclination of their tip. The nature of compaction and deformation of the soil around the foundation was also studied. For this purpose, in the laboratory research on small-scale models in a specially manufactured experimental setup was conducted and it is shown in Fig. 2. Wooden bars with a length of 300 mm and a cross-section size of 30  30 mm were used as models of piles. In total, 5 pairs of piles were made with the tip angles equal to 25, 30, 35, 40 and 45°, as well as one single pile. Photos of pile models are shown in Fig. 3. The piles were plunged by pressing into the dusty sand with a density of 1.9 g/cm3 with a vertical load by steps of 4 kg.

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A vintage field was used to fix the angle of inclination, movement of the piles and the surrounding soil. At each stage of loading, the movement was photographed and the distance between the inclined open piles at the control points was measured.

Fig. 2. Experimental installation for testing models of inclined open piles

In order to verify the obtained dependencies and to analyze the parameters of the stress-strain state of the model, numerical simulation of the experimental samples was performed in the finite element software package “Lira”. We modeled the operation of equally resource-intensive models of traditional double pile driving and IOP, with a rod length of 300 mm with an internal opening angle of 25–35°, submerged in sandy soil. The operation of the base along the side surface was modeled by one-sided two-node finite elements – friction bonds (FE 264), and along the tip – two-node elastic finite elements (FE 55). To analyze the operation of piles, piles were calculated at an angle of 0, 25, 30, 35, 40 and 45° to the vertical axis.

3 Results and Discussions The graph given in Fig. 5 shows the results of laboratory tests of models of inclined open piles submerged using a pile opener, different internal opening angle (25–45°) and a control model of a single model of equal volume. The results of the laboratory experiment show significant increase in the bearing capacity of such inclined open piles in relation to the control model (on average by 60%), depending on the angle of opening. Piles with the highest angle of 40–45° have the highest efficiency. The dynamics of the load-bearing capacity of models for vertical indentation force is well described by an exponential function of the form A exp(B), where A and B are constants that probably depend on the physical and mechanical characteristics of the host soil medium and the scale of the model. The non-linearity of the vertical movement of the pile models indicates the increasing efficiency of the IOP with increasing load, which makes this design most effective when used in heavily loaded and subject to peak short-term loads of foundations.

Effective Driven Inclined Open Pile (IOP)

Fig. 3. Experimental models of inclined open piles

Fig. 4. Design scheme. Types of FE

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The calculation results are given in Tables 1 and 2.

Table 1. The vertical movement of pile caps under the action of horizontal load Horizontal load, H Inclination angle of 0 25 30 35 5 – 1.00 1.12 1.21 10 – 1.99 2.24 2.42 15 – 2.98 3.37 3.63 20 – 3.97 4.49 4.84 25 – 4.97 5.61 6.05

piles 40 1.25 2.50 3.75 5.00 6.25

45 1.25 2.50 3.75 5.00 6.25

Table 2. Horizontal movement of pile caps under the action of horizontal load Horizontal load, H Inclination angle 0 25 5 −3.20 −2.74 10 −6.41 −5.48 15 −9.61 −8.22 20 −12.82 −10.97 25 −16.02 −13.71

of piles 30 35 40 −2.56 −2.36 −2.16 −5.11 −4.71 −4.31 −7.67 −7.07 −6.47 −10.23 −9.43 −8.62 −12.78 −11.78 −10.78

45 −1.96 −3.91 −5.86 −7.82 −9.77

Fig. 5. Load-bearing capacity of models of inclined open piles with a pile opener at laboratory vertical indentation: dotted line – a control model of a pile of equal volume, a bundle of lines – models of inclined open piles with a pile opener of the internal opening angle of 25–45°; full line – approximating exponential function

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It was found that when the angle of inclination increases, vertical deformations and internal forces increase with increasing rigidity in the horizontal direction. Therefore, the appropriate application field of such structural elements is foundation elements that work under conditions of application of prevailing horizontal loads (Fig. 4).

4 Conclusion The efficiency of using IOP depends on the internal opening angle of the elements and is up to 1.5 times in the reinforcement material capacity and up to 2 times in the horizontal rigidity. This, together with the increased load-bearing capacity for vertical loads created by compaction of the soil under the sole of the pile opener and partial inclusion of the side surface of the exposed elements by vertical ground rebound, makes the proposed IOP effective in creating foundation elements that work on horizontal loads, typical for industrial buildings with internal transport, pillars of linear structures, arched structures, including agricultural ones. Acknowledgment. This work was realized in the framework of the Program of flagship university development on the base of the Belgorod State Technological University named after V. G. Shukhov, using equipment of High Technology Center at BSTU named after V. G. Shukhov.

References 1. Xie, Y., Liu, C., Gao, S., Tang, J., Chen, Y.: Lateral load bearing capacity of offshore highpiled wharf with batter piles. Ocean Eng. 142, 377–387 (2017) 2. Li, Z., Escoffier, S., Kotronis, P.: Centrifuge modeling of batter pile foundations under earthquake excitation. Soil Dyn. Earthquake Eng. 88, 176–190 (2016) 3. Fan-ren, L., Ji-ming, Y., Yao-hua, J.: Study on proportional relation-ship of lateral bearing capacity of batter pile by model experiments. Procedia Eng. 16, 8–13 (2011) 4. Zhang, S., Wei, Y., Cheng, X., Chen, T., Zhang, X., Li, Z.: Centrifuge modeling of batter pile foundations in laterally spreading soil. Soil Dyn. Earthquake Eng. 135, 106166 (2020) 5. Nazir, A., Nasr, A.: Pullout capacity of batter pile in sand. J. Adv. Res. 4(2), 147–154 (2013) 6. Ghasemzadeh, H., Alibeikloo, M.: Pile–soil–pile interaction in pile groups with batter piles under dynamic loads. Soil Dyn. Earthquake Eng. 31(8), 1159–1170 (2011) 7. Ghazavi, M., Ravanshenas, P., Lavasan, A.A.: Analytical and numerical solution for interaction between batter pile group. KSCE J. Civil Eng. 18(7), 2051–2063 (2014). https:// doi.org/10.1007/s12205-014-0082-5 8. Akhtyamova, L., Sabitov, L.S., Mailyan, A.L., Mailyan, L.R., Radaykin, O.V.: Technological and design features of designing a modular reinforced concrete foundation for a highrise building of various types. Constr. Mater. Prod. 2(6), 5–11 (2019) 9. Evlakhova, E.Yu., Ivanova, A.V., Zheleznyakov, V.A.: Analysis of the results of monitoring of dynamic impacts during experimental immerson of driving piles at the construction site of the campus of SFU. Constr. Mater. Prod. 2(6), 12–19 (2019) 10. Rybnikova, I.A., Rybnikov, A.M.: Analysis of the results of tensometric studies of natural bored conical piles. Bull. BSTU named after V.G. Shukhov 2, 44–55 (2020). https://doi.org/ 10.34031/2071-7318-2020-5-2-44-55

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11. Bharathi, M., Dubey, R.N., Shukla, S.K.: Experimental investigation of vertical and batter pile groups subjected to dynamic loads. Soil Dyn. Earthquake Eng. 116, 107–119 (2019). https://doi.org/10.1016/j.soildyn.2018.10.012 12. Álamo, G.M., Martínez-Castro, A.E., Padrón, L.A., Aznárez, J.J., Gallego, R., Maeso, O.: Efficient numerical model for the computation of impedance functions of inclined pile groups in layered soils. Eng. Struct. 126, 379–390 (2016)

Interaction of Potassium Oxide with Calcium Aluminate A. O. Erygina(&)

and D. A. Mishin

Belgorod State Technological University named after V.G. Shukhov, Belgorod, Russia [email protected]

Abstract. The main problem of cement production is the presence of circulation of alkaline compounds. Alkali metal salts are always present in the raw mix of cement production. As it is known, these compounds have a negative impact on the technological process of clinker production, contributing to the formation of rings in chain screens and accretions in cyclone heat exchange devices, and also worsen the strength indicators of cement. To solve the problems of neutralizing alkali metal salts, it is necessary to study the possible chemical interactions of these compounds with raw materials and clinker minerals formed during firing in a rotating furnace in all technological zones of the furnace unit. If chemical interactions in the range of temperatures up to 1100 and above 1300 °C have been studied by many researchers, the range of 1100–1300 °C has been not. This work is devoted to the study of possible interactions between one of the main clinker minerals (calcium aluminate) and potassium oxide, which is involved in the internal circulation of alkaline compounds. The study established firing products between C4AF and K2O at 1200 °C: Stage 1 of the reaction: 1200 C

4CaO
Al2 O3
Fe2 O3 þ K2 O ! 2CaO
Fe2 O3 þ K2 O
Al2 O3 þ 2CaO Stage 2 of the reaction: 1200 C

2CaO
Fe2 O3 þ K2 O ! K2 O
Fe2 O3 þ 2CaO: These reactions can occur at firing temperatures corresponding to the zone of exothermic reactions of a rotating cement furnace, with the arranged return of dust from the hot end of the furnace. Keywords: Portland cement clinker minerals
Clinker formation processes
Calcium aluminate
Alkali metal oxides
Potassium oxide
Sodium aluminate
Sodium ferrite
Portland cement clinker
Circulation of alkaline compounds

© The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 179–183, 2021. https://doi.org/10.1007/978-3-030-54652-6_27

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A. O. Erygina and D. A. Mishin

1 Introduction The quality of the main construction material, Portland cement, directly depends on the chemical composition, “purity” of the used raw materials. Each raw material component contains a certain proportion of impurities, which, in turn, have a different effect on the technological processes of clinker production and on its strength indicators. The most undesirable impurity compounds are considered to be soluble salts, SO3, Na2O and K2O [1]. Their content in clays, as the main carrier of impurity elements, should be as minimal as possible. But due to the presence of internal circulation of alkaline compounds in the rotary furnace of cement production, it is not always possible to reduce the content of R2O. To solve the problem of the negative influence of alkali metal salts on the quality of Portland cement clinker and technological processes, it is necessary to study in detail the probability and sequence of chemical interactions of alkali metal oxides and Portland cement clinker minerals in all technological zones of the rotary furnace. The scope of such studies is limited to temperature ranges up to 1100 and above 1300 °C [2–9], and the temperature range of 1100–1300 °C is not fully studied. Therefore, the aim of this research is to study the influence of potassium oxide, as an impurity compound present in a rotating cement production furnace, on the processes of mineral formation in the range of firing temperatures from 1100 to 1300 °C.

2 Research Methods and Materials The synthesis of the clinker mineral C4AF was performed under laboratory conditions (Table 1) using chemical reagents of the purity category “HC”: Ca-CO3, Al2O3, Fe2O3. Finely ground reagents were carefully averaged and formed into tablets by hand, sufficient to preserve the shape, with a diameter of 15 mm. Then the samples were put into a cold furnace with silicon carbide heaters and fired on substrates with a sprinkling of periclase refractory. Table 1. The synthesis conditions of the clinker mineral C4AF Firing parameters Value Firing temperature, °C 1350 Number of firing 2 Speed of gaining temperature, °C/min 8–10 Exposure time, min 60 Cooling method Sharp – in the air

K2CO3 (“HC”) was used to model the chemical interaction of potassium oxide with calcium aluminate. Finely ground potassium carbonate was added to the synthesized clinker mineral C4AF at various molar ratios and the samples were fired at a temperature corresponding to the zone of exothermic reactions of a rotating furnace (Table 2).

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To determine the firing product, x-ray phase analysis of the composition of the burned samples was used, performed on an ARL’TRA diffractometer. Identification of the obtained phases was performed using the computer program Search-Match and [10]. Table 2. Composition of mixtures and firing conditions Composition of basic mixtures C4AF + K2O*

Molar ratio 3:1; 2:1; 1:1; 1:2; 1:3

Firing temperature, °C 1200

Isothermal exposure time, min 10

3 Results and Discussion According to x-ray phase analysis, it is found that the reaction between C4AF and K2O is possible, but the chemical interaction is carried out in several stages, as in the interaction of this clinker mineral with Na2O [11, 12]. At the ratio of components C4AF:K2O = 3:1 (Fig. 1a), the RFA shows the initial stage of the chemical reaction due to the presence of CaO reflections (2.406 ), but the maxima of any other phase other than CaO and C4AF (2.649

, 1.703

, 2.683

,

7.302 ) at 1200 °C were not detected. More precisely, the interaction process of calcium aluminate and potassium oxide is shown by the roentgenogram of firing products, where the ratio C4AF:K2O = 2:1 (Fig. 1b). It is recorded that the part of Al2O3 bound in C4AF begins to interact with K2O, thus forming K2O∙Al2O3 (reflections 2.584 , 2.967). In turn, the composition of the alumoferrite phase is depleted by aluminum oxide and, accordingly, its composition is shifted towards C6AF2 (refractions 2.650 , 2.793 , 7.302 ). When increasing the amount of substance K2O (ratio C4AF:K2O = 1:1) the roentgenogram of the firing products C4AF and K2O (Fig. 1c) shows that as long as the bound Al2O3 is present in the alumoferrite phase, no other chemical interactions will occur except for the production of K2O∙Al2O3 (maxima 2.585 and 2.969 ). At the same time, the amount of bound Al2O3 from the alumoferrite phase will constantly decrease until it all goes to the formation of potassium aluminate, that is, until the C2F phase is obtained (Fig. 1d) 2.673 , 2.704 , 2.819 , 7.387 (the ratio of C4AF: K2O = 1:2). After completing the first stage of interaction, K2O will interact with Fe2O3 bound in C2F to form K2O∙Fe2O3 (Fig. 1e): 2.673 , 2.742 , 2.463 , 4.341 (ratio C4AF: K2O = 1:2) and 2.671 , 2.740 , 2.463 , 3.018 , 4.353 (ratio C4AF:K2O = 1:3). This sequence of interaction of potassium oxide and calcium aluminate in a rotating furnace probably occurs when arranging dust return from the hot end of the furnace.

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Fig. 1. Features of interaction of C4AF with K2O at 1200 °C and the isothermal exposure of 10 min, where a – mixture with a molar ratio of initial components 3:1; b – mixture with a molar ratio of initial components 2:1; c – mixture with a molar ratio of initial components 1:1; d – mixture with a molar ratio of initial components 1:2; e – mixture with a molar ratio of initial components 1:3.

Fine dust caught in the electric filter of the furnace, blown through a separate nozzle, will be picked up by the torch. Part of the dust settles in the zone of exothermic reactions, falling on the material, in which a calcium aluminate has been already formed.

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4 Conclusions K2O reacts with calcium aluminate at the firing temperature at 1200 °C in steps. First, the alkali metal oxide reacts with Al2O3 bound in C4AF – the first stage of interaction. After all Al2O3 interacts with K2O to form K2O∙Al2O3, the second stage of interaction begins - K2O with Fe2O3 will form the compound K2O∙Fe2O3. The complete course of the chemical reaction occurs at the excess amount of potassium oxide (in the ratio of 1:3): Stage 1 of the interaction: 1200 C

4CaO
Al2 O3
Fe2 O3 þ K2 O ! 2CaO
Fe2 O3 þ K2 O
Al2 O3 þ þ 2CaO Stage 2 of the interaction: 1200 C

2CaO
Fe2 O3 þ K2 O ! K2 O
Fe2 O3 þ 2CaO: Acknowledgements. This work was realized in the framework of the Program of flagship university development on the base of the Belgorod State Technological University named after V G Shukhov, using equipment of High Technology Center at BSTU named after V G Shukhov.

References 1. Kolokolnikov, V.S.: Cement Production. M.: Higher School, pp. 45–48 (1967) 2. Klassen, V.K.: Roasting Cement Clinker, p. 323. Stroyizdat, Krasnoyarsk (1994) 3. Klassen, V.K., Dolgova, E.P.: Alkali Metal Chlorides in Cement Production: Monograph, p. 182. BGTU, Belgorod (2015) 4. Luginina, I.G.: Chemistry and Chemical Technology of Inorganic Binders, vol. 2, no. 1, p. 240. BSTU, Belgorod (2004) 5. Taymasov, B.T., Klassen, V.K.: Chemical Technology of Binding Materials: A Textbook, p. 448. BGTU, Belgorod (2017) 6. Klassen, V.K.: Portland Cement Technology: Selected Works, p. 530. BGTU, Belgorod (2017) 7. Khodorov, E.I., Korolkov, A.V.: Circulation of volatile compounds in rotary kilns with heat exchangers and calciner. Bull. Cement 12(1), 13–15 (1984) 8. Taylor, H.: Cement Chemistry; translation from English M.: Mir 560 (1996) 9. Victorenkov, V.I., Volkonsky, B.V.: Circulation of alkalis in furnaces with cyclone heat exchangers. Bull. Cement 12(6), 12–14 (1965) 10. Gorshkov, V.S., Timashev, V.V.: Methods of Physico-Chemical Analysis of Binders, p. 287. M.:Higher School (1963) 11. Erygina, A.O., Mishin, D.A.: Interaction of calcium aluminoferrite with Na2CO3 and Na2SO4. In: High Technologies and Innovations: International Scientific-Practical Conference Belgorod, vol. 12, no. 1, pp. 125–130 (2016) 12. Erygina, A.O., Mishin, D.A., Klassen, V.K.: The sequence of Na2O interactions with clinker mineral in their various combinations. Bull. BSTU named after V.G. Shukhov 12(12), 98– 104 (2018)

Influence of Polycarboxylate Superplasticizer and Mineral Additives of Various Nature on the Kinetics of Early Hardening Stages of Cement Systems T. A. Nizina(&)

, A. S. Balykov

, and D. I. Korovkin

National Research Mordovia State University, Saransk, Russia [email protected]

Abstract. Influence of the polycarboxylate superplasticizer and mineral additives of various natures (siliceous, aluminosilicate, and sulfoaluminate) on the kinetics of early hardening stages of cement systems, characterized by the rate of increase in the plastic strength of cement paste, have been studied with the recording of the following quantitative indicators: the initial and final setting time, time to reach the plastic strength of 5 MPa. The research results showed that the comprehensive use of organic and mineral additives allowed improving positive influence by means of synergetic effect and eliminating the negative influence of each component individually and thereby controlling the properties of cement paste and processes of early structure formation of cement stone. Introducing the carbonate filler (microcalcilte) into non-plasticized cement system (composition No. 5) decelerates the growth of plastic strength to some extent during the first 4 h of hardening as compared to non-modified composition No. 1 (Fig. 2, a). When it replaces 50% of the complex modifier SF +HAM+ESAM (see Table 1, compositions Nos. 7 and 8_1, respectively), it leads to substantial deceleration of both setting time (from 5 to 7.08 h for initial setting time and 6.08 to 8.33 h for final setting time) and the time to reach the plastic strength of 5 MPa (from 7.0 to 9.4 h). Keywords: Cement system
Polycarboxylate superplasticizer additive
Setting time
Plastic strength


Mineral

1 Introduction Currently, one of the high-priority trends in construction material science is the development of modified cement concretes with high performance characteristics differing in a complex multicomponent composition using individual and comprehensive additives of various natures and action mechanisms: chemical, mineral, and organicmineral [1–4]. Using modifiers was a key to solving many process tasks, in particular, contributed to the production of high-strength cement concretes (60–100 MPa and higher) [5, 6], which is proved by the results of own studies [7–9]. An important component of modern modified cement concretes is active mineral additives enabling the control of processes of structure formation and properties of © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 184–190, 2021. https://doi.org/10.1007/978-3-030-54652-6_28

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cement systems. For the formulation of high strength composites, finely dispersed pozzolanic additives have the highest efficiency, which contain amorphous silica, alumina and have an increased reactivity [10–12]: condensed silica fumes, metakaolin, finely dispersed ashes of thermal power plants, blast-furnace granulated slags, etc. Using these modifiers allows for a number of positive structural effects, which include two primary ones [13]: chemical effect, which consists in an opportunity to change the quality of the solid phase forming the frame of cement stone structure; physical effect related to the opportunity to change the porous space geometry by reducing the scope of capillary and process pores by filling the space between coarse cement particles with finely dispersed additive particles. Apart from siliceous and aluminosilicate modifiers, sulfoaluminate and carbonate mineral additives have increased efficiency in the formulation of cement systems. Using expanding modifiers of sulfoaluminate type allows for controlling linear and volumetric changes when hardening cement composites by forming increased volume crystals of hydrate phases (ettringite, etc.). [14, 15]. The action of carbonate rocks (limestones, dolomites) in cement systems is based on the ability of the rock-forming mineral calcite to act as a center of crystallization for new hydrate phases [16, 17]. The authors should note a special role of using highly efficient plasticizing additives in modified compositions of cement concretes, especially IV-generation superplasticizers. These are surfactants based on polycarboxylates and acrylates ensuring a significant reduction of the water-cement ratio and water-demand of concrete mixtures (up to 35–40% or more) [18, 19]. Their liquefaction capability is significantly higher than in conventional plasticizers based on lignosulfonate, sulfo-melamine-formaldehyde, and sulfo-naphthalene-formaldehyde. This paper was intended to study the influence of polycarboxylate superplasticizer and mineral additives of various chemical and mineralogical natures (siliceous, aluminosilicate, sulfoaluminate, and carbonate) on the kinetics of early hardening stages of cement systems characterized by the plastic strength growth and setting time of cement pastes.

2 Methods and Materials The setting time of cement paste was measured using the standard method under GOST 310.3. When finding this characteristic using the Vicat apparatus, two conditional moments are recorded: the initial and final setting time. These indicators give no complete representation of the processes of structure formation of cement systems. The setting process can be characterized in a more comprehensive manner through study of the kinetics of the increase in the plastic strength in a developing structure. To this end, the cone plastometer method developed by the academician Rebinder was used. This method is based on introduction the cone-shaped indentor and consists in measuring the cone immersion depth into the studied samples under the action of constant force F. The plastic strength of cement paste Pcp (MPa) is calculated by the formula

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Pcp ¼ Ka


F ; h2cp

ð1Þ

where F is the force acting on the cone, H; hcp is the cone immersion depth, mm; Ka is the cone constant defined as Ka ¼ ð1=pÞ
cos2 ða=2Þ
ctgða=2Þ;

ð2Þ

where a is the cone apex angle (in its axial cross-section). In the research, the indentor loading was 2.98 N, the cone apex angle was 70°. After the cone contacted the surface of the studied sample, the stopping devices were released and the indentor immersion depth was measured using the clock-type indicator. Melflux 1641 F polycarboxylate superplasticizer (SP) was used as modifier for cement systems along with the following types of mineral additives (MAs): 1) siliceous MA – condensed non-compacted silica fume MK-85 manufactured by Kuznetsk Ferroalloys JSC (SF); 2) aluminosilicate MA – highly active metakaolin MKZhL-2 manufactured by PlastRifey LLC (HAM); 3) sulfoaluminate MA – expanding sulfoaluminate modifier manufactured by ParadRus LLC (ESAM); 4) carbonate MA – microcalcite manufactured by Polypark LLC (MC). The studies used non-plasticized and plasticized cement systems, the mixed binder of which included 90% of Portland cement 500-D0-N (PC) manufactured by Mordovcement PJSC and 10% of a mineral additive. In plasticized compositions, the superplasticizer dosage was 0.1 and 0.25% of the binder weight (PC + MAs). Cement mineral pastes were prepared with the constant water-binder ratio of W/(PC + MAs) = 0.27 corresponding to the normal density of cement paste of no-additive composition. The studied compositions of cement systems are given in Table 1. Table 1. The studied compositions of cement systems (W/(PC+MAs) = 0.27) Composition numbers Portland cement Type of mineral additives SP Melflux 1641 F SF HAM ESAM MC % by weight of binder (Portland cement+mineral additives) 1 100 0 0 0 0 0 2 90 10 0 0 0 0 3 90 0 10 0 0 0 4 90 0 0 10 0 0 5 90 0 0 0 10 0 6_1 100 0 0 0 0 0.25 6_2 100 0 0 0 0 0.1 7 90 3.333 3.333 3.333 0 0.25 8_1 90 1.667 1.667 1.667 5 0.25 8_2 90 1.667 1.667 1.667 5 0.1

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3 Results and Discussions In the experimental study controlled indicators quantitatively characterizing the growth kinetics of plastic strength of cement systems were the initial and final setting time, as well as the time to reach the plastic strength of 5 MPa. The initial and final setting time for cement pastes of the compositions under study are given in Fig. 1, the curves of plastic strength growth of cement systems are given in Fig. 2.

Fig. 1. Initial and final setting time of the studied cement pastes with constant water content.

The studies found that introducing silica fume and metakaolin (compositions Nos. 2 and 3) into the formulation of the control no-additive composition No. 1 instead of 10% Portland cement allowed reducing the initial and final setting time by 40–43 and 27–29%, respectively (Fig. 1). Increased setting rate of the no-plasticized cement pastes of compositions Nos. 2 and 3 is caused by high dispersion of SF and HAM particles being the source of excessive surface energy at the interface and the presence of reactive compounds in modifiers composition (amorphous silica SiO2 and aluminum silicate Al2O3∙2SiO2) promoting intensified hydration at early stages of cement systems hardening. Using expanding sulfoaluminate modifier and microcalcite (compositions Nos. 4 and 5) in non-plasticized compositions has almost no effect on changes in the setting time of cement pastes. Data analysis represented in Fig. 1 shows substantial increase in setting time for plasticized systems. Introducing polycarboxylate superplasticizer Melflux 1641 F into the cement pastes in the amount of 0.1 and 0.25% of the binder weight (PC+MAs) (compositions Nos. 6_2 and 6_1) leads to decelerated setting time as compared to non-

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Fig. 2. Curves of plastic strength growth of the studied non-plasticized (a) and plasticized (b) cement systems with constant water content (W/(PC+MAs)) = 0.27).

plasticized additive-free composition No. 1 by 1.5 to 2.6 times for the initial setting time and 1.5 to 2.3 times for the final setting time, respectively. Comparison of plasticized cement systems without mineral additives Nos. 6_1 and 6_2 with compositions Nos. 8_1 and 8_2 containing complexes of MAs introduced in the amount of 10% of the Portland cement weight (5% (SF+HAM+ESAM) and 5%

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MC, respectively) showed setting time decelerated by 15–16% with the Melflux 1641 F content of 0.1% and acceleration by 7–9% with the plasticizer share of 0.25% of the binder weight (PC+MAs). The analysis of plastic strength growth curves (Fig. 2) generally proves the above conclusions on the effects of plasticizing and mineral additives and their complexes on the kinetics of early hardening stages of cement systems. In particular, introducing 10% SF or HAM (compositions Nos. 2 and 3) into the cement paste formulation allows reducing the time to reach the plastic strength of 5 MPa by 15–16%, at that using the plasticizer in quantity of 0.1 or 0.25% of the binder weight (PC+MAs) (compositions Nos. 6_2 and 6_1) increases this indicator by 1.3 and 2.1 times, respectively. Introducing the carbonate filler (microcalcilte) into non-plasticized cement system (composition No. 5) decelerates the growth of plastic strength to some extent during the first 4 h of hardening as compared to non-modified composition No. 1 (Fig. 2, a). When it replaces 50% of the complex modifier SF+HAM+ESAM (see Table 1, compositions Nos. 7 and 8_1, respectively), it leads to substantial deceleration of both setting time (from 5 to 7.08 h for initial setting time and 6.08 to 8.33 h for final setting time) and the time to reach the plastic strength of 5 MPa (from 7.0 to 9.4 h).

4 Conclusion To sum up the above, it should be noted that the comprehensive use of polycarboxylate superplasticizer and mineral additives of various natures (siliceous, aluminosilicate, and sulfoaluminate) allows improving positive influence by means of synergetic effect and eliminating the negative influence of each component individually and thereby purposeful management of the cement paste properties and processes of early structure formation of cement stone. Acknowledgments. The reported study was funded by RFBR according to the research project № 18-29-12036.

References 1. Zhou, M., Lu, W., Song, J., Lee, G.C.: Application of ultra-high performance concrete in bridge engineering. Constr. Build. Mater. 186, 1256–1267 (2018). https://doi.org/10.1016/j. conbuildmat.2018.08.036 2. Yu, R., Spiesz, P., Brouwers, H.J.H.: Development of an eco-friendly Ultra-High Performance Concrete (UHPC) with efficient cement and mineral admixtures uses. Cement Concrete Compos. 55, 383–394 (2015). https://doi.org/10.1016/j.cemconcomp.2014.09.024 3. Ghafari, E., Costa, H., Júlio, E., Portugal, A., Durães, L.: The effect of nanosilica addition on flowability, strength and transport properties of ultra high performance concrete. Mater. Des. 59, 1–9 (2014). https://doi.org/10.1016/j.matdes.2014.02.051 4. Tran, N.T., Kim, D.J.: Synergistic response of blending fibers in ultra-high-performance concrete under high rate tensile loads. Cement Concrete Compos. 78, 132–145 (2017). https://doi.org/10.1016/j.cemconcomp.2017.01.008

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5. Shin, H.O., Yoo, D.Y., Lee, J.H., Lee, S.H., Yoon, Y.S.: Optimized mix design for 180 MPa ultra-high-strength concrete. J. Mater. Res. Technol. 8(5), 4182–4197 (2019). https://doi.org/ 10.1016/j.jmrt.2019.07.027 6. Lou, C.S., Qi, A., Ye, J.F., Lin, S.Y.: Experimental study on mechanical properties of high strength concrete with solid waste. IOP Conf. Ser.: Mater. Sci. Eng. 392(4), 042012 (2018). https://doi.org/10.1088/1757-899X/392/4/042012 7. Nizina, T.A., Balykov, A.S., Korovkin, D.I., Volodin, V.V.: Physical and mechanical properties of modified fine-grained fibre-reinforced concretes containing carbon nanostructures. Int. J. Nanotechnol. 16(6/7/8/9/10), 496–509 (2019). https://doi.org/10.1504/ijnt.2019. 106621 8. Nizina, T.A., Balykov, A.S., Korovkin, D.I., Volodin, V.V.: Modified fine-grained concretes based on highly filled self-compacting mixtures. IOP Conf. Ser.: Mater. Sci. Eng. 481(1), 012048 (2019). https://doi.org/10.1088/1757-899X/481/1/012048 9. Nizina, T.A., Ponomarev, A.N., Balykov, A.S., Korovkin, D.I.: Multicriteria optimization of the formulation of modified fine-grained fibre concretes containing carbon nanostructures. Int. J. Nanotechnol. 15(4/5), 333–346 (2018). https://doi.org/10.1504/IJNT.2018.094790 10. Rassokhin, A.S., Ponomarev, A.N., Figovsky, O.L.: Silica fumes of different types for highperformance fine-grained concrete. Mag. Civil Eng. 78(2), 151–160 (2018). https://doi.org/ 10.18720/MCE.78.12 11. Kocak, Y.: Effects of metakaolin on the hydration development of Portland–composite cement. J. Build. Eng. 31, 101419 (2020). https://doi.org/10.1016/j.jobe.2020.101419 12. Nedunuri, S.S.S.A., Sertse, S.G., Muhammad, S.: Microstructural study of Portland cement partially replaced with fly ash, ground granulated blast furnace slag and silica fume as determined by pozzolanic activity. Constr. Build. Mater. 238, 117561 (2020). https://doi.org/ 10.1016/j.conbuildmat.2019.117561 13. Jacob, J.D.S., Mascelani, A.G., Steinmetz, R.L.R., Costa, F.A.D., Dalla Costa, O.A.: Use of silica fume and nano-silica in mortars attacked by acids present in pig manure. Procedia Struct. Integrity 11, 44–51 (2018). https://doi.org/10.1016/j.prostr.2018.11.007 14. Carballosa, P., García Calvo, J.L., Revuelta, D., Sánchez, J.J., Gutiérrez, J.P.: Influence of cement and expansive additive types in the performance of self-stressing and selfcompacting concretes for structural elements. Constr. Build. Mater. 93, 223–229 (2015). https://doi.org/10.1016/j.conbuildmat.2015.05.113 15. Le Saoût, G., Lothenbach, B., Hori, A., Higuchi, T., Winnefeld, F.: Hydration of Portland cement with additions of calcium sulfoaluminates. Cement Concrete Res. 43(1), 81–94 (2013). https://doi.org/10.1016/j.cemconres.2012.10.011 16. Celik, K., Hay, R., Hargis, C.W., Moon, J.: Effect of volcanic ash pozzolan or limestone replacement on hydration of Portland cement. Constr. Build. Mater. 197, 803–812 (2019). https://doi.org/10.1016/j.conbuildmat.2018.11.193 17. Lollini, F., Redaelli, E., Bertolini, L.: Effects of portland cement replacement with limestone on the properties of hardened concrete. Cement Concrete Compos. 46, 32–40 (2014). https:// doi.org/10.1016/j.cemconcomp.2013.10.016 18. Smirnova, O.M.: Compatibility of Portland cement and polycarboxylate-based superplasticizers in high-strength concrete for precast constructions. Mag. Civil Eng. 66(6), 12–22 (2016). https://doi.org/10.5862/MCE.66.2 19. Huang, H., Qian, C., Zhao, F., Qu, J., Guo, J., Danzinger, M.: Improvement on microstructure of concrete by polycarboxylate superplasticizer (PCE) and its influence on durability of concrete. Constr. Build. Mater. 110, 293–299 (2016). https://doi.org/10.1016/j. conbuildmat.2016.02.041

Increasing the Resistance of Building Materials with Bioactive Hybrid Coverage M. I. Vasilenko(&)

, E. N. Goncharova

, and Yu. K. Rubanov

Belgorod State Technological University named after V.G. Shukhov, Belgorod, Russia [email protected]

Abstract. The paper presents the results of research on the creation of building materials that are highly resistant to the impact of microorganisms using Sol-gel technologies. A modified waste of galvanic production was used as a biocidal component included in the gel matrix. Biological testing of products was performed using bacteria (Escherichia coli, thiobacteria), green algae and microscopic fungus (Aspergillus niger). The effectiveness of the coverage of concrete materials in relation to the listed microorganisms were already evident at the concentration of biocide used in quantities not exceeding 1% by weight of the Sol-gel mixture. Some technological parameters of the process that provides the formation of a protective surface layer of construction products are identified. The duration of contact between the samples and the Sol-gel mixture, which ensures the fungus resistance of the material, was 2 min for ceramic products, and from 30 s to 1 min for concrete products. It is shown that materials with such a coverage are resistant not only to the impact of microorganisms, but also to the effects of other environmental factors, as well as increased strength (there was an increase in the strength of concrete samples impregnated with polymer, on average, by 1.3–1.5 times) and, as a result, high durability. Keywords: Gel
Biocide additive
Waste
Concrete products
Construction ceramics
Biological resistance
Microscopic fungi
Algae
Bacteria

1 Introduction Problems of accident-free operation and durability of buildings and structures are directly related to the growing use of non-traditional materials, various chemical additives and unusual innovative building materials, as well as aging and premature loss of strength of structures and products due to the negative impact of constantly deteriorating environment and impact of living organisms [1–4]. More than 50% of the recorded damage is due to the activity of microorganisms that accelerate the process of biodegradation by thousands of times (depending on different environmental factors). The main bio-destructors of building materials are bacteria, fungi, algae, lichens, mosses, plants, insects, etc. The settlement and development of these living organisms on the surfaces of building materials leads not only to visual negative consequences, but also to a significant deterioration of the physical and technical properties of products, up to destruction [4–7]. A significant part of all © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 191–197, 2021. https://doi.org/10.1007/978-3-030-54652-6_29

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microorganisms and, especially, mold fungi pose a danger to human health, provoking outbreaks of diseases of the population. The ecosystem of the surface of buildings and structures of the urban environment is the autonomous complex, the biotope of which is the building material, the biocenosis is primarily represented by microorganisms, and the environment is characterized by the increased level of anthropogenic loads due to pollution arising in the process of industrialization and urbanization [8]. Improving the quality of the human environment is directly related to the need to maintain appropriate hygienic conditions, not only inside the premises, but also on the territories of residential development. Biocidicity, as a property of building materials, allows, on the one hand, providing a regime of sterility, for example, in medical premises, as well as in food, pharmaceutical and other industries, on the other hand, preventing the processes of bio-damage to buildings and structures, most often by microorganisms unsafe for people. One of the most effective and long-lasting ways to protect building materials and structures from damage by microorganisms is the use of biocidal preparations, which, as additives, can be introduced into the building mix or into the composition of protective coverage for products. In addition to protection against biological fouling, modern biocide coverage must provide protection against corrosion, have a long service life and low cost, be chemically stable, and be well compatible with the material being covered [9]. Sol-gel technology is the process of obtaining technically valuable inorganic and organic-inorganic materials, which can be catalysts, adsorbents, membranes, ceramic and other composites, based on the transition of a homogeneous solution to Sol and then to the three-dimensional structure of the gel. At using the Sol-gel process, it is possible to obtain nanoparticles and nano-porous materials, thin nanoscale films [10]. The hydrolysis and polycondensation reactions of the alkoxy compounds underlying the Sol-gel process allow including a number of organic and inorganic modifying additives in the formed siloxane grid, the presence of which provides important functional properties of the resulting materials, including resistance to microorganisms. The main aim of the presented research was to obtain biostable products by using a Sol-gel mixture containing a biocidal component based on waste to impregnate the surface of construction cement and ceramic materials by immersion method. The work included an assessment of the effect of the immersion modes of products in a Sol-gel mixture with a biocide and the concentration of the latter in the mixture on the biostability in relation to representatives of the microbecenosis, traditionally attacking the surfaces of buildings and structures, as well as on the strength characteristics.

2 Methods and Materials The construction products under study were concrete (cubes - 2  22 cm) and ceramic (cylinders d = 16 mm; h = 16 mm) samples of construction materials obtained by traditional molding methods (GOST 18105-2010).

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The powder of modified sludge of reagent wastewater treatment of regional galvanic production containing compounds of copper, zinc, nickel, chromium and other metals was used as a biocidal component [11]. At the first stage of Sol-gel synthesis, the initial components: (C2H5O)4Si, C2H5OH, H2O and HNO3 were sequentially mixed at a molar ratio of 1: 1.6: 2.5: 0.001, respectively. The resulting mixture was kept at room temperature in the mixing mode (on a rocker) for 1–2 days. As a result, a transparent Sol was formed, which was used for impregnation of construction samples. The biocidal component was included in the mixture as part of ethyl alcohol, having previously dissolved the necessary amount of modified sludge in it, varying its content from 1% to 5% of the total mass of the Sol-gel mixture (1%, 2%, 5%). The polymer coverage on the surface of the samples was created by dipping them in a Sol-gel mixture for certain periods of time and then drying them at room temperature for two days. At studying the effect of the duration of contact between the sample and the Sol-gel mixture during the impregnation of products on their quality characteristics, samples were kept in a Sol-gel mixture containing 1% of the biocide for 0.5, 1 and 2 min. The determination of fungal resistance of samples and its changes depending on the concentration of waste in the Sol-gel mixture and the duration of keeping in this mixture was carried out by the method of biotesting [GOST 9.048-89] using a microscopic fungus Aspergillus niger as a test object (Method 3), the strength characteristics assessment according to the standard (GOST 18105-2010). In addition, the tested microorganisms were selected as pure cultures of green algae and thiobacteria, the products of which are most aggressive towards concrete, as well as a special nonpathogenic strain of E. coli – a bacterium belonging to sanitary-indicative cultures. Determination of the effect of the amount of biocide in the coverage on the biostability of samples was carried out by establishing contacts of microorganisms with building materials in a culture medium. Cubes covered with Sol and control samples without coverages were placed in a suspension of microorganisms. After 10 days, the cement material was scraped off the walls of the cubes, followed by the preparation of an extract from it, which was sown on a solid nutrient medium. Counting the growing colonies allowed calculating the number of microorganisms per unit mass of the surface of the building material. Escherichia coli were counted using an automatic counter of colonies, cells of thiobacteria and green algae by direct counting using the Goryaev camera.

3 Results and Discussions Studies to identify the fungal resistance of concrete samples impregnated with a gel containing various concentrations of biocide-waste showed that the presence of a gel matrix clearly contributed to increasing the fungal resistance of the samples, the intensity of fungi development did not exceed 1–2 points, while on the surface of control samples (without coverage), “the development of fungi is clearly seen that cover less than 25% of the tested surface”, which corresponds to the intensity of fungi development of 4 points (Table 1).

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Samples Control sample, without coverage Covered with Sol, biocide content −1% Covered with Sol, biocide content −2% Covered with Sol, biocide content −5%

Resistance to the fungus action, points 4

Characteristics according to GOST Not resistant to fungi

2

Fungi resistant

1

Fungi resistant

1

Fungi resistant

In the course of studying the effect of impregnation of samples with a Sol-gel mixture with different concentrations of biocide on the degree of contamination of the treated surface with E. coli bacteria, it was noted that a noticeable effect is observed already at the content of biocide - 1%, wt. The results of the study presented in Table 2, showed that impregnation of samples with Sol containing 1% of the biocide halves the number of bacteria on the surface of products; increasing the concentration to 2% reduces the growth of E. coli by 3.5 times. Table 2. The content of E. coli on the surface of the studied samples Samples

Control sample, without coverage Covered with Sol, biocide content −1% Covered with Sol, biocide content −2%

Average number of E. coli On solid medium, pieces in a Petri dish 269

colonies In 1 g of product surface scraping 54 ∙ 102

% of control 100

118

24 ∙ 102

43.9

78

16 ∙ 102

29

Table 3 shows the results of experiments to assess the biocidicity of concrete samples with biostable gel coverage in relation to thiobacteria and green algae. As it can be seen from the data, the thiobacteria were extremely sensitive to the tested coverage: when the content of the biocidal component in the Sol-gel mixture in the amount of 1%, the number of bacterial cells decreased by 88%, and at a concentration of 2%, it was practically not fixed, accounting for 3% of the number of cells in the control. The number of green algae cells in the presence of covered samples decreased by an average of 75% in both variants. Thus, in real conditions of the urban environment, when the surfaces of buildings and structures are constantly under the influence of microbiocenoses with the prevailing presence of microscopic fungi and algae, it is possible to limit the inclusion of

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Table 3. Quantitative accounting of thiobacteria and green algae in the sample medium Samples

Control sample, without coverage Covered with Sol, biocide content −1% Covered with Sol, biocide content −2%

Number of thiobacteria Number of cells in % of 1 ml of suspension control 100 9.1 ∙ 105

Number of green algae Number of cells in % of 1 ml of suspension control 1.2 ∙ 105 100

1.1 ∙ 105

12

2.4 ∙ 104

29

2.7 ∙ 104

3

1.4 ∙ 104

20

the used biocide in the polymer coverage of concrete materials in quantities not exceeding 1% of the mass of the Sol-gel mixture. When studying the effect of the duration of contact between the sample and the Solgel mixture during the impregnation of products on the fungal resistance and strength, samples were kept in a Sol-gel mixture containing 1% of the biocide for 0.5, 1 and 2 min. The results of evaluating the fungal resistance of the obtained concrete and ceramic samples are presented in Table 4. Table 4. Influence of the duration of keeping samples in Sol-gel mixtures on the fungus resistance of products Material Ceramics

Concrete

Time of keeping in the Solgel mixture, min 0 0.5 1.0 2.0 0 0.5 1.0 2.0

Resistance to the fungus action, points 5 4 3 2 4 2–3 2 1

Characteristics according to GOST Not resistant to fungi Not resistant to fungi Not resistant to fungi Fungi resistant Not resistant to fungi Not resistant to fungi Fungi resistant Fungi resistant

As it can be seen, when testing for fungal resistance by method 3, the intensity of fungi development on the surface of control samples made of ceramics corresponds to 5 points – “it clearly shows the development of fungi that cover more than 25% of the test surface”, on the surface of control samples of concrete – 4 points – “it clearly shows the development of fungi that cover less than 25% of the test surface”. The intensity of fungus development on the surfaces of products impregnated with Sol-gel did not exceed 1–2 points, which determines the fungal resistance of the material: for ceramic samples with a contact time of 2 min, for concrete samples – from 30 s to 1 min.

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It is important to note that the constant quality control of test samples on their strength and the amount of absorption, allows to note a reduction in absorption and increase in strength on average by 1.3–1.5 times for concrete samples, impregnated with the polymer, compared with the control.

4 Conclusion The conducted research in the framework of solving the problems of creating biostable building composites allows expressing the possibility of introducing a biocide of metalcontaining waste obtained by reagent treatment into the Sol-gel matrix of coverage of building materials. The latter also solves the problem of solid industrial waste accumulation. The presence of a gel film on the porous surface of concrete and building ceramics ensures the biostability of products to the impact of microbiocenoses destroying them, leads to an increase in their strength characteristics and stability in conditions of high humidity. Further development of research should be focused on optimizing the technological parameters of the process of obtaining biostable products using Sol-gel technologies, which will in the future make the technology itself more saving and building materials of higher quality. Acknowledgements. The work is realized in the framework of the Program of flagship university development on the base of the Belgorod State Technological University named after V. G. Shukhov, using equipment of High Technology Center at BSTU named after V.G. Shukhov.

References 1. Cuzman, O.A., Tiano, P., Ventura, S., Frediani, P.: Biodiversity on Stone Artifacts, The Importance of Biological Interactions in the Study of Biodiversity. Edited by Dr. Jordi LÃ3pez-Pujol, pp. 367–390 (2011). www.intechopen.com 2. Sverguzova, S.V., Shaykhiev, I.G., Otiti, T., Sapronova, Z.: Increasing the strength and frost resistance of ceramic products at using melasses bards as plasticizer. Constr. Mater. Prod. 1 (2), 19–29 (2018) 3. Erofeev, V.T., Bogatov, A.D., Bogatova, S.N., Kaznacheev, S.V., Smirnov, V.F.: Influence of the operational environment on biological firmness of building composite. Mag. Civil Eng. 7, 23–31 (2012) 4. Goncharova, E.N., Vasilenko, M.I.: Algotsenoza of the damaged city buildings and constructions. Basic Res. 8, 85–89 (2013) 5. Warscheid, T., Braams, J.: Biodeterioration of stone: a review. Int. Biodeterioration Biodegradation 46, 343–368 (2000) 6. Vasilenko, M.I., Goncharova, E.N.: Microbiological features of the process of damage to concrete surfaces. Basic Res. 4, 886–891 (2013) 7. Goncharova, E.N., Vasilenko, M.I., Nartsev, V.M.: Role of microscopic algae in the processes of damage to urban buildings. Bull. BSTU named after V.G. Shukhov 6, 192–196 (2014)

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8. Levequê, C.: Ecology – from ecosystem to biosphere Enfield, NH, USA (2003). Science Publishers, Inc., ISBN 1-57808-294-3 9. Magin, C.M., Cooper, S.P., Brennan, A.B.: Non-toxic antifouling strategies. Mater. Today 13, 36–44 (2010) 10. Huang, S.-I., Shen, Y.-J., Chen, H.: Study on the hydrophobic surfaces prepared by two-step sol–gel process. Appl. Surface Sci. 255, 7040–7046 (2009) 11. Vasilenko, M.I., Goncharova, E.N., Rubanov, Y.K., Shoeva, E.A., Tokach, J.E.: Application of metal-containing waste for the building biocides production. Int. J. Appl. Eng. Res. 10, 42658–42661 (2015)

Features of Expertise in Wooden Housing Construction S. I. Ovsyannikov1(&)

, A. A. Suska2

, and V. M. Kashyna2

1

2

Belgorod State Technological University named after V.G. Shukhov, Belgorod, Russia [email protected] Kharkov National Technical University of Agriculture named after Petro Vasilenko, Kharkiv, Ukraine

Abstract. Wooden house construction is widely used in individual housing construction. The most popular wooden houses are in the United States, Canada, Scandinavian countries, and Northern Europe. Wooden architecture resumes in Russia after a century and a half of oblivion. But during the long break, skills, experience, and skills of building wooden structures were lost, and qualified specialists were not trained in this production. The lack of qualified specialists’ leads to the fact that serious violations often occur during the construction process, which make buildings unusable or require significant investment to eliminate them. In General, this creates a negative image of wooden housing construction as high-quality and durable. The article deals with typical errors in the construction of foundations for wooden buildings, the junction of the log with the Foundation, which directly affects the durability and quality of the structure as a whole. Typical violations and errors that occur when selecting raw materials, manufacturing wall materials in the form of rounded and hewn logs, glued beams, log construction technology, installation of window and door openings are considered separately. This information is of interest to builders and experts in the field of wooden housing construction, developers and owners of wooden residential buildings. Keywords: Wooden house construction Violations and errors


Expertise
Construction
Wood


1 Introduction Wooden house construction is popular in countries where there are large forest resources [1], such as Canada, the United States, Sweden, Norway, and even Japan. Until the twentieth century, one - and two-story wooden buildings were also popular in Russia. This is not surprising, since Russia has the largest supply of wood in the world. Almost everything was made of wood: houses, churches, bridges, and outbuildings. But reinforced concrete and brick replaced wood as a building material. Currently, wooden house construction in Russia is again becoming popular [2]. Wooden structures are environmentally friendly, are quickly erected and put into operation, the service life is increased by processing wooden elements with bio-and fire © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 198–205, 2021. https://doi.org/10.1007/978-3-030-54652-6_30

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protection [3]. All this makes wooden buildings attractive to consumers. An important role in the revival of wooden housing construction is played by the state in the form of granting preferential loans for the purchase of sets of wooden houses [4]. But even with such state support, wooden housing construction accounts for about 12% of the total construction volume and about 24% of the share of low-rise construction. The main constraints to the development of wooden housing construction are prevailing stereotypes among the population about the fragility of wooden buildings, violation of the tightness of seams in crowns, deformation of the frame, and other reasons. In part, these fears are true, because over the years, experience and technologies of wooden housing construction have been lost, unscrupulous contractors often violate construction technology, thereby creating a negative image for wooden buildings. Buying wooden buildings on the secondary market also involves the risk of purchasing low-quality buildings, which reduces their cost and market attractiveness. Difficulties arise here due to the lack of competent experts in the examination of wooden structures, and just qualified practitioners in this area. Examination of wooden structures is carried out during construction to monitor compliance with the technology of work, compliance with design and estimate documentation, when determining the estimated value in the real estate market, in insurance cases, when identifying defects and damage and their assessment [7–9]. A distinctive feature of wooden buildings is the change in the properties of wood as a building material, under the influence of multiple factors [6], which are known to a narrow circle of specialists in this field. Therefore, the purpose of this work is to generalize possible violations and errors in wooden housing construction, identified during construction and when buying low-rise wooden buildings on the secondary market.

2 Methods and Materials Wooden housing construction is regulated by the following normative documents and standards [4, 5]. SP 13-102-2003 Rules for inspection of load-bearing structures and structures. SP 64.13330.2011 Wooden structures. SP 55.133330.2011 single-family residential Buildings. SNiP 3.03.01-87 load-Bearing and enclosing structures. GOST 30974-2002 corner Joints of wooden pavers and log low-rise buildings. The quality of the external surface of buildings must comply with GOST 11047-90 Details and products made of wood for low-rise residential and public buildings. Technical conditions.

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3 Results and Discussions In accordance with the set of rules SP 13-102-2003, the survey of load-bearing building structures must be carried out in this sequence. Preparatory work, during which familiarization is carried out directly with the object of expertise, space-planning and design solutions, design and technical documentation, technical specifications for the examination are developed. Preliminary or visual inspection, in which a visual inspection of load-bearing structures is performed to detect damage and defects, enclosing structures, roofing devices, floors, staircases and platforms. Instrumental investigation defines the parameters of defects and damages, are determined by the strength characteristics of the materials of the basic bearing structures and their elements, analyzes the causes of defects and damages in structures. During the examination of the design and estimate documentation, the following is checked: – ensuring the operational safety of the facility in accordance with the norms and requirements of standards [4, 5]: mechanical safety, electrical safety, fire safety, compliance with temperature and humidity conditions of operation, protection of basements from ground water and gases; – The estimated reliability of the supporting structures for the permissible deformation of structural elements, fasteners of nodal elements, etc.; – The level of architectural decisions regarding the stability and safety of the building; – Optimal and rational use of building materials and natural resources. – During construction works in wooden housing construction, it is necessary to monitor the: – Compliance with the design and estimate documentation, compliance with the requirements and standards of quality and safety standards; – Works on preparation of the territory and arrangement of the Foundation; – performing works on the construction of the frame, floors and roof; – performing internal and external finishing works; – arrangement of the adjacent territory. Typical errors and violations that occur during the construction of wooden buildings. 3.1

Arrangement of the Foundation

If the depth of the foundation is regulated by building rules and regulations, then its protruding part above the soil surface is not regulated. Builders often recommend saving on the foundation and suggest making a height of 35–40 cm. This is often enough for a brick structure. But for wood, this will lead to a number of problems. The lower rims of the walls get wet from the splashes during rain. Snowdrifts can be higher than the foundation and when melting, the lower crowns will get wet. Therefore, for wooden buildings, the height of the basement should be at least 65–70 cm. In snowy areas, the Foundation height should be 10 cm higher than the height of the snow cover in recent years. A prerequisite is waterproofing of the underground and side parts of the Foundation and the junction of the walls with the Foundation. Waterproofing of the

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basement and log house should consist of 2–3 layers of bitumen tape (Fig. 1, a). Between the base and the frame (log house), it is planned to install an antiseptic-treated lining Board (pillow), mainly made of deciduous or coniferous species that are resistant to rot. Often builders suggest that it should not be installed, but replaced with crowns made of oak or larch (Fig. 1, b). But practice shows that changing the Board is much easier than changing the lower crown. In the basement of the Foundation often “forget” to equip ventilation holes or make them only on the exterior walls and do not do on the partition walls. This leads to a violation of air circulation and temperature and humidity conditions in the underground. Logs of the salary crown should be of the largest diameter, having a border 15–20 cm wide for a tight fit to the lining Board.

Fig. 1. Violations in the construction of the Foundation of houses from a log house in the form of the absence of a lining Board: a-partial lack of waterproofing between the Foundation and the crown; b-through cracks between the first crown and the Foundation

3.2

Home of Log Cabins

Violations and errors in the construction of log houses can be divided into those related to the quality of wood and those related to technological violations. The quality of wood depends on many factors, such as the time and season of wood harvesting, storage and drying conditions, and primary processing. If storage conditions are violated, longitudinal (Fig. 2, a) and end (Fig. 2, b) cracks shrinkage, fungal lesions, including fungal colors (Fig. 2, c) occur on logs. It is not allowed to use wood affected by insects (Fig. 2, d). In the future, insects will destroy not only this log, but also a significant part of the log house. The difference in the diameter of logs should not be more than 30 mm. The thickness should not exceed 1 cm/m. p. Logs for the southern and South-Western walls are chosen with the least number of knots of the minimum size, because knots when heated in the sun will emit resin. Rotten and falling out knots, healthy knots of a size more than acceptable according to standards, resin pockets, the presence of an scaling are not allowed on lumber. Technological violations are divided into those that occur during the manufacturing of parts and those that occur during installation. In the process of manufacturing parts, the main gross violations include:

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a

b

c

d

e

Fig. 2. Defects of the construction forest: a-longitudinal cracks of shrinkage; b-end cracks of shrinkage; c-knots that emit resin when heated in the sun; d-fungal lesions and colors; e-insect damage

a

b

c

Fig. 3. Violations in the preparation of construction timber: a-the required depth of the compensation cut; b-insufficient depth of the compensation cut leads to cracking of the log from the bottom; c-lint, mossy and fringe on the logs.

– compensating cuts of insufficient depth, which does not ensure their purpose (Fig. 3, a, b); – longitudinal warpage of the logs in the process of drying in the log house, leading to the formation of gaps between the crowns. Occurs in rounded logs with a curved core arrangement; – hairiness, mossiness, fringe from unseparated wood fibers (Fig. 3, c), is found on hewn logs and when rounding logs with a blunt tool;

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– the width of the longitudinal groove of the intervening connection should be at least 2/3 of the thickness of the logs, for logs with a diameter of 200–220 mm - at least 130–140 mm. 3.3

Technological Violations

Technological violations that occur during installation: – connection of logs crowns to nails or metal pins installed with interference (Fig. 4, a); – insufficient depth of the deepening of the plug, which prevents the settlement of the logs crowns (Fig. 4, b); – the longitudinal connection of logs and timber is made without locks, which leads to the formation of through cracks (Fig. 4, c, d); – commissioning of buildings that are not dried up to 12%, which leads to cracking of logs inside the room (Fig. 4, d); – there is no or insufficient shrinkage gap between the door and window boxes and openings in the log house, not insulated cracks between the salary and the log house; – laying of inter-wall insulation should be carried out with an overhang of the grooves of at least 5 cm for further preliminary caulking; – violations of the rules for the protection of wooden products with antiseptics and flame retardants.

a

b

d

c

e

f

\

Fig. 4. Technological violations during the construction of a log house: a-connections on nails or metal nagels; b-hanging crowns on nagels; c, d – blown longitudinal connections of logs; e – cracking of wet logs inside the room during the heating period; f-installation of a window box without insulation.

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4 Conclusion Wooden house construction is used for the construction of low-rise individual houses. Such houses are not subject to state control during construction and commissioning, which is used by substandard contractors. Violations in the production of materials and construction of wooden structures lead not only to a reduction in the service life, violation of temperature and humidity conditions, tightness of walls and openings, but also to a decrease in the image of wooden buildings. Therefore, the main violations in the construction of wooden houses should be known not only by specialized experts, but also by customers and General builders. Monitoring of compliance with construction rules and regulations should begin at the stage of project development and construction work. Knowledge of the main violations and errors will allow you to exclude gross violations in the construction process, identify hidden defects, conduct a survey of objects for evaluation when buying on the secondary market. Acknowledgement. This work was realized in the framework of the Program of flagship university development on the base of the Belgorod State Technological University named after V G Shukhov, using equipment of High Technology Center at BSTU named after V G Shukhov.

References 1. Balaev, S.Yu.: Analysis of foreign experience of individual low-rise housing construction (IMD) and the possibility of IMD development in Russia. https://www.marketologi.ru/ publikatsii/stati/. Accessed 21 Apr 2020 2. Ovsyannikov, S.I.: Wooden housing construction abroad and in Russia. In: Science and Innovation in Construction: Collection of Reports of the International Scientific and Practical Conference, vol. 2, pp. 309–315. BSTU (2017) 3. Ovsyannikov, S.I., Rodionov, A.S.: Justification of effective structures for the Far North. Bull. Sci. Educ. North-West Russia 3(1), 107–114 (2017) 4. Construction and technical expertise in wooden housing construction. Part 2. Lesprominform. 3(85) (2012) 5. Construction and technical expertise in wooden housing construction. Part 3. Lesprominform 4(86) (2012) 6. Ovsyannikov, S.I., Dyachenko, V.Y.: Wooden nano-composite materials and prospects of their application in wooden housing construction. Mater. Sci. Forum 931, 583–588 (2018) 7. Filiatrault, A., Foschi, R.O.: Static and dynamic tests of timber shear walls fastened with nails and wood adhesive. Can. J. Civil Eng. 18(5), 749–755 (1991) 8. Husin, R., Rafi, A.: The impact of Internet-enabled computer-aided design in the construction industry. Autom. Constr. 12, 509–513 (2003) 9. Olsson, N.: Glulam Timber Arches: Strength of Splices and Reliability Based Optimisation. Civil and Environmental Engineering. Lulea University of Technology, Lulea (2001) 10. Ovsyannikov, S.I., Suska, A.A., Shevchenko, S.A.: The formation of the heat-insulating protecting structures of dome buildings to the Far North. Constr. Mater. Products 2(4), 21– 26 (2019) 11. Chernykh, A.G.: Dereviannoe domostroenie [Wooden house construction]. Saint Petersburg: Saint Petersburg State University of Forestry, p. 343 (2008)

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12. van de Lindt, J.W., Rosowsky, D.V., Pang, W., Pei, S.: Performance-based seismic design of midrise woodframe buildings. ASCE J. Struct. Eng. 139(8), 1294–1302 (2013) 13. Li, M., Lam, F., Yeh, B.J., Skaggs, T., Rammer, D., Wacker, J.: Modeling force transfer around openings in wood-frame shear walls. ASCE J. Struct. Eng. 138(12), 1419–1426 (2012)

Surface Activity of the Fine Disperse Systems on the Basis of Construction Sands M. V. Morozova1,2(&) 1

, M. V. Akulova1

, and M. A. Frolova2

Federal State Budget Educational Institution of Higher Education, «Ivanovo State Polytechnic University», Ivanovo, Russia [email protected] 2 Federal State Autonomous Educational Institution of Higher Education «Northern (Arctic), Federal University named after M.V. Lomonosov», Arkhangelsk, Russia

Abstract. As an energy criterion for ranking raw materials for the production of building materials, it is proposed to use the internal energy reserve of rockforming minerals. This parameter is related to the surface development and the released free surface energy of the system when the material is dispersed. Based on the principles of crystal energy, two sand deposits in the Arkhangelsk region were evaluated for atomization energy, specific weight energy of atomization, and specific volume energy of atomization (energy density). The quantitative evaluation of the potential energy reserve that passed after the material was ground to the surface one, was carried out taking into account the values of the critical surface tension and the specific surface of the raw material (formed after the process of mechanical grinding). The level of possible use of the potential energy reserve due to the formation of a new material surface was characterized by the activity of the surface of fine disperse samples. It was found that, despite the difference in the chemical composition and origin of rocks, the macro-energy parameters have similar values. The energy density values allow classifying the considered sands as high energy dense. The obtained values of surface tension and surface activity showed that the sands of the Kenitsa Deposit, in comparison with the sands of the Krasnoflotsky-Zapad field, are preferable to be used as an active fine disperse component for producing high-quality compositions. Keywords: Polymineral sand
Atomization energy
Energy density
Surface tension
Specific surface area
Surface activity

1 Introduction It is known that the use of nanotechnological approach in the creation of composite materials requires the use of nano-disperse modifiers [1–3]. This approach significantly improves the quality of building materials [4–6]. At the same time, when the raw material is dispersed to a micro-and nanoscale level, the properties of the material change, which ultimately affects its characteristics (water-physical, mechanical, color, etc.) [1, 7]. Micro-and nanoscale effects in such systems ensure the transfer of part of the potential energy of the entire object due to its structure, composition and texture to © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 206–212, 2021. https://doi.org/10.1007/978-3-030-54652-6_31

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excess surface energy [8, 9]. The main role in this plan is assigned to the specific surface area (Ssp), which increases the interaction of raw materials with the composite matrix (a more uniform distribution of particles in the material is achieved), which leads to the optimization of its structure and properties [10]. In works [11] it is shown that the introduction of additives or particles of nano - and micro-scale level into the concrete mix allows obtaining a higher strength and frost resistance of the composite. In addition, during the dispersion of rocks to the ultra - and nanoscale state, the formation of an amorphous phase is possible, which is an important component of increasing the reactivity of a highly dispersed material [12]. For such systems, this parameter is quantitatively characterized by surface activity (ks) [10, 13]. In turn, based on the calculation algorithm, the surface activity depends on the specific weight value of the atomization energy (Em) [14]. Thus, it is ks that allows characterizing quantitatively the transition of potential energy accumulated by the rock during genesis to free surface energy (Es) due to activation of the raw material surface [14, 15]. In this case, the last parameter is equal to the multiplication of the surface tension (rк, Nm) of the studied samples (surface energy of the surface unit) and the value of their specific surface (Ssp, m2/kg). It should be noted that, despite the current availability of a number of methods for determining the surface tension of solid samples, the best results, in our opinion, are shown by the Owens – Wendt – Rabel – Kaelble method (OWRK), based on the measurement of the equilibrium wetting angle of liquids with known values of surface tension and its dispersion and polarization components [8, 16]. So, for the calculation of ks, the necessary value is the macro-energy indicator of the rock – the atomization energy (Ea). Ea is defined as the sum of the standard enthalpy of crystal formation and the heat of formation of constituent atoms (the values are given in the reference literature [17]). However, it is more correct to compare rocks by energy parameters using specific values: specific weight energy of atomization (Em, kJ/g) and specific volume energy of atomization (Ev, kJ/cm3) [13]. In this case, the Ev parameter can be characterized as energy density. The calculation of the value of these macro-energy indicators (Em, Ev, ks) can serve as a justification for ranking and selecting the most effective raw materials for the production of building materials (for example, the composition of a composite binder or a modifying additive for concrete based on a silica-containing component). The aim of this work is to calculate the macro-energy indicators of polymineral sands of the most widely used deposits in the Arkhangelsk region, and a comparative evaluation of fine-disperse systems based on their surface activity.

2 Methods and Materials Two deposits of polymineral construction sands were selected as raw materials: “Krasnoflotsky-Zapad” (river) and “Kenitsa” (quarry). The determination of the main characteristics of the sands (size modulus and initial density) was carried out in accordance with GOST 8735-88. The mineralogical composition of rocks was determined by recording x-ray diffractograms on a Shimadzu XRD-7000 S x-ray diffractometer (CUC “Center for High Technologies”, BSTU

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named after V.G. Shukhov). The chemical composition of the sands was determined using a MetExpert x-ray fluorescence analyzer. To calculate the surface activity value (ks), sand samples were ground to a highly dispersed state using the method of dry dispersion of raw materials in a Retsch PM100 planetary ball mill. The optimal dispersion parameters were selected experimentally to obtain the required particle size. The size characteristics were determined using a Delsa Nano submicron particle size analyzer with photon-correlation spectroscopy method. The specific surface of highly dispersed rock systems was determined by gas sorption (according to BET theory) using an Autosorb-iQ-MP analyzer. The edge wetting angle was determined on the Easy Drop unit at a temperature of 25 ± 1 °C for samples made by pressing ground sand at a load of 20 kPa into a metal mold with a diameter of 20 mm. The surface tension of the samples was calculated using the OWRK method using four working fluids: distilled water, decanol, glycerol, and ethylene glycol.

3 Results and Discussions The selected sand deposits differ in size modulus (Mk). Thus, the river polymineral sand “Krasnoflotsky-Zapad” (S1) is small, the size modulus was 1.7 (the total residue on the sieve was 0.63–8.33%). The quarry sand of the Kenitsa Deposit (S2) can be attributed to medium-sized sands (the size modulus is 2.21, the total residue on the sieve is 0.63–27.84%). The initial density (qinit) of the studied rocks has the following values: for sand S1 qinit = 2.71 g/cm3; for sand S2 qinit = 2.64 g/cm3. The mineral composition of S1 sand is 74% quartz and 17% albite. S2 sand contains: 72% quartz, 14% albite. The chemical composition of rocks, as well as the data needed to calculate their atomization energy is presented in Table 1. Based on the results of chemical analysis of the samples, the enthalpy of formation of the corresponding elements and chemical compounds, the atomization energy for each oxide was calculated, taking into account its quantitative content in the sample. Summing these values allowed calculating the atomization energy for samples S1 and S2. Based on experimentally determined values of the initial density of samples, their energy density was calculated. All the obtained data on atomization energy, specific weight atomization energy, and specific volume atomization energy (energy density) are presented in Table 2. The data obtained show that the sands of both fields have a significant reserve of potential energy. In terms of energy density, sand deposits are characterized as highenergy dense (Ev = 60… 150 kJ/cm3). The surface activity value of the studied sands was calculated for fractions with different scale characteristics and their corresponding specific surface area (Table 3).

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Table 1. Chemical composition of sands in terms of oxides (%) and enthalpy of elements and oxides formations Sand field KrasnoflotskyZapad 93.50 2.92 2.92 2.58 0.67 0.08 1.01 0.59 0.05 0.04 0.69 0.01 0.01 –

Defined component SiO2 Al2O3 MgO Fe2O3 CaO TiO2 K2O SO3 P2O5 Cr2O3 Na2O MnO SrO ZrO2

Kenitsa

E a, kJ/mol

Molar mass of oxide, g/mol

90.56 5.77 0.48 0.80 0.25 0.03 0.28 0.04 0.06 – 1.62 0.02 0.08 0.002

1861.34 3081.90 997.80 2403.80 1062.10 1916.00 789.00 1463.60 3385.80 2683.20 879.04 918.80 1000.40 2199.00

60.084 100.181 40.311 159.695 56.079 79.954 94.203 80.061 141.943 151.989 61.979 70.937 103.619 123.218

Table 2. Energy parameters of sedimentary rocks Energy parameter Sand field Krasnoflotsky-Zapad Kenitsa 1899.53 1910.72 Ea, kJ/mol Em
103, kJ/kg 30.44 30.41 Ev, kJ/cm3 82.48 80.28

Table 3. Grinding time and dispersion characteristics of sand fractions Sand field Krasnoflotsky-Zapad Grinding time, min 10 20 Average particle size, nm 642 ± 5 445 ± 3 Specific surface area, cm2/g 10140 ± 23 15302 ± 15 Parameter

Kenitsa 10 20 559 ± 5 406 ± 3 9920 ± 19 18670 ± 12

To calculate the value of free surface energy (ES), the values of surface tension (rк, N/m) were determined. The calculation of this parameter using the OWRK method is reduced to measuring the edge angle of wetting (h) of the solid surface with working fluids with known values of surface tension (rj, N/m) and constructing a functional dependence:

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ð1Þ P where h – edge angle of wetting of the test material, rL, rD L , и rL – total, dispersion and polarizing surface tension of working fluids (respectively). The angular coefficient of this linear dependence is equal to the polarization part of the surface tension of the sample, and extrapolation of this line to the ordinate axis allows calculating the dispersion component. The surface tension of the analyzed sample is calculated using the P D following expression: rS ¼ rPS þ rD S , where rS and rS are the polar and dispersion components of the surface tension of the test material, N/m. The obtained functional dependencies of the OWRK method for the studied sands are well described by linear equations with a high value of the approximation confidence coefficient (R2). So, for the sample S1 and S2, this equation has the following form (respectively): y = 6.93
x + 4.35 (R2 = 0.98) and y = 7.06
x + 4.24 (R2 = 0.98). The values of the surface tension of the sands and their surface activity characteristics are presented in Table 4.

Table 4. Characteristics of the surface tension of sands. Sand field “Krasnoflotsky-Zapad” “Kenitsa” (S2) (S1) Specific surface area, Ssp, cm2/g 10140 ± 23 15302 ± 15 9920 ± 19 18670 ± 12 48.18 48.54 48.05 48.66 Polar component rPS , mN/m D 19.04 19.01 19.14 Dispersion component rS , mN/m 18.79 Surface tension rs, mN/m 66.97 67.58 67.06 67.81 Free surface energy Es, J/kg 67.94 104.05 66.46 126.96 Surface activity ks · 106 2.23 3.42 2.18 4.18 Defined parameter

From the obtained results, it can be seen that rPS of the samples predominate over This fact may indicate that transformations associated with active surface centers are predominant in these systems. It should be noted that for fine-dispersed samples S1 and S2, which have similar particle size characteristics, almost identical values of the free surface energy of the surface unit (surface tension) are noted, while the total free energy of the entire dispersed system increases with an increase in the specific surface of the samples. Comparing the values of kS1 and kS2 obtained for S1 and S2 (respectively), it can be noted that for the particle size range at 10-min grinding, kS1  kS2. However, increasing the grinding time to 20 min leads to a more significant increase in kS2. This fact may indicate a higher grinding capacity of the sands of the Kenitsa Deposit and the production of a fine powder that can show (in comparison with the powder from the sand of the Krasnoflotsky Zapad field) increased activity in binding compositions. rD S.

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4 Conclusion It was found that the construction sands of two fields in the Arkhangelsk region (Kenitsa and Krasnoflotsky-Zapad) can be classified as high energy dense rocks by their potential energy reserves. The energy density of the sands was Ev = 80.28 kJ/cm3 for the Kenitsa deposit, and Ev = 82.48 kJ/cm3 for the Krasnoflotsky-Zapad field. The grinding capacity of the sands of the Krasnoflotsky Zapad field is lower than that of the Kenitsa deposit, which is reflected in the increased activity of their surface. The construction sands of this field (compared to the sands of the Krasnoflotsky-Zapad field) have more active components for producing binding compositions. Acknowledgements. The reported study was funded by RFBR, project number 19-31-27001.

References 1. Lesovik, V.S., Absimetov, M.V., Elistratkin, M.Yu., Pospelova, M.A., Shatalova, S.V.: On the issue of studying the features of structure formation of composite binders for nonautoclaved aerated concrete. Constr. Mater. Products 2(3), 41–47 (2019) 2. Fedyuk, R.S., Mochalov, A.V.: Issues related to management of the structure formation of a composite binder. AlitInform: Cement. Concrete. Dry mixes. 2(51), 2–10 (2018) 3. Chernysheva, N.V., Shatalova, S.V., Evsyukova, A.S.: Fisher Hans-Bertram features of the selection of the rational structure of the compositional gips binder. Constr. Mater. Products 1 (2), 45–52 (2018) 4. Kozhukhova, N.I., Strokova, V.V., Kozhukhova, M.I., Zhernovsky, I.V.: Structure formation in alkali activated aluminosilicate binding systems using natural raw materials with different crystallinity degree. Constr. Mater. Products 1(4), 38–43 (2018) 5. Gavshina, O.V., Yashkina, S.Yu., Yashkin, A.N., Doroganov, V.A., Moreva, I.Yu.: Study of the effect of particulate additives on the setting time and microstructure of high-alumina cement. Constr. Mater. Products 1(4), 30–37 (2018) 6. Morozova, M., Frolova, M., Makhova, T.: Synthesis of low-base calcium silicates in concrete modified by microdispersed saponite-containing component. In: International Multidisciplinary Scientific GeoConference Surveying Geology and Mining Ecology Management. SGEM, vol. 19, no. 6.1, pp. 427–434 (2019) 7. Fediuk, R.S., Lesovik, V.S., Mochalov, A.V., Otsokov, K.A., Lashina, I.V., Timokhin, R.A.: Composite binders for concrete of protective structures. Mag. Civil Eng. 82(6), 208–218 (2018) 8. Danilov, V.E., Korolev, E.V., Eisenstadt, A.M., Strokova, V.V.: Features of surface free energy calculation based on the Owens–Wendt–Rabel–Kelble interfacial interaction model. Constr. Mater. 11, 66–72 (2019) 9. Danilov, V.E., Ayzenshtadt, A.M., Frolova, M.A., Tutygin, A.S.: Dispersion interactions as criterion of optimization of cementless composite binders. Inorganic Mater.: Appl. Res. 9(4), 767–771 (2018). https://doi.org/10.1134/S2075113318040093 10. Sokolova, Y., Ayzenshtadt, A., Frolova, M., Strokova, V., Kobzev, V.: Energy characteristics of finely dispersed rock systems. IOP Conf. Ser.: Mater. Sci. Eng. 365(3), 032036 (2018) 11. Grishina, A.N., Korolev, E.V.: Efficiency of modifying cement composites with nanoscale barium hydro silicates. Constr. Mater. 2, 72–76 (2015)

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12. White, C.E., Daemen, L.L., Hartl, M., Page, K.: Intrinsic differences in atomic ordering of calcium (alumino)silicate hydrates in conventional and alkali-activated cements. Cement Concrete Res. 67, 66–73 (2015) 13. Volodchenko, A.A., Lesovik, V.S., Zagorodnjuk, L.H., Glagolev, E.S.: On the issue of reducing the energy intensity of the silicate composites production with the unconventional aluminosilicate raw materials use. Mater. Sci. Forum MSF 974, 20–25 (2020) 14. Lesovik, V.S., Frolova, M.A., Eisenstadt, A.M.: Surface activity of rocks. Constr. Mater. 11, 71–74 (2013) 15. Ayzenstadt, A., Frolova, M., Mahova, T., Veshniakova, L., Verma, R.S.: Integrated approach to the assessment of quality system of highly dispersed silica contained rocks. In: International Multidisciplinary Scientific GeoConference Surveying Geology and Mining Ecology Management. SGEM, vol. 3, no. 6, pp. 53–60 (2016) 16. Sokolova, Y.V., Ayzenshtadt, A.M., Strokova, V.V.: Evaluation of dispersion interaction in glyoxal/silica organomineral system. J. Phys.: Conf. Ser. 929(1), 012110 (2017) 17. Binnewies, M., Milke, E.: Thermochemical Data of Elements and Compounds, p. 928. Wiley-VCH, Hannover (2002)

Optimization of the Structure of Flat Metal Tube Trusses V. A. Zinkova(&) Belgorod State Technological University named after V.G. Shukhov, Belgorod, Russia [email protected]

Abstract. Loading optimization of the metal trusses has a variational basis. The universal criterion of optimization is the minimum of potential energy of the system (additional energy) in functional space expanded at the expense of functions fields of configuration and (or) material modules, as well load. The proposed variational method of truss synthesis is based on the principle of possible work and generalization of the variational principles of Lagrange and Castigliano by expanding the functional space of geometric parameters. The criterion of equal strength of the truss established in the linear statement of the variational problem creates the prerequisites for finding its optimal topology and geometry when specifying the type of load, directive parameters, mechanical characteristics of the material, and the flexibility of compressed rods. The global minimum potential energy of deformation of the optimal truss corresponds to the global minimum material consumption. As numerical experiment was P consider the distribution of load Fi = const for the truss with descending (ascending) pivot. It is established the independence of optimal loading variant from truss grating structure. Keywords: Variational statement of problem
Construction topology
Singlespan hinge truss
Optimality criterion

1 Introduction The truss designs were improved as they were used in practice. In V. G. Shukhov’s work “Rafters” practically for the first time the problems of the structure optimization the structure by improving the arrangement of its elements are set and solved. In essence, the author considered the question of optimal topology, if it means the location of nodes and the way they are connected among themselves to form a geometrically unchangeable structure. Detailed theoretical studies of the topology factor of rod structures began in the second half of the XX century. In Mazhid’s work provides formulations and proofs of three theorems on structural changes, and shows the application of these theorems to optimization of the topology of articulated structures. The problem becomes specific in relation of structures for which elements it is necessary to provide stability of the balance. These include the trusses discussed here [1–10]. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 213–218, 2021. https://doi.org/10.1007/978-3-030-54652-6_32

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2 Methods and Materials This paper presents a new approach to the structure optimization of flat metal tube trusses. The expansion of the functional space due to the fields of configuration, elastic modulus and load functions allowed us to formulate variational principles of the synthesis of load-bearing structures as a generalization of the principles of Lagrange and Castigliano. The stationarity of the corresponding functionals with variable design parameters is considered under additional conditions (coupling equations): Z     ~ u w ¼ 0; u ~ w dx ¼ c;

ð1Þ

x

where x is a valid integration region, and c is a given constant. Denoting the Lagrange’s (Castigliano’s) functional J1 (J2), we can write:   Z ~J1 ¼ J1 ~ k1 uð~ wÞdx; q; ~ w þ

ð2Þ

x

  Z ~ ~J2 ¼ J2 ~ k2 uð~ wÞdx; r; w þ

ð3Þ

x

where ~ q is the displacement vector, ~ r – is the stress vector, k – is the Lagrange’s multiplier. The goal of the isoperimetric problem of defining a configuration with a vector ~ wC ~ is to position a given volume [V(wC ) = V0] in such a way as to deliver an absolute minimum to the or functional ~J 1 or ~J 2 . In this case, the Lagrange multiplier µ = const. For a linear physical law, the functionals J1 and J2 are equal in modulus to the potential energy of deformation U. The truss is represented as a virtual system with internal forces Ni/ ui , where u i is the coefficient of reduction of the calculated resistance of the material R for compressed rods, which is taken based on the restriction of the flexibility of the belt and lattice elements. Consider an isoperimetric problem with variable cross-section areas of Ai rods (the initial cause of the configuration change): n X

Ai li ¼ V0 ;

ð4Þ

i¼1

where li is the length of the rod, n is the number of rods. In this case U¼

n n X X Ni2 li þ l Ai li ; 2Eu2i Ai i¼1 i¼1

ð5Þ

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where E is the modulus of longitudinal elasticity. Consequences of the stationarity of the functional U are Eq. (4) and specific equations from the conditions ∂U/∂Ai = 0: 

Ni2 þ l ¼ 0 ði ¼ 1; 2; . . .; nÞ: 2Eu2i A2i

ð6Þ

Since Ni/(ui Ai) is a quasi-stress ~ ri , Eq. (6) takes the form: ~ r2i =ð2E) = l ( = const),

ð7Þ

testifying to the quasi-equal stress of the truss (a generalization of the Vasyutinsky’s theorem formulated without taking into account the loss of stability of the system elements). Given the calculated resistance of the truss material R, we obtain: Ai ¼ Ni =ðui RÞ;

ð8Þ

From the isoperimetric problem with the functional (5), we can proceed to the free variational problem with the functional U¼

n R X Ni li ; 2E i¼1 ui

ð9Þ

which can be used to optimize the topology and geometry of the truss. By entering RAi in (9) instead of Ni/ ui on the basis of (8), we get U ¼ ðR2 VÞ=ð2EÞ;

ð10Þ

that is, the minimum energy U corresponds to the minimum volume of the material V.

3 Results and Discussions The subject of research is the optimal structure of a single-span truss. Alternative solutions are considered in advance (Fig. 1) with varying geometry of the belt and the lattice. The effectiveness of the variational statement of the problem, which reduces to the solution of a system of algebraic equations that determine the optimal configuration, is shown. It forms the basis for a real architectural and planning solution. In addition to the 7 directional nodes of the lower belt, a second node on the symmetry axis is specified. We limit the structure variation to nodes located on vertical lines that serve as panel borders.

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Fig. 1. Variants the truss when the variation of the structure: a – with ascending diagonals, b – with decending diagonals

In each panel, we assume one diagonal, which can be ascending or descending. As a result, we get 12 types of trusses, located in the range from a triangular truss to a truss with parallel belts (Fig. 1). Eight intermediate trusses are considered to be trusses with a polygonal upper belt, according to the accepted terminology. The heights of the stands at the borders of the 1-st, 2-nd and 3-rd panels (h1, h2) are taken as variable parameters. When passing a expanded rod in the category of compressed, in addition to strength, it is necessary to ensure the stability of the equilibrium. In order to simplify the iterative process, the coefficient u was assumed to be 0.5, which does not contradict regulatory requirements. The solution of a system of algebraic equations from the conditions @U=@h1 ¼ 0; @U=@h2 ¼ 0 at F = 70 kN and R = 240 MPa led to the optimal variant five of the truss in Fig. 1 (with ascending diagonal), as shown in Table 1. Variant six loses 0.6% in terms of material volume, but remains competitive for technological reasons Table 1. The potential energy of deformation and the volume of material № trusses U, kJ V, m3 № trusses 1 18.921 0.1380 7 2 12.799 0.0930 8 3 11.452 0.0800 9 4 11.102 0.0810 10 5 10.658 0.0777 11 6 10.723 0.0782 12

U, kJ 18.609 13.245 11.583 11.243 10.804 11.663

V, m3 0.1360 0.0970 0.0845 0.0820 0.0790 0.0850

To optimize the truss structure, we recommend: reducing the number of compressed rods; the adequacy of the location of the material and power lines.

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Starting from variant six of the truss and changing the boundary conditions, we come to the configuration shown in Fig. 2. Potential energy of deformation U = 9.74 kJ, material volume V = 0.071 m3, which is 10% less than for truss six.

Fig. 2. Optimal configuration of the truss

A significant contribution to the optimization of the truss structure was also the development of a new faceless K-shaped node connection of the truss (Fig. 3). The belt is made of tubular profiles of square cross-section, and the grid elements can be rectangular or square cross-section. The cross-section of the belt is rotated around its axis so that it is a rhombus, the diagonal of which is located in the plane of the truss. The grid elements in the place of bracing to the belt have a through V-shaped cutout, completely repeating the geometry of this contiguity. In this case, the connection of each of the grid elements with the belt is carried out both along the contours of the Vshaped cutouts, and along the two side faces.

Fig. 3. Design solutions of a K-shaped faceless node connection of tube truss: a – traditional; b – developed by the author

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The subject of discussion may be to identify the advantages of an optimal statically definable truss over a statically indefinable truss that is close to it.

4 Conclusion The criterion of equal strength of the truss established in the linear formulation of the variational problem creates prerequisites for searching for its optimal topology and geometry when specifying the type of load, Directive parameters, mechanical characteristics of the material and flexibility of compressed strakes. The global minimum of potential energy of deformation of the optimal truss corresponds to the global minimum of material consumption. Acknowledgments. This work was realized in the framework of the Program of flagship university development on the base of the Belgorod State Technological University named after V G Shukhov, using equipment of High Technology Center at BSTU named after V G Shukhov.

References 1. Yuryev, A.G., Zinkova, V.A.: Ata El-Karim Soliman: truss design calculation. Constr. Mater. Products 2(1), 37–44 (2019) 2. Zinkova, V.A., Yuriev, A.G., Peshkova, E.V.: Designing of tube trusses without gusset plate with joint connections. Int. J. Appl. Eng. Res. 5(10), 12391–12398 (2015) 3. Marutyan, A.S., Orobinskaya, V.N.: Constructions optimization with the lattice from circle and oval tubes. Vestnik MGSU 10, 45–57 (2016) 4. Zinkova, V.A.: Optimization of metallic trusses topology. Bull. BSTU named after V.G. Shukhov 2, 37–40 (2015) 5. Yuriev, A.G., Zinkova, V.A., Smolyago, N.A., Yakovlev, O.A.: Structure optimization of metallic trusses. Bull. BSTU named after V.G. Shukhov 7, 41–45 (2017) 6. Tinkov, D.V.: Comparative analysis of analytical solutions to the problem of truss structure deflection. Mag. Civil Eng. 57(5), 66–73 (2015) 7. Tinkov, D.V.: The optimum geometry of the flat diagonal truss taking into account the linear creep. Mag. Civil Eng. 61(1), 25–32 (2016) 8. Indeykin, I.A., Chizhov, S.V., Shestakova, E.B., Antonyuk, A.A., Evtukov, E.S., Kulagin, K.N., Karpov, V.V., Golitsynsky, G.D.: Dynamic stability of the lattice truss of the bridge taking into account local oscillations. Mag. Civil Eng. 76(8), 266–278 (2017) 9. Klyuev, S.V., Abakarov, A.J., Lesovik, R.V., Muravyov, K.A., Tatlyev, R.D.Z.: Optimal engineering of rod spatial construction. J. Comput. Theoret. Nanosci. 6(1), 200–203 (2018) 10. Serpik, I.N., Alekseytsev, A.V., Balabin, P.Yu., Kurchenko, N.S.: Flat rod systems: optimization with overall stability control. Mag. Civil Eng. 76(8), 181–192 (2017)

Composites on the Base of Industrial Waste with Biocidal Components Yu. K. Rubanov(&) , Yu. E. Tokach , M. I. Vasilenko and E. A. Belovodsky

,

Belgorod State Technological University named after V.G. Shukhov, Belgorod, Russia {rubanov46,tokach}@bk.ru

Abstract. The article discusses ways of producing bioresistant building materials containing metal nanoparticles obtained from techno genic wastes; procedures for their introduction into building materials based on Portland cement; assessing the bioresistance of the obtained samples of building materials using a wide arsenal of methods, including microbiological methods with a variety of test objects (microscopic fungi, bacteria, unicellular algae). The aim of the study was to identify effective inhibitors of aggressive metabolites of fungi involved in the destructive process of building materials; determination of the mechanisms for the selective isolation of bioactive monoproducts from complex systems that were used as biocidal additives to provide fungi-resistant materials. As a result of experimental studies, a technology was developed for the physical and chemical treatment of industrial waste in order to obtain a biocidal component, the effectiveness of which was confirmed by biological testing methods using microscopic fungi, algae, and bacteria as test objects. The main representatives of the natural algalosis were defined. The measures have been developed to protect materials from biodeterioration by modifying component compositions and technologies for their preparation. The laboratory samples of building materials with predicted resistance to microbiological damage have been obtained. Keywords: Bioresistant building materials


Biocidal additives

1 Introduction Under the conditions of techno genic habitats, the destructive effect of microorganisms on building materials and structures is amplified. The problem of biological damage to mineral building materials and structures based on them is multifaceted and covers all types of industry. In residential and public buildings in areas with high humidity (in basements, bathrooms, in the basement, in places where water flows from the roof, in pools, etc.), microbiological corrosion becomes an important factor affecting the reliability and durability of building structures. In such buildings, mold fungi infect concrete structures, leading not only to their gradual destruction, but also to the spread of spores and particles of mycelium, as well as the production of toxic and mutagenic metabolites [1, 2]. The insufficiently studied mechanisms of the interaction of © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 219–226, 2021. https://doi.org/10.1007/978-3-030-54652-6_33

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microorganisms with building materials, their high adaptability to a changing environment make the problem of protecting building materials and structures very complex and relevant. The problem of biodeterioration of building materials and products is associated not only with a decrease in the durability of buildings and structures, but also with the effect of biodestructors on public health. A definite solution to the problem of microbiological destruction of structures and buildings is the use of biocidal additives and coatings based on them in the production of building materials. Besides the protection against biological fouling, modern coatings must provide corrosion protection, have a long service life and low cost, be chemically stable, well compatible with the material to be covered, and safe for the environment [3]. Among the variety of such biocides, a special place is occupied by preparations based on chemically pure metal-containing compounds, which are usually quite effective, but expensive [4–8].

2 Methods and Materials In this regard, studies have been conducted aimed at obtaining biocidal compositions for building materials, buildings and structures from industrial wastes containing compounds of copper, chromium, zinc, nickel, etc. The list of investigated waste included solid waste from regional industries: galvanic sludge of reagent sewage treatment from Sokol - ATS ZAO (Belgorod), SOATE ZAO (Stary Oskol), gas cleaning dust from electric furnace furnaces of OEM OAO (Stary Oskol), and vanadium pentoxide production waste Vanadium-Tula enterprises (Tula), abrasive waste of Shebekinsky Machine-Building Plant OAO (Belgorod Region). The chemical composition of the waste obtained by X-ray phase fluorescence analysis using an ARL 9900 WorkStation X-ray fluorescence spectrometer with an integrated diffraction system indicated that all of the analyzed waste contained metal compounds (Table 1), including those that possess toxic effects on living systems, which means they could be considered as potential biocides. As it can be seen from the table, sample No. 3 was characterized by the highest content of metals such as chromium (5.680%), copper (0.668%), nickel (0.505%), cobalt (0.057%), lead (0.025%) and silver (0.013%)) The fungicidal nature of this waste was confirmed by biotesting methods using microscopic fungi of several genera: the fugicidal zone (the zone of lack of fungi growth near the waste located in the center of the cup) exceeded 50% in all cases. Despite the fact that the chemical analysis of galvanic sludge of SOATE ZAO showed a high content of (toxic) biocidal compounds metals, the presence of a fungicidal zone was not detected. The absence of the activity of metals present in significant quantities is probably due to their inclusion in specific complexes that shield the potential reactivity of elements, which can be provided by chemical reagent.

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Table 1. Technical and physico-mechanical characteristics of various types of fibers Waste Galvanic sludge Sokol ATS ZAO Waste of Shebekinsky MachineBuilding Plant OAO Galvanic sludge SOATE ZAO Pentoxide production waste VanadiumTula enterprises Gas cleaning dust from electric furnace furnaces of OEM OAO

Metal content, % weight Fe Zn Cr Cu 3.11 3.89 0.14 0.49

Ni 0.02

Mn 0.03

Co –

Ag 0.01

Pb 0.01

–

0.15

0.04

0.039

0.11

0.02

–

–

2.74

5.68

0.67

0.50

0.03

0.06

0.01

0.02

21.35

–

1.97

–

–

3.32

–

–

–

35.13

2.54

0.18

0.09

0.01

1.81

–

–

0.01

34.77

2.47

The most depressing effect on the growth of green algae and bacteria was exerted by the galvanic sludge of Sokol ZAO (sample No. 1) and gas cleaning dust from electric steelmaking furnaces of OEMK OAO (sample No. 5), which were used in further work.

3 Results and Discussions To obtain the desired components a technological scheme was developed. It included the following: mixing the galvanic sludge with a chlorine-containing component in a stoichiometric ratio, mechanochemical activation of the resulting mixture by grinding in a dry grinding ball mill, leaching the resulting composition with wastewater of the same production at pH  3, and separating the solution from the precipitate by filtration, and the extraction of compounds of the desired metals from the resulting solution by electro flotation at pH = 9–10. Sodium chloride was used as a chlorinecontaining component [9, 10]. The stoichiometric ratio of the components was determined by the equations of chemical reactions.

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For sulfides: MeS þ 2NaCl þ 2O2 ! MeCl2 þ Na2 SO4 For hydroxides: MeðOHÞ2 þ 2NaCl ! MeCl2 þ 2NaOH For carbonates: MeCO3 þ 2NaCl ! MeCl2 þ Na2 CO3 Green and blue-green algae, thionic and nitrifying bacteria, microscopic fungi isolated from the surface of concrete products and structures damaged in real conditions of an urbanized environment were used as test systems for checking the biocidal properties of both the initial waste and concentrates enriched with metal oxides. The fungicidal properties of the studied materials were determined using microscopic fungi of the genera Aspergillus, Pennicillium, and Cladosporium. In all cases, the intensity of the development of the fungus on the surface of the waste corresponded to 0 points of the Fugicidal zone (zone of lack of fungi growth near the waste located in the center of the cup), for these fungi, respectively - 50%, 53%, 52%. Waste treatment (modification) according to the above technology provided the removal of individual components (for example, calcium, potassium, aluminum, sodium, silicium, etc.) and, as a result, there was a concentration at the output of elements that are highly toxic to microorganisms (copper, nickel, zinc and others). This correlated with the increasing toxicity of the treated waste. The fungicidal zone during the development of a microscopic fungus of the genus Aspergillus sp. on solid nutrient medium in the presence of modified waste increased to 100% compared to the variant of the initial waste, where the fungicidal zone was within 50%. In the case of algae (blue-green and green), in contrast to nitrifying and thionic bacteria, which successfully developed in the presence of the initial sludge, there was a complete lack of growth in the presence of both the initial waste and the concentrates obtained (Table 2).

Table 2. Comparative characteristics of the development of microorganisms Test object

Blue green algae − −

Galvanic sludge, initial Galvanic sludge after processing + - growth of the tested organisms; − - lack of growth.

Green algae − −

Nitrifying bacteria + −

Thionic bacteria + −

Fungi + −

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From the data obtained (Table 2), it follows that unicellular representatives of aquatic algaloses against microscopic fungi and bacteria turned out to be the most sensitive to substances containing compounds of toxic metals and did not develop on the surface of the nutrient medium on which there were the samples of both the initial and processed waste. Isolation of specific components from waste with acetic acid leaching. The expected further use of waste in the sol-gel coatings of building materials determined the search for options for obtaining soluble fractions with a high content of toxic metal compounds. In order to concentrate the necessary metal compounds in the biocidal component, the option of isolating the specific components by leaching was selected. Ethane (acetic) acid was used as a reagent due to its active interaction with non-ferrous metal compounds in the form of oxides, hydroxides and carbonates. In this case, the chemical reactions of the formation of water-soluble metal acetates took place according to the following schemes: MeO þ 2CH3 COOH ! MeðCH3 COOÞ2 þ H2 O MeðOHÞ2 þ 2CH3 COOH ! MeðCH3 COOÞ2 þ 2H2 O MeCO3 þ 2CH3 COOH ! MeðCH3 COOÞ2 þ H2 O þ CO2 The resulting solution of metal acetates was separated from the precipitate, and additional precipitation of calcium in the form of gypsum was carried out with a solution of sulfuric acid. After re-separation of the precipitate, the solution was evaporated to obtain a dry powder containing soluble non-ferrous metal salts. The results of the active chemical effect on the waste are shown in Table 3, 4.

Table 3. Comparative characteristics of galvanic sludge due to content of basic metal compounds Waste state

The content of metal ions, mass% Ca Mg Fe Zn Cr Cu Ni Ti Si Pb Initial 15.91 6.64 3.68 4.81 0.205 0.543 0.032 3.67 1.68 0.012 After chemical 1.65 5.60 2.59 17.65 3.640 1.540 1.620 0.013 0.690 0.079 treatment (20.85)* Note. ()* Value is shown before precipitation with sulfuric acid.

Table 4. Comparative characteristics of the gas cleaning dust of electric steelmaking due to content of basic metal compounds Waste state

The content of metal ions, mass% Ca Mg Fe Zn Cr Cu Ni Ti Si Pb Initial 9.59 8.29 50.22 3.16 0.265 0.120 0.013 3.670 5.89 0.213 4.27 3.86 18.55 4.890 2.110 2.110 0.053 1.290 0.960 After chemical 2.46 treatment (30.55)* Note. ()* Value is shown before precipitation with sulfuric acid.

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The fungicidal properties of the studied materials (waste) were determined according to the known method using Aspergillus niger as a test object. Visual inspection of the control (initial samples) clearly shows fugicidal zones (zone of lack of fungi growth near the waste located in the center of the cup), which amounted to 59% in the sludge variant and 21% in the dust variant. After modification of the sludge by treatment with acetic acid, the fungicidal zone increased significantly, amounting to almost 100% (local parietal growth is observed on a site no more than 1 cm wide). The effect of concentration of metal compounds in the dust modification product with acetic acid was noticeable, where there is an increase in zinc in 6 times, and the increase of chromium and copper is more than it by an order of magnitude, and nickel increased more than two orders of magnitude. The result of this was an increase in the fungicidal zone from 21% to 43%, indicating an increase in the biocidality of the specimen (Table 5). Table 5. Fungicidal properties of test waste Waste

Initial

After chemical treatment

Galvanic sludge

Gas cleaning dust of electric steelmaking

Features of the development of green, blue-green algae and bacteria on solid nutrient media in the presence of industrial wastes containing biocidal compounds metals testified to the biostatic effect of the studied wastes in relation to this group of organisms. The results of the experiments are presented in Table 6. Algocide and bactericidal activity of the waste was evaluated by% of dead organisms during cultivation in the presence of waste, performing calculations after staining the microorganisms with vital dye (1% potassium eosin solution) and microscopy of the samples. Features According to the data presented in Table 6, the gas cleaning dust of electric steelmaking gas treated with acetic acid has the highest biocidal activity. Green algae turned out to be more sensitive among the test objects used, the percentage of their death was 70%. In this case, the percentage of dead bacteria increased from 8% in the variant with untreated dust to 25% in the presence of modified waste, which, as it shown by microscopic studies, can be associated with the ability of bacteria to form a glue-like substance, leading to the enlargement of cell conglomerates and, as a result, protection against exposure to biocides.

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Table 6. Algocidal and bactericidal nature of waste Type of waste

% dead organisms Microscopic algae Bacteria

Galvanic sludge - initial 18 - treated with acetic acid 33 Gas cleaning dust of electric steelmaking - initial 35 - treated with acetic acid 70

0 4 8 25

In the case of the addition of a waste of galvanic production modified with acetic acid, a less intense effect of the biocide on algae (dead up to 33%) and bacteria (dead up to 4%) was noted in comparison with the addition of a similarly modified gas cleaning dust of electric steelmaking.

4 Conclusion Thus, the proposed options for the production of biocides from waste, obviously containing a toxic component, by means of their mechanochemical or reagent modifications indicate the possibility of increasing the fungicidal, algocidal and bactericidal properties of materials, and their use in production technologies for products, in particular concrete, guarantees the creation of high-quality long life materials.

References 1. Krylenko, V.A., Vlasov, D.Yu., Dashko, R.E., Startsev, S.A.: Analytics. Problems of preserving the residential and industrial infrastructure of cities from biodegradation. Infrastroy 5(11), 3–13 (2003) 2. Erofeev, V.T., Bogatov, A.D., Bogatova, S.N., Smirnov, V.F., Zakharova, E.A.: Study of the biostability of building materials taking into account their aging. Bull. Volgograd State Univ. Archit. Civ. Eng. 22(41), 73–78 (2011) 3. Magin, C.M., Cooper, S.P., Brennan, A.B.: Non-toxic antifouling strategies. Mater. Today 13(4), 36–44 (2010) 4. Klyuev, S.V., Klyuev, A.V., Shorstova, E.S.: The micro silicon additive effects on the finegrassed concrete properties for 3-D additive technologies. Mater. Sci. Forum 974, 131–135 (2019) 5. Amanda, M., Suzanne, A., Ciftan, H., Shenderova, O.: Nanodiamond particles: properties and perspectives for bioapplications. Crit. Rev. Solid State Mater. 34(1), 18–74 (2006) 6. Kuehn, T.H.: Airborn infection control in health care facilities. Energy Eng. 123(3), 366– 371 (2003) 7. Klyuev, S.V., Bratanovskiy, S.N., Trukhanov, S.V., Manukyan, H.A.: Strengthening of concrete structures with composite based on carbon fiber. J. Comput. Theor. Nanosci. 16(7), 2810–2814 (2019)

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8. Shcherbo, A.P., Antonova, V.B.: Biological damage to hospital buildings and their impact on human health. Ed. SPb: MAPO (2008) 9. Goncharova, E.N., Vasilenko, M.I.: The role of microscopic algae in the processes of damage to urban buildings. Bull. BSTU Named After V.G. Shukhov 6, 192–196 (2014) 10. Vasilenko, M.I., Goncharova, E.N., Rubanov, Y.K., Tokach, Y.E.: Application of metalcontaining waste for the building biocides production. Int. J. Appl. Eng. Res. 10(21), 42658– 42661 (2015) 11. Tokach, Y.E., Rubanov, YuK: Galvanic sludge recycling with the extraction of valuable components. Astra Salvensis Suppl. 2, 491–505 (2017)

Assessment of the Durability of Coatings Based on Sol Silicate Paint A. M. Gridchin1(&) , V. I. Loganina2 , E. B. Mazhitov2 and A. N. Ryapukhin1

,

1

2

Belgorod State Technological University named after V.G. Shukhov, Kostyukova street, 46, Belgorod, Russia Penza State University of Architecture and Construction, st. G. Titova, 28, Penza, Russia [email protected]

Abstract. Information is given on the operational stability of coatings based on sol-silicate paint. It is shown that coatings are characterized by higher resistance to cyclic freezing-thawing. The values of the free surface energy of the coating are given. It was found that coatings based on sol silicate paint have a higher surface free energy with a predominance of the polar component. Determined that the decrease in the FSE of coatings during freezing and thawing occurs mainly due to the dispersion component. The interfacial interaction between the paint and the substrate is considered. It was revealed that the sol-silicate paint is characterized by high adhesion work, wetting work, which determines the high adhesion strength of the paint to the substrate during freezing. The values of adhesion strength of sol silicate paint with the substrate are given. The analysis of experimental data indicates that the decrease in the FSE occurs mainly due to a decrease in the dispersion component. Thus, after 7 days of wetting, the decrease in the FSE coating based on sol silicate paint was 5.084 mN/m, including the dispersion component - 5.35 mN/m. The decrease after 7 days of wetting the FSE coating based on silicate paint is 9.01 mN/m. Keywords: Sol silicate paint
Coating resistance
Interfacial interaction
Free surface energy

1 Introduction In the practice of decorating, silicate paints have proven themselves well [1, 2]. The service life of such coatings is 5–6 years. However, coatings based on silicate paints have low crack resistance, which leads to early “failure” of coatings and additional repair costs. In this regard, it is relevant to solve the problem of developing and putting into practice new crack-resistant silicate paints. It is of interest to use polysilicates as film formers for silicate paints, which provide higher performance properties of coatings [3–5]. Polysilicates are characterized by a wide range of degree of polymerization of anions and are dispersions of colloidal silica in an aqueous solution of alkali metal silicates.

© The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 227–232, 2021. https://doi.org/10.1007/978-3-030-54652-6_34

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We have developed a paint composition based on a polysilicate binder obtained by mixing water glass with a silica sol [6–9]. It was found that coatings based on sol silicate paint are characterized by faster curing, tensile strength is 2.296 MPa, adhesion strength is 0.8 MPa, vapor permeability coefficient is 0.00878 mg/m•h•Pa. The paint forms a coating, with smooth uniform matte surface.

2 Methods and Materials In continuation of further studies, coatings based on sol-silicate paint were tested on cyclic effects of environmental. For determine the resistance of the coatings to the action of freezing and thawing, the samples were painted with silicate and sol silicate paint with intermediate drying for 20 min. After curing of the coatings, frost resistance tests were carried out. Assessment of the appearance of the coatings was carried out according to GOST 6992-68 “Paint coatings. Weathering test method”. For the “refusal”, the state of coverage, rated III.3 points, was taken. Tests for frost resistance were carried out in the following mode. Painted samples of cement-sand mortar after saturation in water were placed in a freezer with a temperature of −15 °C and kept for 4 h, after which they were placed in water with a temperature of 18–20 °C for four hours (one cycle). To determine the free surface energy (FSE) of the coatings, the OVRK method (Ougs, Wendt, Rabel, and Kjelbe method) was used, in which the surface tension was considered from the point of view of the polar and dispersion components of the material [10, 11]. As working fluids, water, ethanol, glycerin, ethylene glycol were selected. The polar and dispersion components were calculated using linear regression qffiffiffiffiffipffiffiffiffiffi r3b r3a pffiffiffiffiffi r ð c þ 1Þ pffiffiffi pffiffiffi ¼ þ rb r 2 r

ð1Þ

where r is the surface tension of the working fluids; rd.f. - the dispersion component of the surface tension of the working fluid; rp.f. - the polar component of the surface tension of the working fluid; rd.m. - dispersion component of the surface tension of the test material; rp.m. is the polar component of the surface tension of the investigated material; h is the contact angle of wetting of the test material. The adhesion strength of the paint to the substrate Rst, MPa was determined by the formula: R¼

P F

where P - separation force, N; F - the contact area with a paint coating, m2.

ð2Þ

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3 Results and Discussions It was found that coatings based on silicate paint are more susceptible to destruction, the state of the coating based on silicate paint after 35 cycles evaluated as AD3, AZ3. The state of the coating based on the developed composition of sol silicate paint after 40 test cycles was evaluated as AD2, AZ2. Adhesion after 50 test cycles in accordance with GOST 31149 “Paint and varnish materials. Determination of adhesion by the lattice notch method” for coatings based on sol-silicate paint was 2 points. The strength of adhesion of the coating to the substrate was also evaluated by the method of tearing off the stamp (Table 1). In assessing the adhesion of a sol of silicate paint to a substrate, the interfacial interaction at the interface of a sol silicate paint - substrate war determined. The studies were carried out using equipment based on the Center for High Technology BSTU. V. G. Shukhov. The contact angle was determined on a KRUSS DSA-30 instrument. Table 2 shows the calculation results Table 1. Adhesion to substrate after freeze and thaw cycles The number of cycles

Evaluation of the adhesion strength of the coating to the substrate by the stamp tear

0

0:8 100 0:78 97:4 0:76 94:8 0,73 92:1 0:7 89:5 0:68 86:9 0:66 86:5 0:62 81:6 0:6 79

5 10 15 20 25 30 35 40

Note: adhesion strength of the finishing composition (MPa) is indicated above the line, strength change of the finishing composition (%) is indicated below the line

It was revealed that the sol-silicate paint is characterized by high adhesion work of 108.132 mN/m, wetting work of 41.95 mN/m, which determines the high adhesion strength of the paint to the substrate during freezing. The results of the studies indicate that coatings based on sol-silicate paint are more resistant to alternating temperatures. The frost resistance mark of the coating was F35. The higher resistance of the coatings based on sol silicate paint compared to silicate paint is due to the large value of the free surface energy (FSE) of the coatings.

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Type of paint Silicate paint Sol silicate paint

Superficial tension, (mN/m) 60.66 66.18

Wetting angle

Cohesion work, (mN/m) 121.32

Wetting coefficient

65

Adhesion work, (mN/m) 86.29

0.711

Wetting work, (mN/m) 25.63

50.66

108.132

132.36

0.816

41.95

This Eq. (1) is solved graphically: we measured the wetting angles of the surface with liquids with known polar and dispersion components and plotted. In Fig. 1 and Table 3 shows the results of calculations.

Fig. 1. Free surface energy (FSE) of silicate coatings: 1 - based on liquid glass; 2 - based on sol silicate paint.

Table 3. Free surface energy (FSE) of coatings with polar and dispersion components Name of paint

FSE, (mN/m)

The dispersion component, (mN/m)

Silicate paint based on potassium water glass Sol silicate paint

63.592

27.04

Polar component, (mN/m) 36.552

74.119

27.56

46.559

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Analysis of the data (Table 3) shows that coatings based on sol silicate paint are characterized by a greater free surface energy. Thus, the FSE of coatings based on silicate paint is 63.592 mN/m, based on sol-silicate paint 74.119 mN/m. For all coatings, the polar component of the FSE predominates. The change in the FSE of silicate coatings after cyclic exposure of the environment was evaluated. A decrease in the FSE of coatings after freezing – thawing was revealed. However, the decrease in the FSE of the coatings based on sol silicate paint after 50 cycles of freezing and thawing is less compared to coatings based on the composition without glycerol. Coatings based on sol silicate paint with glycerol addition is characterized after freezing – thawing by a higher surface free energy (FSE) of 64.035 mN/m (Table 4).

Table 4. Free surface energy (FSE) of coatings Based coating

Free surface energy FSE, (mN/m)

The dispersion component, (mN/m)

Polar component, (mN/m)

Polar to dispersion ratio surface free energy

74:119 1:689 27:56 46:559 Sol 64:035 2:168 20:21 43:825 silicate paint Note. Above the line are the surface free energies before testing, below the line after 40 test cycles

Table 5. Free surface energy of coatings based on sol silicate paint Based coating

Free surface energy, (mN/m)

Dispersion component surface free energy, (mN/m)

The polar component of the free energy of the surface, (mN/m)

Polar to dispersion ratio surface free energy

27:04 63:592 36:552 1:35 Silicate 21:48 54:582 33:552 1:56 paint 74:119 1:689 27:56 46:559 Sol 69:035 2:018 22:21 44:825 silicate paint Note. Above the line are the values of the free energy of the surface before wetting, below the line - after wetting

The decrease in the FSE of coatings occurs mainly due to the dispersion component. The ratio of the polar to the dispersion component of the free energy of the surface for coatings based on sol-silicate paint before testing is 1.689, and after 40 test cycles – 2.168. The change of FSE of silicate coatings after wetting was also evaluated. After moistening for 7 days, the FSE of the coating based on sol-silicate paint was 69.035 mN/m. The analysis of experimental data (Table 5) indicates that the decrease in the FSE occurs mainly due to a decrease in the dispersion component. Thus, after 7 days of

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wetting, the decrease in the FSE coating based on sol silicate paint was 5.084 mN/m, including the dispersion component −5.35 mN/m. The decrease after 7 days of wetting the FSE coating based on silicate paint is 9.01 mN/m.

4 Conclusions It was revealed that the sol-silicate paint is characterized by high adhesion work, wetting work, which determines the high adhesion strength of the paint to the substrate during freezing. It was found that coatings based on sol silicate paint have high resistance during operation.

References 1. Korneev, V.I., Danilov, V.V.: Production and use of soluble glass, p. 216. Stroiizdat, Leningrad (1991) 2. Ailer, P.: Chemistry of silica, p. 416. Mir, Moscow (1982) 3. Figovsky, O., Borisov, Yu., Beilin, D.: Nanostructured binder for acid-resisting building materials. J. Sci. Isr.-Technol. Advant. 14(1), 7–12 (2012) 4. Figovsky, O.L., Kudryavtsev, P.G.: Liquid glass and water solutions of silicates, as a promising basis of technological processes for obtaining new nanocomposite materials. Nanotechnol. Constr. Sci. Internet J. 4(3), 6–21 (2012) 5. Figovsky, O., Beilin, D.: Improvement of strength and chemical resistance of silicate polymer concrete. Int. J. Concr. Struct. Mater. 3(2), 97–101 (2009) 6. Loganina, V.I., Mazhitov, E.B.: Research of inter-phase interaction in ZOL-silicate paints. Int. J. Eng. Technol. 7(45), 605–607 (2018) 7. Loganina, V.I., Mazhitov, Y.B., Skachkov, Yu.P.: Durability of coatings based on sol silicate paint. Mater. Sci. Prop. Technol. 394, 1–4 (2019) 8. Loganina, V., Mazhitov, Y., Skachkov, Yu.: Assessment of the structure of polysilicate binding with added glycerol. Mater. Sci. Forum 987, 15–19 (2020) 9. Loganina, V.I., Mazhitov, E.B.: Estimation of porosity of coatings based on sil of silicate paint. Res. J. Pharm. Biol. Chem. Sci. 10(2), 899–904 (2019) 10. Strokova, V.V., Babaev, V.B., Markov, A.Yu., Sobolev, K.G., Nelyubova, V.V.: Comparative evaluation of road pavement structures using cement concrete. Constr. Mater. Prod. 2(4), 56–63 (2019) 11. Kozhukhova, N.I., Strokova, V.V., Kozhukhova, M.I., Zhernovsky, I.V.: Structure formation in alkali activated aluminosilicate binding systems using natural raw materials with different crystallinity degree. Constr. Mater. Prod. 1(4), 38–43 (2018)

The Role of the Structure and Texture of the Gypsum Matrix in the Formation of Composite Materials V. G. Klimenko(&) Belgorod State Technological University named after V.G. Shukhov, Belgorod, Russia [email protected]

Abstract. This paper summarizes the results of longtime research on the structure of composite and multiphase gypsum binders and materials based on them. Fine additives CaSO4 II, iron ore concentrate of Lebedinsky MPP, waste flint and container broken glass were used as fillers. It is shown that the physical and mechanical characteristics of composite materials based on gypsum binders largely depend on their structure. And it, in turn, depends on the type of binder, the nature and dispersion of additives and fillers, the ionic composition of the medium and the pH value. In the process of hydration and hardening of composite materials based on gypsum binders, additives and fillers, as a rule, do not change themselves, but significantly affect the formation and growth of gypsum crystals. They change the size and morphology of crystalline neoplasms and contribute to the formation of a denser and more uniform fine-crystal structure of the composite material, which leads to a decrease in their porosity and improvement of physical and mechanical parameters. Three types of dependences of the strength of composite materials on the quantity, nature and properties of the filler additive are proposed. Keywords: Composite materials
Anhydrite
Construction gypsum
Iron ore concentrate
Structure
Texture
Hydration mechanism
Fine-ground waste of broken glass of various composition

1 Introduction The feature of the modern level of society development is the widespread use of composite materials, which have a number of undeniable advantages over conventional materials [1, 2]. The construction industry is not an exception in this regard. Society requires environmentally friendly, comfortable to live in, aesthetically attractive materials with improved physical, mechanical and sanitary characteristics, materials for biological protection from ionizing radiation. Dry gypsum building mixes can be the example of such materials, the use of which both in Russia and in foreign countries has a constant tendency to expand.

© The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 233–238, 2021. https://doi.org/10.1007/978-3-030-54652-6_35

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To increase further the volume of use of dry gypsum mixtures in our country, it is necessary to expand their range, including through the use of insoluble anhydrite in the composition, and the production of binders with varying phase composition, as well as various additives and fillers. Currently, anhydrous modifications of gypsum in the production of dry gypsum mixtures are used in our country in small quantities. In addition, despite the apparent simplicity of gypsum systems, the chemistry of the processes occurring during the structure formation of composite materials based on calcium sulfate is not fully understood. There are questions on the role of double and complex salts in the production of gypsum binders, the role of different phases of calcium sulfate in the gypsum anhydrite systems, the influence of structural-phase transitions of the heat-treated activators on strength of insoluble anhydrite, the influence of ultra - and nanodispersed additives on the structural and architectural characteristics of composite gypsum-containing materials, the role of structure and texture of the gypsum matrix in the formation of composite materials. All this determines the relevance of work on generalization and systematization of information in the field of obtaining national anhydrite-containing multiphase gypsum binders and dry building mixes based on them, the development of theoretical provisions for the design of such materials. The aim of this work is to develop further the theoretical basis for designing composite gypsum-containing materials.

2 Methods and Materials Natural and synthetic gypsum, thermal insoluble anhydrite (CaSO4
II), construction gypsum G-5 of CJSC “Mineral Knauf” (b-CaSO4
0,5 H2O), multiphase gypsum binders (MGB), iron ore concentrate of Lebedinsky MPP (IOC), waste flint (K-CBG) and container broken glass (Na-CBG) were studied as initial materials.

3 Results and Discussion The structure of composite gypsum-containing materials depends on the type of binder, the nature and dispersion of additives and fillers, the type of additives that regulate the properties of materials. It is necessary to select materials based on fast-hardening gypsum binders, such as: a - and b-CaSO4
0,5 H2O, a - and b-dehydrated semihydrates and a - and b-CaSO4 III and slow-hardening binders - CaSO4 II, Estrich gypsum [3]. In the first case, the gypsum binder quickly forms the main frame of the material due to the crystallization contacts of elongated prismatic gypsum crystals Fig. 1b. The number of crystallization contacts in such structures is less than that of coagulation. Elongated gypsum crystals can form bundles growing from a single center. The porous structure of the material is formed.

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Fig. 1. Photomicrographs of hydration products of binders: a – CaSO4∙II + (NH4)2SO4; b – bCaSO4∙0.5 H20; c – SGM–50; d – AM–50 c, d – shooting precision 100 l; a – shooting precision 55.5 l; b – shooting precision 39.6 l

Such a structure implies the presence of a certain number of voids between gypsum crystals. In addition, due to the increased value of the water-gypsum ratio (W/G), macro pores are formed in the material. The pore space of the hardened gypsum binder consists of pores formed as a result of the process of crystallization, evaporation of excess water and air inclusion. The type, shape, distribution and number of pores largely determine the properties of hardened gypsum stone. At the standard watergypsum ratio, the porosity is 47–55% by volume. The pores are connected to each other, which makes it possible to absorb quickly and return excess water. The structure of solidified gypsum stone is characterized by high communicating porosity. These are mainly macro pores with a diameter of more than 5 mm. The proportion of micro pores in gypsum building materials is insignificant and is about 2%. For solidified gypsum of the G-4 brand, the open capillary porosity is equal to 41.2%, and the conditionally closed capillary porosity is 2.2% [4]. The porosity of water-resistant gypsum binders differs from the porosity of conventional gypsum binders. The pore volume of micro pores (d < 2 nm) and meso pores (d = 2–50 nm) is 18 and 35–66.5%, respectively, for gypsum and water-resistant

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Rcomp. МPа

Rcomp. МPа

gypsum binders [3]. Modification of gypsum binders with fine-ground fillers reduces the proportion of macro pores in the material, which is clearly visible in photomicrographs of composite materials based on construction gypsum with the addition of IOC 50% (SGM-50) Fig. 1c and anhydrite binder with the addition of LC 50% (AM50) Fig. 1d. The average value W/G of construction gypsum is 55%. The amount of water for its hydration is 15%. Unbound water remains about 40%. Approximately the same amount of medium-sized filler is required to fill the macro pores. And if you take nanodisperse filler, it is necessary to add even more, as in this case the voids between the growing gypsum crystals will also be filled. Voids and pores can be filled with filler particles. It is only important that the size of the filler particles corresponds to the size of the pores and voids. Thus, to create a dense structure of the nanodisperse filler material, 40–60% of them are needed. Construction gypsum is hydrated mainly topochemically. While, anhydrite binders are hydrated through the decomposition of anhydrite single crystals into smaller crystals, the dissolution of calcium sulfate, and the crystallization of gypsum. The shape and size of the formed gypsum crystals are influenced by the ionic composition of the medium and the pH value [5]. In an alkaline medium in the presence of electrolytes, large lamellar gypsum crystals are formed Fig. 1a and in an acidic medium – small elongated prismatic crystals. As CaSO4 II hydrates slowly, contacts between gypsum crystals can disrupt fillers if there is no interaction between them. Fillers that have hydroxide groups on their surface can participate in polycondensation reactions with hydrating phases of calcium sulfate, strengthening the structure of the material. For CaSO4 II, they need to select fillers that interact with calcium sulfate. If there is no interaction between the binder and the filler, the strength of such compositions decreases with an increase in the amount of filler additives (Fig. 2a).

Content of IOC, %

a

Content of IOC, %

b

Fig. 2. Influence of iron ore concentrate additives on mechanical compressive strength, a – anhydrite binder; b – construction gypsum [6, 7].

When physical or chemical interactions occur in the binder – filler system, the dependence of the strength of the material on the amount of filler additive is parabolic with a clearly expressed extremum Fig. 3. In multi-phase gypsum binders (MFB) structure of the material is compacted due to the fine particles of anhydrite formed during decomposition of single crystals of anhydrite. Anhydrite is not fully

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Rсomp. 7 days МPа

hydrated, creating a micro-filler with a structure same to that of gypsum. Strong crystallization bonds are formed between the growing gypsum crystals and the anhydrite micro filler [8, 9].

Ratio of components , % Gх/AnII Fig. 3. MFB based on CaSO4 II and products of heat treatment of gypsum h. ch. (Gx) temperature of gypsum heat treatment, °C: 1 – 122; 2 – 162; 3 – 212; 4 – 360 [10]

Rсomp. МPа

If the filler compacts the structure of the binder, but the interaction of the components is weak, then a third type of strength dependence on the amount of filler additives is possible Fig. 2b. The pH value and ionic composition of the medium affect the construction gypsum to a lesser extent than on anhydrite binders Fig. 4. Thus, depending on the structure of the hardening binder, the dispersion of the filler and the mechanism of interaction between the filler and the binder, we can distinguish three types of strength dependencies on the amount and nature of the filler additive.

рН Fig. 4. Effect of the pH of the shutting liquid on the strength of gypsum binders: 1 – anhydrite binders, 2 – construction gypsum G-5 of CJSC “Mineral Knauf” [10].

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4 Conclusion At designing compositions of composite gypsum-containing materials, it is necessary to take into account the structure and texture of the gypsum matrix, the nature and dispersion of the filler, and the pH of the medium. Acknowledgements. This work was realized in the framework of the Program of flagship university development on the base of the Belgorod State Technological University named after V G Shukhov, using equipment of High Technology Center at BSTU named after V G Shukhov.

References 1. Cherevatova, A.V., Zhernovskaya, I.V., Alehin, D.A., Kozhukhova, M.I., Kozhukhova, N.I., Yakovlev, E.A.: Theoretical aspects of development of composite nanostructured gypsum binder characterized by increased heat resistance. Constr. Mater. Prod. 2(4), 5–13 (2019) 2. Chernysheva, N.V., Shatalova, S.V., Evsyukova, A.S.: Fisher, hans-bertram: features of the selection of the rational structure of the compositional gips binder. Constr. Mater. Prod. 1(2), 45–52 (2018) 3. Ferronskaya, A.V., (ed.): Gypsum Materials and Products (Production and Application). Publishing House ASV, Moscow (2004) 4. Pogorelov, S.A.: Managing the properties of gypsum binders due to physical and chemical processes. Constr. Mater. Prod. 8(22), 19–20 (2003) 5. Klimenko, V.G., Pavlenko, V.I., Gasanov, S.K.: The role of pH medium in forming binding substauces on base of calcium sulphate. Middle East J. Sci. Res. 17(8), 1169–1175 (2013) 6. Klimenko, V.G., Gasanov, S.К., Kashin, G.A.: Research of physical and chemical processes in the calcium sulfate - magnetite system. Bull. BSTU Named After V.G. Shukhov 8, 134– 139 (2017) 7. Klimenko, V.G., Kashin, G.A., Prikaznova, T.A.: Plaster-based magnetite composite materials in construction. IOP Conf. Ser. Mater. Sci. Eng. 327, 032029 (2018). https://doi. org/10.1088/1757–899x/327/3/032029 8. Klimenko, V.G.: Influence of modifying composition of gypsum binders on the structure of composite materials. IOP Conf. Ser. J. Phys. Conf. Ser. 1118, 012019 (2018). https://doi.org/ 10.1088/1742–6596/1118/1/012019 9. Maeva, I.S., Yakovlev, G.I., Pervushin, G.N., Buryanov, A.F., Pustovgar, A.P.: Structure formation of anhydrite matrix by nanodisperse modifying additives. Constr. Mater. 6, 4–5 (2009) 10. Klimenko, V.G.: Multi-Component Activators of Hardening of Composite Anhydrite Binders. Publishing House of BSTU, Belgorod (2018)

Probabilistic Tornado Hazard Criterion for the Nuclear Facilities Siting Areas G. P. Barulin1 1

2

and F. F. Bryukhan2(&)

Scientific and Engineering Centre for Nuclear and Radiation Safety, Krasnoselskaya str. 2/8, bld. 5, 107140 Moscow, Russia Moscow State University of Civil Engineering, Yaroslavskoe sh. 26, 129337 Moscow, Russia [email protected]

Abstract. Due to the significant potential danger of destructive effects of tornadoes on nuclear facilities (NF), national and international safety standards for NF provide for the study of the climate regime of tornadoes and the organization of appropriate protection of NF. An essential feature of the climate in recent decades is the widespread sharp increase in the number of hazardous weather events, including tornado occurrences. This fact determines the need for statistical processing of data on the tornadoes near NFs and assessment of their characteristics, taking into account the existing tornado hazard criteria for the NF siting areas. This study is focused on evaluating design characteristics of tornadoes using additional data on the tornado occurrences in recent years as well as predicting the risk of tornado hazard in the event of intense tornadoes. On the example of one of the tornado-prone zones in the former USSR, the probability of tornado occurrence was calculated. It has been established that the real danger of tornado impact on the NFs would be possible if two or more additional tornadoes of F5 Fujita scale pass across the survey area. Such a situation is possible with the current trend of climate changes. It is noted that there is a need to provide for the collection and analysis of new meteorological data in order to continue maintaining the existing records of registered tornadoes, as well as to expand the categories of industrial facilities that may be affected by emergency events. Keywords: Tornado
Radiation safety criterion
Tornado impact


Nuclear facility
Tornado hazard

1 Introduction Tornadoes are among the most hazardous meteorological phenomena that can have a destructive effect on buildings and structures. According to [1, 2] such an impact can be caused by tornado wind speeds exceeding 100 m/s, a pressure drop between the periphery and the center of rotation of the tornado funnel (over 100 hPa), and strikes of heavy missiles captured by the wind flow. Tornadoes are most often observed in the United States and Canada (about 2/3 of their occurrence in the world), in Bangladesh, and much less frequently in Europe and Russia. According to the US National Weather Service, about 50 tornadoes of the © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 239–245, 2021. https://doi.org/10.1007/978-3-030-54652-6_36

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highest intensity category (F5 on the Fujita scale) were recorded in the United States in 1950–2007 alone [3]. Such tornadoes occur quite rarely – in less than one in 1000 cases. Several destructive tornadoes of this category also occurred in Bangladesh. The most intense tornado recorded in Russia in 1984 was classified as category F4. The greatest potential danger of tornadoes is for nuclear power facilities [2, 4]. Since the consequences of their impact on the NF do not exclude a beyond-design accident with a maximum emergency release (discharge) of radionuclides into the environment. The impact of tornadoes is a potential hazard for other industrial facilities. At the same time, the contribution of nuclear power is about 13.5% of the total electricity production worldwide, and other potentially hazardous industrial facilities are important for the world economy. The need to take into account the potential impact of tornadoes on the NFs is mainly determined by the tornado occurrence frequency in dangerous proximity to the NF and their intensity. Therefore, the decision to consider the potential impact of tornadoes on NFs when developing their engineering protection should be made based on the probability criterion of their danger. The experience accumulated during the NF construction and operation in various countries over many years determines the need to analyze the current regulatory criteria for tornado hazard in the NF siting areas and the possible enhancing the NF safety standards. The main arguments for this analysis are as follows: • • • • • • •

The number of nuclear facilities in the world is steadily growing; Most nuclear facilities are concentrated in the areas of tornado occurrence; Frequency and intensity of tornadoes is increasing as a result of climate change; Tornadoes lead to significant damage – both material and human casualties; Different countries have different probabilistic criteria for tornado hazard; There is a general global trend in improving the environmental safety of nuclear power; In many cases, there is considerable uncertainty in the data on the tornado occurrence.

Currently, there are 192 nuclear power plants with 438 power units operating in 31 countries. Of these, Russia has 10 nuclear power plants with a total of 33 power units. In addition, the total number of research reactors in the world is more than 400, of which 62 are in Russia. Besides, a large number of other types of NFs are concentrated in the world and in Russia, for example, nuclear material storage facilities, radioactive waste storage facilities, etc. At the same time, the total number of operating NFs continues to increase. The specific feature of NFs siting is their concentration on flat territories close to the consumed water resources and in those places where there are no geological conditions hazardous for NFs. But such territories are favorable for the occurrence of tornadoes, since atmospheric vortices move along paths that pass through the lowest altitudes of the area. Due to this fact, the spatial density of the distribution of NFs in flat territories may be significant, for example, in the USA, Canada, and the European part of Russia. Therefore, there were dangerous cases of exposure or approach of tornadoes to the NFs [5]. Currently, as a result of climate changes in the world and in Russia, natural disasters have become more frequent, including dangerous meteorological phenomena, and tornadoes in particular [6, 7]. This trend has been going on for more than 20 years. Therefore, the possibility of F5 tornadoes on the territory of Russia is not excluded.

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According to data published in [8] for the period 1950 to 2011 in the United States, the total damage from tornadoes amounted to about 450 billion dollars. In addition, the number of human fatalities and injuries is estimated at many thousands of people. In Russia and other countries, the main safety criterion for the impact of an external factor on the NF is the condition that the probability of a beyond-design-basis accident with a maximum emergency release (discharge) of radionuclides into the environment PG = 10−7 per reactor per year is not exceeded. However, the effects of tornadoes on the NF may not always inevitably lead to such an accident. This is due to the fact that tornadoes passing through the NF site with a probability of PG may be relatively weak [9]. Due to the relatively high frequency of occurrence of external hazardous phenomena of natural origin and their fairly frequent occurrence, the domestic regulatory requirements [4]. The probability of P0 = 10−4 per reactor per year is accepted as a criterion for making a decision to account for or refuse to account for such phenomena (including tornadoes). Similar criteria are adopted in a number of other countries [10]. At the same time, the United States and China have national standards [11, 12]. which provide for the design of nuclear power plants to take into account tornadoes with a probability of occurrence 10−7 per reactor per year. In many cases, when analyzing the possibility of tornadoes affecting a nuclear facility, there is considerable uncertainty in the data on the passage of tornadoes. Information about tornadoes, as a rule, is of a qualitative nature, and their description contains approximate quantitative characteristics. These circumstances determine the need to analyze the existing probabilistic criteria for tornado hazard in the NF siting areas and the possible enhancing of the NF safety standards. Such a tightening of safety standards implies a revision of the probabilistic criterion of tornado hazard in the areas where nuclear facilities are located.

2 Methods and Materials As noted above, information on tornadoes is usually of a qualitative nature. The main approximate quantitative characteristics are attributed to tornadoes by the Fujita scale [13]. Intensity categories on this scale are determined based on descriptions of the consequences of tornadoes. The characteristic values of the maximum rotation speed of the tornado funnel wall, the length and width of the zone of passage of a category k tornado on the Fujita scale, as well as the pressure drop between the periphery of the tornado and its center are determined using [2, 14–16]. The main design characteristics of a probable tornado (with an intensity category kC) are included in the list of characteristics in the materials on the NF safety analysis. These characteristics make it possible to evaluate potential loads and impacts on the NF buildings and structures: • • • •

The rate of pressure drop inside the premises that fall into the tornado affected zone; Rate of water removal from the NF cooling pond; Characteristics of missiles captured by a tornado, fragments of buildings and structures; Loads on the NF buildings and structures, their combination under the most adverse impact.

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Calculations related to the tornado hazard assessment of the NF siting areas provide for the preliminary collection and analysis of data on tornado occurrences and the preparation of a catalogue of tornadoes. When preparing the catalogue, archival data of the hydrometeorological service, data from scientific institutions, as well as literary data and verified information from the mass media are used. This paper uses data from the Hydrometeorological Centre of Russia and the Institute of Geography of the Russian Academy of Sciences presented in the form of catalogues of tornadoes occurred in the former USSR for the period 1844–1988 and in Russia for the period 1987–2001. These catalogues are published in [2]. Besides, in the framework of this study additional data on tornadoes for the period 2002–2019 was collected. The actual distribution of registered tornadoes in the A-L tornado subzone highlighted in [16] is shown in Table 1. The places where tornadoes were recorded are marked in Fig. 1. As an example, Fig. 2 presents photographs of the destructive effects of a category 2 tornado that passed through the Glazovka village, Gomel region (Republic of Belarus).

Table 1. Statistical distribution of the tornadoes recorded in the A-L tornado subzone during 1844–2019, graded by intensity categories A, thous. km2

T, years

а0

229

59

1.5

Statistical distribution of the recorded tornadoes by intensity categories 0 0.5 1 1.5 2 2.5 19 4 23 5 19 1

Number of the tornadoes recorded 3 3

74

Fig. 1. Location of the tornadoes recorded in A-L subzone

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Fig. 2. Consequences of a tornado in Glazovka village, Gomel region (Republic of Belarus), 7 June 2009

3 Results and Discussions As an example, the estimated parameters of a probable tornado for the A-L tornado subzone are evaluated. The initial data for this evaluation are presented in Table 1. The result of calculating the repeatability of PS tornadoes in the A-L subzone shows that it equals 2.64  10−6 per reactor per year. Thus, the repeatability of PS does not reach the regulatory criterion P0 = 10−4 per reactor per year, which determines the need to make a decision on considering tornadoes to ensure the NF safety [4]. As mentioned above, as a result of the continuing trend of climate change on a global scale, tornadoes are becoming more frequent and more intense. This does not exclude the possibility of high intensity tornadoes (F4 and higher) in Russia. In this regard, it is necessary to organize the systematic collection and analysis of new meteorological data in order to continue maintaining the existing catalogues of the tornadoes recorded. In addition, it seems appropriate to expand the categories of hazardous industrial facilities that can be affected by emergencies. We would like to consider a hypothetical scenario of high intensity tornadoes in the A-L subzone. Calculations show that the condition for PS exceeding the level P0 = 10−4 per reactor per year could be achievable if two F5 scale tornadoes occur in addition to the actually recorded tornadoes presented in Table 1. The results of the corresponding calculations are shown in Table 2. This Table also contains the main design-basis characteristics of a potential tornado.

Table 2. The results of evaluating design-basis parameters of a potential tornado in A-L subzone in the event of hypothetical occurrence of two additional F5 scale tornadoes. P0, per reactor per year 10−4

PS, per reactor per year 1.24  10−4

KP 3.75

VP, m/s 98

UP, m/s 24

DpP, hPa 118

Lk, km 68

Wk , m 679

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The data in Table 2 demonstrates that the parameters of a potential tornado are characterized by significant destructive force. Such values should be taken into account when calculating loads and impacts on buildings and structures of nuclear facilities (wind head, pressure drop between the tornado periphery and its center, impact of objects/missiles carried away by the tornado, etc.) when designing NFs [1, 17]. It should be emphasized that such calculations represent a set of individual serious issues. In addition, it is necessary to assess the almost unknown risks of fires and explosions associated with the passage of tornadoes and their consequences. The appropriate supplementary information and clarifications imply updating the regulatory and technical base in the field of industrial safety and designing engineering protection against the comprehensive impact of tornadoes on objects of a higher level of responsibility.

4 Conclusions The widespread climate changes that cause an increasing frequency of occurrence of dangerous meteorological phenomena determine the need to analyze the potential impact of severe tornadoes on nuclear facilities. This makes it necessary to organize systematic collection and analysis of new meteorological data in order to continue maintaining existing catalogues of registered tornadoes. At the same time, it seems appropriate to expand the categories of hazardous industrial facilities, the impact on which can cause emergencies. Based on the collection and analysis of data on tornado paths through the tornadoprone subzone A-L on the territory of the former USSR, the probability of passing tornadoes through the hypothetical NF site was calculated, showing that it does not exceed the current criterion in Russia – the threshold probability of 10−4 per reactor per year. It has been established that this criterion could be achieved if two or more additional tornadoes of the F5 intensity category on the Fujita scale pass through the studied subzone. For this scenario, calculations were made for the parameters of a probable tornado – the length and width of the tornado path, the intensity category, the maximum rotation speed of the funnel wall, the forward speed, and the pressure drop between the periphery of the vortex and its center. It is noted that it is necessary to clarify and supplement the regulatory and technical base in the field of NF safety and engineering protection design against the comprehensive impact of tornadoes on NFs to ensure their reliable protection.

References 1. Simiu, E., Scanlan, R.: Wind Effects on Structures: an Introduction to Wind Engineering, 3rd edn. Wiley, New-York (2000) 2. RB-22–01: Recommendations for evaluating the tornado characteristics for nuclear power plants. Vestnik Gosatomnadzora Rossii, no 1, pp. 59–90 (2002) 3. NOAA. https://www.spc.noaa.gov/faq/tornado/f5torns.html. Accessed 07 May 2020

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4. NP-064–17: Taking into account of actions of natural and technogenic origin on nuclear power plants. Rostekhnadzor, Moscow (2017) 5. Prevatt, D.O., Agdas, D., Thompson, A., et al.: Tornado damage and impacts on nuclear facilities in the United States. J. Wind Eng. 40, 91–100 (2015) 6. Report on climate risks on the territory of the Russian Federation. Roshydromet Climate Centre, St. Petersburg (2017) 7. Chernokulsky, A.V., Kurgansky, M.V., Mokhov, I.I.: Analysis of changes in tornadogenesis conditions over Northern Eurasia based on a simple index of atmospheric convective instability. Dokl. Earth Sci. 477(2), 1504–1509 (2017) 8. Simmons, K., Sutter, D., Pielke, R.: Normalized tornado damage in the US 1950–2011. Environ. Hazards 12, 132–147 (2013) 9. Bryukhan, F.F., Potapov, A.D.: Tornado regime at the belarus NPP and the threshold probability of tornado danger. At. Energy 115, 346–350 (2014) 10. Development and application of level 1 probabilistic safety assessment for nuclear power plants: specific safety guide no. SSG-3. IAEA, Vienna (2010) 11. Design-basis hurricane and hurricane missiles for nuclear power plants: regulatory guide, 1.221. US Nuclear Regulatory Commission, Washington (2012) 12. Zhu, H., Chen, J., Li, F., et al.: Tornado hazard assessment for a nuclear power plant in China. Energy Procedia 127, 20–28 (2017) 13. Fujita, T.T.: Proposed characterization of tornadoes and hurricanes by area and intensity. Research Paper 91. University of Chicago, Chicago (1971) 14. Extreme meteorological events in nuclear power plant siting, excluding tropical cyclones: a safety guide, 50-SG-S11A. IAEA, Vienna (1981) 15. Markee, E.H., Beckerley, J.G., Sanders, K.E.: Technical basis for interim regional tornado criteria. Technical report no. WASH-1300. US Atomic Energy Commission, Washington (1974) 16. Bryukhan, F.F., Lyakhov, M.E., Pogrebnyak, V.N.: Tornado dangerous zones in the USSR and siting of nuclear power plants. Izvestya Akademii Nauk SSSR, Ser. Geograficheskaya, no. 40–48 (1989) 17. Birbraer, A.N., Roleder, A.Yu.: Extreme Effects on Structures. St. Petersburg State Politechnic University, Sankt-Petersburg (2009)

On the Issue of Designing Structures of Composite Binders R. V. Lesovik(&)

, M. S. Ageeva , A. A. Matyukhina and E. V. Fomina

,

Belgorod State Technological University named after V.G. Shukhov, Belgorod, Russia [email protected]

Abstract. Additive technologies have expanded the horizons for many dynamically developing areas of production. In many sectors of the national economy, the practical applicability of 3D printing is no longer in doubt, such as medicine, mechanical engineering, radio engineering and electronics. Therefore, the next step in the development of 3D printing technology was the printing of building structures and residential buildings. The use of additive technologies in construction requires the development and study of new materials. Predicting the properties of composites for 3D printing is quite a complex task, the solution of which can be achieved by applying mathematical models that take into account and describe the rheology of mixtures, the optimal distribution of fillers in the material structure, as well as dependencies that assess the impact of microfillers on the operating performance of products. It seems appropriate to use composite binders to produce concrete for 3D printing. Proper selection of all components, the type and optimal amount of additives introduced, will allow regulating the properties of the final product at the design stage. Thus, a systematic approach to determining the quality of concrete is being formed, which allows predicting and directing its properties depending on the goals and tasks being solved by builders and technologists. Keywords: Additive technologies
Composite binders
Technogenic sands Plasticizing additives




1 Introduction The development of construction composites with properties adapted to the requirements of construction printing and the formation of principles for their production, determines the relevance, theoretical and practical value of research in this direction [1]. It is obvious that the basis for creating high-quality concrete is the use of highly effective binders, which include composite binders (CB). The creation of such binders is associated with the use of new generation organic modifiers, active mineral additives of natural and technogenic origin, as well as mechanical and mechanical and chemical activation [2, 3].

© The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 246–252, 2021. https://doi.org/10.1007/978-3-030-54652-6_37

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The effect of additives on various cements was studied in order to select further the optimal additive and its dosage for each of the 4 studied binders. This will help design the structure of a composite binder for 3D printing in the future.

2 Methods and Materials The research was carried out for 4 types of CEM I 42.5 N cements of various manufacturers (Belgorod–1, Sebryakovsky–2, Podgorensky–3, Turkish–4). We also studied thin-ground cements (TGC) obtained by finishing grinding of Portland cement in a vibrating mill to specific surface area of 500–550 m2/kg. The optimal costs of additives MELFLUX 5581, F Melment F-10, Murasan BWA 19, Polyplast SP-1 were determined. To study the influence of plasticizing additives and select their optimal concentration and type for particular cement, the parameters of the mini-conus spreading diameter were evaluated at different dosages of additives. The work studied the strength characteristics of the cements with various additives. Quartz sand with a size modulus of M 1.6 was used as filler. The additives were introduced into the solution mixture together with the closing water. Strength properties were determined on 4  4  16 cm beam samples. When adding the additive, the amount of water was reduced to obtain the same spread of the test on the shaking table. The characteristics of the cements used in the work are given in Table 1, 2 and 3. Table 1. Physical and mechanical properties of cement CEM 42.5 N CEM 42.5 N

1 2 3 4

Fineness of grinding Passing through a sieve №0.08%

93.2 97.6 94.3 92.1

Specific surface, m2/kg

345 337 350 405

NDCP, %

25.5 27.5 28 26.3

Gripping time (min)

Tensile Content, strength at % compression, MPa

Beginning Ending 2nd day

28th day

SO3

140 165 190 177

48.5 47.08 57.7 46.5

2.34 2.12 2.64 2.05

200 255 240 221

19.2 15.77 24.4 28.5

Table 2. The chemical composition of cements CEM 42.5 N Chemical composition, mass SiO2 Al2O3 Fe2O3 CaO 1 21.9 5.36 4.26 66.4 2 21.4 5.21 4.48 63.7 3 20.64 4.89 3.54 63.36 4 19.77 4.08 4.00 64.12

% MgO 0.5 1.3 0.77 1.29

SO3 2.34 2.12 0.23 2.65

poi 1.34 1.01 1.36 2.66

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R. V. Lesovik et al. Table 3. Mineral composition of cement clinker CEM 42.5 N Actual mineralogical composition of clinker, % C3S C2S C3A C4AF 1 60.3 16.8 7.0 13 2 64.5 13.6 6.2 13.5 3 60.87 11.49 6.98 10.76 4 64.56 7.98 4.04 12.17

3 Results and Discussions At plasticizing cement systems with chemical additives, in addition to the composition and granulometry of minerals contained in cement, the chemical nature and structure of the molecules of the additives themselves or the formed adsorption layers are of great importance. By adsorbing on the surface of cement grains and hydrate new formations, surfactants reduce the interaction forces between individual particles that form a coagulation structure. The presence of surfactants in cement systems, slowing down the process of hydration, reduces the rate of occurrence of crystallization centers. The system accumulates a huge number of small crystals-germs, the interaction between which is weakened by surfactants. Depending on the chemical nature of surfactants the process of germ formation slows down to various degrees [4–6]. The graphs (Fig. 1, 2, 3 and 4) show the effect of additives on the mobility of cement suspensions based on the studied cements.

Melment F-10

Murasan BWA 19

MELFLUX® 5581 F

Poliplast SP-1

Miniconus spread area,мм2

200 180 160 140 120

100 80 60 40 20 0 0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

Amount of additive,%

Fig. 1. The effect of additives on the mobility of a cement (cement № 1)

On the Issue of Designing Structures of Composite Binders Melment F-10

Murasan BWA 19

MELFLUX® 5581 F

249

Poliplast SP-1

Miniconus spread area,мм2

180 160 140 120 100 80 60 40 20 0

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

Amount of additive,%

Fig. 2. The effect of additives on the mobility of a cement (cement № 2) 180

Miniconus spread area,мм2

160

140 120 100 80 60 40 20

Melment F-10

Murasan BWA 19

MELFLUX® 5581 F

ПОЛИПЛАСТ СП-1(Са)

0 0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Amount of additive,%

Fig. 3. The effect of additives on the mobility of a cement (cement № 3)

Figure 1 shows that the best water-reducing effect for Belgorod cement at optimal flow rate is Polyplast SP-1, followed by Melflux 5581 F, then Melment F-10. The additive Murasan BWA 19 is on the last place. Moreover, the mobility of the suspension on this additive is minimal at all its concentrations. The Melflux 5581 F additive has an optimal flow rate of only 0.2%, whereas for Polyplast SP-1 this value is 0.5%. Polyplast SP-1 and Melflux 5581 F have the same water-reducing effect for Podgorensk cement at a lower dosage of the latter. Next the Melment F-10 comes. The worst is the mobility of the suspension on the additive Murasan BWA 19 (Fig. 2).

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Miniconus spread area,мм2

180

160 140 120 100 80 60 40 20

Melment F-10

Murasan BWA 19

MELFLUX® 5581 F

ПОЛИПЛАСТ СП-1(Са)

0 0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

Amount of additive,%

Fig. 4. The effect of additives on the mobility of a cement (cement № 4)

For Sebryakovsky cement, the same mobility of the suspension occurs when using the additive Melflux 5581 F (optimal flow rate = 0.3%) and Melment F-10 (0.5%). This is followed by Polyplast SP-1. The worst water-reducing effect for this cement at optimal consumption has Murasan BWA 19 (Fig. 3). The mobility of a cement suspension based on Turkish cement using the additive Melflux 5581 F is the highest in comparison with the mobility of other additives. However, its dosage is extremely high for this type of additives, which is economically unjustified for its use. Next the Melment f-10 additive comes, which is close in size of the spread. Polyplast SP-1 and Murasan BWA 19 have very little or no effect on the mobility of the cement suspension, respectively. These features are related to the mineralogical composition of the cement and the composition of the additives themselves (Fig. 4). It is known that the effect of plasticizing additives is different for individual minerals of cement clinker. When introducing additives, their compatibility with cements (due to their content of C3A and gypsum), and mineral dispersed components and between additives during their complex introduction should be taken into account. Plasticizers of hydrophilic action are adsorbed according to the scheme: C3A > C4AF > C3S > C2S, so their most effective use is in “fat” concrete mixes on highaluminum cement. Comparing the mineralogical compositions of 4 cements, it can be seen that the content of C3A and C3S is the same between Belgorod and Podgorensk cements. And Sebryakovsky and Turkish are the same in C3S content, but different in C3A. The minimum C3A content of all 4 cements is in Turkish cement (Table 3). The effect of plasticizers of polycarboxylate type is based on a combination of electrostatic and steric (spatial) effects. Depending on the synthesis conditions, polycarboxylates with different lengths of side of polyester chains are obtained. This allows creating additives with a different ratio of steric effect and anionic activity. Thus, compared to Murasan BWA 19, Melflux ® 5581F plasticizer has more steric effect.

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Increasing the steric effect reduces the effect of polycarboxylates on the hydration of cement grains. Long side chains form a loose adsorption layer through which water freely penetrates to the surface of the cement grains, and short side chains create a dense layer that is difficult for water to overcome [7–9]. Melflux 5581 F and Murasan BWA 19 have approximately the same plasticizing effect on all cements, but the value of this indicator is much higher for the first additive. Murasan BWA 19 additive showed minimal plasticizing effect on all cements. The principle of operation of plasticizers Melment F-10 and Polyplast SP-1 is based on a strong displacement of the n-potential of cement particles in the negative area. Dispersion of cement particles occurs at the very beginning of hydration, while chemisorption of plasticizer molecules on the surface of cement particles takes place, especially with an increased content of C3A and CS phases in the cement [10]. As a result, the best plasticizing effect is found in Belgorod and Podgorensk cements. It was found that the best plasticizing effect for Belgorod cement was provided by Polyplast SP - 1 (0.4%); for Podgorensk - Polyplast SP-1 (0.5%) and Melflux 5581F (0.2%), for Sebryakovsky – Melment F-10 (0.5%) and Melflux 5581F (0.3%), for Turkish cement - Melflux 5581F (05%). Figure 5 shows comparative histograms of the average strength of cements on various additives.

60

No addi ves 48

50

51,4

Melment F-10

53,4

MELFLUX 5581 F 52,1

48,5 45,4

43,8

48,3

44,1

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50,8

Poliplastт SP-1 54,2

49,8

49,2

45,8 46,5

47,1 47,6

43

42,7

R,MPa

40 30

20 10 0

1

2

Types of Cement

3

4

Fig. 5. The histogram of the average strength of cements on various additives

As the least plasticizing effect was observed for all cements on the additive Murasan BWA 19, it was not included in further studies. The obtained dependencies will help to design the structure of the composite binder, taking into account the use of optimal dosages of additives and their types for cements from all 4 manufacturers.

4 Conclusion Thus, the most effective types of plasticizers were identified for the 4 cements under study at their optimal concentration.

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The obtained dependencies will allow obtaining composite binders taking into account the use of optimal dosages of additives and their types for cements from all 4 manufacturers. Managing structure formation by introducing an optimum for each type of cement additives makes it possible to conduct the curing process purposefully and ultimately to improve not only the technological properties of binding systems, but also physical-mechanical and technical properties of the final product—concrete; form a systematic approach to determining quality of concrete. Acknowledgments. The work is realized in the framework of the RFBR according to the research project № 18-29-24113.

References 1. Karthick, M., Kwangwoo, W., Xiao, Z., Kejin, W., Hantang, Q.: Characterizing cement mixtures for concrete 3D printing. Manufact. Lett. 24, 33–37 (2020) 2. Klyuev, S.V., Klyuev, A.V., Shorstova, E.S.: Fiber concrete for 3-D additive technologies. Mater. Sci. Forum 974, 367–372 (2019) 3. Klyuev, S.V., Klyuev, A.V., Shorstova, E.S.: The micro silicon additive effects on the finegrassed concrete properties for 3-D additive technologies. Mater. Sci. Forum 974, 131–135 (2019) 4. Elistratkin, M.Y., Kozhukhova, M.I.: Analysis of the factors of increasing the strength of the non-autoclave aerated concrete. Constr. Mater. Prod. 1(1), 59–68 (2018) 5. Elistratkin, M.Y., Lesovik, V.S., Alfimova, N.I., Glagolev, E.S.: On the development of building printing technologies. Bull. BGTU Named After V.G. Shukhov 5, 11–16 (2018) 6. Ruzhitskaya, A.V.: On the effects of various types of plasticizer additives on the properties of white Portland cement. J. Adv. Chemis. Chem. Technol. 7(87), 49–53 (2008) 7. Elistratkin, MYu., Lesovik, V.S., Alfimova, N.I., Shurakov, I.M.: On the question of mix composition selection for construction 3D printing. Mater. Sci. Forum 945, 218–225 (2019) 8. Botsman, L.N., Ageeva, M.S., Botsman, A.N., Shapovalov, S.M.: Modified pavement cement concrete. IOP Conf. Ser. Mater. Sci. Eng. 327, 032011 (2018) 9. Lesovik, R.V., Ageeva, M.S., Lesovik, G.A., Sopin, D.M., Kazlitina, O.V., Mitrokhina, A. A.: Improving efficiency of polystyrene concrete production with composite binders. IOP Conf. Ser. Mater. Sci. Eng. 11, 042063 (2018) 10. Vovk, A.I.: Hydration of tricalcium aluminate C3A and mixtures C3A - gypsum in the presence of surfactants: adsorption or surface phase formation. Colloid J. 62(1), 31–38 (2000)

Composite Binders Based on Dust of Electric Filters L. H. Zagorodnyuk1(&) , V. D. Ryzhikh1 and D. A. Sinebok2 1

, D. A. Sumskoy1

,

Belgorod State Technological University named after V.G. Shukhov, Belgorod, Russia [email protected] 2 Koneva Street, House17, Flat 80, Belgorod, Russia

Abstract. This paper discusses and suggests ways to use desalinated waste dust of electric filters as an individual or complex binder. The aim is to identify the possibility of the use of dust of cement plant electric filters as a binder material; to select the ratio of Portland cement and dust of cement plant electric filters in the composite bundle to develop a new kind of binder; to study physical and mechanical properties of samples of the binder and determine the most promising compositions. The objectives of this work are: to study sampling of samples; to create a composite solution based on Portland cement, electric filter dust and various types of sand; to study the microstructure of the source material and to develop a composite binder with improved strength and hydration characteristics. In this paper, a comparative analysis of Portland cement PC500D0-N and waste dust of cement plant electric filters was performed; their granulometry, chemical and mineralogical compositions, micro-structures and physical and mechanical characteristics were studied. As a result, the feasibility of using the enriched dust of electric filters as an independent binding material or in a composite bundle with Portland cement was proved, and a promising direction for creating a complex binder was identified. Keywords: Portland cement
Electric filter dust
Dispersion analysis
Microstructure
Strength characteristics


Chemical

1 Introduction At the moment, the production of binders in the Russian Federation is aimed at the progressive principle of development, namely, to improve the quality of products, scientific development and increasing the economic effect. One of the most significant indicators of progress in countries is the results of the cement industry’s output, as the well-being of citizens and construction volumes are directly related to the continuity and share of Portland cement consumption. The scale of cement consumption is determined by its application in the construction materials market. The Portland cement market is an agile industry, the structure of which is determined by the volume of produced products, in which the volume directly depends on demand, the price of products and the distance of transport links. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 253–259, 2021. https://doi.org/10.1007/978-3-030-54652-6_38

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The production of Portland cement is a highly energy-intensive process, in which the cost of the energy share is 25–40% and the concentration of efforts is included in the structure of production costs. It is known that the production of a ton of cement requires energy costs in the amount of 4.5 to 5 GJ [1, 2]. This decrease in energy consumption for product production is due to high consumption, which determines the system “demand-production-economic effect”. Today, the production volumes of Portland cement on the market are growing progressively by 10–20% annually. China, India, Western Europe, Russia and Japan share the leading positions in the production of Portland cement [3]. As you know, the production of Portland cement is a complex technological process with multiple stages, and some of them are particularly sensitive to the problem of dust formation. Thus, the clinker kiln is the main source of its formation. The final stage, which includes the firing of clinker, is equipped with dust-collecting equipment, namely a number of precipitation chambers and electric filters [4]. Dust formation during the production of Portland cement is one of the main problems in the field of regeneration and reuse of industrial waste, from the point of view of the economy. At present, most industries use a return technology, namely, the return of dust caught in precipitation chambers and electric filters to the firing stage or directly to the final product, which negatively affects the quality characteristics of cement. This is due to the high content of alkali metals in the dust (up to 50%). Organization of filtration systems to meet emissions of pollutants into the environment standards and to prevent the maximum permissible concentration is the regulation of legislation of the Russian Federation (Federal Law № 7-FZ “On environmental protection” of 10.01.2002). Without filtration plants, up to 80% of the sublimated dust is released into the environment, and when electric trapping plants are installed, the figure falls to 5–10% [2–5]. It is not possible to achieve a quick and maximum possible economic effect in a short time when returning the dust of electric filters back to production. Finding ways to use electric filter dust as an independent binder with improved performance and low financial investment is an important task for cement production plants.

2 Methods and Materials The used raw materials are Portland cement PC 500-D0-N (GOST 10178-85, GOST 30515-2013) and washed dust of electric filters (WDEF) of the Portland cement production plant. Drying of the dust material of electric filters was carried out in a laboratory drying cabinet. Granulometric analysis was performed on the FRITSCH Analysette 22 NanoTec plus device. The chemical composition and x-ray phase analysis of the samples was performed on an ARL 9900 WorkStation series x-ray fluorescence spectrometer. Microscopic images were shot using a high-resolution scanning electron microscope TESCAN MIRA 3 LMU. Physical and mechanical characteristics were determined during testing of samples-cubes in accordance with the requirements of normative documentation (GOST 10180-2012). In this work, the method of comparative analysis of samples of Portland cement PC 500-D0-N and WDEF with experimental studies of physical and chemical indicators was used.

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3 Results and Discussions In the research a comparative analysis of two materials is carried out – Portland cement PC 500-D0-N and washed dust of electric filters. Preparatory procedures for washing raw materials were carried out to conduct studies of the electric filter dust. The need to wash the electric filter dust is due to the high content of alkalis (potassium) in the composition of the source material. A number of scientific papers indicate the presence of an increased content of alkali in the waste dust of electric filters [1–7]. Washing of the material included three main cyclic technological processes: the first – mixing of dust with clean water; the second – precipitation of electric filter dust to the bottom (about 10 min); the third – removal of an aqueous solution containing potassium from the total volume of dust. An aqueous solution containing potassium has a characteristic yellow color shade. The washing cycle is repeated until the water solution becomes transparent. After washing, the material was dried in a laboratory drying cabinet. For further research, the material was crushed in a steel mortar bowl. Having performed granulometric analysis of samples of Portland cement PC 500D0-N and washed dust of electric filters on the FRITSCH Analysette 22 Nano-Tec plus device graphs were obtained (Fig. 1).

Fig. 1. Granulometric composition of materials: A – PC 500-D0-N; B – WDEF

According to the results of granulometric analysis, it was found that even after hydration, the electric filter dust has a lower dispersion than Portland cement. Table 1 shows the volume ratio of fractional Portland cement and washed dust of electric filters in percentage. Table 1. Comparison of granulometric compositions of PC 500-D0-N and WDEF Type of material

Fractional structure, % 0.1–1 1–10 10–20 20–100 PC 500-D0-N 3.81 28.24 21.32 46.61 Washed dust of electric filters 12.52 78.41 8.7 0.39

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Taking into account the grinding fineness of materials, it should be noted that the small dispersion of the desalinated dust of electric filters during the active hydration process in a composite composition with a fine aggregate should give higher indicators of strength, speed gripping and hardening speed of molded samples than that of Portland cement [5–7]. It should be noted that the specific surface of Portland cement PC 500-D0N is 3300 cm2/g, when the specific surface of WDEF is 8000 ± 100 cm2/g. Chemical and x-ray phase analysis of samples was performed in the laboratory using an ARL 9900 Work-Station series x-ray fluorescence spectrometer. The chemical compositions of PC500-D0-N and WDEF are shown in Table 2. Table 2. Comparison of chemical compositions of PC 500-D0-N and WDEF PC 500-D0-N, % Basic % elements Ca 46.45 Si 9.3 Al 2.77 Fe 2.35 Mg 0.86 Na 0.24 Ti 0.17 K 0.47

Oxide compound CaO SiO2 Al2O3 Fe2O3 MgO Na2O TiO2 K2O

% 67.6 20.7 5.46 3.5 1.43 0.32 0.28 0.56

WDEF, % Basic elements Ca Si Al Fe Mg Na Ti K

% 48.72 3.35 1.68 1.99 0.57 0.44 0.1 0.92

Oxide compound CaO SiO2 Al2O3 Fe2O3 MgO Na2O TiO2 K2O

% 81 8.5 3.76 3.37 0.94 0.59 0.17 1.11

Comparing the chemical compositions of PC500-D0-N and WDEF, it should be noted that CaO content in the dust sample is significantly higher. The content of SiO2, Al2O3, and Fe2O3 in the WDEF sample is present in smaller amounts. The content of impurity elements K, Mg, Na, Ti is within acceptable limits. X-ray phase analysis of a sample of washed dust of electric filters was performed (Fig. 2), which showed the content of hydration products (Ca(OH)2, C2SH(B), C2SH, C3AH6). X-ray phase analysis for PC500-D0-N was not performed, as the mineralogical composition of this material is normalized. PC500-D0-N contains the following minerals: C3S – 59.0 ± 2%; C2S – 18.8 ± 2%; C3A – 7.0 ± 0,2%; C4AF – 13.1 ± 0.25%. The electric filter washed dust is characterized by a fairly uniform structure of fine dispersion. The grains are clearly visible crystalline neoplasms that envelop the entire volume of grains; there is an intertwining of fine-crystalline neoplasms on the surface of WDEF grains that arose due to the hydration of dust during washing (Fig. 3). Tests of samples-cubes of 4  4  4 cm in size, molded from pure materials WDEF and PC500-D0-N were carried out, both individually and in a composite composition, and tested on an electric screw press. The obtained strength characteristics shown in Table 3 indicate that the strength of the WDEF cube samples after 28 days of hardening is less than the strength of the Portland cement cube samples. It should be noted that the composite composition of electric filter dust and Portland cement show

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Fig. 2. Fragment of a radiograph of washed, dried dust of electric filters

Fig. 3. Microphotographs of Portland cement (A) and washed dust of electric filters (B)

fairly high strength indicators. The electric filter dust, having a small dispersion, fills the pores in the composition, hydrating them, which contributes to the creation of a more durable composite. Tests of the obtained binders in composite solutions were carried out, in which polyfractional and ground (fraction  0.14) sands were implemented as filler. Physical and mechanical tests of samples are given in Table 4. Table 4 shows that a sharp increase in strength is observed in samples that include ground sand. The lowest strength indicators are observed in samples without ground sand in the composition of the solution. The samples of the following composition have the greatest strength characteristics: PC500-D0-N, WDEF and ground sand. To date, some scientific work has been carried out on the use of electric filter dust [8–11]. however, taking into account the urgency of this problem, work on the integrated use of natural and technogenic raw materials should be continued.

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NG, % The strength of the samplescubes of 4  4  4 cm, MPA 3 days 28 days PC500-D0-N 2.5 19.4 49 Washed dust of electric filters (WDEF) 30.7 16.9 43 PC500-D0-N + 5% (WDEF) 26.7 21.5 56 PC500-D0-N + 10% (WDEF) 27.5 22.9 59

Table 4. Strength characteristics of samples from composite solutions Solution structure, % Polyfractional PCsand D0-N 90 10 88 9.5 82 8 72 8 42 8 70 12 – 12 60 12 – 12

WDEF – 2.5 10 20 50 – – 10 10

Ground sand (fraction  0,14) – – – – – 18 88 18 78

Strength at the age of 28 days, MPa 8.5 13.5 15.9 23.0 16.5 20.3 26.1 25.3 27.0

Achieving sufficiently high strength characteristics of solutions with a relatively small ratio of binder to aggregate, involves the use of washed dust of electric filters, as an individual binder component or one of the components in the composition of the binder, and removed alkaline components can be used as expensive potash fertilizers.

4 Conclusion The possibility of using washed dust from cement plant electric filters as an individual binder is determined. It was found that the washed dust of electric filters is actively assimilated in the composition with Portland cement at certain ratios. It is proved that even after hydration the washed dust of electric filters crushed in the mortar bowl has a sufficiently high hydration activity.

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Based on the data obtained during the research, it can be concluded that it is possible to release leached waste from electric filters, which can be successfully used in the construction market as an additive or a special binding material. Acknowledgements. The work is realized in the framework of the RFBR support according to the research project № 18-29-24113.

References 1. Kuznetsov, I.O., Sukhorukov, A.V.: Problematic aspects of the treatment, disposal and storage of the collected dust by electric filters. Scientific Works of the Southern Branch of the National University of Biological Resources and Nature Management of Ukraine “Crimean Agrotechnological University” 162, 163–169 (2014) 2. Dudchenko, A.Yu..: Influence of the return of electric filter dust on the quality of clinker. In: International Scientific and Technical Conference of Young Scientists of BSTU Named After V.G. Shukhov, Belgorod, 01–30 May 2015, pp. 134–136 (2015) 3. Salamanova, M.S., Aliyev, S.A.: Ways to reuse cement dust. Bull. GSOTU Eng. Sci 1(15), 88–96 (2019) 4. Gozev, S.V.: The impact of the return of the electric filter dust on the clinker quality. In: International Scientific and Technical Conference of Young Scientists of BSTU Named After V.G. Shukhov, Belgorod, 01–30 May 2015, pp. 95–97 (2015) 5. Gushchina, T.S., Solomatova, S.S., Goncharov, A.A.: Efficiency of using electric filter dust in the production of binding materials. In: International Scientific and Technical Conference of Young Scientists of BSTU Named After V.G. Shukhov, Belgorod, 01–30 May 2015, pp. 118–122 (2015) 6. Aliyev, S.A., Murtazayeva, R.S.A., Salamanova, M.S.: Structure and properties of alkaline activated binders with the use of cement dust. Bull. GSOTU Eng. Sci. 2, 148–157 (2019) 7. Taymasov, B.T., Khudyakova, T.M., Dauletiyarov, M.S., Baymakov, K.A., Abdrazakov, A. A.: Influence of electric filter dust on the processes of hydration and hardening of cements of JSC “South-Kyrgyz cement”. Scientific Works of SKSU Named After M. Auezov 2, 12–18 (2017) 8. Zagorodnyuk, L.H., Shkarin, A.V., Shchekina, A.V., Shchekina, A.Yu., Lutinina, I.G.: Production of composite binders in various grinding units. Bull. BSTU Named After V.G. Shukhov 2, 53–57 (2012) 9. Zagorodnyuk, L.H., Lesovik, V.S., Voronov, V.V.: Features of solidification of building solutions based on dry mixes. Bull. BSTU Named After V.G. Shukhov 10, 32–36 (2016) 10. Lesovik, R.V., Ageeva, M.S., Chernysheva, N.V.: Activation of fine-grained concrete on iron-containing technlogenic sands by a magnetic field. Bull. BSTU Named After V.G. Shukhov 1, 24–28 (2011) 11. Nikitina, M.A., Erygina, A.O., Timoshenko, T.I.: Optimization of raw mix composition of serebryansky cement plant. Constr. Mater. Prod. 1(4), 13–20 (2018)

Influence of Chloride-Containing Media on the Protective Properties of Concrete Viktoriya Konovalova(&) Department of Natural Sciences and Technosphere Safety, Ivanovo State Polytechnic University, Ivanovo, Russian Federation [email protected]

Abstract. The main factor causing the destruction of reinforced concrete is the corrosion of steel reinforcement, about 80% of the damage is due to this phenomenon. Chloride-containing media are aggressive both to cement concrete and to steel reinforcement. Experimental studies of liquid corrosion of cement concretes in chloride-containing media were conducted: in 2% MgCl2 solution and in hydrochloric acid solution with pH = 5. It is established that at the initial stage of concrete corrosion in liquid media, their strength increases due to the formation of corrosion products in the pores. The influence of the type of concrete coating on the electrochemical corrosion of steel reinforcement located in concrete is studied. In concretes containing hydrophobizing additives, the corrosion of steel reinforcement occurs much later compared to the reinforcement found in non-hydrophobized cement concretes. During 6 months of testing, changes in the surface potential of steel reinforcement in hydrophobized concretes exposed to media of various degrees of aggressiveness were not recorded. The studies and data obtained give an idea of the influence of various media on the development of the corrosion processes of reinforcement and concrete and serve as the basis for clarifying the features of corrosion and methods for its elimination in the system “steel reinforcement – concrete”. Keywords: Corrosion of concrete
Corrosion of reinforcement
Chlorideinduced corrosion
Durability
Influence of chloride ions
Hydrophobizing additives

1 Introduction Reinforced concrete is considered as the most famous and important material in the construction industry. Reinforced concrete in comparison with other materials is quite inexpensive, so it is used for the construction of civil and industrial buildings and structures that are operated in various conditions. Many studies are focused at improving the performance characteristics of concrete in accordance with the variety of fields of its application [1, 2]. Sometimes reinforced concrete is produced with violations and deviations from standards, therefore there may be a difference between the quality required by the standard and that obtained during manufacture. In cases of reinforced concrete corrosion, the destruction processes are aggravated by reactions of reinforcement degradation. It is known [3] that the main cause of © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 260–265, 2021. https://doi.org/10.1007/978-3-030-54652-6_39

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destruction of reinforced concrete structures is corrosion of steel reinforcement (approximately 80% of cases). In this regard, many studies are aimed at obtaining materials and new methods for protecting steel reinforcement from corrosion [4, 5]. Some elements of reinforced concrete structures are destroyed mainly due to the corrosion of the reinforcement; therefore, damaged rods directly affect the safety and durability of the structure. Since severe climatic conditions are the main factor causing corrosion of steel reinforcement, all specifications and technical requirements include the conditions for the production of concrete mix, the choice of material, the thickness of the concrete coating and other requirements necessary to maintain the durability of concrete and prevent corrosion of the reinforcement in it. The safety of reinforcement in reinforced concrete structures is largely determined by the properties of the protective layer of concrete, the most important of which is permeability. If the concrete density is insufficient, the diffusion of aggressive agents by the concrete thickness is facilitated, which significantly accelerates the process of neutralization of the cement stone and can cause premature corrosion of the reinforcement [6]. To reduce the permeability of concrete, special additives are introduced into its composition during manufacture, which are deposited in the form of a waterproof film on the pore surface during the formation of the structure of cement stone. As such additives are used salts of fatty acids, wax emulsions, silanes, polymers, sodium silicates [7–9]. An alkaline medium is formed in concrete, since soluble oxides of calcium, sodium and potassium are present in large concentrations in the pores of the material [10]. These oxides form hydroxides obtained by the reaction between the Portland cement particles and the mixing water. The alkaline environment of concrete leads to the formation of a passive layer on the steel surface, which prevents corrosion. If the passive layer is disturbed, the surface of the reinforcement is exposed to an aggressive environment. The main causes of depassivation are: exposure of reinforcement as a result of mechanical damage to the concrete protective layer; neutralization of the protective layer of concrete under the influence of acidic aggressive environments, as a result of which the pH of the pore fluid in the area of the reinforcement is reduced; the effect on reinforced concrete of chlorine-containing and some other aggressive environments that can destroy the protective film at high (over 12) pH values [11, 12]. The continuing interest in corrosion protection of steel reinforcement of reinforced concrete in construction makes it necessary to study the corrosion processes of reinforced concrete in aggressive environments to develop practical recommendations for more rational operation of reinforced concrete structures.

2 Materials and Methods To study the processes occurring during liquid concrete corrosion, samples were made from CEM I 42.5N Portland cement with a water-cement ratio equal to 0.3. The process of concrete corrosion is caused by the diffusion of calcium hydroxide from the concrete

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thickness to its surface bordering the medium, as well as the transition of the substance through the “solid – liquid” interface and dissolution in the liquid medium [13] 2% MgCl2 solution, hydrochloric acid solution with pH = 5 and distilled water were taken as aggressive media. The studies were carried out for 150 days. To study the effect of chloride-containing media on the corrosion of steel reinforcement, rods made of steel of the St3 brand were taken. The corrosion potential of reinforcement was measured on samples that were in direct contact with aggressive media, and on samples that were protected by a concrete coating. For testing, a batch of samples was made of concrete containing a hydrophobizing additive of calcium stearate in the amount of 0.7% by weight of cement, which corresponds to the concrete brand for water resistance W8 [13]. The surface potential of the steel reinforcement was measured relative to the silver chloride electrode.

3 Results and Discussions The images of the sample surface (Fig. 1) show the corrosion products formed by the reactions (1) and (2). CaðOHÞ2 þ 2HCl ! CaCl2 þ H2 O

ð1Þ

CaðOHÞ2 þ MgCl2 ! CaCl2 þ MgðOHÞ2

ð2Þ

Fig. 1. Images of the surface of samples after 150 days of exposure to an aggressive environment: a) HCl solution with pH = 5; b) 2% MgCl2 solution.

A 2% solution of MgCl2 is an extremely aggressive medium for cement concrete; therefore, the corrosion processes in it proceed more intensively, as evidenced by the greater amount of formed corrosion products. Figure 2 shows the curves of changes in the compressive strength of concrete samples on Portland cement during corrosion in various environments. At the initial

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stage of liquid corrosion the strength increases, which can be explained by the filling of pores and voids in the concrete with newly formed corrosion products.

Compressive strenght, %

140 120 100 80

1

60

2

40

3 4

20 0 0

50

100

150

t, days Fig. 2. Kinetics of changes in the strength of concrete samples on Portland cement under compression in 1) 2% MgCl2 solution; 2) HCl solution with pH = 5; 3) water.

The corrosion rate of reinforcement in concrete can be judged by the change in its potential. The test results are presented in Table 1. Table 1. The change in the potential of reinforcement Type of coating

–

Media

Water 2% solution of MgCl2 HCl (pH = 5) Concrete Water 2% solution of MgCl2 HCl (pH = 5) W8 water resistant grade concrete Water 2% solution of MgCl2 HCl (pH = 5)

The surface potential of reinforcement, mV Initial state After 6 month −315 −410 −325 −460 −340 −463 −320 −355 −310 −362 −324 −368 −310 −310 −310 −310 −315 −315

The data show that after 6 months of testing, there is a tendency to shift the potential of the reinforcement at direct contact with the aggressive medium to the

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region of negative values. The sharp shift of the potential of unprotected samples to the negative side is caused by the formation of the first corrosion centers under the influence of chloride ions penetrating to the steel surface. The strength of concrete during liquid corrosion in chloride-containing environments increases only for some time and exceeds the strength of concrete that is not exposed to aggressive environments (Fig. 2). The slower the corrosion process, the later the concrete loses strength. For concrete that is well permeable to liquid, the breaking point of the strength curve and the beginning of visible destruction in an extremely aggressive environment occurs within weeks or months. Usually the fracture of the strength curve occurs after several years. The process of destruction of concrete with an increased pore content of lightweight concrete on porous aggregates is also slowing down, since a significant pore volume allows many neoplasms to be accommodated in it before internal pressure begins to develop. A significant increase in the strength of samples in water is also associated with the passing processes of hydration, in which more hydration products are formed providing a set of concrete strength [14]. When alite and Belite are hydrated, a large amount of free Ca(OH)2 is formed, which reacts with aggressive ions contained in the liquid medium. The calcium hydroxide present in the pore fluid of the concrete, ensures the maintenance of an alkaline environment and prevents corrosion of steel reinforcement. In concrete, the change in the surface potential of the reinforcement occurs less intensively than with direct contact of the reinforcement with an aggressive medium. In concrete containing hydrophobizing additives, the potential of steel reinforcement does not change for 6 months, since the hydrophobizer prevents the penetration of chloride ions into the concrete, therefore, their interaction with the steel surface does not occur, and the reinforcement retains its passive state.

4 Conclusion Chloride ions penetrating concrete when exposed to aggressive environments have a negative effect on both concrete and steel reinforcement. Chlorides reduce the strength of the concrete coating by interacting with the main component of concrete calcium hydroxide. At the same time, the probability of cracks appearing in concrete due to the increased internal pressure because of the formation of corrosion products on the surface of steel reinforcement under the influence of chloride ions. Violation of the continuity of the concrete coating enhances the flow of aggressive medium to the surface of the reinforcement and further spread of corrosion along the length of the reinforcing bar in concrete. The introduction of hydrophobizing additives prevents the interaction of concrete with the components of an aggressive environment and the penetration of liquid into the concrete. Hydrophobized concrete has high corrosion resistance, their application ensures the durability of buildings and structures operating in harsh conditions.

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References 1. Namsone, E., Šahmenko, G., Korjakins, A.: Durability properties of high performance foamed concrete. Procedia Eng. 172, 760–767 (2017) 2. Ayub, T., Khan, S.U., Memon, F.A.: Mechanical characteristics of hardened concrete with different mineral admixtures: a review. Sci. World J. 2014, e875082 (2014) 3. Abouhussien, A.A., Hassan, A.A.A.: Experimental and empirical time to corrosion of reinforced concrete structures under different curing conditions. Adv. Civ. Eng. 2014. e595743 (2014) 4. Wilmot, R.E.: Corrosion protection of reinforcement for concrete structures. J. South Afr. Inst. Min. Metall. 107(3), 139–146 (2007) 5. Fedosov, S., Roumyantseva, V., Konovalova, V.: Phosphate coatings as a way to protect steel reinforcement from corrosion. In: MATEC Web Conferences, vol. 298, p. 00126 (2019) 6. Bi, Z.H., Zhang, P., Wittmann, F.H., Zhao, T.J., Wang, P.G.: Early information on corrosion initiation in reinforced concrete structures exposed to aggressive environment. Restor. Build. Monum. 20(1), 63–70 (2014) 7. Akchurin, T.K., Tukhareli, V.D., Pushkarskaya, O.Y.: The modifying additive for concrete compositions based on the oil refinery waste. Procedia Eng. 150, 1485–1490 (2016) 8. Velichko, E., Polkovnikov, N., Sadchikova, Y.: Efficient concrete increased water resistance modified with mineral and polymeric additives. In: E3S Web Conferences, vol. 97, p. 02017 (2019) 9. Tukhareli, V.D., Tukhareli, A.V., Cherednichenko, T.F.: Expansion of concrete functionality due to use of new hydrophobic additives. Solid State Phenom. 265, 192–197 (2017) 10. Fernandes, I., Broekmans, M.: Alkali-silica reactions: an overview. Part I. Metallogr. Microstruct. Anal. 2, 257–267 (2013) 11. Ahmad, S.: Reinforcement corrosion in concrete structures, its monitoring and service life prediction - a review. Cem. Concr. Compos. 25(4–5), 459–471 (2003) 12. Morzhukhina, A., Nikitin, S., Akimova, E.: Determination of the neutralization depth of concrete under the aggressive environment influence. In: E3S Web Conferences, vol. 33, p. 02010 (2018) 13. Fedosov, S.V., Roumyantseva, V.E., Krasilnikov, I.V., Konovalova, V.S., Evsyakov, A.S.: Monitoring of the penetration of chloride ions to the reinforcement surface through a concrete coating during liquid corrosion. In: IOP Conference Series: Materials Science and Engineering, vol. 463, p. 042048 (2018) 14. Bogdanov, R.R., Ibragimov, R.A.: Process of hydration and structure formation of the modified self-compacting concrete. Mag. Civ. Eng. 5, 14–24 (2017)

The Effect of Latex and Nanocarbon Modifiers ON the Properties of High-Strength Gypsum L. Yu. Matveeva1 , M. V. Mokrova1 , A. V. Yastrebinskaya2(&) , and A. S. Edamenko2 1

Saint Petersburg State University of Architecture and Civil Engineering, Saint Petersburg, Russia [email protected] 2 Belgorod State Technological University named after V.G. Shukhov, Belgorod, Russia [email protected]

Abstract. It is known that gypsum binders and products based on them are effective building materials and are characterized by high technical and economic indicators of production and use in construction, and gypsum products also do not require acceleration of hardening in their manufacture. We can highlight the disadvantages of gypsum materials and products. These are relatively not high strength characteristics and low water resistance. It is possible to reduce the negative properties and increase the operational characteristics of gypsum building products by modifying gypsum binders, creating mixed forms of binders and composites with specified characteristics on their basis. Moreover, complex systems based on gypsum binders are not always stable in their properties and are often unpredictable in difficult operating conditions. The aim of our study is to study the mechanisms of influence of latex, nanocarbon, as well as complex latex-nanocarbon modifiers on high-strength gypsum of the industrial brand G-16. Keywords: Gypsum binders
High-strength gypsum
Modifying additives Nanocarbon modifier
Styrene-butadiene latex
Gypsum properties




1 Introduction Gypsum binders are one of the most popular in construction due to the presence of a significant amount of raw materials and environmental friendliness, both the material itself and the technology for its production, low firing temperatures and, therefore, low energy costs for production, short setting times, and high uniformity of the material at implementation of a specific process [1]. The disadvantages of gypsum materials and products include relatively low strength characteristics and low water resistance. It is possible to reduce the negative properties and increase the operational characteristics of gypsum building products by modifying gypsum binders, creating mixed forms of binders and composites with specified characteristics on their basis [2]. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 266–273, 2021. https://doi.org/10.1007/978-3-030-54652-6_40

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Moreover, complex systems based on gypsum binders are not always stable in their properties and are often unpredictable in difficult operating conditions. The traditional way to improve the strength properties of gypsum material is to control the crystalline structure of the binder. Conventional construction and forming kinds of gypsum with low strength, have a crystalline structure in the form of b-modification of calcium sulphate dihydrate. Get them firing in open devices, communicating with the atmosphere. Under these conditions, when dehydration of dihydrate gypsum, the water is released as vapor, forming loose particles with the developed surface. This gives rise to increased water demand of the binder, rapid setting time, relatively low strength and significant porosity of gypsum. High strength gypsum has much more stability due to the fact that the binder has a crystalline structure in the form of the a-modification of the hemihydrate of calcium sulfate in the form of dense and large crystals and is characterized by low water requirement and, consequently, greater density and less porosity. This structure is formed of gypsum binder when it is received in conditions of high pressure (above atmospheric) in the environment of saturated steam in a closed kiln apparatus [3]. Use high strength gypsum in the manufacture of responsible building products and parts, embossed moldings, ornamental and architectural elements, sculpture, plaster molds for casting, etc. One way to improve the performance of high strength gypsum and increase its durability in adverse conditions is possible by controlling the process of hydration, which is accompanied by the transition of hemihydrate of a-gypsum in dihydrate form in the presence of additives and nanomodifiers. The process of hardening of gypsum binder takes place in two directions: the formation of the crystal structure through the dissolution of a-hemihydrate gypsum, education is first saturated and then supersaturated solution of calcium sulfate because the solubility of the hemihydrate at times more solubility of dihydrate, the formation of nuclei of calcium sulphate dihydrate and the subsequent growth of the crystals; the second way – topochemically, when as a result of penetration of water molecules in the superficial layers of the hemihydrate of calcium sulfate first forms a colloidal system, and then the crystallization of calcium sulphate dihydrate [4, 5]. In fact, in both cases, the process of hydration affects the rate of dissolution of crystalline a-hemihydrate of calcium sulfate. According to the assumptions of some researchers [5, 6] for determining the strength characteristics and water resistance of gypsum is the process of forming spatial structures, and in particular, intergrowth of crystals of calcium sulphate dihydrate in a solid crystalline frame. Thus, the structure digidratirovannogo plaster consists of two stages: the formation of skeleton skeleton – the basis of the crystal structure and splicing, and then filling the intercrystalline free space. Modifying the conditions of crystallization and bonding of crystals of dihydrate gypsum, the introduction of active additives and modifiers can influence the formation of the final spatial structure of the gypsum, the shape, the size and number of aggregates of free volume.

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The rate of formation of crystals of calcium sulphate dihydrate depends on surface energy: the less energy at the interface crystal-solution, the system is more stable. The magnitude of the surface energy can be influenced by the introduction of additives of surfactants and the adsorption of active substances. This is consistent with the thermodynamic theory of Gibbs, according to which the predominantly formed crystal face with the lowest surface energy. Under this condition, the free energy of the system is minimal [7]. This explains the great variety of crystalline forms of gypsum. In different external conditions and in the presence of impurities of different chemical nature are formed microcrystalle different forms: lamellar, columnar or prismatic and needle. Known layered plate with a flat transparent mineral crystals, called – Marino glass. It is quite common Selenite, a translucent parallel - fibrous gypsum. Not rarely found in nature and the cast grain structure – alabaster. Thus, to control the crystalline structure of gypsum stone by impact using active microtubular diffusion processes at the stage of hydration of hemihydrate form of gypsum binder by reducing the diffusion barrier in the process of dissolution of hemihydrate and the diffusion of water molecules in the superficial layers of particles of plaster being colloidal. In recent years there have been many studies on nanomodification gypsum [8–12]. Can be considered quite reasonable the fact that the consistent use of nanoscale additives in cement and gypsum composites can provide improved efficiency in the production of material with improved physical-mechanical and operational characteristics [13–15]. In this case, the authors solved a variety of tasks. For example, shungite rocks containing fullerene allotropic modification of nanocarbon have been used as additives to the gypsum mixture to ensure antielectrostatic intrinsic safety and protection from electromagnetic radiation in the construction of residential and industrial buildings. While plaster coating has a high adhesion characteristics [16]. It is also known that titanium nanodioxide was used in self-cleaning facade compositions, where the self-cleaning effect is manifested by reducing the wetting angle of the surface of nanomodified gypsum stone [17]. The introduction of nanosized nuclei into gypsum materials is aimed at providing directed crystallization of gypsum stone [18–20], both due to dynamic dispersed selfreinforcement, as well as mobility and water reduction of gypsum mixtures due to nanomodification of plasticizers. It is convenient to mix nanoadditives with a gypsum binder in a liquid medium, previously dispersing them in mixing water [19, 21]. The aim of our study is to study the mechanisms of influence of latex, nanocarbon, as well as complex latex-nanocarbon modifiers on high-strength gypsum of the industrial brand G-16.

2 Methods and Materials In the studies, the characteristics of the initial high-strength gypsum binder G-16 produced by the Samara gypsum plant (K - control) were analyzed, the normal density of the test at a gypsum/water ratio of 0.41 was maintained constant in all experiments. We studied samples modified by the addition of styrene-butadiene latex (L), for which,

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together with mixing water, we used a specially prepared 1% aqueous solution of styrene-butadiene latex of the brand DL 460 E manufactured by LARCHFIELD LSN Germany (with a basic substance content of 48.9%), which was added in an amount of 1% wt. to the mixing water. We also studied samples modified with a complex nanocarbon additive (H), which is a composite nanocarbon material in an aqueous solution at a concentration of 10 − 8 wt.%, Consisting of agglomerates (from 3 to 300) of carbon nanotubes of two dimensional types - with a diameter of 49.3 nm and 72 nm with fulleroid nanoparticles localized on the surface and containing active loose carbon with globule sizes of 1– 5 lm. This nanomodifier has proven itself in cement binders [22]. Samples modified with a complex latex-nanocarbon additive (LN), where both modifiers were present together, were also obtained and tested. The compositions of the samples are presented in Table 1, the properties of the tested samples are shown in Table 2. The tables show the average values of the characteristics of the samples obtained in 3 single repetitions, while the deviation of the characteristics from the average result does not exceed 10%. Table 1. Compositions of modified samples of high-strength gypsum G-16 Sample labeling К L N LN

Sample compositions Gypsum + water in the ratio of 0.41 The same, with the addition of 1% by weight of the solution of latex 1% The same with the addition of a 1% solution of nanomodifier The same, with the addition of 1% by weight of a solution of latex 1% and 1% solution of nanomodifier

Density, g/cm3 1.484 1.461 1.491 1.442

Testing the properties of gypsum was carried out according to standard methods in accordance with GOST 23789-2018 “Plaster binders. Test Methods”. The tests were carried out on the 7th day after the manufacture of the samples. The samples were kept at room temperature at a temperature of 20 ± 2 °C, the samples were dried to constant weight in a heating cabinet at a temperature of 45–55 °C. Strength characteristics of standard prism samples with dimensions, mm: 40  40  160, namely, the tensile strength in bending and the compressive strength were determined according to the current regulatory documentation, physical properties were determined according to standard methods. The study of adhesion to concrete was carried out on a tear-off machine SWITZERLAND Z 25 PROCEQ SA ZURICH made in Switzerland (Table 2). The study of the structure of gypsum stone was carried out by electron scanning microscopy; for this, a scanning electron microscope of the TESCAN VEGA 3SEM brand (Czech Republic) was used.

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Designation samples

Bending Strength, MPa

Compressive strength, MPa

Water absorption, %

K L N LN

6.0 6.7 6.8 7.5

26.7 27.7 25.5 25.4

17.7 17.0 16.7 17.5

Compressive strength in water saturated condition 9.1 10.0 11.0 9.5

Adhesion to concrete, MPa 10.4 19.1 12.2 18.2

3 Results and Discussions From the data presented in Table 2, it can be noted that as a result of the modification of the gypsum binder, the bending strength has steadily changed in all modified samples, and especially in the LN sample modified with a complex modifier. Adhesion to concrete increased in samples modified with latex (L) and complex modifier (LN). Obviously, it was latex, even in such a small amount as 1% by weight, that played a positive role in increasing the adhesion of gypsum stone to concrete. With regard to the increase in bending strength, the revealed structure of gypsum stone will help explain the increase in performance. Figure 1 shows micrographs of the structure of gypsum stone samples, the original and modified with the above modifying microadditives. The structure of the samples modified with latex (L) and nanoparticles (N) does not differ significantly from the control sample, with the only difference being that in the modified samples the predominant number of more elongated and elongated gypsum single crystals is noticeable, while the shape of the crystals practically does not change. Sample L also shows a slightly more organized package with an advantage in one direction. In sample N, a noticeably increased content of small crystals filling up the free volume to a greater extent than in the control sample. These minor structural changes, however, may well affect the magnitude of the bending characteristic and serve as an explanation for the increase in tensile strength in bending. The structure of the sample modified by the complex modifier (LN) differs markedly from other samples: elongated needle and columnar crystals are completely absent, gypsum stone is formed by small short fused and tightly packed lamellar crystals of tetrahedral and hexagonal shapes. The difference in structure is so obvious that it can explain the differences in the strength properties of this sample.

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c)

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b)

d)

Fig. 1. The structure of gypsum stone: a) unmodified (control sample - K); b) modified with latex 1% - L; c) modified with nanoparticles 1% - N; d) modified with a complex modifier latex + nanoparticles - LN.

4 Conclusion Thus, as a result of the studies, it was confirmed that the structure and properties of high-strength gypsum stone can be controlled by using microadditives on the dissolution processes of calcium sulfate a-hemihydrate at the colloidation stage, and on gypsum crystallization processes during the formation and growth of calcium sulfate dihydrate crystals. The combined effect of two microadditives that differ in the mechanism of action plasticizing surfactant latex and carbon nanoparticles with high surface energy affects both of these processes and leads to a significant change in the crystalline form of gypsum stone, and, accordingly, affects its physical and mechanical characteristics. Acknowledgements. The work is realized in the framework of the Program of flagship university development on the base of the Belgorod State Technological University named after V. G. Shukhov, using equipment of High Technology Center at BSTU named after V.G. Shukhov.

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References 1. Chernysheva, N.V., Evsyukova, A.S., Shatalova, S.V.: Fisher Hanz-Bertram. Features of selection of the rational composition of the composite gypsum binder. Constr. Mater. Prod. 1 (2), 45–52 (2018) 2. Klimenko, V.G., Pavlenko, V.I., Hasanov, S.K., Mamin, S.N.: Hypsopeno-polystyrene composites for building application. Bull. BSTU Named After V.G. Shukhov 9, 169–174 (2016) 3. Gorchakov, G.I., Bazhenov, Yu.M.: Construction Materials. Publishing House “Book on Demand”, Moscow (2012) 4. Derevyanko, V.N., Chumak, A.G., Telyanov, V.A., Kondratyev, V.N.: Nanomodification of the structure of gypsum binders. Bull. Pridneprovsk State Acad. Civ. Eng. Archit. (PDABA). 6, 1–6 (2012) 5. Edamenko, A.S., Matveeva, L.Yu., Yastrebinskaya, A.V.: Influence of gypsum binder phase composition on operational and mechanical properties of the hydration product. Solid State Phenom. 299, 1086–1090 (2020) 6. Butt, Yu.M., Sycheva, M.M., Timashev, V.V.: Dehydration. Chemical technology of binders. Higher School, Moscow (1980) 7. Prigozhin, I., Dezhi, R.: Chemical thermodynamics, Novosibirsk (2010) 8. Bazenov, Yu.M., Korolev, E.V.: Estimation of technical and economic efficiency of nanotechnologies in building materiology. Constr. Mater. 6, 66–67 (2009) 9. Kuzmina, V.P.: Mechanisms of the impact of nanosupplements on gypsum products. Dry Build. Mixes 3, 23–25 (2016) 10. Derevyanko, V.N., Chumak, A.G., Vaganov, V.E.: The effect of nanoparticles on hydration processes of semi-aquatic gypsum. Build. Mater. 7(715), 22–25 (2014) 11. Korolev, E.V., Bazenov, Yu.M., Beregovoi, V.A.: Modifying of construction materials by nanocarbon tubes and fullerenes. Constr. Mater. 8, 2–4 (2006) 12. Shapovalov, N.A., Strokova, V.V., Cherevatova, A.V.: Management of structure and properties of the high-concentrated disperse system with use of nanoprocesses and technologies. PGS 8, 17–18 (2007) 13. Li, G.Y., Wang, P.M., Zhao, X.: Pressure-sensitive and microstructure of carbon nanotube reinforced cement composites. Cem. Concr. Res. 29(5), 377–382 (2007) 14. Chaipanich, A., Nochaiya, T., Wongkeo, W., Torkittikul, P.: Compessive strength and microstructure of carbon nanotubes – fiy ash cement composites. Mater. Sci. Eng. 52, 1063– 1067 (2010) 15. Letenko, D.G., Mokrova, M.V., Matveeva, L.Yu., Tikhonov, Yu.M.: Influence of the size distribution of nanomodified latex particles on the structure of gypsum materials. Bull. Civ. Eng. 4(75), 95–101 (2019). SPbGASU, St. Petersburg 16. Patent R.F. No. 2307809 Dry building mix. V.I. Bykov, 102784/03, declared. 02/01/2006; publ. 10/10/2007 (2006) 17. Kuzmina, V.P.: Titanium nanodioxide. Application in construction. Nanotechnology in construction: scientific 4, 82–90 (2011) 18. Gordina, A.F, Tokarev, Yu.V., Yakovlev, G.I, Kerene, Ya., Spudulis E.: Differences in the formation of the structure of a gypsum binder modified with carbon nanotubes and lime. Build. Mater. 2, 34–37 (2012) 19. Chumak, A.G., Derevyanko, V.N., Petrunin, S.Y., Popov, M.Y., Vaganov, V.Y.: Structure and properties of composite material based on gypsum binder and carbon nanotubes. Nanotechnol. Build (Nanobuil.ru) 2, 27–36 (2013)

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20. Strokova, V.V., Cherevatova, A.V., Zhernovsky, I.V., Voitovich, E.V.: Features of phase formation in a composite nanostructured gypsum binder. Build. Mater. 7, 9–11 (2012) 21. Maeva, I.S., Yakovlev, G.I., Pervushin, G.N., Buryanov, A.F., Pustovgar, A.P.: Structuring the anhydrite matrix with nanodispersed modifying additives. Build. Mater. 6, 4–5 (2009) 22. RF patent 2627335 C2 Raw mix for building materials. Application 2016 101022, dated 2016.01.15., Publ. 2017.08.07

Smalt Based on The Broken Colored Container Glasses N. I. Bondarenko(&) , D. O. Bondarenko and K. A. Valuiskikh

,

Belgorod State Technological University named after V.G. Shukhov, Belgorod, Russia [email protected]

Abstract. Areas of use of glass industry waste in the production of various types of products are analyzed. The possibility of using broken colored container glasses for the production of smalt is considered. It was experimentally confirmed that due to the introduction of liquid glass into the glass powder, the firing temperature of the smalt decreases. The optimal sintering temperature of tiles was experimentally determined. The micro-hardness of smalt based on blue and olive container glass without adding liquid glass and with the addition of liquid glass of different concentrations was studied. The dependence of the influence of liquid glass concentration on micro-hardness is established. The obtained results indicate that the optimal content in the mixture is 20% of the aqueous solution of liquid glass. The rational firing temperature is set at 700 °C for blue smalt and 725 °C for olive smalt, at which maximum micro-hardness is observed. A wide range of colors, as well as a variety of forms of smalt allows using it in the interior of any style direction. It is also very valuable at finishing bathrooms, pools, as it has zero water absorption, low abrasion, no pores. The use of secondary raw materials will make it possible to reduce significantly the cost of production and increase the competitiveness of smalt. Keywords: Smalt Firing temperature


Colored container glass
Liquid glass
Micro-hardness


1 Introduction Today, one of the main environmental challenges is the safe disposal of household and industrial glass waste, which has a number of problems: lack of funding, strategic planning and marketing research. It is necessary to create long-term plans for recycling of secondary raw materials both at the local and federal level, which will allow eliminating it competently and reliably using effective methods. Glass is a valuable material that allows recycling it. Broken glass recycling is a promising direction for creating thermal insulation and facing materials, protective and decorative coatings and composites for various purposes [1–5]. These materials have increased physical, chemical and mechanical characteristics, as well as a wide variety of decor [6–8].

© The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 274–279, 2021. https://doi.org/10.1007/978-3-030-54652-6_41

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Smalt is also of interest to consumers of decorative and finishing materials due to its high water absorption, wear resistance, acid resistance, alkali resistance, frost resistance and heat resistance. It has a wide range of colors, which over time under the influence of aggressive media and adverse operating conditions does not lose its color resistance [9, 10]. However, the technology of smalt production is very energy-intensive and requires expensive raw materials. The use of special colored container glasses in the manufacture of smalt will reduce the cost of the final product.

2 Methods and Materials The main material for the production of smalt was container glass of blue and olive colors. Glass colored bottles were crushed in a crushing laboratory device, then the glass was placed in a ball laboratory porcelain mill with ceramic grinding bodies. The resulting glass powder was sifted on a sieve with the nominal size of the cell side in light 0.071 mm (Fig. 1).

Fig. 1. Glass powder of olive and blue containers.

The chemical composition of colored glass containers was determined by X-ray fluorescence method on the APL9900 “Thermo scientific” spectrometer (Table 1). Table 1. Chemical composition of colored glass containers Color of container Mass SiO2 Blue 64.5 Olive 72.0

content, wt% Al2O3 CaO MgO Na2O Fe2O3 K2O SO3 Co3O4 1.78 8.7 5.6 19.2 0.14 0.45 0.12 0.062 2.3 5.76 4.0 15.5 0.19 – 0.5 –

Liquid glass with densities of 1.02, 1.08 and 1.16 g/cm3 was used to reduce the firing temperature of the smalt. 20%, 40% and 60% aqueous solutions of liquid glass were prepared to moisten the glass powder. The humidity of the glass powder was 57%. Tiles in the form of squares of 20  20  5 mm were pressed from the moistened

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powder (Fig. 2). Some of the tiles were moistened with a solution of water-based liquid glass of various concentrations. Pressed tiles were dried in a drying cabinet, and then placed in a muffle furnace and subjected to heat treatment at temperatures of 675, 700, 725, 750, 775, 800 and 825 °C. Smalt does not have a specific melting point, the approximate sintering temperature was determined experimentally. The firing time was 5 min.

a

b Fig. 2. Molded smalt tiles: a – olive; b – blue

Smalt hardness was determined using a Nexus 4000 Hi-end hardness tester for automatic Vickers, Knoop, and Brinell hardness measurements in the load range from HV1 to HV50. The 4-position fully automated measurement turret was configured with various indenters for tasks, stages, and image analysis systems. The micro-hardness of the smalt was determined using the Vickers method. This method allows providing for high reproducibility and repeatability of test results, and the closed type of cell control– for all calculations and digital data management in the 32-bit embedded processor of the system. The loading mechanism is fully automatic; the loading time is 10 s.

3 Results and Discussions The powder particles of smalt tiles without adding liquid glass begin to fuse at a temperature of 700 °C. When a 20% aqueous solution of liquid glass was added at the same temperature, the glass powder particles were completely fused. Blue and olive smalt without adding liquid glass at a firing temperature of 750 °C is represented on Figs. 3 and 4. The introduction of liquid glass reduces the firing temperature of smalt and reduces the overall energy consumption for its production. The optimal content in the mixture is 20% aqueous solution of liquid glass, as the composition does not bubble and there is no mottling. When adding a 40% aqueous solution of liquid glass, the composition has

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Fig. 3. Blue smalt without adding liquid glass at firing temperature of 750 °C

Fig. 4. Olive smalt without the adding of liquid glass at a firing temperature of 750 °C

a

b

c

Fig. 5. Blue smalt at a firing temperature of 750 °C with the addition of an aqueous solution of liquid glass: a – 20%; b – 40%; c – 60%

mottling, and the composition with a 60% aqueous solution of liquid glass has a strong bubbling and the color characteristics of the smalt are lost (Fig. 5).

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It is known that the hardness of glass and glass-crystal materials is influenced by its chemical composition. Thus, CaO and B2O3 significantly increase micro-hardness, and an increase in the content of alkaline oxides in the glass contributes to its reduction. The results of the study of the micro-hardness of smalt with the addition of a 20% aqueous solution of liquid glass at different firing temperatures are presented in Table 2. The micro-hardness of blue smalt is lower than that of olive smalt. This is due to the high content of Na oxide in the composition (Table 1). Table 2. Micro-hardness of smalt with the addition of 20% aqueous solution of liquid glass Firing temperature, °C Microhardness of smalt, HV Blue Olive 700 557.42 560.45 725 513.48 575.52 750 538.51 565.14 775 560.43 564.18

The maximum micro-hardness for blue smalt is observed at 700 and 775 °C, which indicates that it is impractical to increase the firing temperature.

4 Conclusion It should be noted that the amount of micro-hardness of the smalt is influenced by both the firing temperature and the concentration of the added liquid glass. According to the results of the experiment, it can be seen that the optimal content in the mixture is 20% of an aqueous solution of liquid glass, and the rational firing temperature for blue smalt is 700 °C and 725 °C for olive smalt, at which the maximum micro-hardness is observed. The development of smalt technology based on broken glass consists in selecting the concentration of liquid glass and the sintering mode, which will ensure optimal strength characteristics of smalt, as well as reduce energy costs during production. Acknowledgements. This work was realized in the framework of the Program of flagship university development on the base of the Belgorod State Technological University named after V G Shukhov, using equipment of High Technology Center at BSTU named after V G Shukhov.

References 1. Dorokhova, E.S., Zhernovoi, F.E., Izotova, I.A., Bessmertnyi, V.S., Zhernovaya, N.F., Tarasova, E.E.: Shrink-free face material based on cullet and colemanite. Glass Ceram. 73 (3–4), 103–106 (2016)

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2. Bessmertnyi, V.S., Zhernovoi, F.E., Dopochova, E.S., Izotova, I.A.: Methodology and development of the predicting the properties of composites based on cullet. Bull. BSTU Named V.G. Shukhov 3, 130–134 (2015) 3. Min’ko, N.I., Kalatozi, V.V.: The use of cullet in materials technology for construction purposes. Bull. BSTU Named V.G. Shukhov 1, 82–88 (2018) 4. Bondarenko, D.O., Bondarenko, N.I., Bessmertnyi, V.S., Strokova, V.V.: Plasma-chemical modification of concrete. Adv. Eng. Res. 157, 105–110 (2018) 5. Lazko, E.A., Minko, N.I., Bessmertniy, V.S., Lazko, A.A.: Modern lines of gathering and processing of glass fight. Bull. BSTU Named V.G. Shukhov 2, 109–112 (2011) 6. Zhernovaya, N.F., Doroganov, E.A., Zhernovoy, F.E., Stepina, I.N.: Materials study, obtained by sintering in the system of clay glass. Bull. BSTU Named V.G. Shukhov 1, 20– 23 (2013) 7. Bondarenko, N.I., Bondarenko, D.O., Kochurin, D.V., Bragina, L.L., Yakovenko, T.A.: Sheet construction glass with protective and decorative coatings. Constr. Mater. Prod. 2(4), 11–16 (2019) 8. Dorokhova, E.S., Zhernovaya, N.F., Bessmertnyi, V.S., Zhernovoi, F.E., Tarasova, E.E.: Control of the structure of porous glass-ceramic material. Glass Ceram. 74(3–4), 95–98 (2017) 9. Bondarenko, N.I., Bondarenko, D.O., Bondarenko, M.A., Doroganov, E.A.: Facing and decorative materials based on glass domestic waste. Bull. BSTU Named V.G. Shukhov 11, 79–85 (2019) 10. Onishchuk, V.I., Zhernovaya, N.F., Doroganov, E.A.: Mosaic smalt for construction. Constr. Mater. 8, 13–15 (2007)

Possible Criterion for Evaluating the Compatibility of Components in the Building Mixtures A. M. Ayzenshtadt

, A. A. Shinkaruk(&)

, and M. A. Frolova

Northern (Arctic) Federal University named after M.V. Lomonosov, Arkhangelsk, Russia [email protected]

Abstract. In this paper, based on the theoretical provisions of the theory of molecular interaction, the results of testing the algorithm proposed by the authors are presented for calculating the Hamaker constant as a characteristic of the dispersion interaction based on experimental data obtained during the study of a composition of fine powders of basalt and polymineral sand. The concept of the Hamaker analog constant is introduced; the method of determining and calculating it is based on a number of assumptions. The desired constant was calculated based on the measured equilibrium angles of wetting the surface of the dispersed material with liquids with known surface tension values. Water solutions of ethanol with different volume concentrations of the organic component were used as such liquids. For the correct application of water-alcohol systems in the proposed method, the physical and chemical constants of the water-ethanol system are calculated. It was found that the change in the structure of the powder composition allows controlling the intensity of the van der Waals interaction in the mixture, which is quantified by the value of the Hamaker constant. This fact makes it possible to select restoration (repair) construction compositions that are characterized by an increased affinity to the main material. The proposed experimental approach and algorithm for calculating the van der Waals interaction constant in fine powder systems can be used for compiling an informational reference database. Keywords: Hamaker constant
Restoration materials
Affinity of structures Compatibility of components




1 Introduction The state of monuments of architectural and historical heritage is largely determined by the interaction of various factors, the main of them are natural and climatic conditions. Historical and architectural monuments were created from traditional building materials, which are more or less destroyed or changed over time; their composition is subject to the processes of technogenic metasomatism. Therefore, the choice or creation of a material for restoration should be based on the implementation of the law of affinity of structures [1], the main criterion for the implementation of which is the compatibility of components (the restored and repair material). Along with the © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 280–286, 2021. https://doi.org/10.1007/978-3-030-54652-6_42

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developed general principles of material selection, taking into account environmental problems, legislation and laws, etc., a quantitative criterion of compatibility of the components of mixtures is necessary. This criterion should take into account a generalized thermodynamic assessment of the nature of interacting elements or an optimal combination of various raw materials components, which allows getting as close as possible to the values of the selected characteristic of the base material. The scientific basis of this approach can be the theory of molecular interaction between macro-bodies, proposed by Deryagin and co-authors [2]. Thus, to characterize the forces of molecular (dispersion) interaction in condensed systems, we use the constant A (Hamaker constant) proposed by Hamaker, the value of which is determined by the nature of the substance. The practical implementation of such a solution can be associated with the initial stage of selection of raw materials for restoration work, associated with the experimental determination of the Hamaker constant of the main (restored) material and the choice of the composition of the raw mixture, the combination of components in it gives a value close to the value of A. So, if we denote the Hamaker constant of the main substance as A0, and the same parameter for, for example, two components of the raw mixture Ax and Ay, then based on [2, 3], the mathematical expression of the quantitative criterion of the law of affinity of structures can be the following equation: A0  Axy ¼

pffiffiffiffiffiffiffiffiffiffi Ax Ay

ð1Þ

Carrying out restoration (or repair) works involves, first of all, the interaction of the surfaces of the contacting phases of the main and repair materials. Direct splicing of such surfaces is an adhesion technology that has already been developed, for example, for connection of silicon plates [4]. However, this principle, in our opinion, can be used as much as possible only when the material is chosen for repair or restoration purposes. Thus, the direct binding of two surfaces is determined by the attractive forces between them at submicron distances. The attractive forces at the border are van der Waals forces, electrostatic forces, and forces arising from chemical interactions. But at the stage of selecting raw materials, the determining factor may be the possible prediction of the intensity of the van der Waals interaction of surfaces, which creates a certain minimum critical distance between the reacting surfaces, at which chemical bonds can be formed. The van der Waals attractive force is caused by the collective dispersion forces of interactions between the atoms or molecules of one body and the atoms or molecules of another. For two surfaces located at distances less than h (nm), the dependence of the attractive force F on the distance h between two surfaces separated by the medium is given by the expression (2) [2]: F¼

A 6ph3

ð2Þ

Thus, by determining (calculating) the constant A, it is possible to quantify the ability of two bodies to interact.

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The Hamaker constant can be obtained experimentally for two pressed macroscopic bodies at a submicron distance from each other by measuring the attractive force, or calculated from the absorption spectra of electromagnetic radiation using Lifshitz theory [5]. These experiments are complex and very time-consuming. At the same time, the development of experimental methods for determining the value of the Hamaker constant of various materials and compiling a database for simple and complex substances may be of some interest to researchers involved in the design of building mixtures. The value of A for some substances can be found in the reference literature [6, 7]. But for the construction materials industry, which uses rocks of various genetic groups as the main raw materials, there is no such information base. This fact may be determined by the lack of a scientifically based algorithm for calculating this value based on experimental data obtained using a reliable instrumental method. Theoretical provisions of the physical chemistry of the surface of dispersed systems [2, 3] allow applying a method for determining the Hamaker constant, which is based on measuring the equilibrium wetting edge angle (h0) of the surface of the analyzed material. In this case, they use reference (with known value of surface tension, rliq) working fluids. So, according to the Frumkin-Deryagin equation, the equilibrium edge angle is associated with the wedging pressure that occurs in the liquid film. Taking into account the equation proposed by Hamaker for the attraction force  A [2] and the (dispersion interaction) of the surface unit between micro-bodies  6ph 3 functional relation of the wedging pressure with the force of dispersion attraction [3], we can obtain the following expression: cosh0 ¼ 1 þ

A ; 12prliq h2min

ð3Þ

where hmin – the smallest film thickness that corresponds to the van der Waals distance (0.24 nm) [2]. However, there are objective experimental difficulties in reproducible determination of the equilibrium edge angle of a liquid drop on the surface of powders [8] in the transition zone between a bulk liquid and a flat equilibrium film with a thickness of hmin (transition of the liquid profile to a flat equilibrium film) [9]. However, the edge angles of wetting the same surface with the film and the bulk phase of the liquid may differ and are determined only by the physical and chemical properties of the liquid itself (under constant external factors). At this stage, having the surface of the powder material, this difference is not possible to be taken into account. Therefore, in our research (taking into account this necessary simplification at this stage), we introduce the concept of the Hamaker analog constant (Am), determined by the equilibrium wetting angle of the bulk phase of a liquid drop. Thus, having a functional dependence cosh0  1 ¼ f ðr1 liq Þ obtained on the basis of experimental measurement of the equilibrium angles of wetting the surface of a dispersed material with liquids with known values of surface tension; it is possible to calculate the constant Am of the analyzed material. So, according to Eq. (3), this dependence will be described by a linear expression of the form:

Possible Criterion for Evaluating the Compatibility of Components

283

cosh0  1 ¼ a
r1 liq

ð4Þ

Am ¼ 12a
p
h2min

ð5Þ

Hence

In previous studies [10], we showed the possibility of determining experimentally the value of the Hamaker analog constant (Am), which characterizes the energy of the dispersion interaction of a solid surface in contact with an aqueous-ethanol (weakly polar) solution (Am01). Index “0” indicates the liquid phase (aqueous ethanol solution) in contact with the surface of the analyzed solid (fine powder) – “1”. To determine Am01, the functional dependence (3) is used. Meanwhile, Am01 is functionally related to the properties of the solution (A0) and the solid phase itself (A1) by the equation [11]: Am01 ¼ A1 þ A0  2

pffiffiffiffiffiffiffiffiffiffi A1 A0

ð6Þ

By means of algebraic transformations from Eq. (6), we can obtain an expression for calculating A1 from the known values of Am01 and A0. So: A1 ¼ Am01 þ 2

pffiffiffiffiffiffiffiffiffiffiffiffiffiffi Am01 A0  A0

ð7Þ

To conduct experiments to determine the wetting angle of the surface of experimental samples (for example, by the method of G.A. Zisman), a number of weakly polar solutions with a surface tension of no more than 35 mn/m are required. This condition is provided by using a water-ethanol system with mass alcohol content of 100 to 70%. In work [12], an algorithm for calculating A0 (J) for monatomic alcohols is given. In [13], we calculated the values of the Hamaker constant for water-ethanol solutions based on reference and experimental data (taking into account the volume of the drop applied by the dispenser to the surface of the test sample of 0.00954 cm3). Calculations showed that in the range of alcohol concentrations from 96 to 60 percent by volume, the value of A0 remains almost constant, equal to A0 = (3,92 ± 0,02).10−20 J. In this paper, in continuation of experiments conducted in the study of fine powders of basalt and polymineral sand [13], the results of testing the presented algorithm for calculating A1 (basalt powder), A2 (polymineral sand powder), as constants of the dispersion interaction of fine particles and A12 – a similar value for a fine twocomponent powder: basalt (1) and polymineral sand (2).

2 Methods and Materials Dropout of basalt of Myandukha Deposit (Plesetsk district of the Arkhangelsk region) and silt polymineral quartz-feldspar quarry sand of Kholmogorskoe Deposit (Kholmogorsky district of the Arkhangelsk region) were used as objects of research.

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Grinding of basalt and sand was carried out by mechanical dry grinding lasting 20 min at 420 rpm with large grinding bodies with a diameter of 2 cm on a planetary ball mill Retsch RM100. The size of the obtained highly dispersed particles was determined using a Delsa Nano analyzer. To calculate the Hamaker constant A12 as a model of a possible variant of the restored composite, a mechanical mixture of basalt and sand containing 50% and 60% (mass) basalt was ground together according to the above regime. To determine the equilibrium wetting angle of highly dispersed materials, experimental samples were made by compacting the corresponding samples of basalt powders, sand and a mixture at a load of 1.5 kPa into metal forms with a diameter of 10 mm. The surface tension of water solutions of alcohol (96% technical hydrolysis alcohol was used for research) and the wetting angle of the surface were measured at a temperature of 20 °C on the KRUSS Easy Drop unit. When conducting experiments, a specialized computer program selected the time of the first contact of the liquid with the solid surface of the material. For all test cases, this state of the system was considered pseudo-equilibrium. All experiments were accompanied by mandatory three parallel measurements. The constants Am01, Am02 and Am012 were calculated based on the  values of the

slope angle tangent of the functional dependence cosh0  1 ¼ f r1 liq . Constants A1,

A2 and A12 (experimental samples) were calculated taking into account A0 = 3.92
10−20 J (water-alcohol solutions) according to the expression (7).

3 Results and Discussion The measured dimensional characteristics of basalt and sand samples allow concluding that a fairly narrow dispersion fraction and good reproducibility of results are achieved under the specified grinding modes (Table 1). Table 1. Indicators of dispersed systems №

Ms*, %

Average volume particle size, nm

1 0 1062 ± 216 2 40 1122 ± 128 3 50 867 ± 238 4 100 1053 ± 142 * Mass concentration of sand in the mixture.

Coefficients of the equation cosh0 − 1 = a (1/rliq) + b a
103 b 2.3 −0.15 4.2 −0.21 3.8 −0.20 0.6 −0.19

r2

(Am) 1020, J

0.99 0.99 0.99 0.97

Am01 = 0.50 Am012 = 0.91 Am012 = 0.83 Am02 = 0.13

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To calculate the constants  Am01, Am02 and Am012 we constructed functional for all experimental series, which are linear in dependencies cosh0  1 ¼ f r1 liq nature with a high value of the approximation confidence coefficient (r2). The values of coefficients for these linear dependencies and the resulting constants are shown in Table 1. Table 2. Indicators of dispersion interaction and the wetting angle of the surface Ms, % Angle h0 for solutions of different concentrations of ethanol (%) 96 80 70 60 0 21.0 21.4 21.9 22.4 40 18.9 19.7 20.7 21.7 50 19.7 20.5 21.2 22.2 100 33.8 34.0 34.0 34.2

A
1020, J

A1 = 7.22 A12 = 8.61 A12 = 8.36 A2 = 5.53

Table 2 shows the results of calculating constants A1, A2 and A12 for the analyzed powder materials and determined experimentally values of the equilibrium wetting angle h0 of the surface with working solutions. The data presented in Table 2 show that the strength of the dispersion interaction of fine basalt particles is 1.3 times higher than that of the polymineral sand particles of the used deposit, even with comparable dimensional characteristics. At the same time, the mechanical mixture of the above-mentioned components does not obey the rule of additivity. In this case, changing the composition allows controlling the intensity of the van der Waals interaction in the mixture. This fact makes it possible to select restoration (repair) construction compositions that are characterized by an increased affinity to the main material.

4 Conclusion 1. A quantitative criterion for the selection of raw materials for the creation of restoration mixtures is proposed, which allows evaluating their dispersion interaction with the surface of the main material. 2. The Hamaker constant can be used as a criterion, calculated from the value of the analog component. It is established that the value of the Hamaker constant is a function of the response of the nature of the analyzed materials. 3. The experimental approach and algorithm for calculating the van der Waals interaction constant in fine powder systems are proposed, which can be used to compile information reference database.

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Acknowledgements. The study was funded by state assignment, project No. 0793-2020-0005.

References 1. Lesovik, V., Volodchenko, A., Glagolev, E., Lashina, I., Fischer, H.B.: Geonics (geomimetics) as a theoretical basis for new generation compositing. In: 14th International Congress for Applied Mineralogy (ICAM2019). Springer Proceedings in Earthand Environmental Sciences, pp. 344 –347 (2019) 2. Deryagin, B.V., Abrikosov, E.M., Lifshits, E.M.: Molecular attraction of condensed bodies. Phys. Chem. Suc. 185(9), 982–1001 (2015) 3. Yakavets, N.V., Krut’ko, N.P., Opanasenko, O.N.: Determination of surface free energy of powdery resin-asphaltene substances by Owens–Wendt–Rabel–Kaelble method. Sviridov. Read. (8) 253–260 (2012) 4. Timoshenkov, S.P., Prokopyev, E.P.: Features of the process of direct connection of silicon plates. Mater. Sci. 5, 43–45 (1999) 5. Goesele, U., Abe, T., Letavic, T.J., Pinker, R.D., Arnold, E., Spierings, G.A.S.M., Haisma, J.: In: Semiconductor Wafer Bonding: Science, Technology and Applications, The Electrochemical Society Proceedings 92-7, pp. 18–31 (1992) 6. Chernyakov, A.L.: Filtration of nanoaerosols by porous materials taking into account desorption processes. Coll. J. 5, 121–125 (2016) 7. Uryev, N.B.: Dynamic aggregate and structural stability of highly concentrated colloiddispersed systems. Phys. Chem. Surf. Protect. Mater. 1, 105–114 (2017) 8. Danilov, V.E., Korolev, E.V., Aysenstadt, A.M., Strokova, V.V.: Features of surface free energy calculation based on the Owens–Wendt–Rabel–Kjelble interfacial interaction model. Constr. Mater. 11, 66–72 (2019) 9. Boynovich, L.B., Emelyanenko, A.M.: Hydrophobic materials and coatings: principles of creation, properties and applications. Chem. Success. 77(7), 619–638 (2008) 10. Frolova, M.A., Tutygin, A.S., Aysenstadt, A.M., Lesovik, V.S., Makhova, T.A., Pospelova, T.A.: Criteria for evaluating energy properties of the surface. Nanosystems: phys. Chem. Math. 2(4), 120–125 (2011) 11. Mutsuom, A.A., Gaonkar, G., Tohru, T.: The estimation of Hamaker constants of alcohols and interfacial tensions at alcohol-mercury interfaces. Bull. Inst. Chem. Res. Kyoto Univ. 58 (5-6), 523–533 (1980) 12. Ayzenshtadt, A., Lesovik, V., Danilov, V., Fomina, E.: Termodynamic method of describing the state of building composites as a macroscopic system. In: International Multidisciplinary Scientific GeoConference Surveying Geology and Mining Ecology Management, vol. 19, no. 6.1, pp. 467–474. SGEM (2019) 13. Danilov, V.E., Ayzenshtadt, A.M., Frolova, M.A., Tutygin, A.S.: Dispersion interactions as criterion of optimization of cementless composite binders. Inorg. Mater.: Appl. Res. 9(4), 767–771 (2018). https://doi.org/10.1134/S2075113318040093

Influence of Modified Bituminous Binders on the Properties of Stone Mastic Asphalt D. A. Kuznetsov(&) , A. V. Kurlykina , A. O. Shiryaev and D. P. Litovchenko

,

Belgorod State Technological University named after V.G. Shukhov, Belgorod, Russia [email protected]

Abstract. One of the important reasons for reducing the service life of asphalt concrete surfaces (ruts, plastic deformations, potholes, cracks, etc.) is the low quality of used road oil bitumen. This determined the relevance of the development of bituminous binders with increased physical and mechanical properties. This is especially true for organic binders that are used in the production of Stone Mastic Asphalt (SMA). The paper presents the results of a study of BND 70/100 bitumen modified by the introduction of polymers (atactic polypropylene APP and styrene-butadiene thermoplastic SBS L 30-01A), using a single-stage technology for preparing a polymer-bituminous binder. The influence of binder modification on the physical, mechanical and operational properties of road asphalt concrete is shown on the example of Stone Mastic Asphalt (SMA-20) relative to the basic samples made to control the dynamics of changes in the properties of composites. A comprehensive assessment of the effectiveness of modifying the composite based on various binders was performed on the basis of generalized quality criteria obtained by determining the partial quality criteria of the composite, taking into account the weighting coefficients. The comparison and analysis of the obtained performance criteria is made. The comprehensive assessment of the performance indicators of binders and composites based on them demonstrates that obtaining an objective conclusion about the quality of bituminous binders is not correct without investigating their influence on the properties of the final product, in the case of SMA. Keywords: Polymer-bituminous binders Asphalt


Modified bitumens
Stone Mastic

1 Introduction Receiving quality roads with high maintenance period was and is a priority at the construction of roads, and at the same time reducing the cost needed to maintain the operational status of the traffic object and its repair. Asphalt concrete was and would remain the main structural material in road construction in the near future. However, its sensitivity to temperature fluctuations of the external environment in combination with mechanical influences from transport loads can lead to insufficient operational reliability. Therefore, improving the quality of asphalt concrete for road surfaces is an © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 287–293, 2021. https://doi.org/10.1007/978-3-030-54652-6_43

288

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urgent task. A promising direction in the production of road asphalt concrete in order to improve its operational reliability is the use of various methods of modified road composites, including by means of bituminous binders [1–9].

2 Methods and Materials The aim of this work is to study bitumen modified with polymer additives and analyze the influence of the obtained binders on the parameters of the physical and mechanical properties of bitumen, as well as its performance characteristics. The objects of research were polymer-bitumen binders (PBB) based on BND 70/100 bitumen modified with polymer additives: atactic polypropylene APP and styrene-butadiene thermoplastic elastomer SBS l 30-01A. Based on the prepared PBB60, the compositions of SMA-20 were selected and the influence of binders on asphalt concrete was studied. During the research, the task was to select the most effective PBB composition using the designated polymers. Polymer-bituminous binders were obtained in a laboratory paddle mixer. When preparing binders using atactic polypropylene (APP) (compositions №1, №2), its content varied in the amount of 3% and 5% by weight. In the preparation of the PBB with SBS its content was 3.0% and 3.5% wt of polymer in plasticizer (extract of brand A). Preparation of the binder was carried out using a singlestage technology. The system was mixed to a homogeneous state for 1 h and 30 min. After that, the PBB was matured in a drying cabinet, until the final formation of the binder structure within 1 h. PBB testing and study of SMA-20 samples based on them were performed using standard methods. The work also included studies of the ruts stability of Stone Mastic Asphalt on the laboratory unit InfraTest20-4000.

3 Results and Discussions Prepared PBB compositions were evaluated for compliance with quality indicators. The obtained data is shown in Table 1. According to the data obtained, the prepared formulations meet the requirements of regulatory documentation for PBB 60. In compositions № 1, № 2, there is a slight change in the depth of penetration of the needle at 25 °C, while the softening temperature increases and the brittleness temperature decreases. Higher deformative properties are noticeable at low temperatures. The modifying additive APP modifies the bitumen, providing it with a rigid spatial grid that resists deformation. The SBS polymer reduces the temperature sensitivity of the binder, as evidenced by a proportional increase in the viscosity and softening temperature. Binders under №3 and №4 are characterized by the highest elasticity, which is obviously due to the structure formed when combining bitumen and polymer. The use of additives for modifying bituminous binders is a complex task for which we identified parameters that, in our opinion, make the maximum contribution to the achievement of their quality parameters. For this purpose, particular performance

Influence of Modified Bituminous Binders on the Properties of SMA

289

Table 1. Physical and mechanical properties of the studied bituminous binders Indicators

Needle penetration depth: at 25 °C, 0.1 mm at 0 °C, 0.1 mm Ring and ball softening temperature, °C Extensibility, cm: at 25 °C

Requirements of GOST R52056-2003 PBB 60

BND 70/100

No less than 60 No less than 32 No less than 54

No less than 25

at 0 °C No Brittleness No temperature, °C Elasticity,%, at temperature at 25 °C No at 0 °C No

APP №1

№2

SBS L 3001A №3 №4

73.1 36.3 47.7

72.0 43.0 64.6

70.0 42.0 68.1

68.7 41.0 52.2

66.7 34.0 61.7

>150

94.1

79.8

97.9

40.7 −22

41.6 −22

43.7 −21

85.5 70.4

88.2 70.4

87.5 71.2

less than 11 higher 20

5.6 −19

21 113.4 54.4 −23

less than 80 less than 70

– 41.1

84.3 70.4

criteria were used [11]. The indicators regulated by the normative document were taken as the basic quality parameters. A particular performance criterion was calculated as the ratio of the actual value of the i-th indicator (3iind: ) to the base value of the indicator (3iGOST ): Kefi ¼

3iind: ; 3iGOST

ð1Þ

The obtained partial criteria for the effectiveness of binders are presented in Table 2. The durability and operational reliability of the road surface largely depends on the quality of the binder. To assess the effectiveness of the PBB compositions under consideration, the multi-criteria optimization method [10] was used to evaluate the complex effect of modifications on property indicators. Optimization was performed using a generalized efficiency criterion, which has the form of an additive function. The results of calculating the generalized efficiency criterion for the studied binders are presented in Table 2. Analyzing the data obtained, we can conclude that bituminous binders modified with polymer additives are more effective than the reference composition by more than 40%. Composition № 1 has a maximum coefficient. Based on the prepared PBB, the compositions of SMA-20 were selected and their physical and mechanical characteristics were evaluated. The test results are shown in Table 3.

290

D. A. Kuznetsov et al. Table 2. Efficiency criteria of the studied bituminous binders Indicator

APP

SBS L 3001A №1 №2 №3 №4

Particular efficiency criteria Needle penetration depth: at 25 °C, 0.1 mm 1.20 1.26 at 0 °C, 0.1 mm 1.34 1.31 Ring and ball softening temperature, °C 1.20 1.26 Extensibility, cm: at 25 °C 4.54 3.76 at 0 ° C 4.95 3.70 Brittleness temperature according to Fraas, °C, 1.15 1.10 Elasticity, %, at temperature at 25 °C 1.05 1.07 at 0 °C 1.01 1.01 Generalized efficiency criteria 1.64 1.55

1.31 1.33 1.28 1.06 0.97 1.14 3.19 3.92 3.78 3.97 1.10 1.05 1.10 1.09 1.01 1.02 1.46 1.49

Table 3. Indicators of SMA-20 properties Indicator

Binder content, % by weight over 100% of the mineral part Average density, kg/m3 Porosity of the mineral part, % Residual porosity, % Water saturation, % Binder runoff, % Compressive strength limit at 50 °C, MPa Compressive strength limit at 20 °C, MPa Crack resistance, MPa, at 0 °C Uniaxial shear stability: Internal friction coefficient Shear strength at 50 °C, MPa

Requirements of GOST 31015

Binder BND 70/100 5.2

№1

№2

№3

№4

5.6

5.7

5.6

5.7

– 15-19

2353 15.5

2370 16.3

2370 16.15

2370 16.3

2380 16.27

1.5-4.5 1.0-4.0 0.07-0.15 0.65 no less

2.5 2.7 0.13 0.67

2.5 2.4 0.14 0.78

2.7 2.1 0.13 0.80

2.5 1.5 0.14 1.76

2.5 1.2 0.17 2.0

2.2 no less

2.6

2.7

2.8

4.5

4.65

2.5-6.0

4.2

4.3

4.8

4.9

4.05

0.93 no less 0.18 no less

0.98 0.20

0.97 0.19

0.96 0.26

0.92 0.32

0.94 0.36

Influence of Modified Bituminous Binders on the Properties of SMA

291

Rut depth, mm

Currently, it is a well-known fact that asphalt concrete materials that meet the requirements of GOST often turn out to be fragile and prone to rutting. In this regard, it was of interest to determine the rut stability of the basic and modified SMA. The obtained results of measuring the depth of the rut are shown in Fig. 3.

0

2000

4000

6000

8000

Number of canals, cycle 10000 12000 14000 16000 18000 20000

0 -1

-2 -3 -4 -5

BND 70/100

№1

№2

№3

№4

Fig. 3. Dynamics of changes in the depth of the SMA-20 rut depending on modification

The comprehensive assessment of the effectiveness of the studied samples of SMA20 on various binders was performed according to specific criteria for the effectiveness of composites. The following criteria were considered as calculation parameters: strength criteria, high-temperature strength criteria, shear stability criteria, and rut resistance criteria. The formula for determining each of the criteria was as follows: kði¼4Þ ¼

Pmod: Pbas:

ð2Þ

where Pmod and Pbas. – criteria for the modified and basic SMA. The results of particular criteria for the effectiveness of the SMA are listed in Table 4. The comprehensive assessment of the effectiveness of modifying the SMA on the basis of various binders was performed on the basis of generalized quality criteria obtained by determining the specific quality criteria of the composite, taking into account the weighting coefficients. The calculation was performed using the formula [10]. ð3Þ where

d1 ,

d2 .

–

weighting

coefficients;

);

292

D. A. Kuznetsov et al. Table 4. Results of calculation of specific quality criteria of SMA-20 Indicator

Value of specific efficiency criterion BND 70/100 №1 №2 №3 №4

Physical and mechanical properties Strength criterion, kRcom20 High-temperature strength criterion, kRcom50 Shear resistance criterion, kshear Operational properties Resistance criterion to rut formation, krut

1.0 1.0 1.0

1.04 1.08 1.73 1.79 1.16 1.19 2.63 2.99 0.94 1.27 1.50 1.73

1.00

0.45 0.72 1.00 1.00

The calculation results are presented in Table 5. Table 5. Contribution of weighting coefficient indicators to the generalized quality criterion of SMA performed on modified binders Weighting coefficients δ1 = 0.3 δ 2 = 0.7 δ 1 = 0.4 δ 2 = 0.6 δ 1 = 0.5 δ 2 = 0.5 δ 1 = 0.6 δ 2 = 0.4 δ 1 = 0.7 δ 2 = 0.3

BND 70/100 1.00 1.00 1.00 1.00 1.00

Composition of SMA mixture №1 №2 №3 0.78 0.95 1.27 0.82 0.98 1.36 0.86 1.02 1.45 0.89 1.05 1.54 0.92 1.08 1.63

№4 1.33 1.44 1.55 1.66 1.77

The analysis of Table 5 shows that the compositions of SMA №3, №4 are more effective relative to the base composition. It is worth noting that when evaluating the quality of the modified binder, the maximum efficiency was demonstrated by composition №1, at the same time, this sample showed the minimum efficiency in the composition of SMA. A similar relationship is true for the PBB sample №2. Obviously, this is due to the fact that the PBB, on the basis of which the SMA mixture was prepared, is characterized by a low compatibility index with the stone material used in the work. At the same time, the use of SBS-type polymers increases the heat resistance of the binder and, as a result, the shear stability of asphalt concrete. Also, it can be assumed that when using PBB compositions №3 and №4 on the surface of mineral grains, a film of binder with high rates of cohesive-adhesive interaction is formed.

4 Conclusion In this paper, the effectiveness of the developed modified bituminous binders is studied. The comprehensive assessment of the effectiveness of PBB and SMA-20 compositions based on them was made. It was found that the performance indicator of a bituminous binder without the results of its behavior in a specific asphalt concrete mixture is not an objective indicator. It was stated that the polymer modifier is more effective in the composition of the SMA mixture.

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Acknowledgements. This work was realized in the framework of the Program of flagship university development on the base of the Belgorod State Technological University named after V G Shukhov, using equipment of High Technology Center at BSTU named after V G Shukhov.

References 1. Vysotskaya, M.A., Shekhovtsova, S.Y.: Development and analysis of compositions of polymer-bitumen binders based on the multicriteria optimization method. Constr.: Sci. Educ. 7(4), 51–60 (2017) 2. Vysotskaya, M.A., Shekhovtsova, S.Y.: The influence of morphology on the quality indicators of polymer-bitumen binder. The world of petroleum products. Bull. Oil. Co. 11, 18–24 (2015) 3. Vysotskaya, M.A., Kuznezov, D.A., Litovchenko, D.P., Barkovsky, D.V., Shiryaev, A.O.: Plasticizer in the production of polymeric bituminous binders – as a need. In: Bulletin of BGTU named after V.G. Shukhov, no. 5, pp. 16–23 (2019) 4. Mirsepahi, M., Tanzadeh, J., Ghanoon, S.A.: Laboratory evaluation of dynamic performance and viscosity improvement in modified bitumen by combining nanomaterials and polymer. Constr. Build. Mater. 233, 117183 (2020) 5. Kumar, K., Singh, A., Maity, S.K., Srivastava, M., Sahai, M., Singh, R.K.: Rheological studies of performance grade bitumens prepared by blending elastomeric SBS (styrene butadiene styrene) co-polymer in base bitumens. J. Ind. Eng. Chem. 44, 112–117 (2016) 6. Ranieri, M., Celauro, C.: Improvement of high modulus asphalt mixtures with average quality aggregate and bitumen by application of polymeric additives. Constr. Build. Mater. 178, 183–194 (2018) 7. Sun, Z., Yi, J., Feng, D., Kasbergen, C., Scarpas, A., Zhu, Y.: Preparation of bio-bitumen by bio-oil based on free radical polymerization and production process optimization. J. Clean. Prod. 189, 21–29 (2018) 8. Behnood, A., Gharehveran, M.M.: Morphology, rheology, and physical properties of polymer-modified asphalt binders. Eur. Polym. J. 112, 766–791 (2019) 9. Imad, A.A., Vysotskaya, M.A., Kurlykina, A.V.: Directed regulation of properties of asphalt concrete by nanocarben objects. Constr. Mater. Prod. 2(3), 65–71 (2019) 10. Shekhovtsova, S.Y., Vysotskaya, M.A., Korolev, E.V.: Criteria for thermo-destructive processes in asphalt based on oxidized and residual bitumen bulletin of higher educational institutions. Construction 5, 58–70 (2018)

Physico-Chemical Properties of Fuel Ashes as Factor of Interaction with Cationic Bitumen Emulsion A. Yu. Markov(&) , V. V. Strokova , I. Yu. Markova and M. A. Stepanenko

,

Belgorod State Technological University named after V.G. Shukhov, Belgorod, Russia [email protected]

Abstract. To maintain the stability of bitumen emulsions, the constancy of the hydrogen index of the introduced components is of great importance. However, the establishment of the pH value of the water extraction of fuel ashes does not allow fully assessing the effect and giving a reliable predictive assessment of the stability of the emulsion in the cationic bitumen emulsion – fuel ash system. The paper presents the results of a comparative assessment of four types of fuel ashes with three indicators: acid-base properties, their electrokinetic potential in an aqueous medium, and the hydrogen index of an aqueous extract from a waterash solution. The methods used for assessing the physicochemical properties of fuel ashes are necessary but, not all are informative in terms of assessing their potential and effectiveness in using cationic bitumen emulsion. It is shown that assess the effect of evils on the decay rate of a cationic bitumen emulsion, the H0 and f-potential are the most informative for use in the rapid assessment of the possibility of using this type of technogenic raw material. The studied types of ash were ranked to reduce the degree of negative influence on the stability of the cationic bitumen emulsion. Keywords: Fuel ashes
Cationic bitumen emulsion concrete
Road construction


Cement-reinforced

1 Introduction Bitumen emulsions were widely used in road construction: preparation of dense emulsion-mineral mixtures (including the soil), primer, the arrangement of pavement layers by impregnation, cold recycling and novochip technology, patching, surface treatment of asphalt concrete coatings [1, 2]. The specificity of bitumen emulsions allows obtaining composites with low bitumen content but with the required performance characteristics. When using bitumen emulsion in various composites, it must be taken into account that it is a multi-component material. Besides, emulsions are divided into two types: anionic and cationic. In road construction, preference is given to cationic emulsions. This process is due to their versatility concerning the composition of mineral materials, while anionic emulsions apply exclusively to alkaline rocks [3]. The main task of © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 294–300, 2021. https://doi.org/10.1007/978-3-030-54652-6_44

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modifying emulsions is to structure the film formed by a bitumen emulsion directly in the composition of the final polydispersed organo-mineral composite. This relation makes it possible to vary its quality characteristics. One of the promising composites, the structure of which is formed by a hybrid binder (Portland cement, bitumen emulsion), is cement-asphalt concrete [4–6]. Here, bitumen film formed on the surface of grains of gravel is of interest. The positive experience of using fuel ashes to improve the structural and mechanical characteristics of viscous road bitumen [7–10] suggests the possibility of their use in bitumen emulsions as well. The use of fuel ashes to modify the layers of bitumen in the structure of cement-asphalt concrete allow the creation of movable (so-called «hinged») elements due to the structure of ash particles. This ability increase the damping ability of the material, which positively affect its durability [11]. Modification of bitumen films formed by the emulsion, taking into account its uniform distribution over the surface of grains of gravel, is possible only with the introduction of ash directly into the emulsion. It should be noted that bitumen emulsion, like other emulsion systems, is thermodynamically unstable. This relation is expressed in the desire to enlarge bitumen particles. Accordingly, the introduction of a new component with the composition of the emulsion can dramatically affect its stability, in particular the decay rate. In this case, the physicochemical properties of the introduced component play a decisive role. Thus, it was found that a change in the hydrogen index (pH) of a bitumen emulsion leads to rapid decay [12]. However, taking into account the specificity of the mineral components introduced into the emulsion, the determination of only the hydrogen index is not enough for a reliable predictive assessment of the stability of the resulting system. In this regard, there is a need to use a set of techniques and equipment to establish a correlation of the results and identify the most informative indicators to establish the feasibility and effectiveness of the introduction of fuel sols bitumen emulsion, taking into account the preservation of its stability.

2 Methods and Materials As mineral additives for introducing into the composition of the emulsion, the fuel ashes of four manufacturers were studied, which differ in the type of fuel burned, the technology of its combustion, and the technology for removing residues from burning (Table 1). The fuel ashes used in work have the following chemical composition (Table 2). As an organic binder, an emulsion of bituminous road cationic decaying grade EBDK S was used. This emulsion is manufactured by LLC Avtodorstroy-contractor, Belgorod. Table 3 shows the composition of this emulsion. For evaluating the complex of physicochemical properties of fuel ashes, we determined such characteristics as the hydrogen index (pH) of an aqueous-mineral solution of ash, the acid-base properties of mineral particles of technogenic raw materials, and the electrokinetic potential (f-potential). Determination of the hydrogen index (pH) based on water-mineral solutions, which were prepared with each ash sample, the ratio of components in the solution was 35 ml

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№

Name of the manufacturer of fuel ash

Type of ash

Type of fuel

Ash content, %

1

Troitskaya State District Power Station Reftinskaya State District Power Station Novotroitskaya CHPP Nazarovskaya TPP

Sour

Coal of the Ekibastuz Deposit

40

2

3 4

Main

6–12

Brown coal of IrshaBorodinsky deposit

Method of burning fuel Dry

Waste disposal method

Wet

Wet

Dry

Dry

Dry

Table 2. The chemical composition of the waste of fuel and energy enterprises Source of ash Troitskaya State District Power Station Reftinskaya State District Power Station Novotroitskaya CHPP Nazarovskaya TPP

Content, % SiO2 Al2O3 CaO Fe2O3 SO3 MgO Na2O K2O п.п.п. пp. 62.53 28.75 0.61 4.10 0.21 1.06 1.05 0.29 4.95 1.40 60.20 30.92

1.28 3.35

0.15 0.58

0.53

0.75 1.90

2.24

56.20 27.70 1.35 6.18 31.55 8.84 37.80 8.99

0.10 4.64 4.40 6.31

1.16 0.76

1.18 4.85 0.20 3.15

1.49 1.15

Table 3. The composition of the emulsion of the bituminous road cationic medium decay grade EBDK S Bitumen emulsion components Bitumen BND 60/90 Emulsifier Hydrochloric acid 30% Water

Content, % 60 0.25 0.22 39.53

of distilled water of the material per 5 g of ash. The prepared solutions were measured using an Extech OYSTER-10 instrument to determine the pH level. The acid-base properties of fuel ash were determined using an indicator method based on the adsorption of monobasic indicators on the surface of solid particles in an aqueous medium. A change in the colour of indicators as a result of adsorption

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characterizes the amount of adsorption activity of the material, which is characterized by the Brandsted and Lewis acid and main activity centres. For this, indicators in the range from −5 to +18 pKa were used. The study of the electrokinetic potential (f-potential) was carried out on a watermineral (ash) solution using a Zetatrac laser analyzer. The decay rate of the bitumen emulsion using the studied mineral materials was determined according to the standard method GOST R 55422-2013.

3 Results and Discussions A stable cationic bitumen emulsion, as a rule, has a pH level of 2–5 [11]. An increase in pH leads to a decrease in the stability of the cationic emulsion. Analysis of the hydrogen index of the extraction of the water-mineral solution of the analyzed fuel ashes (Table 4) showed that its value is in the range from 6.47 to 10.28. Table 4. Hydrogen indicator of the studied materials Source of ash PH value f potential, mV Troitskaya State District Power Station 6.47 –6.61 Reftinskaya State District Power Station 7.19 –4.45 Novotroitskaya CHPP 6.37 2.27 Nazarovskaya TPP 10.28 2.67

Since the hydrogen index of the considered fuel ashes (Table 4) is higher than emulsions, there is a high probability of an adverse effect of these technogenic mineral materials on the stability of the emulsion. An analysis of the data shows that according to the degree of influence on the stability of the emulsion, the studied aluminosilicate technogenic materials can be ranked in the following sequence (from worst to best): Novotroitskaya CHPP ! Troitskaya State District Power Station ! Reftinskaya State District Power Station ! Nazarovskaya TPP. However, along with the hydrogen index, it is necessary to take into account the electrokinetic potential (f-potential) of fuel ashes. It is known that particles of cationic bitumen emulsion have a negative charge. Accordingly, in order for the emulsion to maintain stability, it is advisable to use materials having the same charge. Otherwise, the use of mineral materials with a positive charge will lead to the early decay of the emulsion. Among the aluminosilicate technogenic raw materials under consideration, fuel ashes of the Novotroitskaya CHPP and Nazarovskaya TPP have a positive electrokinetic potential. This fact does not allow evaluating these materials as valid components of the bitumen emulsion. Given the negative values of the electrokinetic potential, fuel ashes of the Troitskaya State District Power Station and Reftinskaya State District Power Station should be recommended. Based on the data on the electrokinetic potential, the studied mineral materials can be arranged in sequence according to the degree of influence on the emulsion stability (from worst to better):

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Nazarovskaya TPP ! Novotroitskaya CHPP ! Reftinskaya State District Power Station ! Troitskaya State District Power Station. As a result of a comprehensive study, in addition to the considered hydrogen index (pH) and electrokinetic potential (f-potential), an analysis of acid-base properties was carried out (Table 5).

Table 5. Acid-base properties of fuel ashes Source of fuel ash

Troitskaya State District Power Station Reftinskaya State District Power Station Novotroitskaya CHPP Nazarovskaya TPP

The number of adsorption centres, 103 mg-equiv/g Lewis Bronsted Bronsted Lewis acids foundations acids foundations >13 7…13 0…7 −4,4…0 14.3 45.42 70.91 5.05

H0 Total

135.68

7.28

13.24

53.32

83.79

5.24

155.59

7.48

3.94

21.39

48.99

2.7

77.02

8.33

7.93

4.38

27.86

0

40.17

9.26

The experimental procedure provides for the calculation of the acidity function (H0), which is equivalent to the hydrogen index (pH). This detail allows comparing the data obtained using various methods and determining with high accuracy the effect of mineral components on the properties of the emulsion. The ranking of fuel ashes by the value of the acidity function is identical to the sequence obtained by the f-potential index. All three methods used for assessing the physicochemical properties of fuel ashes are necessary but, as studies have shown, not all are informative in terms of assessing their potential and effectiveness in using cationic bitumen emulsion. In this regard, the comparison of the results of the evils ranking according to the above properties with their influence on the decay rate of bitumen emulsion (EBDK S) is carried out. The decay rate of the emulsion is characterized by the decay index Ir (Table 6), and the higher the index value, the lower the decay rate of the emulsion. The analysis showed that all the studied types of evils increase the decay rate to a greater or lesser extent. It should also be noted that the actual values of the decay index tend to the lower limit of the required values. At the same time, the decay index of the emulsion using acid fuel ashes of the Troitsk State District Power Station and Reftinskaya State District Power Station is within the required values. While using the acid ash of the Novotroitskaya CHPP and the main ash of the Nazarovskaya TPP is below the permissible limit value (Table 6).

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Table 6. The decay rate of cationic bitumen emulsion depending on the type of mineral material used Name of the used mineral material

The decay index of cationic bitumen emulsion EBDK S, Ir Required values Actual values Quartz sand 201–260 223 Ash of Troitskaya State District Power Station 207 Ash of Reftinskaya 205 State District Power Station Ash of Novotroitskaya CHPP 200 Ash of Nazarovskaya TPP 190

Taking into account the dependence of the decay rate of the emulsion on the decay index value, the technogenic mineral materials used can be ranked in order to reduce their negative effect on the stability of the emulsion in the sequence coinciding with the change in the numerical values of the acidity function H0 and f-potential: Nazarovskaya TPP ! Novotroitskaya CHPP ! Reftinskaya State District Power Station ! Troitskaya State District Power Station.

4 Conclusion The performed studies have established that: 1. The most informative from assessing the effect of fuel ashes on the stability of cationic bitumen emulsions are methods for assessing the acidity function and fpotential, which allows recommending them for rapid assessment of this type of technogenic raw materials. 2. Among the four studied types of fuel ashes for use as part of a cationic bitumen emulsion, the most preferred are the ashes of the Troitsk State District Power Station and Reftinskaya State District Power Station. In connection with the established effect of fuel ashes on the decay rate of the emulsion, in the future, it is necessary to establish a rational amount of ashes in the cationic bitumen emulsion, which will preserve the stability of the binder before interacting with coarse aggregate of the final semi-rigid type composite. In turn, this will make it possible to obtain modified bitumen films on the surface of mineral grains of coarse aggregate (crushed stone) of a semi-rigid organ mineral composite and to improve its operational properties. Acknowledgments. The work is realized in the framework of the President Grant in Russian Federation № NSh-2584.2020.8 using the equipment of the Center for High Technologies of BSTU named after V.G. Shukhov.

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References 1. Izmailova, G.G., Sivokhina, E.S., Yelshibaev, A.O.: On the issue of using bitumen emulsion as part of a recycled layer. In: Bulletin of the Kazakh Academy of Transport and Communications named after M. Tynyshpaeva, vol. 2, no. 105, pp. 182–188 (2018) 2. Iwański, M., Chomicz-Kowalska, A.: Application of the foamed bitumen and bitumen emulsion to the road base mix in the deep cold recycling technology. Baltic J. Road Bridge Eng. 11(4), 291–301 (2016) 3. Buldakov, S.I., Sarafanov, K.V.: On the use of bitumen emulsion in the road sector. Actual problems of road design. In: Collection of Scientific Papers of JSC GIPRODORNII, vol. 5, no. (64), pp. 72–75 (2014) 4. Balabanov, V.B., Nikolaenko, V.L.: Rolled road concrete zolasf. Archit. Constr. Russ. 1, 19–24 (2012) 5. Kukielka, J., Bankowski, W.: The experimental study of mineral-cement-emulsion mixtures with rubber powder addition. Constr. Build. Mater. 226, 759–766 (2019) 6. Strokova, V.V., Babaev, V.B., Markov, A.Yu., Sobolev, K.G., Nelyubova, V.V.: Comparative evaluation of road pavement structures using cement concrete. Constr. Mater. Prod. 2(4), 56–63 (2019) 7. Markova, I.Yu., Strokova, V.V., Dmitrieva, T.V.: Influence of ash and entrainment of viscoelastic characteristics of road bitumen. Build. Mater. 11, 28–31 (2015) 8. Lebedev, M.S., Chulkova, I.L.: The study of the rheological properties of bitumen compositions filled with fly ash of various compositions. In: Bulletin of the BSTU named after V.G. Shukhov, vol. 11, pp. 45–52 (2016) 9. Sobolev, K., Ismael, F., Saha, R., Wasiuddin, N., Saltibus, N.: The effect of fly ash on the rheological properties of bituminous material. Fuel 116, 471–477 (2014) 10. Lishtvan, I.I., Lyakhevich, G.D., Lyakhevich, A.G., Dudarchik, V.M., Kraiko, V.M., Zvonnik, S.A.: Experimental studies and the efficiency of using brown coal ash and oil shale in asphalt mixtures. In: News of the National Academy of Sciences of Belarus. A Series of Physical and Technical Sciences, vol. 3, pp. 118–124 (2016) 11. Sprince, A., Pakrastins, L., Gailitis, R.: Long-term parameters of new cement composites. In: SAP 2019: 3rd International Conference on the Application of Superabsorbent Polymers (SAP) and Other New Admixtures Towards Smart Concrete, vol. 24, pp. 85–94 (2020) 12. Petlenko, S.V., Koshkarov, V.E., Koshkarov, M.A.: Analytical studies of the properties of anionic and cationic bitumen emulsions, analysis of the development of their production. Actual problems of road design. In: Collection of Scientific Papers of JSC «Giprodornii», vol. 3, pp. 83–89 (2012)

The Study of Bitumen with Stabilizing Additives for SMA by Infrared Spectroscopy Method Dmitry Yastremsky(&)

, Tatiana Abaidullina

, and Petr Chepur

Industrial University of Tyumen, Volodarskogo Str. 38, Tyumen 625001, Russia [email protected]

Abstract. Increasing the volume of macadam-mastic asphalt concrete used in the upper layers of road surfaces requires the development of effective stabilizing additives that ensure the uniformity of the asphalt mix during short-term storage and transportation, as well as improving the properties of asphalt concrete. Such additives include the complex stabilizing additive of the following composition: 90% cellulose fibers from waste paper, 5% rubber powder, 5% viscous petroleum bitumen of the ORB 90/130 brand. This article presents the results of a study of bitumen with the additive “Viatop 66” and the complex cellulose-containing stabilizing additive (CSA). Using the method of IR-Fourier spectroscopy, graphical data were obtained, as a result of their analysis, it was found that the interaction of stabilizing additives for macadam-mastic asphalt concrete with bitumen leads to the occurrence of additional absorption bands characteristic of aromatic compounds (CH, benzene ring), sulfur-containing functional groups S = O st, R-SO-R, R-SO-OH, R-SO2-R, C = S st, as well as for groups C-O-H. X-ray spectral analysis confirmed the presence of additional sulfur-containing spectra in the composition of stabilizing additives. It was found that depending on the chemical composition of stabilizing additives, the physical and mechanical characteristics of the bituminous binder and the resulting asphalt concrete change. Keywords: Asphalt concrete
Macadam-mastic asphalt concrete additive
Infrared spectroscopy
Bitumen


Stabilizing

1 Introduction Currently, one of the most common materials for the arrangement of the upper layers of road surfaces is macadam-mastic asphalt concrete (SMA). Its popularity is due to its high strength characteristics, which make it the most durable material. It is noteworthy that in contrast to traditional asphalt concrete, the composition of SMA contains stabilizing additives, the main task of which is to prevent the stratification of the mixture during short-term storage and laying of asphalt concrete. In this paper, the authors studied the effect of stabilizing additives on ORB 90/130 bitumen using IR-Fourier spectroscopy and X-ray spectral analysis. Bitumen is a complex mixture of highmolecular hydrocarbons of petroleum origin, including paraffin (CnH2n + 2), naphthenic (CnH2n), aromatic (CnH2n − 6) series, as well as their derivatives containing © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 301–306, 2021. https://doi.org/10.1007/978-3-030-54652-6_45

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oxygen, sulfur, nitrogen and complex metal compounds. The introduction of stabilizing additives of various nature and chemical composition will allow modifying bitumen, improving its rheological characteristics [1–6].

2 Methods and Materials For qualitative and quantitative phase analysis, the method of IR-Fourier spectroscopy was used on the “Nicolet iS10” device. The infrared spectroscopy method is a universal physical and chemical method that is used in the study of structural features of various organic and inorganic compounds. The method is based on the phenomenon of absorption of electromagnetic radiation in the infrared range by groups of atoms of the test object. Absorption is associated with the excitation of molecular vibrations by quanta of infrared light. When irradiating a molecule with infrared radiation, only those quanta whose frequencies correspond to the frequencies of valence and deformation vibrations of the molecules are absorbed. The result of the study is the dependence of the intensity of scattered radiation on the scattering angle [7]. The study was conducted on samples: №1 ORB 90/130 Bitumen; №2 ORB 90/130 + “Viatop 66”; №3 ORB 90/130 Bitumen + CSA. IR spectra of compounds were recorded in the range of 4000–400 cm−1 (Fig. 1). The results of the study were processed using the “OMNIC” software package.

Fig. 1. IR spectra of samples: №1 ORB 90/130 Bitumen; №2 ORB 90/130 + “Viatop 66”; №3 ORB 90/130 Bitumen + CSA

Preparation of samples of the study was carried out as follows: from beforehand prepared samples №1, №2, №3, an average sample of bitumen was selected. These samples were thoroughly mixed with KBr powder in a ratio of 1: 100, and then placed in an IR-Fourier spectrophotometer “Nicolet iS10”, which was used to record the IR spectra of all samples.

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3 Results and Discussions The results of IR-Fourier spectroscopy of samples №1, №2, №3 are shown in Fig. 1. When decoding the obtained IR spectra in Fig. 1, it was found that in the area of 4000–400 cm−1, with the exception of peaks in the intervals from 1700 to 1500 cm−1, from 1000 to 500 cm−1, there are intense bands characteristic of bitumen in the area of 2852 and 2921 cm−1 (valence fluctuations of CH in CH2 groups, indicating a significant amount of limit hydrocarbons, bitumen, paraffin, oils [8, 9]. Analysis of these spectra indicates an increased content of high-molecular asphaltenes in modified bitumen with a slight increase in structuring resins. Therefore, to identify the IR spectra of ORB 90/130 bitumen, ORB 90/130 bitumen + “Viatop 66” and ORB 90/130 bitumen + CSA, the “fingerprint” area of 1800– 400 cm−1 was selected, as the main distinctive features of the location of absorption peaks, their relative intensity are located in this interval. For ease of identification of absorption bands, this area was divided into two intervals from 1800 to 1200 cm−1 (Fig. 2) and from 1200 to 600 cm−1 (Fig. 3).

Fig. 2. IR spectra in the spectrum absorption area 1800–1200 cm−1: №1 ORB 90/130 Bitumen; №2 ORB 90/130 + “Viatop 66”; №3 ORB 90/130 Bitumen + CSA

The distinctive features of the IR spectra of ORB 90/130 bitumen, ORB 90/130 bitumen + “Viatop 66” and ORB 90/130 bitumen + CSA samples in the “fingerprint” area are shown in Table 1. Analysis of the obtained data (Fig. 2a) allowed identifying that in the absorption area from 1750 to 1640 cm−1 there are differences in the distribution of absorption peaks and their relative intensity in all samples. In this area, sample № 1 has absorption bands of 1697.12 cm−1 and 1603.64 cm−1, 1304.66 cm−1. Sample №2 has absorption bands of 1695.67 cm−1 and 1668.05 cm−1, 1312.87 cm−1 with some offset from sample № 1, as well as additional absorption bands of 1538.76 cm−1 and 1504.45 cm−1 characteristic

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Fig. 3. IR spectra in the spectrum absorption area 1200–600 cm−1: №1 ORB 90/130 Bitumen; №2 ORB 90/130 + “Viatop 66”; №3 ORB 90/130 Bitumen + CSA a) the spectrum absorption area cпeктpoв 1800–1200 cm−1

of “Viatop 66”. Sample №3 has absorption bands of 1697.03 cm−1, 1600.25 cm−1, 1310.59 cm−1 with some offset from sample №1, as well as additional absorption bands characteristic of CSA 1702.54 cm−1, 1673.73 cm−1, 1659.72 cm−1, 1650.24 cm−1, 1558.64 cm−1, 1537.52 cm−1, 1503.3 cm−1, 1261.31 cm−1. In the area of 1200–600 cm−1, there are absorption bands characteristic of aromatic compounds, and out-of-plane deformation vibrations of C-H in the area of 1000– 650 cm−1: In the area of 1200–400 cm−1, the following characteristic absorption bands are present for sample №1: 1032.81 cm−1, 964.54 cm−1, 870.12 cm−1, 814.56 cm−1, 744.35 cm−1, 722.06 cm−1. Sample №2 has absorption bands characteristic of bitumen in the area 1032.81 cm−1, 964.54 cm−1, 870.12 cm−1, 813.29 cm−1, 745.56 cm−1, 721.88 cm−1, and also additional absorption bands characteristic of “Viatop 66” - 1076.30 cm−1. Sample №3 has absorption bands characteristic of bitumen in the area 1033.66 cm−1, 969.66 cm−1, 867.25 cm−1, 812.82 cm−1, 745.31 cm−1, 721.48 cm−1, and also additional absorption bands: 1165.13 cm−1, 1180.80 cm−1, 1072.51 cm−1, 1057.70 cm−1, 920.14 cm−1, 875.49 cm−1, 783.69 cm−1, 678.88 cm−1, 660.49 cm−1, 647.77 cm−1. Thus in samples №2 and №3 in addition in contrast to sample №1 absorption bands characteristic of aromatic compounds occurred C = H гpyппa, Sulphur-containing functional groups S = O st, R-SO-R, R-SO-OH, R-SO2-R, C = S st, and also for groups C-O-H. It is also found that a large amount of Sulphur organic compounds are formed in bitumen with CSA (Table 2), which is due to the presence of rubber powder in the additive.

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Table 1. Distinctive features of IR spectra of absorption bands of samples № 1–3. Absorption bands

Structural fragments

For ketones

a, b unsaturated C = C-CO arylalkyl ketones Ar-CO-Alk diaryl ketones Ar-CO-Aк b- Diketone Enol form -COC = C-OH Acids with H-bonds Carboxylate anions -COH = CHCOOR a, b, - unsaturated C = C-CHO Conjugate polyenes C = CC=C Aromatic Monosubstituted

For carboxylic acids For complex ethers For aldehydes

For aromatic compounds

1,2-substituted 1,4- and 1,2,3,4-substituted 1,2,3 substituted For sulphur-containing functional groups

S = O st R-SO-R R-SO-OH R-SO2-R C = S st

For other fluctuations related to the CO-H group

R-O-H

Wave numbers, cm−1 1695–1660 1700–1680 1170–1660 1640–1535 1680–1650 1650–1550 1655–1635 1705–1685 1680–1660 1715–1695 770–730, 710–690 770–735 860–800 800–770, 720–685 1225–980 1060–1015 *1100 1170–1110 1100–1020, 1070–1000 750–650

4 Conclusion When CSA is introduced into bitumen, absorption bands of different intensity are formed (1165.13 cm−1; 1180.80 cm−1; 1072.51 cm−1; 1057.70 cm−1; 920.14 cm−1; 875.49 cm−1; 783.69 cm−1; 678.88 cm−1; 660.49 cm−1; 647.77 cm−1), that are typical for this additive. The presence of such a number of bands is due to the presence of rubber powder in the composition of the CSA, which, when interacting with bitumen, forms aromatic and Sulphur organic compounds due to the partial dissolution of rubber powder particles in the bitumen. The introduction of stabilizing additives in bitumen leads to the formation of additional chemical bonds, which improves the quality of bitumen and macadammastic asphalt concrete.

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References 1. Kiryukhin, G.N., Smirnov, E.A.: Coverings from macadam-mastic asphalt concrete, no. 176. LLC Publishing house “Elite”, Moscow (2009) 2. Yastremsky, D.A., Chepur, P.V., Abaydullina, T.N.: Numerical simulation of the stress-strain state of the road surface made of SMA with the use of the stabilizing additive “Armidon”. Fundam. Res. 7(2), 277–281 (2016) 3. Herren, K.H., Erhard, H., Hoggenmuller, F., Kast, O.: Splittmastixasphal, no. 27. LEITFADEN, Deutscher Asphaltverband (DAV) (2000) 4. Emery, J., Woodman, C., Burlie, R.: Stone Mastic Asphalt technology for urban pavements. In: XIII IRF World Meeting, Toronto, Ontario, Canada (1997) 5. NAPA (National Asphalt Pavement Association) Designing and Constructing SMA Mixtures - State of the Practice. QIP 122 (1999) 6. Louay, N.M., Zheng, Z.T., Baoshan, H.: Fundamental properties of SMA and CMHB Mixes. In: Proceedings BCRA’98, Norway (1998) 7. Ivanova, L.V., Safieva, R.Z., Koshelev, V.N.: IR spectrometry in the analysis of oil and petroleum products. Bull. Bashkir Univ. 13(4), 869–875 (2008) 8. Abdrafikova, I.M., Kayukova, G.P., Vandyukova, I.I.: Study of the composition of asphaltenes and their fractionation products by IR Fourier spectroscopy. Bull. Kazan Technol. Inst. 49, 179–183 (2011) 9. Ayupov, D.A., Potapova, L.I., Murafa, A.V., Fakhrutdinova, V., Khakimullin, Y., Khozin, V.G.: Study of the interaction of bitumen with polymers. News KSUAE 1(15), 140–145 (2012)

Composite Binder on the Basis of Concrete Scrap R. V. Lesovik

, N. M. Tolypina , Ahmed Anees AlAni(&) and Al-bo-ali-wathiq Saeed Jasim

,

Belgorod State Technological University named after V.G. Shukhov, Belgorod, Russia [email protected]

Abstract. The object of research is to obtain binders from fragments of destroyed buildings and structures for the production of various building elements. The properties of fractions (0.0–0.16 mm, 0.16–0.315 mm, 0.315– 0.63 mm, 0.63–1.25 mm, 1.25–2.5 mm and 2.5–5 mm) obtained from fragments of destroyed buildings and structures were studied. Using known chemical and physical methods, experimental results were obtained on the influence of the fraction size and specific surface area on the degree of hydration of binders during the hardening process. It was found that the amount of alite and belite decreases with the transition from the 0.0–0.16 mm fraction to the 2.5–5 mm fraction. At the same time, the amount of quartz and minerals increases that are characteristic of a large aggregate. The smallest fractions of concrete scrap (pulverized and 0.16–0.316 mm) contain the maximum amount of alite C3S and belite C2S, which can harden when interacting with water, compared to larger fractions. To evaluate the ability to hydraulic hardening, the obtained fractions of concrete scrap were crushed in a laboratory mill to a specific surface area of 316–387 m2/kg. The maximum compressive strength was shown by samples of fractions 0.0–0.16 and 0.16–0.315 mm 6–7 MPa. Thus, the greatest hydraulic activity was shown by powders of two small fractions that hardened both under normal conditions and during steaming. Their compressive strength is 1.5–2 times higher than that of samples prepared from powders of larger fractions. Keywords: Effective composites
Fragments of destroyed buildings Construction waste
Green construction




1 Introduction Currently, one of the problems in some states is the use of fragments of destroyed buildings and structures for the production of construction materials. The production of composite binders based on technogenic raw materials from destroyed buildings and structures with improved, and sometimes with fundamentally new performance properties and a certain predetermined structure is possible by controlling the processes of structure formation in the hardening system [1–3]. The basis for obtaining such binders is based on the principle of purposeful management of the technology at all its stages: © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 S. V. Klyuev et al. (Eds.): BUILDINTECH BIT 2020, LNCE 95, pp. 307–312, 2021. https://doi.org/10.1007/978-3-030-54652-6_46

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the development of optimal compositions, the use of mechanic and chemical activation of components, the use of active mineral additives, and some other techniques. Numerous studies conducted on the use of concrete scrap for the manufacture of concrete products and structures have confirmed its high efficiency [4–10]. However, the question of the possibility of obtaining multi-component binders using concrete scrap has not been sufficiently studied yet, although the available data suggest its high value in this quality. These questions are very important and serve as the aim of this research to establish the actual role that fraction sizes play in the production of binder on the basis of concrete scrap. It is expected that this study will also provide more information to understand the interaction of new generation building materials and empirical fact to promote green environment, and its overuse in mass concrete structures such as pedestrian walkways and blinding to the foundation of reinforced concrete structures among other applications. In this paper, the influence on the binder compressive strength of concrete scrap was studied. In this experiment, two fractions of waste up to 5 mm were used. The positive results of using recycled waste in the form of a binder allow using them and solving a negative environmental problem [11–15].

2 Materials and Methods To use concrete scrap in the production of building materials, it is necessary to make a careful selection and control of the used raw materials. In this regard, its influence on the processes of structure formation in concrete and on the performance properties of composites were found, such as porosity, crack resistance, and frost resistance. We used dropouts of rubble fragments of destroyed buildings and structures (Fig. 1).

Fig. 1. Fragments from destroyed buildings and structures

Crushed fragments of different fractions were used to study the effect of the size of concrete scrap fractions on the properties of the resulting binder. The concrete scrap was crushed on a laboratory jaw crusher, dispersed into fractions of 0.0–0.16 mm; 0.16–0.315 mm; 0.315–0.63 mm; 0.63–1.25 mm; 1.25–2.5 mm; 2.5–5 mm in accordance with GOST 8735-88 “Sand for construction works. Test methods”: the granulometric composition of concrete scrap crushing dropouts is presented in Table 1. The granulometric composition of concrete scrap crushing dropouts shows that the maximum amount of 35% is a fraction of 2.5–5 mm. The content of the other fractions

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Table 1. Granulometric composition of concrete scrap crushing dropouts Indicator

Size 2.5 Mass of the residue on the sieve, g 350 Specific remains, % 35 Full remains, % 35

of sieves holes, mm 1.25 0.63 0.315 0.16 83 113 133 155 8.3 11.3 13.3 15.5 43.3 54.6 67.9 83.4