Recent Advances in Structural Engineering: Select Proceedings of NCRASE 2020 (Lecture Notes in Civil Engineering, 135) 9813363886, 9789813363885

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Lecture Notes in Civil Engineering

Srinivasan Chandrasekaran Shailendra Kumar Seeram Madhuri   Editors

Recent Advances in Structural Engineering Select Proceedings of NCRASE 2020

Lecture Notes in Civil Engineering Volume 135

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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Srinivasan Chandrasekaran · Shailendra Kumar · Seeram Madhuri Editors

Recent Advances in Structural Engineering Select Proceedings of NCRASE 2020

Editors Srinivasan Chandrasekaran Department of Ocean Engineering Indian Institute of Technology Madras Chennai, Tamil Nadu, India

Shailendra Kumar Department of Civil Engineering Guru Ghasidas Vishwavidyalaya Bilaspur, Chhattisgarh, India

Seeram Madhuri Department of Civil Engineering National Institute of Technology Jamshedpur Jharkhand, India

ISSN 2366-2557 ISSN 2366-2565 (electronic) Lecture Notes in Civil Engineering ISBN 978-981-33-6388-5 ISBN 978-981-33-6389-2 (eBook) https://doi.org/10.1007/978-981-33-6389-2 © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 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 Singapore Pte Ltd. The registered company address is: 152 Beach Road, #21-01/04 Gateway East, Singapore 189721, Singapore

Preface

National Conference on Recent Advances in Structural Engineering—2020 (NCRASE—2020) The Department of Civil Engineering, National Institute of Technology Jamshedpur organized a National Conference on Recent Advances in Structural Engineering— 2020 from 21st to 22nd August 2020. The conference was aimed to bring the experts, academicians, consultants and students to a single platform and share the knowledge across the country in the field of structural engineering. The conference has been held in the themes of Advanced Structural Materials, Analysis and Design of Structures, Bridges, Structural Dynamics and Special Loads on Structures. The conference was planned carefully with keynote addresses from subject experts Prof. Srinivasan Chandrasekaran from IIT Madras and Prof. Shailendra Kumar from Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur. All the papers accepted for Springer have been reviewed thoroughly by the subject experts across the country with meticulous reviews, corrections and suggestions to the authors. The online sessions were organized with a session chair and co-chair to get clarified with queries from participants and students. The online platform gave a very good opportunity to the students as well as researchers on gaining knowledge in the conference themes. The organizers (Dr. S. Madhuri, Dr. Keshav Kumar Sharma and Dr. Shashi Ranjan Pandey) have expressed regards to the administration of NIT Jamshedpur for kind approval and providing facilities to conduct the conference. The conference was sponsored by Technical Education Quality Improvement Program (TEQIP—III), NPIU New Delhi. Organizers have expressed gratitude to the conference committee, technical advisory committee and paper reviewers for timely support and on selecting quality papers with significant comments. The organizers are also thankful to Springer Publishers for accepting to publish the selected papers.

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Preface

Further, the organizers are thankful to all the authors who participated actively and submitted their research contributions to this conference for making it a grand success and bringing up this conference book. Prof. Srinivasan Chandrasekaran Department of Ocean Engineering, IIT Madras, Tamil Nadu, India Prof. Shailendra Kumar Department of Civil Engineering, School of Engineering & Technology, Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur, India Dr. Seeram Madhuri Jamshedpur, Jharkhand, India

Contents

Advanced Structural Materials A Sustainable Concrete with Manufactured Sand in Different Aggressive Environments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Deep Tripathi, Rakesh Kumar, P. K. Mehta, and Amrendra Singh

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Mechanical Performance of Self-compacting Concrete with Pozzolanic Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Amrendra Singh, Rakesh Kumar, P. K. Mehta, and Deep Tripathi

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Studies on Infiltration Rate of Pervious Concrete . . . . . . . . . . . . . . . . . . . . . Nune Srikanth and N. R. Dakshina Murthy

21

Properties of Concrete with Bagasse Ash and Stone Dust Exposed to Sulphate Attack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pooja Jha, A. K. Sachan, and R. P. Singh

29

Torque and Twist Response of High-Grade Concrete Beams with “U” Jacketing of Ferrocement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gopal Charan Behera

39

Stress–Strain Behaviour of Self-consolidated Processed Recycled Aggregate Concrete . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Nune Srikanth, N. R. Dakshina Murthy, and M. V. Seshagiri Rao

51

Study of Compressive Strength of Self-compacting Concrete Using Rice Husk Ash and Nano Silica as a Partial Replacement to Cement: A Comparative Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Vijay Kumar, Shashi Ranjan Pandey, and Aman Kumar

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Analysis and Design of Structures Bayesian Finite Element Model Updating Without Requirement of Mode-Matching and Sub-structuring of System Matrices . . . . . . . . . . . Ayan Das and Nirmalendu Debnath

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Contents

Free Vibration Analysis of Reissner–Mindlin Plates Using FEniCS . . . . . G. Verma, S. Sengupta, S. Mammen, and S. Bhattacharya Response of Delamination on Static Behaviour of Simply Supported Composite Conoidal Shell Roofs . . . . . . . . . . . . . . . . . . . . . . . . . . Suman Pandey and Dipankar Chakravorty

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Effect of Steel Fibre on Mechanical Properties of Metakaolin-Mixed Concrete . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 Vishal Rawat, Rakesh Kumar, A. K. Sachan, and Deep Tripathi Dynamic Analysis of Telecommunication Tower Subjected to Wind Load with Different Configurations of Bracings . . . . . . . . . . . . . . . . . . . . . . 111 P. Venkata Reddy, Keshav Kumar Sharma, and Brajkishor Prasad Effect of Stiffeners on the Natural Frequencies of Stiffened Plate . . . . . . . 121 Deepak Kumar Singh and Keshav Kumar Sharma Bridges Damage Evaluation of Reinforced Concrete Bridge Subjected to Blast Loading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131 Roouf Un Nabi Dar and Mehtab Alam Structural Dynamics Performance of RC Frames with Stiffness Irregularity Under Sequential Ground Motion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145 Athar Tauheed, Mehtab Alam, and T. K. Datta Influence of Marine Growth on the Static Response of Jacket Wind Turbine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155 Seeram Madhuri, Sitesh Subhra Bera, and Brajkishor Prasad Dynamic Time History Analysis of Masonry Tower Using Macro Modelling Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167 Ambareesh Kumar and Kumar Pallav Special Loads on Structures Performance of One-Way Concrete Slabs Reinforced with Conventional and Polymer Re-bars Under Air-Blast Loading . . . . . 179 S. M. Anas, Mehtab Alam, and Mohammad Umair Structural Vulnerability of Buildings Exposed to Earthquake in Hilly Region: A Conceptual Framework . . . . . . . . . . . . . . . . . . . . . . . . . . . 193 Aditi Singh and D. P. Kanungo

Contents

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Active Seismic Control of Structures Using Pole Placement Technique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201 Faisal Rather and Mehtab Alam Response of Multi-Storeyed Structures Subjected to Blast Loading . . . . . 213 T. K. Bharath and Y. K. Guruprasad Efficacy of Lateral Load Resisting Systems in High-Rise Structures . . . . 223 Anup Anilkumar Shukle and Y. K. Guruprasad Stability Analysis of an RC Structure with RC Shear Walls in the Event of a Fire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233 T. K. Bharath and Y. K. Guruprasad A Comparative Study of Wind Effects on High-Rise Structures Having Different Shapes in Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243 Anup Anilkumar Shukle and Y. K. Guruprasad Experimental and Numerical Modeling of Wave Transmission Over Submerged Breakwater and Rigid Vegetation . . . . . . . . . . . . . . . . . . . 253 Munireddy G. Mutukuru, P. Kishorekumar Reddy, and Gorle Giridhar

About the Editors

Prof. Srinivasan Chandrasekaran is at Department of Ocean Engineering, IIT Madras, Chennai, India. He obtained Gold Medal in his B. E Civil Engineering (1987–1991) from Bharathiar University, Coimbatore; M. Tech in Structural Engineering and PhD from IIT Delhi. He was a Post-doctoral Fellow from University of Naples Federico II, Naples, Italy. He has wide spectrum of areas of research such as structural dynamics and earthquake engineering, dynamic analysis and design of offshore structures, development of new-generation compliant offshore platforms for ultra-deepwater oil and gas exploration, structural health monitoring of ocean structures, risk and reliability of structures, fire-resistant design of structures, analysis, design, and construction of marine risers with functionally graded materials (FGM), health, safety & environmental (HSE) management in process industries. In addition to academics, he has industrial and research experience. He did several sponsored and industrial projects. He published various papers in reputed international journals and conferences. He authored several books on the advanced analysis and design of floating offshore structures and written executive reports in the international level. He has delivered keynote lectures on national and international platforms. In addition to teaching at IIT Madras, he is offering online courser in NPTEL and Swayam portals for the learners and industry experts across the world. Dr. Shailendra Kumar is a Professor at Department of Civil Engineering, School of Engineering & Technology, Guru Ghasidas Vishwavidyalaya, Bilaspur. He did his Under Graduation at NIT Jamshedpur, Post Graduation from NIT Rourkela and PhD from IIT Kharagpur. His main research areas are fracture mechanics of concrete, computer application on RC structures, fibre reinforced concrete and alternate construction materials. He published several papers in national and international journals and conferences. He authored books on concrete fracture mechanics and simplified testing methods of concrete fracture models. He has guided many PhD, M. Tech and B. Tech students for their projects. He has executed various sponsored research projects under MHRD. Apart from research and academic work he extended his knowledge in the consultancy and industrial projects. He became life member and senior member in national and international professional bodies. He was honoured with Indian National Group of the IABSE medal award for the best xi

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About the Editors

paper entitled “Shear Strength of Reinforced Fibrous Concrete Beams without Web Reinforcement” published in journal the Bridge and Structural Engineer. He acted as a key member in various technical committees. Dr. Seeram Madhuri is an Assistant Professor at Department of Civil Engineering, NIT Jamshedpur. She obtained her undergraduate degree from Sri Venkateswara Hindu College of Engineering, Nagarjuna University; M.S (by research) and PhD from Ocean Engineering Department, IIT Madras. Her research areas are structural dynamics, offshore structures, and offshore wind turbine supporting structures, experimental techniques, port and harbour structures and analysis & design of structures. She started her career as a project assistant at SERC Chennai. She worked on consultancy projects in ocean engineering department, IIT Madras, with her guide. She worked as assistant professor at Department of Civil Engineering, JNTUK Kakinada before joining in NIT Jamshedpur. She worked in a real field consultancy project, CRP Jacket Marine Growth Analysis for Reliance Industries Limited. She did sponsored research project on the design of Tension Leg Platform Wind Turbine. She published various papers in national and international journals and conferences. She contributed as reviewer for IEI Series (A) and Elsevier journals.

Advanced Structural Materials

A Sustainable Concrete with Manufactured Sand in Different Aggressive Environments Deep Tripathi, Rakesh Kumar, P. K. Mehta, and Amrendra Singh

Abstract Concrete plays a key role in every construction and a large amount of concrete is used widely. Natural river sand is one of the main ingredients of the concrete but is becoming expensive for various reasons. Also, the concern for environment is making the sand quarrying more and more difficult. Thus, there is a need of a cost-effective alternative and that is available in the form of manufactured sand (M-sand). In this experimental study, M-sand and fly ash (FA) were used for partial replacement of fine aggregate and ordinary Portland cement (OPC), respectively, in preparation of self-compacting concrete (SCC). After optimizing the dose of M-sand and FA in the final mix, 100 mm cubes were cast to investigate the following: loss in compressive strength and visual changes. The cubes of SCC with and without replacement of fine aggregate and OPC were cured separately, in 4% solutions of nitric acid (HNO3 ), sulphuric acid (H2SO4 ) and ammonium sulphate [(NH4 )2 SO4 ] for 12 weeks, after 28 days curing in tap water to investigate the durability of different mixes. XRD analysis of the concrete samples was carried out to study the microstructural changes. The SCC made of M-sand and FA shows better performance in different aggressive environments. Keywords Self-compacting concrete · Manufactured sand · Fly ash · XRD · Aggressive environment

D. Tripathi (B) · R. Kumar · P. K. Mehta · A. Singh CED, MNNIT Allahabad, Prayagraj, U.P. 211004, India e-mail: [email protected] R. Kumar e-mail: [email protected] P. K. Mehta e-mail: [email protected] A. Singh e-mail: [email protected] © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021 S. Chandrasekaran et al. (eds.), Recent Advances in Structural Engineering, Lecture Notes in Civil Engineering 135, https://doi.org/10.1007/978-981-33-6389-2_1

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D. Tripathi et al.

1 Introduction Durability is the main and serious concern for the concrete because it is highly susceptible to aggressive environment caused due to acid or sulphate attack. This has led to the failure of several concrete structures worldwide. Sulphate adversely affects the concrete durability. The main sources of sulphate salts are soil, ground water, sea water, industrial effluents and air pollution. Sulphuric acid is a strong and aggressive acid that reacts with the free lime available in cement and gypsum form [1]. Ettringite is a very expansive compound and creates an internal pressure on the surrounding concrete. This leads to the formation of cracks and results in the loss of strength and durability. In sewer structures, hydrogen sulphide gas is released due to different chemical and microbiological reactions. An exposure to H2 SO4 causes extensive formation of gypsum in the surface regions which ultimately leads to spalling [2]. The addition of pozzolanic materials in the concrete stabilizes the liberated calcium hydroxide during the hydration process of the cement to form additional C–S–H gel. The resultant binder matrix of concrete is chemically more resistant, and this is improved further by virtue of its dense microscopic pore structure [3]. Several researchers conclude that there is a slight decrease in acid attack on concrete that contains mineral admixtures [4–6]. The SCC represents one of the most important developments in concrete technology. Owing to no proper compaction of concrete, its performance reduces. When the strength of the concrete structures became a major problem in Japan, a sufficient skilled worker was needed to obtain durable concrete structures. This requirement led to the development of SCC and its development was first reported in 1989 [7]. Zhu et al. [8] have defined SCC as a high-performance concrete which flows under its own weight, and there is no need for any compaction. The high flowability of SCC makes it possible to fill the formwork without vibration [9]. It reduces the environmental impacts too [6]. The use of mineral admixtures in concrete increases the strength compared to concrete prepared with cement only [10, 11]. The attention of several European countries was drawn towards the application of SCC after successful use in Japan. Dinakar et al. [12] studied the effect of H2SO4 solution (3%) on normally vibrated concrete (NVC) and SCC for a period of 90 days. It is reported that the concrete of lower strength (20–30 MPa) shows a lower weight loss in SCC in comparison to the NVC, with the increasing FA content. SCC incorporating mineral admixture has improved workability and strength [13].

2 Experimental Investigation 2.1 Materials and Their Properties Cement: The OPC (brand: MP Birla) of grade 43 was used for this experimental programme. The cement test results were: Normal consistency = 27%; initial setting

A Sustainable Concrete with Manufactured Sand in Different Aggressive …

5

time = 45 min; final setting time = 480 min; specific gravity = 3.14; compressive strength = 48.69 MPa (28 days). The test values satisfy the provisions of IS: 81121989 [14]. Fine aggregate: The river sand (conforms Zone II, IS: 383-1987 [15]); bulk density = 1680 kg/m3 ; specific gravity = 2.65; fineness modulus = 2.7. Coarse aggregates: 10 mm (specific gravity = 2.66; water absorption = 1.0%; bulk density = 1590 kg/m3 ; fineness modulus = 6.7) and 20 mm (specific gravity = 2.7; water absorption = 0.9%; bulk density = 1560 kg/m3 ; fineness modulus = 7.2) (conforms IS 383-1987 [15]). M-sand: It was procured from Jhansi, U.P., conforms Zone II, IS: 383-1987 [15]; bulk density = 1744 kg/m3 ; specific gravity = 2.72; fineness modulus = 3.08. Class F-FA: It was procured from NTPC Unchahar, U.P.; colour = grey; specific gravity = 2.13 (conforms, IS 3812-2000 [16]). Superplasticizer: Polycarboxylic ether-based Master Rheobuild 817RL; density = 1.08 (approx.). Water for mix design and curing: Tap fresh potable water.

2.2 Mix Proportioning The SCC mix was designed as per the EFNARC specifications [17]. Grade = M25; water/binder (w/b) ratio = 0.44; total binder content = 450 kg/m3 ; fine aggregate = 890 kg/m3 ; coarse aggregate = 750 kg/m3 ; superplasticizer dose = 4.95 kg/m3 . The final mix proportion of 1:1.98:1.66 (binder:fine aggregate:coarse aggregate) was found. The OPC was partially replaced by FA at different percentage levels, by mass (i.e. 10, 15, 20 and 25%). To check the workability of the mixes, slump flow, T50 time, V-funnel, L-box, U-box and J-ring tests were performed. Total 24 cubes of size 100 mm were prepared for different mixes. To optimize the dose of FA, the compressive strength of all mixes was found at 7 and 28 days tap water curing as per IS: 516-1959. The mix proportions, w/b ratio of SCC, the fresh properties and compressive strengths of SCC with different percentages of FA are given in Table 1. The optimum replacement level of OPC by FA was found to be 20% with respect to the compressive strength. After optimizing the dose of FA in SCC, the fine aggregate was partially replaced by M-sand at different levels, by mass (i.e. 30, 40, 50 and 60%). The mix proportions, w/b ratios, fresh properties and compressive strengths of SCC with different percentages of M-sand are given in Table 2. The optimum replacement level of fine aggregate by M-sand was found to be 50% with respect to the compressive strength. Two types of mixes were prepared, viz., M-1 [SCC without M-sand; SCCIII (20% FA), column 5 in Table 1] and M-2 [SCC with Msand; SCCIII + 50% M-sand, column 5 in Table 2] for further study and the results after 28 days tap water curing are given in Table 3. Thereafter, the cubes of 100 mm size were prepared and cured in tap water for 28 days, and then cubes were immersed separately in 4% HNO3 , 4% H2SO4 and 4% (NH4 )2 SO4 solutions and tap water for a period of 12 weeks. The compressive strength of these samples was determined after 1st, 2nd, 4th, 8th and 12th week of exposure and the results are presented in Table 4. The visual assessments for colour change were also carried out.

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Table 1 Mix proportioning, fresh properties and compressive strength of concrete mixes S. No.

Mix properties

SCCI (10% FA)

SCCII (15% FA)

SCCIII (20% FA)

SCCIV (25% FA)

1.

w/b ratio

0.44

0.44

0.44

0.44

2.

OPC (kg/m3 )

405

382.50

360

337.50

3.

FA (kg/m3 )

45

67.50

90

112.50

(kg/m3 )

4.

Coarse aggregate

750

750

750

750

5.

Fine aggregate (kg/m3 )

890

890

890

890

6.

Water (kg/m3 )

190

190

190

190

(kg/m3 )

7.

Superplasticizer

4.95

4.95

4.95

4.95

8.

Slump flow (mm)

670

680

700

730

9.

T50 slump (s)

6

6

5

4

10.

V-funnel (s)

12

11

10

9

11.

L-box (h2 /h1)

1

0.9

0.9

0.8

12.

U-box (mm)

30

30

27

26

13.

J-ring (mm)

14.

Compressive strength (N/mm2 )

10

10

9

8

7 days

23.67

22.33

21.33

21.00

28 days

31.67

32.33

33.33

32.00

Table 2 Mix proportioning, fresh properties and compressive strength of concrete mixes S. No.

Mix properties

SCCIII + 30% M-sand

SCCIII + 40% M-sand

SCCIII + 50% M-sand

SCCIII + 60% M-sand

1.

w/b ratio

0.44

0.44

0.44

0.44

2.

OPC (kg/m3 )

360

360

360

360

(kg/m3 )

3.

FA

90

90

90

90

4.

Coarse aggregate (kg/m3 )

750

750

445

750

5.

Fine aggregate (kg/m3 )

623

534

445

356

6.

M-sand

267

356

445

534

7.

Water (kg/m3 )

190

190

190

190

8.

Superplasticizer (kg/m3 )

4.95

4.95

4.95

4.95

9.

Slump flow (mm)

695

695

685

670

10.

T50 slump (s)

5

6

6

8

11.

V-funnel (s)

10

11

12

14

12.

L-box (h2 /h1)

0.9

1.0

1.0

1.2

13.

U-box (mm)

28

29

30

32

14.

J-ring (mm)

10

10

10

12

15.

Compressive 7 days strength (N/mm2 ) 28 days

21.33

22.00

24.33

23.67

33.33

34.67

36.00

34.33

A Sustainable Concrete with Manufactured Sand in Different Aggressive …

7

Table 3 Compressive strength (N/mm2 ) of M-1 and M-2 type mixes after 28 days curing in tap water S. No.

Mix designation

Period (weeks) 1

2

4

8

12

1.

M-1

34.33

35.67

36.33

37.00

38.67

2.

M-2

37.00

38.33

39.00

40.33

41.67

Table 4 Compressive strength (N/mm2 ) of M-1 and M-2 type mixes in different exposure conditions S.

Period Exposure condition No. (weeks) 4% HNO solution 3 M-1

M-2

4% H2SO4 solution

4% (NH4 )2 SO4 solution

M-1

M-1

M-2

M-2

1.

1

34.33

37.00 34.33

37.00 34.33

37.00

2.

2

35.67

38.33 35.67

38.33 35.67

38.33

3.

4

34.00

37.00 34.33

37.33 35.33

38.33

4.

8

34.33

38.00 34.33

38.33 36.00

39.67

5.

12

35.33

39.00 35.67

39.33 37.33

40.67

3 Results and Discussion 3.1 Compressive Strength Loss

M-1 type M-2 type

8 6 4 2 0 1

2 4 8 12 No. of Weeks

(a) Exposure in HNO 3 Solution

10

M-1 type

8

M-2 type

Loss of Strength (%)

10

Loss of Strength (%)

Loss of Strength (%)

The loss in compressive strength of the samples after exposure to HNO3 solution was determined with respect to the referral, cured in tap water and the results are presented in Fig. 1a. A significant loss of strength was observed in the samples after 2 weeks. The loss ranges between 4 and 9% up to 12 weeks. After 12 weeks, a maximum loss of 8.63% was observed in case of M-1 samples, while a minimum loss of 4.56% was observed in M-2 samples.

6 4 2 0 1

2 4 8 No. of Weeks

12

(b) Exposure in H2SO4 Solution

10

M-1 type

8

M-2 type

6 4 2 0 1

2 4 8 12 No. of Weeks

(c) Exposure in (NH4)2SO4 Solution

Fig. 1 Percentage loss in compressive strength in 4% concentration of different solutions

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D. Tripathi et al.

The compressive strength losses of different samples immersed in H2 SO4 solution (4%) were determined with respect to the referral cured in tap water, and the results are presented in Fig. 1b. It has been observed that within first two weeks, the SCC samples were not affected by H2 SO4 exposure. A significant deterioration in strength was observed in all the samples after two weeks. The loss in compressive strength was observed in the range of 4–8% up to 12 weeks. A maximum loss of 7.75% was observed in case of M-1 type sample, and a minimum loss of 4.28% was observed in case of M-2 type sample. When samples were immersed in (NH4 )2 SO4 solution (4%), the loss in strength is presented in Fig. 1c. It is found that within first two weeks, the SCC samples were not affected by (NH4 )2 SO4 . The loss in compressive strength was observed in the range of 2–4% up to 12 weeks. A maximum loss of 3.5% was observed in case of M-1 type sample, and a minimum loss of 1.2% was observed in case of M-2 type sample.

3.2 Visual Inspection Visual examination of concrete specimens immersed in nitric acid, sulphuric acid and ammonium sulphate solutions was carried out after 1, 2, 4, 8 and 12 weeks of exposure, and the photographs are shown in Figs. 2 and 3. It was observed that few holes were found in the samples exposed to nitric acid solution. After the eight weeks immersion, a considerable change in the colour of surface was observed. Also, some spalling of the concrete due to acid attack was observed. The colour change of specimens may be due to leaching out the soluble salts from the concrete and deposition of the same on the surface of the specimens. Addition of FA and M-sand in SCC reduced the free lime content and refined the pore structure. This reduces the leaching action of soluble salts in M-2 type samples in comparison to the M-1 type.

(a) HNO3 Solution (4%)

(b) H2SO4 Solution (4%)

(c) (NH4)2SO4 Solution (4%)

Fig. 2 Photograph of M-1 type sample (2–12 weeks)

(a) HNO3 Solution (4%)

(b) H2SO4 Solution (4%)

Fig. 3 Photographs of M-2 type sample (2–12 weeks)

(c) (NH4)2SO4 Solution (4%)

A Sustainable Concrete with Manufactured Sand in Different Aggressive …

9

3.3 XRD Analysis To predict/interpret the performance of any concrete, its microstructural analysis plays an important role. XRD analysis is one of the methods to find the presence of mineral compounds in the concrete specimen. The XRD analysis of both M-1 type and M-2 type specimen cured separately in HNO3 , H2SO4 and (NH4 )2 SO4 solutions up to 12 weeks was carried out. The typical XRD results are presented in Figs. 4 and 5. Some major crystalline phases identified include: Quartz (Q), calcium silicate hydrate (C–S–H), calcium hydroxide (CH), ammonium sulphate hydrate (ASH), gypsum (G), monosulphate (CASH), brucite (B), calcium nitrate dihydrate (CNH) and ettringite (E). More peaks of ettringite are visible in M-1 type SCC in comparison to the M-2 type, after exposure in sulphate solution. From XRD analysis, it is clear that within a short duration, nitric and sulphuric acid deteriorate concrete samples more in comparison to the ammonium sulphate solution.

(a) HNO3 Solution

(b) H2SO4 Solution

(c) (NH4)2SO4 Solution

Fig. 4 XRD of M-1 type specimen exposed to different solutions (4%) for 12 weeks

(a) HNO3 Solution

(b) H2SO4 Solution

(c) (NH4)2SO4 Solution

Fig. 5 XRD of M-2 type specimen exposed to different solutions (4%) for 12 weeks

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4 Conclusion From the experimental results, it is concluded that: (i) The loss of compressive strength in aggressive environment is least in case of M-2 samples; (ii) Ammonium sulphate affects concrete in longer duration in comparison to the nitric and sulphuric acid; (iii) The inclusion of supplementary cementitious material (FA) improves the resistance of concrete in aggressive environment; (iv) FA and M-sand improve the pore structure of the SCC; (v) Specimen containing FA + M-sand has good resistance against acid and sulphate attack; (vi) More/higher peaks of ammonium sulphate hydrate (ASH), gypsum (G), monosulphate (CASH), brucite (B), calcium nitrate dihydrate (CNH) and ettringite (E) are present in M-1 type mix, adversely affecting the durability.

References 1. E.K. Attogbe, S.H. RizkallaI, Response of concrete to sulphuric acid attack. ACI Mater. J. 84(6), 481–488 (1988) 2. D. Israel, D.E. Macphee, E.E. Lachowski, Acid attack on pure reduced cement. J. Mater. Sci. 32, 4109–4116 (1997) 3. J. Monteny, N. De Belie, E. Vincke, W. Verstraete, L. Taerwe, Chemical and biological test to simulate sulphuric acid corrosion of polymer modified concrete. Cem. Concr. Res. 31(9), 359–1365 (2001) 4. W.H. Harrison, Durability of concrete in acidic soils and waters. Concrete 21(2), 18–24 (1987) 5. D.M. Roy, P. Arjunan, N.R. Silsbee, Effect of silica fume, metakaolin and low calcium fly ash on chemical resistance of concrete. Cem. Concr. Res. 31(12), 1809–1813 (2001) 6. G. Praveen, K. Rakesh, Y.K. Gupta, P.K. Mehta, Effect of acidic environment on self compacting concrete. Int. J. Civ. Eng. Technol. (IJCIET) 8(2), 595–606 (2017) 7. N. Bouzoubaa, M. Lachemi, Self-compacting concrete incorporating high volumes of class F fly ash: preliminary results. Cem. Concr. Res. 31, 413–420 (2001) 8. W. Zhu, J.C. Gibbs, P.J.M. Bartos, Uniformity of in-situ properties of self compacting concrete in full scale structural elements. Cem. Concr. Compos. 23(1), 57–64 (2001) 9. F.M. Kilinckale, The effect of MgSO4 and HCL solution on the strength and durability of pozzolan cement mortars. Cem. Concr. Res. 27(12), 1911–1918 (1997) 10. D. Tripathi, R. Kumar, P.K. Mehta, A. Singh, Silica fume mixed concrete in acidic environment. Mater. Today Proc. 27(1), 1001–1005 (2020) 11. A. Singh, R. Kumar, P.K. Mehta, D. Tripathi, Effect of acidic environment on rice husk ash steel fibre reinforced concrete. Mater. Today Proc. 27(1), 995–1000 (2020) 12. P. Dinakar, K.G. Babu, M. Santhanam, Durability properties of high volume fly ash self compacting concretes. Cem. Concr. Compos. 30, 880–886 (2008) 13. D. Tripathi, R. Kumar, P.K. Mehta, A. Singh, Optimum Dose of Binary Admixture in Self Compacting Concrete. Int. J. Innov. Exploring Eng. 9(1), 103–108 (2019) 14. IS: 8112-1989, Specification for 43 Grade Ordinary Portland Cement. Bureau of Indian Standards, New Delhi, India 15. IS: 383-1987, Specification for Coarse and Fine Aggregate from Natural Sources for Concrete. Bureau of Indian Standards, New Delhi, India 16. IS: 3812-2000, Specification for Pulverized Fuel Ash, Part 1: For Use as Pozzolana in Cement Cement Mortar and Concrete 17. EFNARC, Specifications and Guidelines for Self Compacting Concrete. EFNARC, UK. www. efnarc.org. (2002), pp. 1–32

Mechanical Performance of Self-compacting Concrete with Pozzolanic Material Amrendra Singh, Rakesh Kumar, P. K. Mehta, and Deep Tripathi

Abstract Self-compacting concrete (SCC) is a highly flowable concrete which has more binder content as compared to normal concrete and there is no need of vibration for the compaction. The use of waste materials for part replacement of ordinary Portland cement (OPC) in SCC can enhance its mechanical properties. Fly ash (FA) is the most widely used pozzolanic material for making SCC. Its inclusion in concrete improves both the workability and strength of SCC. At the early ages, the SCC made using FA shows lower compressive strength in comparison to the SCC made using OPC only; however, it gives higher strength later on. In this experimental study, workability and strength properties of M30 grade SCC were studied with variables. The replacement levels of OPC by FA were varied: 5, 10, 15, 20 and 25%. Fresh concrete properties were measured by L-box slump flow, V-funnel flow time, Ubox and J-ring tests. Other (mechanical) properties were determined in terms of compressive strength (CS), split tensile strength (STS) and flexural strength (FS). The X-ray diffraction (XRD) and scanning electron microscope (SEM) analyses were also carried out to study the micro-level changes in SCC. Keywords Referral self-compacting concrete · Optimum self-compacting concrete · Scanning electron microscope

A. Singh (B) · R. Kumar · P. K. Mehta · D. Tripathi CED, MNNIT Allahabad, Prayagraj, U.P. 211004, India e-mail: [email protected] R. Kumar e-mail: [email protected] P. K. Mehta e-mail: [email protected] D. Tripathi e-mail: [email protected] © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021 S. Chandrasekaran et al. (eds.), Recent Advances in Structural Engineering, Lecture Notes in Civil Engineering 135, https://doi.org/10.1007/978-981-33-6389-2_2

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1 Introduction Self-compacting concrete is a concrete that can flow and compact under its own weight, pass through the spaces between the congested reinforcing bars to completely fill the formwork and simultaneously maintain its stable composition [1–3]. The SCC shall possess the adequate workability (flowability, passing ability and segregation resistance) and high strength besides gain durability [4]. To meet these requirements, the highest amount of OPCs, the highest volume of viscosity-modifying admixtures, chemical admixtures, and active mineral admixtures (MA) is used. The main disadvantages of SCC made using only OPC are higher costs and the environmental impacts [3–5]. The SCC is notable from normal concrete mainly by higher binder content (MA and cement). The replacement of partial OPC by MA can reduce the OPC consumption, and help in reducing the cost of SCC and emission of CO2 [6]. MAs are usually incorporated in SCC along with OPC. Several ternary binders (Two MAs + OPC) have been used in the production of SCC [7]. The addition of FA enhances the fresh properties due to shape of the particle. The shape of FA is spherical and it also enhances the strength and durability of SCC due to its chemical composition [8–10]. The part replacement of OPC by FA can improve fresh properties of flowing concrete and SCC [11–15]. Use of waste material from industry as a part replacement of cement in concrete enhances hardened properties and also has positive effect on durability of SCC [15, 16]. The voids can be reduced by inclusion of pozzolanic materials and permeability can be reduced to a significant level. The SEM images show that the CSH gel is formed by the pozzolanic reaction of MAs. The SEM also verifies the increased compactness of the concrete and fewer micro-cracks, leading to higher strength [16, 17].

2 Experimental Investigation 2.1 Materials and Their Properties The properties of different materials used in this experiment are as follows: OPC grade = 43; brand: Prism Cement; normal consistency = 27%; initial setting time = 45 min; final setting time = 480 min; CS at 28 days = 48.67 N/mm2 , conforms with IS 8112–1989 [18]. Class F-FA: It was procured from NTPC Unchahar, U.P.; colour = grey; specific gravity = 2.13. The XRD and SEM of FA are shown in Figs. 1 and 2, respectively. The spherical shaped particles of FA (Fig. 2) act as ball bearings within the concrete mix, providing a lubricating effect. Fine aggregate: natural river sand; fineness modulus (FM) = 2.462; specific gravity (SG) = 2.48; bulk density (BD) = 1680 kg/m3 , conforms with zone II (IS 383-1987) [19]. Coarse aggregate: 10 mm [SG = 2.67; FM = 6.25; water absorption (WA) = 1.2; BD = 1590 kg/m3 ] and 20 mm (SG = 2.7; FM = 7.27; WA = 1.1%; BD =

Mechanical Performance of Self-compacting Concrete with … Fig. 1 XRD of FA

13

SiO2

1200

Experimental Pattern Fly Ash

Intensity

1000

800

600

400

Fe2O3 Al2O3

200

0 0

5

10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100

2 theta

Fig. 2 SEM of FA

1560 kg/m3 ) size, conforms with IS: 383-1987 [19]. The compositions of OPC and FA as supplied by the company are presented in Table 1. Table 1 Composition of OPC and FA

S. No.

Chemical compositions (%)

OPC 52.55

FA

1

CaO

2

Fe2 O3

3.23

4.19 6.82

3

Al2 O3

4.64

19.98

4

SiO2

19.45

55.40

5

MgO

2.15

2.03

6

K2 O

0.76

1.92

7

Na2 O

0.22

0.61

8

Loss on ignition

2.76

2.41

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A. Singh et al.

2.2 Mix Proportioning Concrete mixes were prepared as per EFNARC specifications besides the BIS draft recommendations [20]. Grade = M30; water/binder (w/b) ratio = 0.44; total binder content = 450 kg/m3 ; fine aggregate = 900 kg/m3 ; coarse aggregate = 828 kg/m3 and SP = 5.85 kg/m3 , respectively. The replacement levels of OPC by FA = 5, 10, 15, 20 and 25% are given in Table 2.

2.3 Fresh Properties For the fresh properties of SCC, the tests were conducted: Slump flow (mm), Jring (mm), U-box (h2 /h1 ), V-funnel (s) and L-box (h2 /h1 ). The flowing ability was estimated by slump flow (higher slump flow shows a higher flowing ability). The passing ability was estimated by J-ring (higher the J-ring value shows poorer passing ability). The plastic viscosity was estimated by V-funnel time (higher V-funnel time shows higher plastic viscosity).

2.4 Hardened Properties The CS of concrete cubes was determined, as per the provisions contained in IS: 516-1959 [21]. The STS was determined by casting, curing and testing the cylinders, as per the provisions of IS: 5816-1999 [22]. To determine the FS, beams were cast, cured and tested, using two-point method on loading frame of capacity 500 kN at a loading rate of about 180 kg/min, without any shock, as per the provisions contained in IS: 516-1959 [21]. All the strength parameters were found at 7 and 28 days. The XRD and SEM analyses for referral and optimum SCC (FA20) were carried out for samples cured at 28 days.

2.5 XRD and SEM Analysis The XRD and SEM are the techniques used for phase identification and to obtain micrograph of the compounds present in concrete. The outcome of the microstructural studies of concrete gives a clear idea about the development and distribution of hydration products in the concrete sample.

w/b

0.44

0.44

0.44

0.44

0.44

0.44

Mixture details

Referral SCC

FA05

FA10

FA15

FA20

FA25

337.50

360.00

382.50

405.00

427.50

450.00

Cement (kg/m3 )

112.50

90.00

67.50

45.00

22.50

0.00

FA (kg/m3 )

Table 2 Mixture proportions and workability parameters

200

200

200

200

200

200

Water (kg/m3 )

740

730

715

710

690

680

Slump flow

8.7

9.0

9.5

10.0

11.0

11.5

V-Funnel

1.00

0.97

0.95

0.94

0.90

0.85

L-box

11.6

12.0

13.0

14.0

15.0

16.0

U-box

5.0

5.2

5.6

5.4

5.9

6.0

J-ring

Mechanical Performance of Self-compacting Concrete with … 15

Mix proportion

(a) Slump flow

1 0.9

10

0.8

8

0.7

6

0.6

Mix proportion

(b) L-box and V-funnel

30 25 20 15 10 5 0

U- Box J- Ring

10 8 6 4 2

J- Ring (mm)

12

1.1

U- box ( h2-h1) mm

V-funnel L-box

L-box ratio (h2/h1)

14

Refe… FA5 FA10 FA15 FA20 FA25

800 740 680 620 560 500

V-funnel time (sec)

A. Singh et al.

Referral FA5 FA10 FA15 FA20 FA25

Slump-flow (mm)

16

0

Mix proportion

(c) J-ring and U-box

Fig. 3 Workability parameters of SCC

3 Results and Discussion The constituent materials’ quantities and workability parameters of the SCC mixes investigated are presented in Table 2.

3.1 Fresh Properties The workability properties of fresh SCC incorporating FA are presented in Table 2. In this study, the w/b ratio is kept constant. The inclusion of FA increases the flowing and the passing abilities of SCC but decreases the plastic viscosity of SCC. The FA consisted of relatively large amount of spherical particles which decreased the water demand (Table 2 and Fig. 3), and induced a ball-bearing effect, increasing thereby the flowing ability and decreasing the plastic viscosity of the concrete. The fresh properties such as slump flow value, L-box value, V-funnel time, J-ring value and U-box value of the referral SCC are 680 mm, 0.85, 11.5 s, 6 mm and 16 mm, respectively. The changes in all the above fresh properties for optimum SCC, formed by replacement of 20% OPC by FA, are +50 mm, +0.12, −2.5 s, −0.8 mm and −4.0 mm, respectively. The variations in all the fresh properties of different SCC mixes are presented in Fig. 3a–c.

3.2 Hardened Properties The optimum replacement level of OPC by FA in SCC was 20% with respect to the CS. The values of different strength parameters for different SCC mixtures are presented in Table 3 and Fig. 4a–c. The maximum values of CS, STS and FS of SCC are found at optimum replacement level and these are higher by 15.51, 13.47 and 14.64%, respectively, in comparison to the referral SCC. This increase in strength

Mechanical Performance of Self-compacting Concrete with …

17

Table 3 Compressive strength (CS), split tensile strength (STS) and flexural strengths (FS) of SCC mixes Mixture details

CS (MPa)

STS (MPa)

FS (MPa)

7 Days

28 Days

7 Days

28 Days

7 Days

28 Days

Referral

26.34

38.67

3.21

4.60

4.90

7.24

FA5

26.34

41.67

3.15

5.06

4.88

7.50

26.00

43.34

3.05

5.11

4.85

8.06

26.00

44.00

2.88

5.17

4.80

8.20

FA20

25.67

44.67

2.80

5.22

4.76

8.30

FA25

25.00

43.34

2.59

5.18

4.68

7.96

7

7

28

Mix proportion

(a) CS ( at 7 and 28 days)

28

6 5 4 3 2 1 0

FS (MPa)

50 45 40 35 30 25 20 15 10 5 0

STS (MPa)

CS (MPa)

FA10 FA15

Mix proportion

(b) STS ( at 7 and 28 days)

9 8 7 6 5 4 3 2 1 0

7

28

Mix proportion

(c) FS (at 7 and 28 days)

Fig. 4 Different strength of SCC mixes at 7 and 28 days

parameters is because of the formation of additional CSH gel in concrete on addition of FA.

3.3 XRD and SEM Analyses of Referral and Optimum SCC Figures 5 and 6 show the XRD of the RSCC and OSCC, respectively, at 28 days. A higher peak of quartz (SiO2 ) and lower peak of calcium silicate hydrate (CSH) is observed in RSSC, while the opposite is observed in case of OSCC. The SEM analysis shows (Figs. 7 and 8) that the amount of calcium hydroxide (CH) present in RSCC is more than that in the OSCC, while the amount of CSH gel in OSCC is more than that in the RSCC. The decrease in CH content and increase in CSH gel in OSCC on addition of FA to RSCC, as observed in Figs. 5, 6, 7 and 8, are responsible for increase in all the strength parameters of SCC.

18 Fig. 5 XRD of RSCC at 28 days

Fig. 6 XRD of OSCC at 28 days

Fig. 7 SEM of RSCC at 28 days

A. Singh et al.

Mechanical Performance of Self-compacting Concrete with …

19

Fig. 8 SEM of OSCC at 28 days

4 Conclusions From the present work, the following are concluded: (i) The slump flow value of SCC mix increases with the FA content; (ii) The optimum replacement level of OPC by fly ash is 20% with respect to all the strength parameters; (iii) The compressive, split tensile and flexural strengths of optimum SCC at 28 days are higher by 15.51, 13.47 and 14.64%, respectively, in comparison to the referral SCC; (iv) A higher peak of CSH is found in optimum SCC than that in referral SCC; (v) The amount of CH is more while the amount of CSH gel is less in referral SCC in comparison to the optimum SCC.

References 1. H. Okamura, M. Ouchi, Self-compacting high performance concrete. Prog. Struct. Eng. Mater. 1, 378–383 (1998) 2. The European Guidelines for Self-compacting Concrete, Specification, Production and Use. Norfolk: The Self-Compacting Concrete European Project Group (2005) 3. Guidelines for Viscosity Modifying Admixtures for Concrete. Norfolk: The European Federation of Specialist Construction Chemicals and Concrete Systems (EFNARC) (2006) 4. M. Safiuddin, Development of self-consolidating high performance concrete incorporating rice husk ash. Ph.D. thesis, University of Waterloo, Canada (2008) 5. M. Geso˘glu, E. Güneyisi, E. Özbay, Properties of self-compacting concretes made with binary, ternary, and quaternary cementitious blends of fly ash, blast furnace slag, and silica fume. Constr. Build. Mater. 23, 1847–1854 (2009) 6. G. De Schutter, P. Bartos, P. Domone, J. Gibbs, Self-Compacting Concrete (Whittles Publishing, Caithness, Scotland, UK, 2008). 7. P.L. Domone, Self-compacting concrete: an analysis of 11 years of case studies. Cem. Concr. Compos. 28, 197–208 (2006) 8. B. Sukumar, K. Nagamani, R. Srinivasa Raghavan, Evaluation of strength at early ages of self-compacting concrete with high volume fly ash. Constr. Build. Mater. 22, 1394–1401 (2008)

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9. N. Bouzoubaâ, M. Lachemi, Self-compacting concrete incorporating high volumes of class f fly ash: preliminary results. Cem. Concr. Res. 31, 413–420 (2001) 10. J.M. Khatib, Performance of self-compacting concrete containing fly ash. Constr. Build. Mater. 22, 1963–1971 (2008) 11. R. Siddique, Properties of self-compacting concrete containing class F fly ash. Mater. Des. 32, 1501–1507 (2011) 12. D. Tripathi, R. Kumar, P.K. Mehta, A. Singh, Silica fume mixed concrete in acidic environment. Mater. Today Proc. 27(2), 1001–1005 (2020) 13. A. Singh, R. Kumar, P.K. Mehta, D. Tripathi, Effect of acidic environment on rice husk ash steel fibre reinforced concrete. Mater. Today Proc. 27(2), 995–1000 (2020) 14. D. Tripathi, R. Kumar, P.K. Mehta, A. Singh, Optimum dose of binary admixture in self compacting concrete. Int. J. Innov. Exploring Eng. 9(1), 103–108 (2019) 15. E. Koehler, D. Fowler, Aggregate in self-consolidating concrete. ICAR Project 108, International Center for Aggregates Research, The University of Texas at Austin (2007), p. 362 16. F. Christopher, A. Bolatito, S. Ahmed, Structure and properties of mortar and concrete with rice husk ash as partial replacement of ordinary Portland cement—a review. Int. J. Sustain. Built Environ. 6, 675–692 (2017) 17. D.S. Parveen, M.T. Junaid, B.B. Jindal, A. Mehta, Mechanical and microstructural properties of fly ash based geopolymer concrete incorporating alccofine at ambient curing. Constr. Build. Mater. 180, 298–307 (2018) 18. IS: 8112-1989, Specification for 43 Grade Ordinary Portland Cement. Bureau of Indian standards, New Delhi, India 19. IS: 383-1987, Specification for Coarse and Fine Aggregate from Natural Sources for Concrete. Bureau of Indian Standards, New Delhi, India 20. EFNARC-2002, Guidelines for Self-compacting Concrete (Association House, London, UK), pp. 32–34 21. IS: 516-1959, Methods of Tests for Strength of Concrete 22. IS: 5816-1999, Splitting Tensile Strength of Concrete-Method of Test

Studies on Infiltration Rate of Pervious Concrete Nune Srikanth and N. R. Dakshina Murthy

Abstract Concrete is the only material in the construction engineering for which the usage has been multifold over the last decade. Owing to rapid urbanization, there has been an increase in the consumption of construction materials by which the natural resources are depleting day by day. Porous concrete or no fines concrete or permeable concrete is known as special type of concrete which allows the water to penetrate through the concrete, thereby reducing the external runoff and boosting the ground water table. As pervious concrete has little to no fine aggregate, the voids of coarse aggregate particles will be filled by the cementitious paste to preserve the interconnectivity. The perviousness is the only parameter which indicates the penetrability of no fines concrete. Since the rate of infiltration depends upon pore sizes, geometry and interconnectivity of coarse aggregate, it exactly indicates the effectiveness of pervious concrete. To preserve the water quality for future generations, the pervious concrete can be used as sustainable construction practice. In the current study, the experiments were carried out with a constant water/cement, varying cement/aggregate and also varying size of aggregate in the total aggregate content. The compressive strength was determined for standard cubes of 150 × 150 mm. The falling head permeability apparatus was designed to determine the coefficient of permeability for various samples. The cylinder-shaped casts of 11 cm in diameter and 18 cm in depth were used to determine the rate of infiltration by conducting permeability test on pervious concrete. The mix proportion satisfying infiltration rate and strength properties is recommended as the sustainable pervious concrete. Keywords Pervious concrete · Rate of infiltration · Compressive strength · Permeability

N. Srikanth JNTUH, Hyderabad, India e-mail: [email protected] N. R. Dakshina Murthy (B) CBIT, Hyderabad, India e-mail: [email protected] © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021 S. Chandrasekaran et al. (eds.), Recent Advances in Structural Engineering, Lecture Notes in Civil Engineering 135, https://doi.org/10.1007/978-981-33-6389-2_3

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N. Srikanth and N. R. Dakshina Murthy

1 Introduction In Western countries to overcome the problem of runoff during heavy snowfall the pervious concrete can be used in various applications, like parking places, footpaths, play fields, subsurface of pavements, internal roads around residential buildings/apartments, commercial buildings etc. On comparing the cost analysis, India has an advantage of handling it at a very low cost as it does not require construction machinery which is done in Western countries; hence it can be a solution for rural pavements which also saves the overall cost of the project. As the need of the hour is sustainable construction, pervious concrete applications in countries like India can become more popular at the same time increasing the ground water levels and also permitting surface runoff. Parmar et al. [1] in his technical paper suggested that “the Pervious Concrete is more suitable for rural and urban areas to decrease the rainstorm water runoff, to upsurge the earth rainwater table and therefore it has become a strategy to mitigate a host of materials which are related to environment”. Swe et al. [2] conducted experimental investigation on penetrable concrete using reprocessed aggregate instead of natural aggregate and found that “there is an intensification in coefficient of perviousness and void content, at the same time there is a decrease in the compressive and splitting tensile strength”. Patil [3] observed through experimental investigations that the “compressive strength of pervious concrete increases as the water/cement ratio decreases up to optimum w/c ratio of 0.38. Compressive strength increases with increase in volume of paste”. Yadav et al. [4] in their technical paper discussed that “Pervious concrete is a cost-effective and environmentally friendly solution to support sustainable construction”. This type of concrete is a unique solution to control the surface runoff, improve the ground water table, efficient earth management and cost beneficial to answer the major problems in India pertaining to water logging which creates many ill health hazards to the surrounding people. Pervious concrete does a role of green buildings by improving the properties related to green technologies and the role of this concrete has a major part in Indian construction industry. Ajamu et al. [5] “investigated on the size of coarse aggregate that the smaller size of aggregate could able to produce a higher compressive strength and at the same time produce a higher permeability rate”. The mixtures with higher aggregate/cement ratio 8:1 and 10:1 are considered to be useful for a pavement that requires low compressive strength and high permeability rate. Also, in their studies on pervious concrete showed that “the compressive strength has increased by addition of 5% fine aggregates but the strength decreased with further with increase in percentage of fine aggregates”. Compressive strength decreased with increase in cement/total aggregate ratio. Obla [6] in his observations on pervious concrete concluded that “much of construction can be done manually without any heavy equipment and at a lower cost even in rural areas”.

Studies on Infiltration Rate of Pervious Concrete

23

2 Materials and Mix Design 2.1 Material Properties Cement Ordinary Portland cement of 53 grade was used for the investigation which is confirming to IS: 12269–2013. The physical properties of cement are shown in Table 1. Aggregates Coarse aggregate is locally available crushed granite from quarries and of fine aggregate. It was obtained from nearby river source [7, 8]. The physical properties of fine aggregates and coarse aggregates are shown in Tables 2 and 3, respectively. Table 1 Physical properties of cement SI. No.

Property

Test results

1

Standard consistency

35%

2

Specific gravity

3.02

3

Initial setting time

120 min

Final setting time

192 min

4

Fineness of cement

6%

Table 2 Physical properties of fine aggregates Property

Test results

Specific gravity

2.63

Fineness modulus

2.5

Table 3 Physical properties of coarse aggregates Property

Natural coarse aggregate 12.5 mm

20 mm

Specific gravity

2.65

2.75

Bulk density (g/cc)

1.4

1.5

Fineness modulus

7.0

7.20

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N. Srikanth and N. R. Dakshina Murthy

2.2 Mix Design Moulds Steel cylindrical moulds having 11 cm in diameter and 18 cm in height are designed to conduct permeability test on pervious concrete. Mix Proportions In order to attain sufficient strength and permeation level, the pervious concrete is typically premeditated considering more than 20% void content to permit quick percolation. In addition, the void ratio, w/c ratio of the mix also plays a dynamic role in improving the strength of pervious concrete. To attain the desired strength and durable pervious concrete, a moderate water/cement ratio has been adopted after conducting number of trial mixes. Low and high water/cement (w/c) ratio leads to adverse effects which are not desirable. Literature survey reveals that the w/c ratio ranging from 0.28 to 0.42 spectacles better aggregate coating for no fines concrete. The moisture content corrections in aggregate have to be done carefully in order to avoid errors in water/cement ratio as it plays a vital role in permeation and strength properties. The water/cement ratio of no fines concrete cannot be equated with conventional concrete. Cement content in a concrete mix plays a dynamic role in attaining the satisfactory mechanical properties of concrete. An insufficient cement content may lead to unsatisfactory results. Hence, optimum cement content plays a dynamic role in the design of pervious concrete and it depends on the gradation of aggregate but generally varies from 270 to 420 kg/m3 . Generally, the size of coarse aggregate varies from 10 to 20 mm. Mix can be designed using a single size aggregate or gradation. Tables 4 and 5 show the test results of seven days compressive strength using 20 and 12.5 mm size, respectively. As per the codal specifications [9], all the supplementary cementitious materials can be used in the concrete mix but there is no need of using chemical admixtures as the pervious concrete is having low workability. Therefore, retarding admixtures can be used as it delays the setting time of concrete. Viscosity enhancing agents are also beneficial as they can improve workability [10]. Measurement of Hydraulic Conductivity: Owing to the large number of voids in pervious concrete, we cannot compare its hydraulic conductivity with that of conventional concrete. Figure 1 shows falling head perviousness experimental setup. To measure the hydraulic conductivity, falling head permeability test procedure has been adopted. The setup was designed as shown in Fig. 2 using 180 mm lengthy steel Table 4 Seven days compressive strength using 20 mm aggregate w/c ratio

Agg/Cement ratio

Compressive strength (kg/cm2 )

0.42

7:1

34.50

0.42

8:1

21.80

0.42

10:1

18.80

Studies on Infiltration Rate of Pervious Concrete

25

Table 5 Seven days compressive strength using 12.5 mm aggregate w/c ratio

Agg/Cement ratio

Compressive strength (kg/cm2 )

0.42

7:1

47.80

0.42

8:1

21.50

0.42

10:1

18.70

Fig. 1 Falling head perviousness experiment arrangement

Fig. 2 Casting and curing of cylindrical specimens for infiltration

cylinder with an inner diameter of 110 mm, and a 50 mm diameter regulator joins the bottom part of the tube to an upright pipe through which water can trench out. This pipe is placed 10 mm above the uppermost part of the case so that no unsaturated stream occurs during the examination. A graduated steel tube of 300 mm length was attached to the topmost of the specimen assemblage and fastened firmly using a neoprene sleeve. This was used to observe the level of water during the examination. Table 6 shows the coefficient of permeability values for 20 mm aggregate size. Water was poured into the graduated tube to plug the sampling chamber and the draining conduit. The case was preconditioned by permitting H2 O to trench out through the conduit until the level in the graduated conduit was similar at the top of the trench tube. This jettisoned any air pockets in the sample and confirmed that the sample was fully waterlogged. With the regulator fastened, the graduated tube was

26

N. Srikanth and N. R. Dakshina Murthy

Table 6 Coefficient of permeability for 20 mm aggregate Agg/Cement ratio

w/c ratio

Coefficient of permeability (cm/s * 103 )

7:1

0.42

1.6

8:1

0.42

2.5

10:1

0.42

3.14

jam-packed with water. The regulator was then unlocked, and the period in seconds (t) necessary for water to drop from an original head of h1 to an ultimate head of h2 measured. The average value of time period for three trials has been calculated. Tables 7 and 8 show the number of specimens cast using 20 and 12.5 mm size aggregate and average infiltration rate (K) of pervious concrete (vs.) time. Experimental results of permeability are shown in Fig. 3. Using Darcy’s law the coefficient of permeability (K) is calculated as shown below:   h2 aL log10 K = 2.303 At h1 where A a t h1 and h2 L

area of sample in cm2 (95.033 cm2 ) area of standpoint pipe (0.950 cm2 ) time period in seconds is the original and ultimate head length of sample.

Table 7 Number of specimens cast using 20 and 12.5 mm size aggregate Mix proportions adopted w/c ratio = 0.42

Number of samples Aggregate size 12.5 mm

20 and 12.5 mm

1:7

3

3

1:8

3

3

1:10

3

3

Table 8 Average infiltration rate (K) of pervious concrete (vs.) time Mix proportions with w/c = 0.42

Average infiltration rate (K) of pervious concrete (cm/s)

Time (s)

1:7 with 12.5 mm aggregate

6.66 × 10−3

13.22

10−3

19.44

1:7 with 50% gradation of 12.5 and 20 mm aggregate

4.83 ×

1:8 with 50% gradation of 12.5 and 20 mm aggregate

10.91 × 10−3

11.67

1:8 with 12.5 mm aggregate

11.00 × 10−3

11.56

Studies on Infiltration Rate of Pervious Concrete

27

Fig. 3 Test results of permeability

2.3 Results and Discussions • The coarse aggregate properties are within the specified codal limits specified by ACI. • It was observed that as the size of coarse aggregate increased from 12.5 to 20 mm the compressive strength value decreased from 45 to 35%. • The coefficient of permeability value for aggregate/cement ratio of 10:1 with aggregate size 12.5 and 20 mm are 3.14 × 10−3 and 3.65 × 10−3 cm/s, respectively. • The material properties of coarse aggregate are within the range of values specified by ACI code. • The coefficient of permeability value for aggregate/cement ratio of 7:1 and 8:1 with aggregate size of 10 mm are 6.66 × 10−3 and 11.0 × 10−3 cm/s, respectively.

3 Conclusions 1. 2.

3. 4.

High permeability rate and compressive strength were observed for 12.5 mm size of coarse aggregate. As the aggregate/cement ratio increases, it was noticed that it has lower compressive strength even though it has higher permeability rate and such mixes can be recommended for pavement applications. Infiltration rate and compressive strength can be considered as vital parameters in pervious concrete. More research has to be done in the area of pervious concrete making an allowance for abrasion, impact resistance, traffic volume studies and vehicular loading.

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References 1. D.K. Parmar et al., Study on the engineering properties of pervious concrete. Int. J. Sci. Res. Eng. (IJSRE) 1(1), 1–7 (2017) 2. T.M. Swe et al., Properties of pervious concrete aiming for LEED green building rating system credits. Eng. J. 20(2), 61–72 (2016). ISSN: 0125-8281 3. P.K. Patil et al., Study on the properties of pervious concrete. Int. J. Eng. Res. Technol. (IJERT) 3(5), 819–822 (2014). ISSN:2278-0181 4. N.B. Yadav et al., Pervious concrete: solution for low cost construction. Int. J. Innov. Sci. Modern Eng. (IJISME) 1(10), 38–41 (2013). ISSN:2319-6386 5. S.O. Ajamu, Evaluation of structural performance of pervious concrete in construction. Int. J. Eng. Technol. (IJET) 2(5), 829–836 (2012). ISSN:2049-3444 6. K.H. Obla, Pervious concrete—an overview. Indian Concr. J. (ICJ), 10–18 (2010) 7. N. Srikanth, N.R. Dakshinamurthy, M.V. Seshagiri Rao, Basic studies on SCC using recycled aggregate. In: International Conference On Advances in Concrete, Structural & Geotechnical Engineering, February 2018, pp. 735-738. Bloomsbury India, New Delhi, ISBN:978-93-8747169-6 8. IS 2386-1963 (All parts), Methods of Tests for Aggregate of Concrete 9. IS 516-1959, Methods of Test for Strength of Concrete, 16th reprint, Jan 1976 10. A. Suchith Reddy, P. Rathish Kumar, P. Anand Raj, (2020) Development of sustainable performance index (SPI) for Self-Compacting Concretes. J. Building Eng. 27, 100974

Properties of Concrete with Bagasse Ash and Stone Dust Exposed to Sulphate Attack Pooja Jha, A. K. Sachan, and R. P. Singh

Abstract In recent studies, it has been found that sulphate attack (Sa) on the concrete is being a significant issue in the field of durable concrete structure. This paper focus on the effect of bagasse ash (Ba) and stone dust (Sd) on the strength performance of concrete exposed to the sulphate environment. Cement is partially replaced by 10% Ba by weight, and natural sand is partially replaced by Sd in proportions of 10, 20, 30, 40 and 50% to determine the compressive strength loss (CSL) by calculating the compressive strength (CS) after 180 and 365 days water curing and 10,000 ppm sulphate solution (SS) curing to access the durability. Results also include the characterization of the optimum concrete sample using the scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) techniques. Results show that % loss of Cs after 180 and 365 days were 7.52 and 12.03, respectively, when cubes cured in 10,000 ppm sodium sulphate solution. Ettringite was formed after 180 and 365 days when cubes cured in a sodium sulphate solution, which is the primary factor of sulphate attack that can be seen by the SEM analysis. Addition of 10% bagasse ash (Ba) and 40% stone dust (Sd) may significantly enhance the resistance to sulphate resistance. This sample 10Ba40Sd found to be an optimum sample as the strength is maximum and % loss of Cs is minimum after 180 and 365 days. Keywords Compressive strength · Sulphate solution · Durability · Ettringite · Optimum sample

1 Introduction Concrete is used as construction materials all over the world. India is a fast-developing country, and the rate of construction activity is increasing day by day. This requires a large quantity of cement and aggregates as they are the essential components of concrete. Large-scale CO2 emission during the production of cement causes environmental problems [1] and also extensive depletion of natural aggregates, as P. Jha (B) · A. K. Sachan · R. P. Singh Department of Civil Enginerring, Motilal Nehru National Institute of Technology, Allahabad 211004, India e-mail: [email protected] © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021 S. Chandrasekaran et al. (eds.), Recent Advances in Structural Engineering, Lecture Notes in Civil Engineering 135, https://doi.org/10.1007/978-981-33-6389-2_4

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P. Jha et al.

the consumption of aggregates is approximately 70% of concrete mix volume [2]. For making the cement and aggregates sustainable and resolving the environmental issues, there is a need for searching their equivalent alternatives. Ba may be used as partial replacement of cement and Sd can be used as partial replacement of natural sand (Ns). Durability is one of the major concerns in construction industries all over the world [3]. Sulphate attack on concrete becomes a focus of durability research in civil engineering [4], mainly because the sulphate ions reacts with the calcium hydroxide Ca(OH)2 and calcium aluminate hydrates to form gypsum and ettringite [5]. Sulphate attack is influenced by many factors, such as type of binder [6, 7], the water-to-binder ratio [8], concrete porosity [9], period, condition and concentration of sulphate exposure [10–12] and participant cation [13], which influence the degradation that resulted from sulphate attack; therefore, it is very a complicated phenomenon. Many researchers have worked on the influence of sodium sulphate solution concentration on the performance of concrete before and after sulphate attack [14] and also on the damage process of concrete exposed to sulphate attack [15–17].

2 Experimental Program 2.1 Materials Used Cement Ordinary Portland cement of 43 grade was used in this investigation. The specifications were as per IS 269:2013 [18], and the physical properties of cement were determined in the structural lab of MNNIT, Prayagraj, Uttar Pradesh. The consistency, specific gravity, initial setting time and final setting time were 27%, 3.13, 37 min and 443 min, respectively. The characterization of cement was performed using the XRD, SEM and EDS techniques and has been reported [19]. Coarse Aggregates Crushed aggregates of size 20 and 10 mm (in the ratio 60:40) were used in the research work, and the test procedures were as per IS 383:2016 [20]. The fineness modulus was 6.7, and the specific gravity of 20 and 10 mm size aggregates was 2.76 and 2.65, respectively. Fine Aggregates Natural sand was used as fine aggregates, and the test procedures were as per IS 383:2016 [20]. The fineness modulus, specific gravity and water absorption of fine aggregates were 2.80, 2.60 and 1%, respectively. Water Water used for cleaning and mixing of concrete cubes was as per IS 456:2000 [21]. Bagasse Ash Ba was collected from the sugar mill near Balrampur city, Uttar Pradesh, India. The specific gravity (2.16) was determined in the structural laboratory, MNNIT, Allahabad and characterization of this ash was done by using XRD, SEM and EDS analyses, and the same has been reported [19] .

Properties of Concrete with Bagasse Ash and Stone Dust Exposed …

31

Table 1 Details of CS for 28 days water curing Mix No.

Name

1.

Control mix 100

Cement (%) Bagasse ash (%) Fine aggregate (%) Stone dust (%) 0

2.

5Ba

95

5

100

0

3.

10Ba

90

10

100

0

4.

15Ba

85

15

100

0

5.

20Ba

80

20

100

0

6.

25Ba

75

25

100

0

7.

10Ba10Sd

90

10

90

10

8.

10Ba20Sd

90

10

80

20

9.

10Ba30Sd

90

10

50

30

10.

10Ba40Sd

90

10

60

40

11.

10Ba50Sd

90

10

50

50

100

0

Stone Dust It was collected from the crushing unit of Lucknow and collected in a dry state. The fineness modulus, specific gravity and water absorption were 2.92, 2.45 and 1.1%, respectively, and the test procedure as per IS 383:2016 [20].

2.2 Concrete Sample Preparation Mix proportions were calculated as per IS 10262-2009 [22], and M25 grade of concrete with 0.45 water/cement ratio was used after preparing trail mixes. Initially, six mixes were prepared for 28 days testing by replacing cement with 0, 5, 10, 15, 20 and 25% Ba. Control mix consists of 0% replacement of cement with Ba and 0% replacement of fine aggregates with stone dust (0Ba0Sd) and other five mixes with 10% Ba replacement and varying the percentage of Sd 10%, 20%, 30%, 40% and 50% in order to get optimum level. Fine aggregates were partially replaced by Sd. Table 1 shows the details of the design mix designations of various concrete samples.

2.3 Methods Compressive Strength In this investigation, CS of concrete was determined after 180 and 365 days water curing using the cubes of size 150 mm in the universal testing machine as per IS Code 516:1959 [23]. Sulphate Resistance CS of concrete was determined after 180 and 365 days sulphate solution curing using the cubes of size 150 mm as per ASTM C 452-02 [24].

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P. Jha et al.

10,000 ppm sodium sulphate solution was taken for the analysis. Sulphate attack (Sa) was determined by calculating the CSL. SEM and EDS Analyses The samples were prepared by drying it for 1 day at a temperature of 110 °C to remove the moisture content. Sieve the samples using 300 µ and store in airtight bags. The SEM and EDS analyses were performed using the CARL ZEISS EVO 50 SEM instrument at IIT Kanpur. The chemical compositions were determined by EDS along with elemental mapping.

3 Results and Discussion 3.1 Compressive Strength (CS) Initially, the compressive strength of concrete was determined for 7 and 28 days when cement is partially replaced by Ba in proportions of 0, 10, 15, 20 and 25% by weight, respectively, in concrete, and it was observed that CS was maximum at 10% replacement by Ba. Therefore, the optimum replacement level of Ba was 10%. After attaining the optimum percentage, compressive strength was determined with 10% Ba (fix) along with 10, 20, 30, 40 and 50% replacement of sand with Sd. Results indicate that strength increases up to 40% replacement by Sd, and the same has been reported [25]. Details of Cs are as shown in Table 2. Percentage Loss of Compressive Strength (CSL) Cubes of size 150 mm were immersed in the sodium sulphate solution at the concentration of 10,000 ppm and Table 2 Details of CS for 28 days water curing Mixes

Average compressive strength (N/mm2 ) 7 days

28 days

Control mix

28.29

34.64

5Ba

27.66

33.62

10Ba

28.72

35.38

15Ba

25.29

30

20Ba

23.50

28.36

25Ba

20.26

26.79

10Ba10Sd

25.9

33.01

10Ba20Sd

26.01

33.86

10Ba30Sd

27.88

34.18

10Ba40Sd

29.98

36.34

10Ba50Sd

28.01

35.44

Properties of Concrete with Bagasse Ash and Stone Dust Exposed …

33

Fig. 1 Comparison of CS (N/mm2 ) of concrete at 180 and 365 days when cured in water and cured in 10,000 ppm SS

tested for strength after 180 and 365 days using Ba and Sd in concrete. After that, CSL was determined to access the performance of Sa. It was observed that the CS was slightly higher in the case of cubes cured in water than cubes cured in sulphate solution (10,000 ppm) and is shown in Fig. 1. The CS of control mix for 180 days was found to be 40.11 N/mm2 (water curing) and 36.45 N/mm2 (10,000 ppm SS curing), and after 365 days, it has 43.01 N/mm2 (water curing) and 36.42 N/mm2 (10,000 ppm SS curing). Lee et al. [26] have reported that the total strength loss will be higher in concrete specimens without pozzolanic material compared to those with pozzolanic materials. The compressive strength of 10Ba40Sd sample was found to be 41.22 N/mm2 (water curing) and 38.12 N/mm2 (10,000 ppm SS curing) after 180 days and 45.01 N/mm2 (water curing) and 39.59 N/mm2 (10,000 ppm SS curing) after 365 days. The CS was observed maximum in this sample. Percentage loss in compressive strength of the control mix was 10.24 and in 10Ba40Sd sample was 7.52 after 180 days. After 365 days, the percentage loss in CS of control mix was 15.3 and in 10Ba40Sd sample was 12.03. Strength and loss in compressive strength after 365 days was slightly higher than the CS and strength loss seen after 180 days. The minimum loss for 10Ba40Sd sample obtained after 180 and 365 days was 7.52 and 12.03%, respectively. Minimum CSL was found for 10Ba40Sd at 180 days compared with the compressive strength of water curing as well as SS curing.

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Fig. 2 SEM image of 10Ba40Sd sample with magnification of 6.00 KX when sample cured in sulphate solution and tested for 365 days

3.2 SEM and EDS Analyses The characterization of 10Ba40Sd concrete sample after 180 and 365 days was done using the SEM and EDS techniques. The clear quality image of the surface of the optimum concrete sample (10Ba40Sd) at 365 days when 10,000 ppm sulphate solution concentration was used is shown in Fig. 2. This figure shows a needle-like structure known as ettringite in samples which is the main cause of sulphate attack. Needle-like crystal structure of ettringite has been found by many researchers [27]. Batic et al. [28] studied the ettringite forms in SS with the passage of time. For EDS analysis, the SEM image of 10Ba40Sd concrete sample when sample cured in 10,000 ppm sulphate solution and tested for 365 days is shown in Fig. 3, which shows particles of optimum concrete mix (10Ba40Sd) containing mainly oxygen, silicon, calcium, aluminium, iron, sulphur and so on.

4 Conclusions The following conclusions can be derived from various experimental results obtained in the investigation: 1.

CS had reached higher values when cement was replaced with 10% Ba, and fine aggregates were replaced with 40% Sd. so, these are the optimum replacement level (10Ba40Sd mix).

Properties of Concrete with Bagasse Ash and Stone Dust Exposed …

35

Fig. 3 EDS images show particles of concrete mix (10Ba40Sd) when sample cured in sulphate solution and tested for 365 days

2.

3.

4.

5.

CS was highest at 10Ba40Sd concrete sample after 365 days in 10,000 ppm concentration of SS, but this strength was slightly less than the strength of the control mix. Highest strength (39.59 N/mm2 ) was shown in 10,000 ppm sulphate solution. The CSL was minimum for 10Ba40Sd mix sample for 180 and 365 days when cubes cured in water and 10,000 ppm sulphate exposure. In the case of 10,000 ppm sulphate solution, 10Ba40Sd sample has been found best from the durability point of view as well as the strength point of view. The SEM image of the optimum concrete sample (10Ba40Sd) shows a needlelike structure which conforms the ettringite formation, which shows the sulphate attack on the sample at 180 and 365 days. EDS shows the elemental composition of the particle of optimum concrete mix (10Ba40Sd) which contains mainly oxygen, silicon, calcium, aluminium, iron, sulphur and so on.

Acknowledgements The authors are grateful to the Director of MNNIT, Prayagraj for contributing necessary help and support required. One of the authors, Ms. Pooja, a research scholar, is also thankful to MHRD, New Delhi for providing financial assistance for research work.

References 1. J. Zhang, G. Liu, B. Chen, D. Song, J. Qi, X. Liu, Analysis of CO2 emission for the cement manufacturing with alternative raw materials: a LCA-based framework. Energy Procedia 61, 2541–2545 (2014)

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2. J. Zuquan, S. Wei, Z. Yunsheng, J. Jinyang, L. Jianzhong, Interaction between sulphate and chloride solution attack of concretes with and without fly ash. Cem. Concr. Res. 37(8), 1223– 1232 (2007) 3. W.G. Hime, B. Mather, “Sulphate attack”, or is it? Cem. Concr. Res. 29(5), 789–791 (1999) 4. E.E. Hekala, E. Kishar, H. Mostafa, Magnesium sulphate attack on hardened blended cement pastes under different circumstances. Cem. Concr. Res. 32, 1421–1427 (2002) 5. C. Karakurt, ˙IB. Topçu, Effect of blended cements produced with natural zeolite and industrial by-products on alkali-silica reaction and sulphate resistance of concrete. Constr. Build. Mater. 25(4), 1789–1795 (2011) 6. A.M. Diab, M.A. Abd Elwahab, H.E. Elyamany, M. Abd Elmoaty, Guidelines in compressive strength assessment of concrete modified with silica fume due to magnesium sulphate attack. Constr. Build. Mater. 36, 311–318 (2012) 7. Z. Tang, W. Li, G. Ke, J.L. Zhou, V.W. Tam, Sulphate attack resistance of sustainable concrete incorporating various industrial solid wastes. J. Cleaner Prod. 218, 810–822 (2019) 8. J.K. Chen, M.Q. Jiang, Long-term evolution of delayed ettringite and gypsum in Portland cement mortars under sulphate erosion. Constr. Build. Mater. 23(2), 812–816 (2009) 9. Q. Zhou, J. Hill, E.A. Byars, J.C. Cripps, C.J. Lynsdale, J.H. Sharp, The role of pH in thaumasite sulphate attack. Cem. Concr. Res. 36(1), 160–170 (2006) 10. E.E. Hekal, E. Kishar, H. Mostafa, Magnesium sulphate attack on hardened blended cement pastes under different circumstances. Cem. Concr. Res. 32(9), 1421–1427 (2002) 11. M. Heidari-Rarani, M.R.M. Aliha, M.M. Shokrieh, M.R. Ayatollahi, Mechanical durability of an optimized polymer concrete under various thermal cyclic loadings—an experimental study. Constr. Build. Mater. 64, 308–315 (2014) 12. R.S. Gollop, H.F.W. Taylor, Microstructural and microanalytical studies of sulphate attack. I. Ordinary Portland cement paste. Cem. Concr. Res. 22(6), 1027–1038 (1992) 13. P. Liu, Y. Chen, Z. Yu, Z. Lu, Effect of sulphate solution concentration on the deterioration mechanism and physical properties of concrete. Constr. Build. Mater. 227, 116641 (2019) 14. J.B. Wang, D.T. Niu, Y.L. Zhang, Mechanical properties, permeability and durability of accelerated shotcrete. Constr. Build. Mater. 95, 312–328 (2015) 15. E. Roziere, A. Loukili, R.E. Hachem, Durability of concrete exposed to leaching and external sulphate attacks. Cem. Concr. Res. 39, 1188–1198 (2009) 16. N.M. Al-Akhras, Durability of metakaolin concrete to sulphate attack. Cem. Concr. Res. 36, 1727–1734 (2006) 17. W.Y. Ouyang, J.K. Chen, M.Q. Jiang, Evolution of surface hardness of concrete under sulphate attack. Constr. Build. Mater. 53, 419–424 (2014) 18. IS, B. C., 269-2013, Ordinary Portland Cement, 33 Grade—Specification (2013) 19. P. Jha, A.K. Sachan, R.P. Singh, Microstructure analysis of concrete: using bagasse ash waste as partial replacement of cement. Indian J. Environ. Prot. 40(3), 269–275 (2020) 20. BIS, I., IS 383-2016: Specification for Coarse and Fine Aggregates from Natural Sources for Concrete (2016) 21. BIS, I., 456: 2000. Plain and Reinforced Concrete Code of Practice. Bureau of Indian Standards, Fourth Revision (2000) 22. Proportioning-Guideline, I. S. C. M., IS 10262: 2009. Bureau of Indian Standards, New Delhi (2009) 23. IS, B. C., 516-1959. Code of Practice for Methods of Tests for Strength of Concrete (2002) 24. ASTM C 452-02, Standard Test Method for Potential Expansion of Portland Cement Mortars Exposed to Sulphate. ASTM International, United States (2002) 25. A.K. Sahu, S. Kumar, A.K. Sachan, Crushed stone waste as fine aggregate for concrete. Indian Concr. J. 87(1), 845–848 (2006) 26. S.T. Lee, H.Y. Moon, R.N. Swamy, Sulphate attack and role of silica fume in resisting strength loss. Cem. Concr. Compos. 27(1), 65–76 (2005)

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27. Portland Cement Association, Ettringite Formation and the Performance of Concrete (No. 2166). Portland Cement Association (2001) 28. O.R. Batic, C.A. Milanesi, P.J. Maiza, S.A. Marfil, Secondary ettringite formation in concrete subjected to different curing conditions. Cem. Concr. Res. 30(9), 1407–1412 (2000)

Torque and Twist Response of High-Grade Concrete Beams with “U” Jacketing of Ferrocement Gopal Charan Behera

Abstract Designers are more interested in strength of structures at cracking rather than ultimate stage. Evaluation of torque and twist of high strength concrete distressed beams with “U” wrap made by ferrocement has been presented here. These parameters are evaluated by experimental and analytical method. The above two methods are not providing quick solutions, rather the first one is based on destruction of prototype structure for evaluation of strength. To overcome this, soft computing methods have been employed. Two methods MARS and WASPAS are employed here to compute the torsional strength of “U” wrapped beams. These two methods provide quick solutions to estimate the torque and twist at cracking. The predicted values by these methods are within the acceptable limits. The cracking torque is found to be increased by 40.94% when a ferrocement “U” wraps is provided without any reinforcement in the core. With reinforcement in the core, this value increased to 47.22% and twist also increased significantly. This proves the efficacy of ferrocement “U” wrap on outer periphery. Keywords Torque at cracking · Twist at cracking torque · “U” wrap of ferrocement · WASPAS

1 Introduction Torsion is one of the basic structural loads. It occurs in two forms, either primary or secondary torsion. Torsion occurs in the structures either individually or with combination of other structural loads. Concrete is the most common construction material. The distressed structural concrete elements need to be repaired rather than demolition. Repair of concrete with addition of other materials is required to reinforce concrete against its low tensile strength and poor toughness. Repair can be done with epoxy, steel jacket or FRP. Karayannis et al. [1] found availability of labour, duration of time and cost may make a decision on type of the retrofitting material. In recent G. C. Behera (B) Government College of Engineering Kalahandi, Bhawanipatna, Odisha 766002, India e-mail: [email protected] © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021 S. Chandrasekaran et al. (eds.), Recent Advances in Structural Engineering, Lecture Notes in Civil Engineering 135, https://doi.org/10.1007/978-981-33-6389-2_5

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past FRP is used as a good retrofitting material for concrete structures and enhances the strength reasonably. Retrofitting for torsion may require full jacketing. In some of the cases this full jacket may not be possible. This may be due to connection of upper portion of beam with lower portion of slab. A significant research on FRP with full jacket for torsional retrofitting has been carried out [2]. With FRP “U” wrap some investigations were carried out and it has been found that there is significant improvement in strength [2, 3]. The deteriorated structures must be retrofitted rather demolishing. Retrofitting must be economic. The retrofitting process should be easy and practicable. Time of repair may be another factor. All these factors are fulfilled when a ferrocement wrap is taken into consideration. According to ACI Committee [4], this material is easily flowable, impermeable, durable and possess higher strength. Investigation by Shannag and Mourad [5] shows that ferrocement has the ability to arrest microcracks.

1.1 Research Significance Shear and bending are induced due to torsion. Shear is better registered by closed stirrups. So, if a closed loop in the form of wrap is provided, it will be more beneficial to resist torsion. The study by Salom et al. [6] presents a solution for torsional strength of closed FRP wraps. Always full wrap is not practicable. Investigation by Behera et al. [7] provides solution of “U” wrap. Determination of torque and twist of “U” wrap by experimental and analytical method is found from the works of Behera et al. [8, 9]. The various works mentioned above prove that ferrocement can be a wrapping material in place of FRP. No such single equation is derived from the experimental results to predict torque and twist at cracking of RC beams of different sections or with different materials. Analytical method is tedious and timeconsuming to predict the torsional strength. This challenge inspired to find a solution to predict cracking torque and twist with easy methods. Here, with the help of soft computing, solution is found out. The output of the present study is to determine torsional parameters such as torque and twist at cracking of RC beams with higher grade concrete.

2 Methods to Predict Torque and Twist 2.1 Experimental Program Beams tested by the author during his doctoral program are taken into consideration. Cross-sections of all beams are of 125 mm wide and 250 mm depth. Length of the beams is 2 m. Details of beams and material properties are given in Table 1. Figure 1 presents the cross-section and torsion test rig.

L4H

T4H

U4H

U

L

T

C

3

4

5

6

7

8

Co4H

To4H

Lo4H

BO4H

2

Designation

BH

Series

1

S. No.

55 55 55 55 55 55

125 × 250

125 × 250

125 × 250

125 × 250

125 × 250

125 × 250 60

60

60

60

60

60

60

55

125 × 250

Concrete (MPa)

60

Ferrocement matrix (MPa)

125 × 250

Dimensions (mm)

Table 1 Beam designation and material properties

6 nos., 12 mm

6 nos., 6 mm

6 nos., 12 mm

6 nos., 6 mm

“–”

6 nos., 12 mm

“–”

“–”

440

350

440

350

“–”

440

“–”

“–”

2 legged,10 mm @ 70 mm c/c

2legged,10 mm @ 70 mm c/c

2 legged, 6 mm @ 70 mm c/c

2 legged, 6 mm @ 70 mm c/c

2 legged 10 mm @ 70 mm c/c

“–”

“–”

“–”

Diameter, spacing

No. of bars, diameter

Yield strength (MPa)

Transverse steel

Longitudinal steel

445

445

350

350

445

“–”

“–”

“–”

Yield strength (MPa)

4

4

4

4

4

4

4

No. of mesh layers

Torque and Twist Response of High-Grade Concrete Beams … 41

42

G. C. Behera Transverse Reinforcement in Core Concrete

Reacon End Loading End Twist measuring meters Jack

Ferrocement with 3 or 4 or 5 numbers of mesh layer

Transverse Reinforcement in Core Concrete

West East end

Translaon only

Load cell

Rotaon only

Dial Gauge for Twist mt.

Tinius-Olsen m/c.

Fig. 1 Beam cross-section and torsion testing

2.2 Analytical Model With the help of softened truss model and applying modifications in material properties, the author has developed an analytical model which was fully covered [8, 9].

2.3 Soft Computing Method Experimental method employed to evaluate torque and twist at cracking is a timetaking process as demolition of specimen is involved. Analytical method requires computational procedure. To overcome these problems, soft computing method can play a vital role.

2.3.1

Multivariate Adaptive Regression Spline (MARS)

In MARS method, some experimental results are taken for fitting and others are used for testing. Simple equations were developed by multivariate adaptive regression spline (MARS) to predict the desired parameters. No such basic assumptions are required for this method. So, sometimes it is known as black box method. The performer is unable to find the relation between various parameters. This model is the outcome of research work by Friedman [10]. With the help of MARS, final equations for torque and twist at cracking were found as mentioned below: C racking = max (0, yield strength of long. steel-350) * 0.00154 + 5.5324 − max (0.350-yield strength of transverse steel) * 0.0002689 + max (0, mortar strength40) * 0.0680449 + max (0, spacing) * 0.0012240-max (0, 40-mortar strength) * 0.0206587.

Torque and Twist Response of High-Grade Concrete Beams …

43

θ Cracking (rad/m) = max (0, yield strength of long. steel-350) * 0.0000008816 + 0.0053610664 + max (1.62926-Area of long. Ferrocement steel) * 0.0002050043 − (40-mortar strength) * 0.0000723768.

2.3.2

WASPAS Method

Weighted aggregated sum product assessment (WASPAS) method for solving multicriteria decision-making (MCDM) problems was suggested by Zavadskas et al. [11]. The procedure is the combination of weighted sum method (WSM) and weighted product method (WPM). The various steps of WASPAS procedure are taken from Madic et al. [12, 13] and Zavadskas et al. [11]. Step 1. Initialization of matrix. Step 2. Apply normalization to matrix using maximization and minimization criteria xi j = xi j / max xi j

(1)

xi j = min xi j

(2)

i

i

where x ij, assessment value of the ith alternative with respect to jth criterion. Step 3. Calculation of total relative importance of ith alternative, Q i(1) =

n 

xi j .w j

(3)

j=1

Step 4. Application of WPM method next to find Q i(2) =

n 

w

xi j j

(4)

j

Step 5. Calculation of optimum value Q i = λ.Q i(1) + (1 − λ).Q i2

(5)

Consider the values of λ from 0 to 1.0. In general, it takes a value of 0.5. Table 2 presents the experimental and predicted values of torque and twist at cracking.

44

G. C. Behera

Table 2 Experimental and predicted torque and twist at cracking Beams Cracking torque (kNm) BOH

Cracking twist (rad/m)

Ext

Analytical MARS WASPAS Expt

4.61

Analytical MARS

WASPAS

NA

4.61

NA

0.00280

NA

0.00280 0.00448

BO4H 6.50

6.52

6.46

6.42

0.00546

0.00560

0.00536 0.00448

L4H

6.79

NA

6.69

6.64

0.00582

NA

0.00582 0.00530

T4H

6.59

NA

6.54

6.61

0.00569

NA

0.00569 0.00500

U4H

6.42

6.52

6.42

6.55

0.00541

0.00548

0.00536 0.00523

Lo4H

6.68

6.52

6.78

6.71

0.00539

0.00521

0.00544 0.00539

To4H

6.62

6.52

6.64

6.58

0.00540

0.00531

0.00536 0.00567

Co4H

6.72

6.52

6.78

6.74

0.00541

0.00505

0.00544 0.00583

3 Interpretation of Test Results After obtaining experimental and predicted values by different methods, errors in predicted values are estimated to observe the suitability of these methods for evaluation of torsional capacity.

3.1 General Behaviour of High Strength Beams Tested beams are similar to BOH. These beams are provided with some amount of reinforcement in core concrete. Beam BOH was a high strength beam of M60 grade concrete without any reinforcement and tested under pure torsion. Beam BO4H was cast with a ferrocement “U” wrap of 25 mm thick with four numbers of mesh layers and no reinforcement in core concrete. Cracking torque is controlled by cross-section and material properties of beam. Longitudinal reinforcement in RC structures also controls the cracking torque. A reinforced beam may be having reinforcement in longitudinal or in transverse direction only known as singly type reinforcement. Singly type reinforced beams can be treated as plain beams as they lack one load carrying element. In this investigation L4H is having only longitudinal reinforcement and T4H has only transverse reinforcement. U4H, Lo4H, To4H and Co4H were cast with reinforcement in both directions.U4H is an under-reinforced beam, as it is having reinforcement in both directions less than a balanced beam. Completely overreinforced beam Co4H is having more reinforcement than a balance section in both longitudinal and transverse directions. Lo4H is longitudinally over-reinforced while To4H is transversely over-reinforced. So, the beams with all six states of torsion, control specimen as BOH and BO4H were covered here. First crack was initiated on longer face in all the beams. As torsion induces shear, cracks are found to be 45°.

Torque and Twist Response of High-Grade Concrete Beams …

45

3.2 General Behaviour of High Strength Beams The beam BOH when tested under pure torsion failed with a singly potential crack initiated on longer face. The beam could not sustain any further torque beyond cracking. Cracking torque of beam depends on amount of longitudinal reinforcement, and maximum increase was up to 5% over plain beams. But when the beams are provided with “U” wraps, the cracking torque was found to be increased much more. Cracking torque of beam BOH was 4.61 kNm, while the same was found to be experimentally 6.50, 6.79, 6.59, 6.42, 6.68, 6.62 and 6.72 kNm for BO4H, L4H, T4H, U4H, Lo4H, To4H and Co4H, respectively. Figure 2 presents the details of the torque found experimentally and predicted by different methods. Cracking torque is more dependent on grade of concrete and mortar rather than reinforcement present in cross section. The percentage of error in predicted values of cracking torque and increase in cracking torque with respect to control specimen BOH and BO4H were presented in Fig. 3. The maximum errors in analytical, MARS and WASPAS were found to be 2.92, −1.45 and −2.18%, respectively. As the error was within 3%, we can utilize these methods in evaluation of cracking torque of high strength beams. The percentage of increase of cracking torque of Co4H, To4H, Lo4H, U4H and BO4H over plain beam BOH was found to be 45.63, 43.50, 44.73, 39.31, 47.22 and 40.94, respectively. This proves the efficacy of ferrocement “U” wrap. Beam BO4H without any reinforcement in core was able to enhance cracking strength up to 40.94% over plain beams. The percentage of increase in cracking torque of Co4H, To4H, Lo4H, U4H, BO4H over plain ferrocement “U” wrap beam BO4H was found to be 3.33, 1.82, 2.69, -1.16, 1.38 and 4.46, respectively. The increase in cracking torque of these reinforced beams was found to be within 4.46% which is below 5%. The same has been observed by Behera [14].

Fig. 2 Experimental and predicted cracking torque of high strength beams

46

G. C. Behera

Fig. 3 Percentage of error predicted cracking torque and percentage increase in cracking torque over BOH and BO4H of high strength beams

3.3 Twist at Cracking Torque of High Strength Beams The effect of reinforcement on twist at cracking torque of high strength ferrocement “U” wrap beams is discussed in this section. When a plain beam BOH was taken, it was able to sustain a twist of 0.0028 rad/m. But when the same BOH beam was jacketed, the beam BO4H was able to rotate up to 0.00546 rad/m with high cracking torque. The beams with reinforcement in core concrete were able to undergo twist of 0.005820, 0.00569, 0.00541, 0.00539 and 0.00540 rad/m, respectively, for beams L4H, T4H, U4H, Lo4H, To4H and Co4H. The predicted values obtained by MARS, WASPAS and analytical method were presented in Fig. 4. The percentage of error in predicted values and increase in twists with respect to control specimen were presented in Fig. 5. Maximum errors in predicted values by analytical method, MARS and WASPAS were found to be −6.6, −1.8 and −18%, respectively, for ferrocement “U” wrap beams. The twists at cracking torque of ferrocement “U” wrap beams BO4H, L4H, T4H, U4H, Lo4H, To4H and Co4H were found to be enhanced by 95, 107.8, 103.2, 93.1, 92.4, 92.9 and 93.1% over plain beam BOH, respectively. This proves the effectiveness of “U” wraps. The enhancement of twist of L4H, T4H, U4H, Lo4H, To4H and Co4H over control specimen BO4H was very nominal. The maximum value was found to be 6.6%.

Torque and Twist Response of High-Grade Concrete Beams …

47

Fig. 4 Experimental and predicted twist at cracking torque of high strength beams

Fig. 5 Percentage of error in predicted twist at cracking torque and percentage increase in twist over BOH and BO4H of high strength beams

48

G. C. Behera

4 Conclusions Cracking torques and twists are presented here for RC “U” wrapped high strength beams with and without reinforcement using four methods. From the above results, the following conclusions were drawn. Plain “U” Wrapped Beams • There is an increase of 47.22% in cracking torque of ferrocement “U” wrap RC high strength beam over its unwrapped beam. The amount of increase in cracking torque justifies the importance of a “U’ wrap on periphery. • Core concrete and ferrocement shell controls the cracking torque of “U” wrapped beams. “U” Wrapped Reinforced Concrete Beams • The increase in cracking torque due to longitudinal reinforcement is marginal. • Singly type reinforcement in the core is unable to enhance torsional parameters like torque and twist at cracking. • The enhancement of cracking torque is maximum for completely over-reinforced beams and the value is more than 47.22% over unwrapped beam. • There is significant enhancement of cracking twist for high strength ferrocement “U” wrap beams over their unwrapped beams. • The predicted results are well in agreement with experimental values. MARS and WASPAS methods can be employed for evaluation of cracking torque and twist.

References 1. C.G. Karayannis, C.E. Chalioris, G.M. Sirkelis, Local retrofit of exterior RC beam-column joints using thin RC jackets—an experimental study. Earthquake Eng. Struct. Dynam. 37–5, 727–746 (2008) 2. S. Panchacharam, A. Belarbi, Torsional behavior of reinforced concrete beams strengthened with FRP composites, in Proceedings of First FIB Congress, Osaka, Japan, 2002, pp. 1–11. 3. C.E. Chalioris, Torsional strengthening of rectangular and flanged beams using carbon fibrereinforced-polymers—experimental study. Constr. Build. Mater. 22(1), 21–29 (2008) 4. ACI Committee 549. Ferrocement-Materials and Applications. ACI Symposium Proceedings SP-61: American Concrete Institute 549, 1979, Farmington Hills, Michigan 5. M.J. Shannag, S.M. Mourad, Flowable high strength cementations matrices for ferrocement applications. Constr. Build. Mater. 36, 933–939 (2012) 6. P.R. Salom, J.R. Greeley, Y.T. David, Torsional strengthening of spandrel beams with fiberreinforced polymer laminates. J. Compos. Constr. ASCE 157–162 (2004) 7. G.C. Behera, T.D.G. Rao, C.B.K. Rao, Torsional capacity of high strength concrete beams jacketed with ferrocement U wraps. Asian J. Civ. Eng. 9(4), 411–422 (2008) 8. G.C. Behera, T.D.G. Rao, C.B.K. Rao, Analytical model for torsional response of RC beams strengthened with ferrocement U-Wraps. Struct. Eng. Int. 4, 509–520 (2014)

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9. G.C. Behera, T.D.G. Rao, C.B.K. Rao, A study on post cracking torsional behaviour of high strength reinforced concrete beams with ferrocement “U” wraps. Slovak J. Civ. Eng. 1–12 (2014) 10. J. Friedman, Multivariate adaptive regression splines. Ann. Stat. 19, 1–141 (1991) 11. E.K. Zavadskas, Z. Turskis, J. Antucheviciene, A. Zakarevicius, Optimization of weighted aggregated sum product assessment. Elektron. Elektrotech. 122, 3–6 (2012) 12. M. Madi´c, V. Gecevska, M. Radovanovi´c, D. Petkovi´c, Multicriteria economic analysis of machining processes using the WASPAS method. J. Prod. Eng. 17, 1–6 (2014) 13. M. Madic, J. Antucheviciene, M. Radovanovic, D. Petkovic, Determination of manufacturing process conditions by using MCDM methods: application in laser cutting. Eng. Econ. 27, 144–150 (2016) 14. G.C. Behera, A model to predict the torsional stiffness of ‘U-wrapped’ reinforced concrete beams. Struct. Build. Proc. Inst. Civ. Eng. 171(9), 676–687 (2018)

Stress–Strain Behaviour of Self-consolidated Processed Recycled Aggregate Concrete Nune Srikanth, N. R. Dakshina Murthy, and M. V. Seshagiri Rao

Abstract Self-consolidating concrete (SCC) is considered as a special concrete that streams and strengthens by its self-weight and passes through the congested reinforcement without any segregation and mechanical vibration. In the recent era, a bombastic amount of construction and demolition (C&D) scrap produced from deteriorated structures and ready mix concrete plants is creating a severe environmental pollution. This has encouraged the reuse of C&D scrap as aggregates in concrete. Utmost investigation was carried out on the consumption of recycled coarse aggregate (RCA) in self-consolidating concrete. In the present study an experimental investigation has been carried to develop SCC mixes of standard grades M35 and M45 using unprocessed and processed RCA at different percentage replacements of natural coarse aggregate (NCA) (0, 25, 50, 75 and 100% by weight) as per Nan-Su method. The processing of RCA is done using Deval’s abrasion testing machine for different number of revolutions. Fresh properties of SCC were determined by means of slump-flow, L-box and V-funnel. The perfunctory properties such as compressive strength and stress–strain behaviour were determined. It has been observed that the usage of processed recycled coarse aggregate obtained higher compressive strength compared with unprocessed recycled coarse aggregate in SCC. The portion of recycled aggregate content increase has shown that the peak stresses are lower and their corresponding strains are higher. From the experimental findings it has been noticed that the processing of recycled aggregate up to 500 revolutions and 50% replacement of natural aggregate showed the optimum results. Keywords Self-consolidating concrete · Unprocessed recycled coarse aggregate · Reprocessed coarse aggregate · Stress–strain behaviour N. Srikanth JNTUH, Hyderabad, India e-mail: [email protected] N. R. Dakshina Murthy (B) Hyderabad, India e-mail: [email protected] M. V. Seshagiri Rao Hyderabad, India e-mail: [email protected] © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021 S. Chandrasekaran et al. (eds.), Recent Advances in Structural Engineering, Lecture Notes in Civil Engineering 135, https://doi.org/10.1007/978-981-33-6389-2_6

51

52

N. Srikanth et al.

1 Introduction Self-consolidating concrete (SCC) is a specialized type of concrete, characterized by its high flowability and resistance to segregation. It was originated in Japan by Okamura in the late 1980s. This specialized concrete originally was developed to compensate the growing shortage of skilled labour and has many advantages like reduction in work force, smooth surface finishes, easier placing, thinner concrete sections, reduced sound levels, no vibration, improved durability and safe working environment. In the recent years, production of construction and demolition (C&D) scrap and consumption of naturally available materials in the construction sector have been growing due to rapid industrialization and infrastructural developments. Both of these aspects create serious ecological and environmental problems. Safiuddin et al. [1] conducted a thorough review on the utilization of recycled aggregate in concrete and suggested that use of this material as a substitute of natural coarse aggregate to produce fresh concrete appears to be a possible solution. Santos et al. [2] proved that the recycled coarse aggregate (RCA) can serve as a viable substitute to natural coarse aggregate (NCA) for different incorporation ratios. Panda et al. [3] from their experimental investigations concluded that presence of old mortar attached with original aggregates is one of the main reasons that RCA has lower density, low specific gravity, larger water absorption and smaller mechanical strength than the NCA. Rao et al. [4] in their technical paper stated that the density of recycled aggregate concrete (RAC) is less than that of concrete with virgin aggregates which can be used where the lightweight concrete is preferred in the structures. Silva et al. [5] observed that the production of self-consolidating concrete using recycled aggregate and supplementary cementitious materials is eco-friendly and environmentally sustainable. Revathi et al. [6] in their technical paper suggested that as the percentage of RCA in SCC mixes increases an additional content of superplasticizer is to be added to maintain enough flow ability, filling ability and passing ability according to EFNARC-2005 specifications. Satish et al. [7] from their studies on SCC using RCA concluded that certain percentage utilization of RCA can improve economic and environmental aspect in construction industry. Rao et al. [8] found that recycled aggregate suits better to achieve self-consolidating concrete mixes without any reduction in strength. Bhikshma et al. [9] conducted experimental investigations on stress–strain curves for recycled aggregate concrete and concluded that nondimensional zed theoretical stress–strain curve almost matches with experimental curves. Belen et al. [10] witnessed that longitudinal strain of the recycled aggregate concretes improved with the amplified percentage of recycled coarse aggregate (RCA) and the shape of stress–strain curves of recycled aggregate concrete is nearly matching with traditional concrete. The objective of this study is to investigate the stress–stain behaviour of recycled aggregate self-consolidating concrete through substituting the normal coarse aggregate through recycled coarse aggregate (RCA) at various replacement levels in both processed and unprocessed state.

Stress–Strain Behaviour of Self-consolidated Processed …

53

2 Experimental Program 2.1 Cementitious Materials The cement utilized was ordinary Portland cement of 53 grade confirming to IS 269:2015 [11]. Fly ash was bought from Kakatiya thermal power plant (KTPP) and confirmed to Class-F.

2.2 Aggregates Fine aggregate used was obtained from a nearby river source conforming to IS 383:2016 (zone II) [12]. The source of natural coarse aggregate is from granite quarries. RCA used in this study was obtained from the concrete scrap available at concrete technology lab of our institute.

2.3 Superplasticizer Superplasticizer mainly influences the flow characteristics of the self-consolidating concrete. Superplasticizer used was CAC-Hyper fluid R100 of poly-carboxylic ether based, a product by Concrete Additives & Chemicals Pvt. Ltd.

2.4 Mix Proportions Standard grade SCC mixes M35 and M45 grade of concrete were produced as per Nan-Su method. The mix proportions are later adjusted as per EFNARC-2005 specifications [13] to suit to the requirements of fresh and hardened properties. The mix proportions of SCC are as shown in Table 1. Table 1 Mix proportions of RASCC Mix designation

Cement (kg/m3 )

Fine aggregate (kg/m3 )

Coarse aggregate (kg/m3 )

Fly ash (kg/m3 )

Water (kg/m3 )

SP (kg/m3 )

M35

373

880

802

135

188

5.5

M45

395

899

792

122

182

5.68

54

N. Srikanth et al.

2.5 Preparation of Specimens Concrete mixes were prepared under laboratory conditions. Tests were conducted on RASCC mixes to determine fresh properties like flow test, L-box and V-funnel. After testing the RASCC mixes in fresh state the concrete moulds were cast in 3 No. of 150 mm cubes and 3 No. of 150 × 300 mm cylinders. They were de-moulded a day after casting and were cured in water at 27 °C for 28 days. The cylindrical specimens were tested under axial compression by capping with a thin layer of Plaster of Paris. The cube specimens were used to obtain the compressive strength and cylindrical specimens for stress–strain characteristics. Test procedure: The cylindrical specimen of 150 mm diameter and 300 mm height which was capped; compressometer consisting of two axial strain gauges (G1 and G2), with a gauge length of 200 mm, were installed at the centre of the specimens. The strain devices have minimum count of 0.02 mm. The two axial strain gauges were 180° a part from each other and tested in compression using 200 tons capacity compression testing machine (CTM) under strain rate control in accordance with IS 516 [14] to develop the stress–strain characteristics.

2.6 Green Properties of RASCC Flow test, L-box test and V-funnel test were performed in the laboratory to find filling ability, passing ability and segregation resistance [15–18]. The results of fresh properties of RASCC mixes are shown in Tables 2, 3 and 4.

3 Results and Discussion 3.1 Compressive Strength The results on compressive strength of RASCC mixes were presented in Table 5. Figures 1 and 2 facilitate easy comparison of the RASCC mixes results. It is witnessed that the intensification in compressive strength of cube specimens for 28 days is obtained at 50% replacement of NCA with RCA and later on there is a decrease in strength from 50 to 100% replacement of NCA with RCA in both unprocessed and processed states. For M35 grade of concrete the increase in strength in unprocessed state is 50.86 MPa; similarly, in processed state for 500 revolutions, it is 51.32 MPa and in processed state for 1000 revolutions, it is 52.61 MPa. For M45 grade of concrete the increase in strength in unprocessed state is 53.61 MPa; similarly, in processed state for 500 revolutions it is 54.47 MPa and in processed state for 1000 revolutions it is 53.80 MPa. By comparing strength results of processed state (1000

5

2

4

5

25%

50%

75%

100%

6

5

4

4

600

610

600

630

620

630

640

635

3

2

3

4

6

4

4

3

620

720

680

700

600

640

650

670

2

3

3

4

6

4

2

3

640

705

655

720

610

680

650

650

% of NCA Unprocessed state Processed state (500 R) Processed state (1000 R) replaced by T (cm) Slump diameter (mm) T (cm) Slump diameter (mm) T50 (cm) Slump diameter (mm) 50 50 RCA M35 M45 M35 M45 M35 M45 M35 M45 M35 M45 M35 M45

Table 2 Slump flow test results of M35 and M45 grade in unprocessed and processed state

Stress–Strain Behaviour of Self-consolidated Processed … 55

56

N. Srikanth et al.

Table 3 V-funnel test results of M35 and M45 grade in unprocessed and processed state % of NCA replaced by RCA

Unprocessed state

Processed state (500 R)

T5mins

T5mins

Processed state (1000 R) T5mins

M35

M45

M35

M45

M35

M45

25%

10

12

11

11

11

11

50%

15

12

15

13

12

10

75%

18

11

18

14

18

18

100%

20

15

19

15

19

14

Table 4 L-box test results of M35 and M45 grade in unprocessed and processed state % of NCA replaced by RCA

Unprocessed state

Processed state (500 R)

Processed state (1000 R)

Blocking ratio (H2 /H1 ) Blocking ratio (H2 /H1 )

Blocking ratio (H2 /H1 )

M35

M45

M35

M45

M35

M45

25%

0.71

0.82

0.75

0.87

0.76

0.80

50%

0.72

0.81

0.73

0.85

0.72

0.82

75%

0.70

0.84

0.74

0.81

0.74

0.81

100%

0.70

0.80

0.69

0.82

0.68

0.85

Table 5 Compressive strength of M35 and M45 grade of concrete Mix designation

M35 Grade of concrete

M45 Grade of concrete

Average compressive strength (N/mm2 ) @ 28 days

Average compressive strength (N/mm2 ) @ 28 days

Unprocessed Processed Processed Unprocessed Processed Processed state state (500 state (1000 state state (500 state (1000 R) R) R) R) Control mix

48.07

RASCC-25

46.24

RASCC-50

50.86

RASCC-75

–

–

53.43

–

–

51.90

49.55

49.60

53.17

52.40

52.61

51.32

53.61

54.47

53.80

43.74

50.83

48.32

51.06

52.14

51.90

RASCC-100 36.91

45.18

490

50.51

50.00

50.80

revolutions), processed state (500 revolutions) and unprocessed state, it is observed that processed recycled coarse aggregate (500 revolutions) obtained greater strength values than the unprocessed recycled coarse aggregate as well as processed recycled coarse aggregate (1000 revolutions). This is due to the removal of adhered cement mortar present on the recycled coarse aggregate by abrasion which decreases the water absorption and increases the strength of concrete.

Stress–Strain Behaviour of Self-consolidated Processed …

57

Fig. 1 Variation of compressive strength for various replacement levels of RCA (unprocessed state and processed state) for M35 and M45 grade of concrete

3.2 Stress–Strain Curves Figure 2 illustrates that the peak stress of the RASCC mixes and the corresponding peak strain of the RASCC mixes increases and decreases with the increasing percentage replacement of RCA. The typical stress–strain curves of RASCC mixes are as shown in Fig. 2.

4 Conclusions In this technical study, experimental results for the stress–strain behaviour of selfconsolidating concrete with recycled coarse aggregate in unprocessed and processed state were presented and discussed. From this research, the following conclusions can be drawn. • Abrasion treatment of recycled coarse aggregate produces good results in terms of enhancement of properties, especially removal of adhered mortar content on the surfaces of RCA, and consequently on their water absorption. • From the observations recorded in the current examination, the fresh properties of unprocessed and processed mixes have decreased with the increase of recycled coarse aggregate content. • The densification strength of unprocessed and processed mixes decreased with an increase in RCA content. By comparing the strength results of processed and unprocessed state, it was observed that processed recycled coarse aggregate gained greater strength values than the unprocessed recycled coarse aggregate. This may be due to the deletion of bonded cement motor present on the recycled coarse aggregate by abrasion which decreases the water absorption and increases the strength of concrete.

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Fig. 2 Variation of stress–strain curves for various replacement levels of RCA (unprocessed state and processed state) for M35 and M45 grade of concrete

• The peak stress of RASCC blends is inferior to that of control mix. It decreases as the RCA content increases, and the corresponding peak strains of RASCC mixes are high when compared with control mix. • There is an urgent need to mandate the practice of reprocessed coarse aggregates in IS codal stipulations to save the natural coarse aggregates and at the same time to protect the nature. • It is concluded that the processing of recycled aggregate up to 500 revolutions and 50% replacement of natural aggregate showed optimum results. However, this percentage could change depending on the properties of the materials used in the

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concrete mixtures, the design mixture and the type and amount of superplasticizer used in the mixtures.

References 1. M. Safiuddin, A review on use of recycled concrete aggregate in concrete. J. Civ. Eng. Manage. 19(6), 796–810 (2013). ISSN 1392-3730. https://doi.org/10.3846/13923730.2013.799093 2. S.A. Santos, Mechanical performance evaluation of self-consolidating concrete with fine and coarse recycled aggregates from the precast industry. Materials 10, 904 (2017). https://doi.org/ 10.3390/ma10080904 3. K.C. Panda, Properties of SCC using recycled concrete aggregate, in Elsevier Journal, 3rd Nirma University International Conference on Engineering, Ahmadabad. https://doi.org/10. 1016/j.proeng.2013.01.023 4. M. ChakradharaRao, Influence of field recycled coarse aggregate on properties of concrete. Mater. Struct. 44, 205–220 (2011). https://doi.org/10.1617/s11527-010-9620-x 5. Y.F. Silva, Properties of self-consolidating concrete on fresh and hardened with residue of masonry and recycled concrete. Constr. Build. Mater. 124, 639–644 (2016) 6. P. Revathi, Investigations on fresh and hardened properties of recycled aggregate self consolidating concrete. J. Inst. Eng. India Ser. A (August–October 2013) 94(3), 179–185. https://doi. org/10.1007/s40030-014-0051-5 7. K. Satish, Fly ash induced self consolidating concrete with recycled concrete aggregate. Int. J. Mech. Solids 9(2), 151–168 (2017). ISSN 0973-1881 8. K. JagannadhaRao, Flexural behavior of reinforced self-consolidating concrete beams with recycled aggregate. J. Struct. Eng. 39(4), 393–398 (2012) 9. V. Bhikshma, Development of stress–strain curves for recycled aggregate concrete. Asian J. Civ. Eng. (Build. Housing) 11(2), 253–261 (2010) 10. G.-F. Belen, Stress–strain relationship in axial compression for concrete using recycled saturated coarse aggregate. Constr. Build. Mater. 25, 2335–2342 (2011) 11. IS 269: 2015 Ordinary Portland Cement-Specifications 12. IS 383: 2016 Specification for Coarse and Fine Aggregates for Concrete 13. EFNARC, Specification and guidelines for self-compacting concrete, European Federation of Producers and Applicators of Specialist Products for Structures, May 2005 14. IS 516-1959, Methods of test for strength of concrete, 16th reprint, Jan-1976 15. C. Sumanth Reddy, Recycled aggregate based self consolidating concrete (RASCC) for structural applications, in RN Raikar Memorial International Conference &Dr. Suru Shah Symposium on Advances in Science & Technology of Concrete 16. IS 2386-1963 (All parts), Methods of tests for aggregate of concrete 17. Specification for coarse and fine aggregate for concrete, IS 383:2016, Bureau of Indian Standards, New Delhi, India, January 2016 18. Ordinary Portland Cement-Specification, IS 269:2015, Bureau of Indian standard, New Delhi, December, 2015

Study of Compressive Strength of Self-compacting Concrete Using Rice Husk Ash and Nano Silica as a Partial Replacement to Cement: A Comparative Study Vijay Kumar, Shashi Ranjan Pandey, and Aman Kumar Abstract Self-compacting concrete do not require shaking even in packed reinforcement as it gets compressed under its own load. But the biggest question is its durability and economy. When these mineral admixtures are replaced by a part of the Portland cement, then the self-compacting concrete’s cost will decrease proportionally by reducing the heat of hydration. But there is a question on durability as this decreases the alkalinity on concrete and hence increases the risk of corrosion in the reinforcement. This paper shows an experimental investigation on aspects like compressive strength and durability by measuring the cube strength and carbonation depth. The methodology adopted is that cement has been partially replaced with the rice husk without any nano-silica and with 2% of nano-silica by weight of cement with a varying percentage of 0, 5, 10, 15, 20, 25 and 30%. The following conclusions are made such that the best possible dose of superplasticizer and mineral admixture increased the flowing property of concrete and met the requirements of construction industries. The improvements in the flowing and the filling ability of the self-compacting concrete were detected. The compressive strength of concrete without nano-silica enhances after pozzolanic reaction up to 20% replacement with RHA at an age after 60 and 90 days. Addition of nano-silica further improved the compressive strength of concrete on all ages. However, there was a question on the durability as the concrete gets more vulnerable to corrosion because carbonation depth on concrete with nano-silica is more than concrete without nano-silica. From this point of view, the more economical self-compacting concrete design can be developed by incorporating reasonable amounts of rice husk ash and nano-silica provided if proper attention regarding durability aspects is taken into consideration. Keywords Rice husk ash (RHA) · Nano-silica (NS) · Self-compacting concrete (SCC) · Compressive strength

V. Kumar (B) · A. Kumar RTCIT, Ranchi, Jharkhand, India e-mail: [email protected] S. R. Pandey NIT Jamshedpur, Jamshedpur, Jharkhand, India © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021 S. Chandrasekaran et al. (eds.), Recent Advances in Structural Engineering, Lecture Notes in Civil Engineering 135, https://doi.org/10.1007/978-981-33-6389-2_7

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1 Introduction Development of self-compacting concrete (SCC) is an achievement in the building industry to overcome troubles in the cast-in-situ concrete in congested reinforcement. A self-compacting concrete should have the properties like self-compaction under its own weight, homogenous throughout the placing of the concrete and easily flowable via congested reinforcement. There is no requirement of skilled workers for placing self-compacting concrete which is not affected by the dimension and the number of reinforcing rods or the structural arrangement. Because of its high fluidity and nonsegregating nature it can be pumped over to large distances. However, heat of hydration generated is more due to high content of cement also prone to plastic shrinkage. Addition of RHA makes the concrete economical but durability of concrete gets affected. In most cases RC structures does not perform adequately due to improper design, bad construction, inadequate materials selection, severe environment or a combination of all actors. In concrete the major problem is steel’s corrosion. The structure’s failure because of reinforcement corrosion affects the structural serviceability characterised by concrete cracking and also leads to collapse of the structure. Durability of concrete is the property of concrete to withstand a long duration of time without any deterioration. Steel’s corrosion is one of the most important problem of durability in RC structures. Presence of chloride, carbonation of concrete and permeability of concrete are also responsible for corrosion of rebar in RC structures. Formation of carbonic acid due to consumption of alkaline material in concrete through ingress CO2 from atmosphere in the presence of moisture takes place and is known as carbonation. Most of the RC structures are affected by concrete’s carbonation and steel’s corrosion, though with different rate depending upon the exposure condition, quality of work and material used. In concrete the carbonation takes place due to the presence of calcium-bearing phases that are attacked by CO2 from atmosphere which changes to CaCO3 . The cement paste contains about 25–50 wt% calcium hydroxide (Ca(OH)2 ) making the concrete alkaline having pH = 13, which yields a shielding layer (passive coating) to the steel reinforcement against corrosion. A fully carbonated paste has a pH of about 7. At about pH 11 loss of passivity takes place. The atmospheric carbon dioxide causing concrete’s carbonation leads to reduction of pH. Carbonation process requires water’s availability because CO2 after dissolving in water forms H2CO3 . If the concrete is very dry with relative humidity (RH) < 40%, then CO2 can’t dissolve and hence no carbonation can occur. If, on the other hand, it is wet with RH > 90% then CO2 will not enter the concrete and the carbonation process won’t occur. For the carbonation to occur the optimal conditions are at RH of 50% (varying between 40 and 90%).

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2 Proposed Methodology and Discussion The paper is based on experimental results of the mechanical characteristics of SCC after adding RHA as partial replacement of cement with or without nano-silica and its durability. The experimental method involves the casting of cubes (of dimension (150 mm × 150 mm × 150 mm)) for the M30 grade concrete on the basis of the Indian standard method to find the concrete’s compressive strength for different proportion of RHA varying from 0, 5, 10, 15, 20, 25 to 30%, with and without 2% of nano-silica. For the mix design of M30 grade concrete Nansu mix design method [1] has been used.

3 Material Characteristics Cement: Ordinary Portland cement (OPC) of 53-grade Coromandal King Brand, obtained from INDIA Cements Pvt. Ltd (Jamshedpur) was used conforming to IS 12269-2013 [2] for the chemical composition of OPC 53 (Table 1). Aggregate: These are collected from the local market of Jamshedpur and are tested according to Indian standard procedure confirming to “IS383-1970” [3]. Size of aggregate is 20 and 10 mm down. The 20 mm down aggregate is taken as 65% and 10 mm down aggregate is taken as 35% to get maximum density (Table 2). Mineral admixture: With controlled burning of the rice husk between 550 and 700 °C the incinerating temperature for about 10–12 h converts the silica content into an amorphous state possessing cementatious property. For this work the RHA Table 1 Typical properties of OPC 53 grade cement S. No.

Properties

Results obtained

IS: 12269-2013 Specifications

1

Fineness retained on IS sieve 90 µ

1.9%

–

2

Soundness (mm)

3.85

10 (max)

3

Normal consistency

33%

–

4

Initial setting time (min)

87

30 (min)

5

Final setting time (min)

315

600 (max)

6

3 days compressive strength (MPa)

25.4

27

7

7 days compressive strength (MPa)

38.2

37

8

28 days compressive strength (MPa)

57.3

53

9

Specific gravity

3.04

3.15

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Table 2 Typical properties of aggregate S. No.

Property

Fine aggregate

Coarse aggregate

1

Specific gravity

2.46

2.78

2

Fineness modulus

2.63

6.66

3

Water absorption (%)

1.66

0.15

4

Free moisture content (%)

1.57

0.24

5

Silt content

3.17%

–

6

Bulk density (kg/m3 )

1448

1565

7

Aggregate impact value

–

12.14

8

Aggregate crushing value

–

13.10

Table 3 Chemical composition of RHA S. No.

Particulars

Proportion (%)

1

Silicon dioxide

87.64

2

Aluminium oxide

0.26

3

Iron oxide

0.14

4

Calcium oxide

0.38–2.15

5

Magnesium oxide

0.27–0.65

6

Sodium oxide

0.15–0.83

7

Aluminium oxide

0.25

8

LOI

6.85

is being obtained from BMW Industry, Jamshedpur (Jharkhand) having particle size finer than 20 µ and specific gravity 2.33 (Table 3). Chemical admixture: PCE-based admixture with viscosity-modifying agent (VMA), i.e., MasterGlenium SKY 8567 is used (Table 4).

4 Experimental Test and Result Slump Flow Test: The test is performed without any obstruction to determine the horizontal flow of concrete. It provides good evaluation of the filling ability. This test also determines the resistance against segregation. According to EFNARC the slump flow should lie between 650 and 800 mm. Figure 1 shows that slump flow increases up to 10% replacement of RHA. RHA in little proportion acts as a ball bearing which enhances the flow ability. With further increase of RHA proportion the flow ability decreases due to higher surface area of RHA because of which it absorbs more water. EFNARC guideline for SCC was fulfilled up to 20% replacement of RHA.

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Table 4 Mix proportion of different mix with and without nano-silica % RHA

Cement (kg/m3 )

Fine aggregate (kg/m3 )

Coarse aggregate (kg/m3 )

Water (kg/m3 )

SP dose (kg/m3 )

RHA (kg/m3 )

No. of cubes

0%

482.25

832.6

731.37

192.5

5.73

0

21

5%

467.19

832.6

731.37

192.5

5.73

23.06

21

10%

436.13

832.6

731.37

192.5

5.73

47.12

21

15%

412.06

832.6

731.37

192.5

5.73

73.18

21

20%

365.01

832.6

731.37

192.5

5.73

95.24

21

25%

362.95

832.6

731.37

192.5

5.73

121.3

21

30%

346.89

832.6

731.37

192.5

5.73

145.36

21

% RHA

% NS

Cement (kg/m3 )

Fine aggregate (kg/m3 )

Coarse aggregate (kg/m3 )

Water (kg/m3 )

SP dose (kg/m3 )

RHA (kg/m3 )

No. of cubes

0

2

472.61

832.6

731.37

192.5

5.73

0

21

5

2

457.84

832.6

731.37

192.5

5.73

23.06

21

10

2

427.46

832.6

731.37

192.5

5.73

47.12

21

15

2

403.81

832.6

731.37

192.5

5.73

73.18

21

2

357.70

832.6

731.37

192.5

5.73

95.24

21

2

355.69

832.6

731.37

192.5

5.73

121.3

21

30

2

339.95

832.6

731.37

192.5

5.73

145.36

21

728

747

763

733

683

624

0%

5%

10%

15%

20%

25%

slump flow in (mm)

20 25

800 600 400

567 30%

Mix of (RHA+2%NS) in percentage…

Fig. 1 Slump flow value of different mix

Fig. 2 V-funnel value for different mix

V-Funnel test: It is performed to calculate the concrete’s filling ability. The flow down time taken by the concrete is recorded. If the concrete indicates segregation then the flow time will rise very significantly. As per EFNARC the V-funnel value should lie between 8 and 12 s.

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Figure 2 shows that flow time decreases for all ages but up to 20% replacement of RHA and the EFNARC guideline for SCC was fulfilled. L-Box test: The test evaluates the flow of the concrete, and calculates the degree to which it is subjected to blocking by reinforcement. According to EFNARC the ratio (H2 /H1) should lie between 0.8 and 1. Figure 3 shows that with the increase in % of RHA as partial replacement of cement, the result of L-box, i.e., the ratio (H2 /H1) decreases. However, up to 20% replacement of RHA the EFNARC guideline for SCC was achieved. Compressive strength: Cubes of size 150 mm of M30 grade with W /C = 0.35 and superplasticizer dose of 1.2% were casted for different proportions of RHA; then they are cured and tested at the following ages of 7, 28, 60 and 90 days maturity as per “IS:516-1959” [4]. Table 5 shows that the compressive strength reduces with % rise in the cement’s replacement with RHA at all ages. However, at 20% replacement with RHA the target mean strength was achieved which is due to pozzolanic reaction (Figs. 4 and 5). Table 6 shows that the compressive strengths increase with % rise in replacement of cement with RHA and 2% of nano-silica at all ages. However, at 20% replacement with RHA and 2% of NS, the strength achieved was maximum which is due to pozzolanic reaction.

Fig. 3 L-Box value of different mix

Table 5 Compressive strength test result for all ages with RHA % RHA

7-day strength (N/mm2 )

28-day strength (N/mm2 )

60-day strength (N/mm2 )

90-day strength (N/mm2 )

0

26.25

39.14

39.18

39.20

5

26.05

38.48

38.47

39.10

10

25.25

37.36

37.87

37.95

15

22.28

33.45

37.35

37.65

20

18.45

33.11

36.65

37.48

25

11.78

18.33

21.34

23.25

30

9.36

14.45

17.46

19.64

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Fig. 4 Compressive strengths of M30 grade of concrete

Fig. 5 Compressive strength of M30 grade of concrete

Table 6 Compressive strength test result for all ages (RHA + 2% nano-silica) % RHA

% nano-silica

7-day strength (N/mm2 )

28-day strength (N/mm2 )

60-day strength (N/mm2 )

90-day strength (N/mm2 )

0

2

27.25

39.54

39.98

40.20

5

2

27.05

39.48

39.77

40.10

10

2

26.25

38.36

39.37

39.95

15

2

23.26

34.45

38.34

39.65

20

2

19.46

34.19

37.67

38.493

25

2

12.78

19.33

22.34

24.29

30

2

10.39

15.49

18.48

20.68

Durability test of concrete Carbonation “Carbonation is a chemical process that slowly alters the structure of the concrete in the course of time and induces changes into its physical and chemical properties”. Carbonation chamber is utilised in the research work to obtain the accelerated carbonated condition in order to evaluate the carbonation depth or the depth till which carbon dioxide can penetrate through the cube during the exposure period in chamber with provided condition. Euro code for carbonation is followed for the carbonation of concrete. Carbonation chamber condition maintained during the testing period of 70 days is as follows. CO2 concentration = 4% ± 0.5% Temperature = 20 °C ± 5 °C. Relative humidity = 55 ± 5% (Figs. 6 and 7; Tables 7 and 8).

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Fig. 6 Carbonation chamber

Fig. 7 Carbonated cubes after applying phenolphthalein

Table 7 Carbonation depth of various compositions with RHA as partial replacement with cement after 90 days carbonation Fly ash replacement

0%

5%

10%

15%

20%

25%

30%

Carbonation depth (mm)

5.3

10.5

13.9

18

23.3

27.4

29.6

Table 8 Carbonation depth of various compositions with (RHA + NS) as partial replacement with cement after 90 days carbonation Fly ash replacement

0%

5%

10%

15%

20%

25%

30%

Carbonation depth (mm)

8.8

11.7

16.8

20.7

26.7

31.4

34.5

5 Conclusion Based on the experimental investigations and analysis, the following conclusions are made: 1.

Incorporating RHA as a partial replacement of cement we can make an economical self-compacting concrete. At the same time, the strength gets further

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2. 3.

4. 5.

69

enhanced because of the addition of nano-silica that fills the gaps arranging the particles in more compact manner, thus increasing the density of concrete. Partial replacement of cement by RHA and nano-silica resists the thermal cracks generated due to hydration of cement and makes the concrete durable. The partial replacement of cement by RHA and nano-silica chemically reacts with calcium hydroxide in moisture’s presence to convert it into C-S-H gel and improves the transition zone which is the weakest link of the concrete. Use of RHA and nano-silica increases the packing density of concrete which result in impervious concrete. Carbonation depth increases with the addition of RHA and nano-silica at all ages, which affects the durability and there is occurrence corrosion in reinforcement. If members of structure are constructed.

References 1. P. Sulapha, S.F Wong, T.H. Wee, S. Swaddiwudhipong, Carbonation of concrete containing mineral admixtures. J. Mater. Civ. Eng. 134–143 (2003) 2. IS: 12269-2013, Specifications of Ordinary Portland Cement 53 Grade, Bureau of Indian Standards, New Delhi 3. IS: 383 (1970) Specification for coarse and fine aggregate from natural sources for concrete. Bureau of Indian Standards, New Delhi 4. IS: 516 (1959) Indian standard code of practice—methods of test for strength of concrete. Bureau of Indian standards, New Delhi (India) 5. S.H. Mahure, V.M. Mohitkar, Effect of rice husk ash on fresh and hardened properties of self compacting concrete. Int. J. Sci. Eng. Res. 7(5), 833–839 (2015) 6. B. Chatveera, P. Lertwattanaruk, Durability of conventional concrete containing black rice husk ash. J. Environ. 1(92), 59–66 (2010) 7. H. Thanh, S. Thanh, N. Guyena, Study on high-performance fine-grained concrete containing rice husk ash. Int. J. Concrete Struct. Mater. 8(4), 301–307 (2014) 8. S.P. Arredondo-Rea, R. Corral-Higuera, J.M. Gómez-Soberón, J.H. Castorena-González, V. Orozco-Carmona, J.L. Almaral-Sánchez, Carbonation rate and reinforcing steel corrosion of concretes with recycled concrete aggregates and supplementary cementing materials. Int. J. Electrochem. 7, 1602–1610 (2012) 9. N. Su, K.-C. Hsu, H.-W. Chai, A simple mix design method for self-compacting concrete. Cement Concrete Res. 33(2), 1799–1807 (2001) 10. RILEM CPC-18 Measurement of Carbonation Depth, Recommendations for the Testing and Use of Constructions Materials 56–58 (1988)

Analysis and Design of Structures

Bayesian Finite Element Model Updating Without Requirement of Mode-Matching and Sub-structuring of System Matrices Ayan Das and Nirmalendu Debnath

Abstract Sub-structuring of structural system matrices is an important procedure in a typical finite model updating process. The conventional approach of Bayesian model updating is observed to depend on the procedure of sub-structuring of system matrices to a great extent. Without this procedure, detailed formulation for the expression of updated parameters is difficult to obtain in Bayesian framework especially without requirement of mode matching. But sub-structuring is not an easy task to perform in case of complex structures where it is not always easy to write computer program for FE modelling of such structures. Besides, sub-structuring procedure does not yield satisfactory results in case of updating parameters such as geometric properties like depth, width of beam, and beam offset. In order to remove this difficulty, the updated structural parameter in each iteration of linear optimization is obtained using numerical optimization technique where the objective function contains only the structural parameters as variables and last updated values of other updating parameters like system mode shapes as constants. Detailed formulation of the proposed method is carried out along with the estimation of uncertainty and damage detection of model parameters. One numerical example in the form of a three-dimensional steel cantilever beam is considered for demonstration purpose. Computer programs for FE modelling of the cantilever beam is created in MATLAB. Satisfactory performances in updating of model and detection of damage are observed for the structure using the proposed approach. Keywords Model updating · Bayesian framework · Sub-structuring · Numerical optimization

A. Das · N. Debnath (B) Department of Civil Engineering, NIT Silchar, Silchar, India e-mail: [email protected] A. Das e-mail: [email protected] © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021 S. Chandrasekaran et al. (eds.), Recent Advances in Structural Engineering, Lecture Notes in Civil Engineering 135, https://doi.org/10.1007/978-981-33-6389-2_8

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1 Introduction The subject of updating of finite element (FE) models has gained much popularity in recent times as a means to bridge the gap between the experimental modal properties of a structure and the predictions of a numerical model. Owing to various types of errors such as modelling errors, there is significant discrepancies between the results of FE model and the actual/measured results. Hence, FE model updating is a very significant application in this regard to reduce such errors. The fundamental idea of FE model updating is to update/refine the initial numerical model so that the modal properties of the updated model is highly correlated with that of the experimental/real structure. Thus, the updated model attains the capability of replicating the real structure more efficiently. FE model updating techniques based on vibration data of the structure have been widely used in the field of structural health monitoring [1, 2]. In this regard, few of the pioneering works on model updating include works by Friswell and Mottershead [3–5]. One of the most popular model-updating techniques in recent times is the sensitivity technique [6]. Besides, the method adopted in this paper is the Bayesian framework, which is one of the most popular probabilistic methods for model updating. One such class of model-updating method is the Bayesian probabilistic updating by maximizing the posterior probability density function (PDF) known as maximum a posteriori (MAP). Many such works [7–9] can be observed where Bayesian statistical framework is utilized not only for system identification but also for identification of updating parameters. Yuen [10, 11] developed a technique of model updating in Bayesian framework by maximizing the posterior PDF where matching of modes between analytical and measured modes is not required which is of prime significance in case of large structures. Besides, a book by Yuen [12] elaborately describes Bayesian FE model updating techniques, model class selection and various topics related to it. Few of the works based on Bayesian framework for model updating include works by Das and Debnath [13] where the authors updated mass and stiffness by assigning the parameters with lognormal distribution, and works by Cheung and Bansal [14] and Das and Debnath [15] where the authors utilize incomplete complex modal data. In the literature review, it has been observed that the FE model updating in Bayesian probabilistic framework mainly performs sub-structuring procedure for model updating. This procedure involves obtaining the sub-structure matrices corresponding to each updating parameter. This procedure is likely to perform well in Bayesian framework of model updating after obtaining the structural matrices of the sub-structures corresponding to each updating. But, in case of geometric parameters like sectional dimensions (e.g., width, height, etc.) which influence both mass and stiffness parameters, though sub-structuring of structural matrices is possible corresponding to the updating parameters, but the detailed formulation is not easy to obtain and the performance of the model-updating procedure is also doubtful. Thus, there exists a scope for developing an effective approach to perform the Bayesian updating of structural parameters without the requirement of sub-structuring of system matrices, that is, without obtaining the mass or stiffness matrices of the

Bayesian Finite Element Model Updating Without Requirement …

75

sub-structures. Rarely any such work is performed without the requirement of sub-structuring and mode matching at the same time in Bayesian framework. In this paper, the Bayesian FE model updating without the requirement of substructuring of mass or stiffness matrices approach using modal measurements is presented to update structural parameters. Detailed formulations of obtaining the updated parameters are presented thereby. Furthermore, estimation of uncertainty and damage detection from probabilistic point of view are also developed. The proposed approach does not need solving eigen equation in each iteration or matching modes between measured and analytical modes, thus saving much computation time and thereby avoiding possible mode-pairing error. The proposed approach has the added advantages of model updating of complex structures whose FE modelling is not easy to program and updating of parameters which influence both mass and stiffness matrices. Subsequently, the proposed approach is demonstrated using a numerical example in the form of a three-dimensional steel cantilever beam, where sectional dimension (width and height) and Young’s modulus of the beam elements are considered as updating parameters. In this example also one damage case is considered by decreasing the parameters at specific beam locations. The model updating of structural parameters along with estimation of uncertainty in posterior PDF leading to detection of damage is performed for the structure. Satisfactory efficiency of the proposed approach is observed in model updating as well as damage detection of the structural parameters.

2 Formulation of the Bayesian Updating Method The basic Bayes’ formula [16] in the model updating framework of a N d -degrees of freedom (DOF) structure can be expressed in Eq. (1), where the posterior PDF is obtained from likelihood function and prior PDF. p(, θ|D) =

p(D|, θ) p(, θ) = k1 p(D|, θ) p(, θ) p(D)

(1)

Here, and θ are the unknown system mode-shape and model parameter-vector, ˆ  ) is the known measured data consisting of measured respectively, while D = (λ, ˆ eigenvalues (λ) and measured eigenvectors ( ). Besides, p(, θ) represents prior PDF, the likelihood function is represented by p(D|, θ) and p(D) represents a normalizing constant. Also, N m measured modes are considered for the model updating of Nθ number of structural parameters. Lastly k 1 is a normalizing constant. In the present work, the system mode shapes () are updated/optimized targeting the measured eigenvectors ( ). Being optimization parameter, the system mode shapes are basically varying to facilitate the updating/optimization. The system mode shapes are, however, occasionally treated as non-varying (or constant) based on the requirements of updating/optimization like partial differentiation and so on. 





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2.1 Formulation of p(Φ, θ ) The PDF p(θ) is assumed to follow multivariate normal distribution and can be expressed as in Eq. (2). p(θ) = (2π )

−Nθ /2

| θ |

−1/2

     1 η T −1 η exp − θ − θ  θ θ − θ 2

(2)

where the nominal values vector θη and  θ represent the mean-vector and covariancematrix of θ, respectively. On the other hand, the prior PDF p() of system  T eigenvectors  = (1)T , (2)T , . . . , (Nm )T is assumed to follow uniform distribution.

2.2 Formulation of p(D|Φ, θ ) 

ˆ The PDF p(D|, θ) has two parts p(λ|, θ) and p( |) independent of each other. ˆ The component p(λ|, θ) is obtained by assuming a Gaussian distribution for error ˆ in a standard eigen vector function obtained by putting observed eigenvalues λ equation and is shown in Eq. (3).

ˆ p(λ|, θ) = (2π )

−Nd Nm /2

−Nd Nm σeq

Nm  2

1

  exp − 2  K − λˆ (m) M (m)  2σeq m=1

 (3)

The mass matrix and stiffness matrix in Eq. (3) are functions of structural parameters depending on the choice of structural parameters. Besides, the covariance matrix 2 . On the other hand, the is considered as diagonal with variance values equal to σeq 

component p( |) is obtained by assuming Gaussian distribution for the error vector function measuring the discrepancies between the analytical mode shape and measured mode shape and is shown in Eq. (4). 

T

 1  − L  p( |) = (2π )−0.5Nm N0 | ε |−1/2 exp −  − Lo   −1 o ε 2 





(4)



The covariance matrix of measurement noise ε =  − Lo  is considered to be an estimate of the  covariance matrix ( ε ) as in the likelihood function. Besides, Lo ∈ R Nm No ×Nm Nd is a matrix of 0 and 1 used for mapping of analytical eigenvectors with their experimental counterpart. 

Bayesian Finite Element Model Updating Without Requirement …

77

2.3 Objective Function of the Optimization Problem The updated values of the unknown parameters correspond to that value which maximizes the posterior PDF expressed in Eq. (1). In this work, the posterior PDF is not maximized directly, rather a minimization procedure is performed where the negative logarithm of the posterior PDF (neglecting the constant values) is considered as the objective function as shown in Eq. (5). T   1 η θ − θη  −1 θ θ−θ 2 Nm  2

1

 ˆ (m) M (m)  K − λ +   2 2σeq m=1

T

1  − Lo   −1  − Lo  + ε 2

F(, θ) =





(5)

2.4 Optimization Framework The model updating is performed by minimization of the objective function shown in Eq. (5). By minimizing the objective function with respect to , the optimal mode shape vector ∗ can be obtained as shown in Eq. (6). −1 T −1  −2 Gφ + LoT  −1 Lo  ε  ∗ = σeq ε Lo



(6)

where Gφ is represented as in Eq. (7).  2  (2)∗ ∗ 2 ∗ Gφ = diag λˆ (1) M∗ − K∗ λˆ M − K∗

2  ∗ · · · λˆ (Nm ) M∗ − K∗

(7)

Nd Nm ×Nd Nm

where diag [·] represents a diagonal matrix with diagonal elements mentioned in [·]. The updated parameter θ∗ is obtained by minimizing the objective function with respect to the structural parameter vector. Now, the expression for the updated structural parameter can be derived explicitly only if the sub-structuring of the mass and stiffness matrices is performed as done in [12]. But the updated parameter can also be obtained without the process of sub-structuring or obtaining the mass and stiffness matrices of the sub-structures, by numerical optimization of the objective function with respect to the updating parameter using standard nonlinear optimization tool as can be seen in Eq. (8).

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Nm  2

T   1 1

 η (m) (m)  ˆ K − λ θ − θη  −1 θ − θ + θ = min M    θ 2 θ 2 2σeq m=1



∗

(8)

The parameters  and θ are updated based on Eqs. (6) and (7) sequentially one by one in an iterative manner until the parameters are well converged.

3 Estimation of Uncertainty in Posterior PDF   The posterior PDF is assumed to be centred at ∗ , θ∗ . As explained in [8, 12], the covariance matrix is equal to the inverse of the Hessian matrix [shown in Eq. (9)]. Owing to the non-requirement of sub-structuring of system matrices, components of the Hessian matrix corresponding to the structural parameters have to be computed numerically.  H(, θ) =

  −2 σeq Gφ + LoT  −1 ε 22 Lo sym

∂2 F ∂∂θ ∂2 F ∂θ2



The diagonal and off-diagonal elements of the Hessian matrix, that is, ∂2 F ∂∂θ

(9) ∂2 F ∂θ2

and

are obtained by typical numerical differentiation methods like finite difference method. Finally, the standard deviation of θ can be estimated from the square root of the diagonal values of the covariance matrix obtained from the Hessian matrix. The probabilistic damage detection of the structural parameters may be performed using the approach adopted in [12].

4 Validation and Applicability of the Updating Method The proposed approach is validated using one numerical example using beam structure. Further details are presented in this subsection regarding the structure and the model updating results. It is interesting to note that geometric properties like depth, width of section, beam offset and so on influence both mass and stiffness matrices of a structural. Sub-structuring of the matrices with respect to these parameters may be possible in a similar fashion as shown in [10–13] where the structural sub-matrices are to be updated in each iteration of the linear optimization framework. But, formulation of the updated parameters is not as same as in the conventional approach, hence performance of the updating procedure using the procedure of sub-structuring is doubtful. In order to demonstrate the proposed approach in updating both material and geometric properties of a structure, a three-dimensional steel cantilever beam is considered of grade Fe500. As seen in Fig. 1, the beam consists of five elements each having Young’s modulus 2.486 × 1010 N/m2 and density 2403 kg/m3 . The analytical

Bayesian Finite Element Model Updating Without Requirement …

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Fig. 1 Cantilever beam

Table 1 Details of frequency for all the cases Mode No.

1

2

3

4

5

6

Undamaged case

8.163

8.163

49.022

49.022

132.295

132.295

Damage case

6.603

7.270

46.238

46.445

121.729

129.080

(undamaged) model of the beam is assumed to be of square section of 0.4 m each side, making the cross-sectional area of 0.16 m2 . One damage case is simulated by reducing the Young’s modulus of first element by 20%, width of second element by 25% and depth of third element by 10%. Frequencies of the undamaged and damage case are shown in Table 1. The structural parameters considered in this example are the values of Young’s modulus, width and depth each of all the elements, making a total of 15 parameters expressed in terms of fractional values with respect to nominal values. Considering 6 DOFs for each node for the 3D beam, the beam consists of 30 DOFs. Generally, the mass contribution to rotational DOF in a structure is zero; hence, by static condensation [17], the effective system matrices are considered for only translational DOFs, thereby reducing the total DOFs of the structure to only 15. The structure is improved/calibrated using the method shown in Sect. 2. First six translational modes of the structure are assumed for model updating, and out of 15 DOFs, 8 DOFs are considered as measured DOFs. Performance in updating of frequencies is shown in Fig. 2 for the damage case. It shows that the updated frequencies are close to the target ones as compared to the initial frequencies for the

Fig. 2 Frequencies of the initial, target and updated model for the damaged case using the proposed approach

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Table 2 Updated parameter values with COV for the damage case using the proposed approach Parameters

Target

Updated

COV (%)

E1

0.8

0.8357

4.38E−06

E

2

1

1.1000

1.53E−05

E

3

1

1.0661

4.86E−06

E

4

1

1.0738

1.02E−05

E

5

1.14E−05

1

1.0742

b1

1

0.9678

1.77E−06

b2

0.75

0.7238

5.71E−06

b3

1

0.9720

3.05E−06

b4

1

0.9634

4.70E−06

b5

1

0.9647

5.65E−06

d1

1

0.9742

2.42E−06

d2

1

0.9578

3.07E−06

d3

0.9

0.8689

4.19E−06

d4

1

0.9658

2.70E−06

d5

1

0.9647

1.97E−06

analytical model. Also, MAC values are improved for the damage case from 0.9999 to 1.0000 (1st mode), 0.9987 to 1.0000 (2nd mode), 0.9981 to 1.0000 (3rd mode), 0.9961 to 1.0000 (4th mode), 0.9912 to 1.0000 (5th mode) and 0.9950 to 1.0000 (6th mode) which shows quite satisfactory performance in improvement of MAC values after updating using the proposed approach. Besides, the updated values of the structural parameters and their corresponding measure of deviation (coefficient of variation (COV) values) are shown in Table 2 for the damage case. The COV values are obtained based on the procedure of uncertainty estimation presented in Sect. 3 while the updating parameters considered for this example is the fractional values of the actual values with respect to their respective nominal values. It may be observed that the performance is satisfactory in achieving the target values for all the damage cases while COV values are quite low. Lastly, probabilistic damage detection of the three sets of structural parameters (as shown in Fig. 3) using the procedure explained in [8, 12] shows detection of damage consistent with assumed values of damage.

5 Conclusion The present work is based on FE model updating in Bayesian framework where matching of analytical and experimental modes is avoided along with nonrequirement of parameterization or sub-structuring of system matrices with respect to the updating parameters. Hence, a novel updating procedure is proposed where

Bayesian Finite Element Model Updating Without Requirement …

(a)

(b)

81

(c)

Fig. 3 Probability of change/damage with respect to extent of damage of a Young’s modulus parameters, b breadth parameters and c depth parameters for the damage case

an iterative optimization procedure with an inner numerical optimization performed within each iteration of the main optimization process. This numerical optimization process helps in avoiding sub-structuring of system matrices, which makes the proposed method more appealing. Detailed formulations along with the uncertainty estimation are presented in the proposed framework. The proposed approach is validated using one numerical example in the form of a three-dimensional steel cantilever beam with one damage case by simulating reduction of parameters in Young’s modulus and also in beam dimension. Inclusion of beam dimension (breadth and width) as unknown parameter also makes the sub-structuring procedure difficult. Efficiency of the updating method is evaluated from updating as well as damage detection point of view and the proposed approach proves to be effective for the structure.

References 1. S.W. Doebling, C.R. Farrar, M.B. Prime, A summary review of vibration-based damage identification methods. Shock Vib. Dig. 30, 91–105 (1998) 2. H.P. Chen, Structural Health Monitoring of Large Civil Engineering Structures (John Wiley & Sons (Asia) Private Limited, 2018) 3. M.I. Friswell, J.E. Mottershead, Finite Element Model Updating in Structural Dynamics (Kluwer Academic Publishers, Boston, 1995) 4. J.E. Mottershead, M.I. Friswell, Physical understanding of structures by model updating, in Proceedings of the International Conference on Structural Identification (Kassel, Germany, 2001), pp. 81–96 5. J.E. Mottershead, M.I. Friswell, Model updating in structural dynamics: a survey. J. Sound Vib. 167, 347–375 (1993) 6. J.E. Mottershead, M. Link, M.I. Friswell, The sensitivity method in finite element model updating: a tutorial. Mech. Syst. Signal Process. 25, 2275–2296 (2011) 7. J.L. Beck, System Identification methods applied to measured seismic response, in Proceedings of the Eleventh World Conference on Earthquake Engineering (1996) 8. J.L. Beck, L.S. Katafygiotis, Updating models and their uncertainties. I: Bayesian statistical framework. J. Eng. Mech. 124(4), 455–461 (1998) 9. M.W. Vanik, J.L. Beck, S.K. Au, Bayesian probabilistic approach to structural health monitoring. J. Eng. Mech. ASCE 126(7), 738–745 (2000)

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10. K.V. Yuen, An extremely efficient finite-element model updating methodology with applications to damage detection, in Proceedings of Enhancement and Promotion of Computational Methods in Engineering and Science X, Sanya, Hainan, China, 21–23 August 2006, pp. 166–179 11. K.V. Yuen, J.L. Beck, L.S. Katafygiotis, Efficient model updating and health monitoring methodology using incomplete modal data without mode matching. Struct. Control Health Monit. 13, 91–107 (2006) 12. K.V. Yuen, Bayesian Methods for Structural Dynamics and Civil Engineering (John Wiley & Sons (Asia) Private Limited, 2010) 13. A. Das, N. Debnath, A Bayesian finite element model updating with combined normal and lognormal probability distributions using modal measurements. Appl. Math. Model. 61, 457– 483 (2018) 14. S.H. Cheung, S. Bansal, A new Gibbs sampling based algorithm for Bayesian model updating with incomplete complex modal data. Mech. Syst. Signal Process. 92, 156–172 (2017) 15. A. Das, N. Debnath, A Bayesian model updating with incomplete complex modal data. Mech. Syst. Signal Process. 136, 106524 (2020) 16. J.M. Bernardo, A.F.M. Smith, Bayesian Theory (Wiley, England, 2000) 17. A.K. Chopra, Dynamics of Structures: Theory and Applications to Earthquake Engineering, 3rd edn. (Pearson Education India, 2007)

Free Vibration Analysis of Reissner–Mindlin Plates Using FEniCS G. Verma, S. Sengupta, S. Mammen, and S. Bhattacharya

Abstract FEniCS is a Python-based powerful open-source package for solving partial differential equations. The FEniCS computing platform was created under FEniCS research and software project with the aim of an automated solution to mathematical models (partial differential equations) through finite element methods. FEniCS environment provides a high-level user-interface which allows easy reproduction of mathematical formulation and rapid implementation of high-performance solvers. In the present work, the potential of the FEniCS package is utilized to numerically analyse the modal characteristics of a thin square Reissner–Mindlin plate having different boundary (edge) conditions. Sensitivity analyses are performed to study the variation with change in a number of elements and the order of the interpolating polynomial. The eigenvalues and mode shapes obtained are subsequently compared with both analytical results and the results obtained from commercial finite element package. Keywords FEniCS · Python · Finite element method · Reissner–Mindlin plate · Eigenvalues

G. Verma (B) · S. Sengupta · S. Mammen · S. Bhattacharya Research Reactor Design and Projects Division, Bhabha Atomic Research Centre, Mumbai 40085, India e-mail: [email protected] S. Sengupta e-mail: [email protected] S. Mammen e-mail: [email protected] S. Bhattacharya e-mail: [email protected] © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021 S. Chandrasekaran et al. (eds.), Recent Advances in Structural Engineering, Lecture Notes in Civil Engineering 135, https://doi.org/10.1007/978-981-33-6389-2_9

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1 Introduction The governing equations of continuum mechanics problems primarily consist of linear or nonlinear partial differential equations (PDEs) with initial and boundary conditions. In general, computational mechanics is used for complex problems of continuum mechanics for which the analytical solutions are difficult to obtain. Finite element methods are widely used as a mathematical tool to solve these PDEs for various problems in engineering and research. FEniCS is one such open-source package which utilizes the finite elements approach. FEniCS package is a Python-based software which solves PDEs using finite element methodology. The FEniCS computing platform was created in 2003 under FEniCS research and software project in collaboration with universities and research institutions worldwide with the aim of an automated solution to mathematical models [1]. The FEniCS package uses dynamic object-oriented library for FINite element computation (DOLFIN), a C++/Python library as its primary user interface. It uses a collection of Python and C++-based open-source libraries such as FEniCS form compiler (FFC), finite element automatic tabulator (FIAT), unified form language (UFL), unified form-assembly code (UFC), mshr, and so on as its building blocks [2–4] (Fig. 1). In the present work, FEniCS package is used to investigate eigenvalues and mode shapes for thin square Reissner–Mindlin plate with different boundary conditions. Thin fuel plates are often used in high flux research nuclear reactors to keep the core compact to obtain high neutron flux. Sensitivity analyses are performed for variation in the number of discretized elements and the order of the interpolating polynomial. Subsequently, the modal characteristics of the Mindlin plate obtained External Libraries

Core Components FIAT Interface

PETSc uBLAS

UFL

NumPy

Applications

SLEPc FEniCS Application

UMFPACK DOLFIN

FFC

Instant

SCOTCH VTK Trilinos

UFC

GMP FErari

ParMETIS CGAL MPI

Fig. 1 Flow diagram representing FEniCS architecture [4]

Free Vibration Analysis of Reissner–Mindlin Plates Using FEniCS

85

through FEniCS are compared with the analytical values and the values obtained from the commercial finite element code.

2 Finite Element Formulation of the Reissner–Mindlin Plate [5, 6] For an isotropic Reissner–Mindlin thin square plate of thickness h and equal edge lengths a under bending deformation, the neutral surface occupies a domain  ⊂ R 2 as shown in Fig. 2. The transverse deflection is given by w, and the rotation of the neutral surface along y-axis and x-axis is given by β = [βx β y ]T . The vector of unknowns for three independent variables at any point in the neutral axis is given by u, ⎡

⎤ w u = ⎣ βx ⎦ βy

(1)

The deflected plate curvature κ and the shear strain γ are given as, κ = Ld β

(2)

γ = ∇w + β

(3) x, u

βy

Reissner-Mindlin Plate

Neutral Surface (Mid-Surface)

z, w

Fig. 2 Schematic of a Reissner–Mindlin plate with positive vertical displacement w and two rotations βx , β y

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where L d is a differential operator matrix given as, ⎡  ∂ ∂x ⎢ 0 Ld = ⎣ ∂ ∂y

⎤ 0 ∂ ⎥ ∂y ⎦ ∂ ∂x

(4)

  T and ∇ = ∂ ∂ x ∂ ∂ y . For static Reissner–Mindlin plates, the governing differential equations are given as, ∇.Db κ(β) + Gkhγ = 0 in 

(5)

Gkh∇.γ + p = 0 in 

(6)

w = w, β = β on  = ∂

(7)

The finite element weak form for the dynamic equilibrium equation for the Reissner–Mindlin plates is given in Eq. (8) 

 δκ T Db κd + 

 δγ T Ds γ d +



δu T m ud ¨ =0

(8)



where δ is the Dirac-Delta function, and Db is the flexural rigidity given as, ⎡ ⎤ 1v 0 Eh 3 ⎣v 1 ⎦ Db = 0  12(1 − v 2 ) (1 − v) 00 2

(9)

with E being the Young’s modulus, v is the Poisson’s ratio and G is the modulus of rigidity. Ds is the shear rigidity which is given as per Eq. (10), Ds = khG

10 01

(10)

where k is the shear correction factor depending upon the boundary condition. m is the mass matrix as per Eq. (11) with density ρ and thickness h. ⎡

⎤ 0 0 3 ⎢ ⎥ m = ⎣ 0 ρh 12 0 ⎦ 3 0 0 ρh 12 ρh

(11)

Free Vibration Analysis of Reissner–Mindlin Plates Using FEniCS

87

The eigenvalues of the Reissner–Mindlin plates can be obtained using the form (K − ω2 M)d = 0

(12)

where K is the global stiffness matrix and M is the global mass matrix. K e and Me is the elemental stiffness and mass matrices given as in Eqs. (13) and (14). 

 Bb T Db Bb de +

Ke = 

Bs T Ds Bs de

(13)

 Me =

N T m N de

(14)

e

where N 1 , N 2 , N 3 and N 4 correspond to the basis function for each node in an element.

3 FEniCS Implementation In the algorithm (Fig. 3), the approach adopted to perform modal analysis on Reissner–Mindlin plates using FEniCS is presented. In this approach quadrilateral elements and selective reduced integration (SRI) approach prevent shear locking because of strong symmetry. The system stiffness and mass matrices are defined as PETSc matrices using their appropriate forms from the standard Galerkin weak

Import Libraries (PETSc and NumPy)

Input Material Parameters for Isotropic Linear Elastic Materials

Define Plate Flexural, Shear Rigidity, Material Constitutive Relation

Mesh Generation using quadrilaterals and Interpolation Function

FEniCS Environment with DOLFIN Interface Define Domain, Boundary Conditions

Modal Analysis using SLEPcEigenSolver and Mode Extraction

Fig. 3 Flow diagram of the algorithm

Obtain System Mass and Stiffness Matrices using Variational Form as PETSc Matrix

Trial and Test Function Space

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formulation. The boundary conditions are applied to the stiffness matrix to preserve symmetry. Finally, modal analysis is performed on the system using SLEPcEigenSolver. In general, SLEPc computes the largest eigenvalues but with the use of a spectral transform and a spectral shift, the eigenvalues are computed close to the spectral shift value (zero in the present case study). Also, for this, the problem type is specified as generalized Hermitian eigenvalue problem [2].

3.1 Results and Discussion In the present work, the modal dynamic analysis results are obtained for thin square Reissner–Mindlin plate having different boundary conditions through FEniCS simulation with equal edges. For a Mindlin plate with h = 2 mm and equal edge length a = 1000 mm (a/b = 1), Table 1 presents the eigenvalues of first six modes and its mode shapes for four different boundary conditions such as fully clamped (C-C-C-C), clamped-free-clamped-free (C-F-C-F), clamped-simply supported-clamped-simply supported (C-SS-C-SS) and simply supported-free-simply supported-free (SS-F-SSF). In Table 1, the FEniCS results for 100 meshes (number of elements) and second degree of interpolating polynomial (sensitivity analysis for which are presented in the following subsection) obtained are compared with analytical values predicted by Leissa [7]. In addition, eigenvalues obtained through commercial finite element code are also presented in Table 1 for the discussed boundary conditions. Figure 4 shows the mode shapes of the fully clamped thin square Reissner–Mindlin plates. Diagonal nodal patterns are observed for 1st, 2nd and 5th mode of the plate, whereas circular nodal patterns are obtained for 6th mode. It is important to note that these diagonal and circular nodal patterns are observed only for fully clamped boundary condition. From Table 1, it is evident that eigenvalues estimated using FEniCS are in very good agreement with analytical results where percentage relative error is below 1%. Figures 5, 6 and 7 display the mode shapes for the thin square Reissner– Mindlin plates with clamped-free-clamped-free (C-F-C-F), clamped-simply supported-clamped-simply supported (C-SS-C-SS) and simply supported-freesimply supported-free (SS-F-SS-F) boundary conditions, respectively. According to Table 1, eigenvalues predicted using FEniCS show good agreement with analytical results where percentage relative error is below 1%. Figure 8 shows the mesh sensitivity for fully clamped thin square Reissner– Mindlin plate for first and fourth modal frequency for second degree of interpolating polynomial. Mesh sensitivity is performed for five different mesh values, that is, 10, 20, 50, 100 and 200. It is observed from Fig. 8 that even for relatively less number of elements, the eigenvalues predicted by FEniCS show stability and relative accuracy saving considerable computation time. In Fig. 9, sensitivity to variation in the degree of continuous interpolation for fully clamped thin square Reissner–Mindlin plate for first and fourth modal frequency for 100 elements are plotted. From Fig. 9 it is observed that even for the lower degree of interpolating polynomial, the estimated

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89

Table 1 Eigenvalues and modal shapes for a thin square Reissner–Mindlin plate with different boundary conditions obtained through FEniCS and commercial FE Mode No.

FEniCS (Hz)

Commercial FE (Hz)

Analytical (Hz)

Error [7] (%)

Mode (n, m)

1

17.646

17.652

17.643

~0

(0,0)

2

35.989

36.002

35.986

~0

(0,1) − (1,0)

3

35.989

36.002

35.986

~0

(0,1) + (1,0)

4

53.062

53.082

53.073

0.02

(1,1)

5

64.517

64.542

64.529

0.02

(2,0) − (0,2)

6

64.824

64.848

64.823

~0

(2,0) + (0,2)

Fully clamped (C-C-C-C)

Clamped-free-clamped-free (C-F-C-F) 1

10.884

10.888

10.917

0.31

(0,0)

2

13.003

13.008

13.004

~0

(0,1)

3

21.455

21.460

21.403

0.24

(0,2)

4

30.031

30.043

30.130

0.32

(1,0)

5

33.030

33.043

33.112

0.24

(1,1)

6

39.204

39.210

39.168

0.1

(0,3)

Clamped-simply supported-clamped-simply supported (C-SS-C-SS) 1

14.193

14.197

14.191

~0

(0,0)

2

26.837

26.841

26.834

~0

(0,1)

3

33.989

34.000

33.984

~0

(1,0)

4

46.363

46.374

46.365

~0

(1,1)

5

50.113

50.117

50.105

~0

(0,2)

6

63.293

63.315

63.280

0.02

(2,0) (0,0)

Simply supported-free-simply supported-free (SS-F-SS-F) 1

4.739

4.739

4.721

0.38

2

7.974

7.974

7.909

0.82

(0,1)

3

18.078

18.079

18.004

0.41

(0,2)

4

19.135

19.136

19.093

0.21

(1,0)

5

23.016

23.017

22.911

0.45

(1,1)

6

34.816

34.816

34.676

0.40

(1,2)

90

(a) nodal lines (0,0)

G. Verma et al.

(b) nodal lines (0,1) - (1,0)

(c) nodal lines (0,1) + (1,0)

(d) nodal lines (1,1)

(e) nodal lines (2,0) - (0,2)

(f) nodal lines (2,0) + (0,2)

Fig. 4 Modal shapes for fully clamped thin square Reissner–Mindlin plate

(a) nodal lines (0,0)

(b) nodal lines (0,1)

(c) nodal lines (0,2)

(d) nodal lines (1,0)

(e) nodal lines (1,1)

(f) nodal lines (0,3)

Fig. 5 Modal shapes for thin square Reissner–Mindlin plate with clamped-free-clamped-free boundary condition

(a) nodal lines (0,0)

(b) nodal lines (0,1)

(c) nodal lines (1,0)

(d) nodal lines (1,1)

(e) nodal lines (0,2)

(f) nodal lines (2,0)

Fig. 6 Modal shapes for thin square Reissner–Mindlin plate with clamped-simply supportedclamped-simply supported boundary condition

(a) nodal lines (0,0)

(b) nodal lines (0,1)

(c) nodal lines (0,2)

(d) nodal lines (1,0)

(e) nodal lines (1,1)

(f) nodal lines (1,2)

Fig. 7 Modal shapes for thin square Reissner–Mindlin plate with simply supported-free-simply supported-free boundary condition

eigenvalues are quite accurate, which again implies the potential of FEniCS package to lower computation time and cost.

Free Vibration Analysis of Reissner–Mindlin Plates Using FEniCS

91 53.100

17.648

17.647

53.075

17.646

53.050

17.645

0

20

40

60

80

100

120

140

160

180

Frequency (Hz)

Frequency (Hz)

1st Mode Frequency 4th Mode Frequency

53.025 200

Number of Elements

Fig. 8 Mesh sensitivity for fully clamped thin square Reissner–Mindlin plate for first and fourth modal frequencies 53.125

17.652

17.650

53.100

17.648

53.075

17.646

53.050

17.644

0

1

2

3

4

Frequency (Hz)

Frequency (Hz)

1st Modal Frequency 4th Modal Frequency

53.025

Degree of Continous Interpolation

Fig. 9 Sensitivity for fully clamped thin square Reissner–Mindlin plate for first and fourth modal frequencies with respect to variation in the degree of continuous interpolation

4 Conclusion In the present work, the potential for the Python-based powerful open-source FEniCS package was utilized to numerically analyse the modal characteristics of thin square Reissner–Mindlin plate with different boundary conditions. The eigenvalues and mode shapes obtained from FEniCS were subsequently compared with both analytical results and the results obtained from commercial finite element code. Sensitivity analyses were also carried out to explore the capabilities of FEniCS by studying

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the variation in number of elements and the order of the interpolating polynomial. It was observed that FEniCS capabilities could be greatly explored for complex, memory-intensive problems.

References 1. H.P. Langtengen, A. Logg, Solving PDEs in Python: The FEniCS Tutorial I, Simula Springer Briefs on Computing 3, 2016 2. J. Bleyer. Numerical Tours of Computational Mechanics with FEniCS, Zenodo, (2018) 3. Q. Zhu, J. Yan, A moving domain CFD solver in FEniCS in application to tidal turbine simulations in turbulent flows. Comp. Maths. Appl. (2019) 4. A. Logg, K.A. Mardal, G.N. Wells, Automated Solution of Differential Equations by the Finite Element Method: The FEniCS Book, Lec. Notes Comp. Sci. Eng., Vol. 84 (Springer, Berlin Heidelberg, 2012) 5. Y.B. Chai, W. Li, Z.X. Gong, An Edge-Based Smoothed Three-Node Mindlin Plate Element (ES-MIN3) for Static and Free Vibration Analyses of Plates (ICCM, Cambridge, England, 2014). 6. V.H. Loung, T.N.T. Cao, J.N. Reddy, K.K. Ang, M.T. Tran, J. Dai, Static and dynamic analyses of Mindlin plates resting on viscoelastic foundation by using moving element method. Inter. Jou. Struc. Stab. Dyn. 18(11), 1850131 (2018) 7. A.W. Leissa, The free vibration of rectangular plates. Jou. Sou. Vib. 31(3), 257–293 (1973)

Response of Delamination on Static Behaviour of Simply Supported Composite Conoidal Shell Roofs Suman Pandey and Dipankar Chakravorty

Abstract In the present paper static analysis of laminated composite conoidal shells in the presence of delamination is investigated. Simply supported conoidal shells are subjected to uniform loading. Finite element method using eight-noded curved quadratic isoparametric shell element with 5 degrees of freedom (d.o.f) per node is used in the present research work. To ensure compatibility between deflection and equilibrium of moments and forces, an advance feature known as MPC algorithm is integrated in the present model. This generates an unsymmetrical stiffness matrix. The exactness of present model is verified by comparing with the results of previous researchers’ works. Studies are done by varying the lamination schemes, extent of delamination and aspect ratio for composite conoidal shells. Boundary condition is kept as simply supported for all the shells considered in the present study. Keywords Boundary condition · Conoidal shell roofs · Delamination · Finite element · Simply supported · Static analysis

Nomenclature a b w¯ w q0

Length of conoidal shell in plan Width of conoidal shell in plan Non-dimensional deflection, given as w¯ = (wh 3 E 22 /q0 a 4 ) × 103 Vertical deflection Intensity of transverse load

S. Pandey (B) Civil Engineering Department, Techno India University, Kolkata 700091, India e-mail: [email protected] D. Chakravorty Civil Engineering Department, Jadavpur University, Kolkata 700032, India e-mail: [email protected] © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021 S. Chandrasekaran et al. (eds.), Recent Advances in Structural Engineering, Lecture Notes in Civil Engineering 135, https://doi.org/10.1007/978-981-33-6389-2_10

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1 Introduction Fields like civil, aerospace and mechanical engineering have a great demand for laminated composite shell structures because of their high-class mechanical properties and a number of other advantages. But sometimes these materials undergo a very serious type of damage known as delamination. Delamination occurs due to built-up defects, air entrapment, impact loading or overloading during service conditions. A brief review of earlier investigations is presented below, comprising study on shell structures with or without delamination. The preceding researcher, Hadid [1] explored the bending behaviours of conoidal shells both analytically and experimentally. Gim [2] worked on delaminated plate using finite element method. He modified this for conducting the static analysis of partially damaged shells. Studies on damage and impact response of composite cylindrical shells with curved panels are conceded out by Krishnamurthy et al. [3]. Isotropic and composite shells of cylindrical form were investigated by Tafreshi [4– 6] using 3D finite element model. Acharyya et al. [7, 8] did finite element analysis of damaged shallow shells of cylindrical form. They studied the static behaviour of shells subjected to uniformly distributed load. Rout et al. [9] investigated the free vibration behaviour of pretwisted stiffened cylindrical shell. They used finite element approach to study the consequences of delamination on the pretwisted shells. The detailed literature review reveals that majority of the research work on delamination deals with beams, plates and cylindrical shells only. Consequently, in this paper in-depth analysis of static characteristics of conoidal shells having mid-plane delamination and simply supported edge condition is done.

2 Mathematical Formulation In the present mathematical modelling, a curved quadratic isoparametric element with eight nodes and five degrees of freedom per node is used. The mid-plane displacements of any universal point at a distance z within the thickness of the shell are related to the corresponding mid-plane components in similar way as used by Kumari et al. [10]. Formulation of undelaminated composite conoidal shells is taken the same as used by Das et al. [11]. Formulation of the delaminated zone is taken the same as suggested by Gim [2]. Thus, it can be shown that {ε0 }l = {ε0 }1 + zl0 {k}1

(1)

Here the delaminated portions which are marked as 2 and 3 in Fig. 1 are denoted by suffix l. Suffix 1 (Fig. 1) is used to denote the undelaminated portion, {ε0 } are

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Fig. 1 Details of undelaminated and delaminated common zone

mid-surface in-plane strain vectors, {k} are curvature vectors and zl0 transverse direction distance between the mid-surface of undelaminated and delaminated portions, respectively. The static equilibrium problem takes the following form: {δ} = [K ]−1 {P}

(2)

Here {δ} represents displacement vector, [K] represents global stiffness matrix, and {P} represents global load vector.

3 Benchmark Problems To know the exactness of the mathematical model used in the present work, the authors have solved two benchmark problems (solved earlier by other researchers). The results of present approach are in alignment with first benchmark problem (Hadid [1]) results. This proves the right inclusion of conoidal shell form in the present model. While solving the first benchmark problem, the authors have kept both shear and elasticity modulus the same in all the directions so as to maintain isotropic characteristic of composite materials. Again, the outcomes of current approach are in alignment with the outcomes of second benchmark problem (Parhi et al. [12]). This validation proves the accuracy of composite shell with mid-plane damage in the present mathematical model. For conoidal shell model, the authors have given high value to the twist radius of curvature Rx y , whereas constant value is maintained for the radius of curvature R y (Fig. 2).

4 Results and Discussion The authors have successfully solved additional numerical problems in the same context. The below mentioned parametric variations are taken into consideration

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Fig. 2 Deflection profile of isotropic conoid with UDL along y = 0.5 [first benchmark]. a = b = 95 in., h = 0.05 in., hl = 9.0 in., hh = 18.0 in., E = 562 × 104 psi, q = 60 psf, ν = 0.15

to analyse damaged composite conoidal shell’s bending behaviour, subjected to uniformly distributed load: 1. 2. 3. 4. 5. 6.

Extent of damage (c/a) is ranged from 0 to 0.75 in steps of 0.25. Aspect ratios (a/b) are ranged from 0.5 to 2.0 in steps of 0.25. 2 four-layered angle ply laminates. 2 four-layered cross ply laminates. Two from above are symmetric and remaining are anti-symmetric. Material properties for composite are taken as

E 11 /E 22 = 25, G 12 /E 22 = G 13 /E 22 = 0.5, G 23 /E 22 = 0.2, v12 = 0.25 Here, E11 , E22 are elastic moduli, G12 , G13 and G23 are shear moduli, while ν12 represents Poisson’s ratio. Subscripts 1, 2 and 3 denote the axes of fibres. 7.

All simply supported conoidal shells have the following set of fixed parameters.

hl = 0.25 hh, a = 100 h. Here hl and hh denote lower and higher height of conoid, respectively, h is the total thickness of shell. The results thus obtained for simply supported conoidal shell roofs which have wide industrial applications are displayed in Table 1. The position of maximum deflection is also provided in the same table. The shells have a delaminated zone (c × d) in the centre of mid-plane. In general, increase in delamination area shows Table 1 Natural frequencies of simply supported delaminated cylindrical shells [second benchmark]

R y /a

c/a

Parhi [12] (Hz)

Present result (Hz)

5

0

129.04

128.99

0.5

104.56

104.51

0.75

98.24

98.19

103.03

103.04

0.5

69.60

69.61

0.75

59.88

59.92

10

0

Response of Delamination on Static Behaviour of Simply …

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increase in deflection. This is quite expected because delamination means loss of stiffness without any loss of mass. However, in few cases, deflection value shows a decreasing tendency with increase in area of delamination. In fact, in these cases, the shell surface around the maximum deflection position assumes the shape of a depressed basin and hence maximum deflection may decrease. Bracketed values (x, ¯ y¯ ) denotes the position of critical deflection

4.1 Effects of Aspect Ratio on Maximum Transverse Deflection • Results of Table 2 indicate that increase in aspect ratio leads to increase in deflection value for most of the cases taken up here. In other words, we can say that higher aspect ratio shows higher maximum deflection in most of the cases. • Symmetric angle ply shells show more effect of delamination than antisymmetric ones excluding few cases. The same effect is also observed in case of antisymmetric and symmetric cross ply ones. • Angle ply laminates show lesser deflection value as compared to cross ply ones. This observation is true for most of the cases considered here, excluding only one case of symmetrical cross ply shell for a/b = 0.75 with c/a 0.75.

4.2 Effects of Extent of Delamination on Maximum Transverse Deflection • It is evident from Table 2 results that deflection value of undelaminated and delaminated conoidal shells increase with increase in area of delamination for almost all the cases of laminations considered here. • Comparison among symmetric and antisymmetric angle ply shells shows that symmetric sequences give more deflection value than antisymmetric ones, excluding few cases. A similar observation in case of cross ply laminates shows that symmetric cross ply shells show more deflection value than antisymmetric ones with increase in delamination area. • On comparing angle ply and cross ply shells, it is observed that angle plies perform better than the cross ply ones.

5 Conclusions On the basis of present research work, the following conclusions have been drawn: 1.

In general, increase in aspect ratio increases maximum deflection.

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Table 2 Effect of extent of delamination and aspect ratio on maximum transverse deflections   w¯ × 104 Stacking sequence (0o /90o )2

c/a ratio

0.5

0.75

−1.213

−2.546

(0.19,0.81)

(0.23,0.25)

0.25

−1.225

−2.573

(0.19,0.81)

(0.19,0.75)

0.5

−1.399

−3.002

(0.19,0.75)

(0.23,0.25)

−2.240

−4.700

(0.19,0.19)

(0.19,0.19)

0

−1.270

−2.498

(0.16,0.38)

(0.28,0.63)

0.25

−1.280

−2.584

(0.16,0.25) 0.5

−1.443

0

2

−4.283

−10.094

−18.414

(0.31,0.25)

(0.56,0.5)

(0.62,0.5)

−4.305

−10.617

−19.579

(0.31,0.25)

(0.56,0.5)

(0.75,0.5)

−4.897

−10.298

−19.413

(0.47,0.62)

(0.62,0.5)

(0.31,0.25)

−20.662 (0.62,0.75)

−4.494

−10.005

−17.100

(0.38,0.5)

(0.47,0.5)

(0.62,0.5)

−4.956

−10.277

−17.824

(0.33,0.5)

(0.38,0.5)

(0.56,0.5)

(0.62,0.5)

−2.801

−16.109

−10.791

−19.003

(0.16,0.38)

(0.19,0.63)

(0.25,0.25)

(0.47,0.5)

(0.62,0.5)

−2.550

−4.707

(0.12,0.38)

(0.19,0.5)

0

−0.831

−1.424

(0.16,0.25)

(0.19,0.19)

0.25

−0.833

−1.455

(0.16,0.25)

(0.19,0.19)

−0.940

−1.531

(0.16,0.25)

(0.19,0.19)

−1.206

−2.223

(0.12,0.19)

(0.19,0.19)

−0.879

−1.447

(0.16,0.25)

(0.19,0.19)

−0.883

−1.478

(0.16,0.25)

(0.19,0.19)

0.5

−1.043

−1.620

(0.16,0.25)

(0.23,0.25)

0.75

−1.798

−5.928

(0.16,0.38)

(0.28,0.25)

0.5 0.75 (+45o /−45o )S

1.5

−12.970

0.75 (+45o /−45o )2

1

(0.47,0.25)

0.75 (0o /90o )S

Aspect ratio (a/b)

0 0.25

−7.377 (0.81,0.25)

−5.593

−10.846

−19.597

(0.25,0.25)

(0.38,0.5)

(0.75,0.5)

−1.996

−3.798

−10.771

(0.25,0.19)

(0.38,0.5)

(0.44,0.5)

−2.045

−3.831

−11.286

(0.25,0.19)

(0.38,0.5)

(0.44,0.5)

−2.202

−4.330

(0.25,0.19)

(0.47,0.25)

−3.466

−6.917

(0.25,0.19)

(0.56,0.19)

−2.030

−3.894

(0.25,0.19)

(0.38,0.5)

−11.430 (0.75,0.31) −13.883 (0.75,0.25) −10.766 (0.44,0.38)

−2.084

−3.954

−11.221

(0.25,0.19)

(0.38,0.5)

(1.0,0.44)

−2.335

−4.558

−11.824

(0.25,0.19)

(0.47,0.25)

−4.226

−7.342

(0.25,0.19)

(0.38,0.19)

(0.44,0.38) −14.317 (0.75,0.25)

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With the increase in extent of damage, maximum transverse deflection also increases. The deflections of angle ply conoidal shells are distinctively lower than cross ply shells for most of the cases. Antisymmetric lamination scheme is more preferable than symmetric one.

References 1. H. A. Hadid. An Analytical and Experimental Investigation into the Bending Theory of Elastic Conoidal Shells. Ph.D. Dissertation, University of Southampton. 1964 2. C.K. Gim, Plate Finite Element Modeling of Laminated Plates. Comput. Struct. 52(1), 157–168 (1964) 3. K.S. Krishnamurthy, P. Mahajan, R.K. Mittal, A Parametric Study of the Impact Response and Damage of Laminated Cylindrical Composite Shells. Composites Science and Technology. 61(12), 1655–1669 (2001) 4. A. Tafreshi, Efficient Modeling of Delamination Buckling in Composite Cylindrical Shells under Axial Compression. Compos. Struct. 64(3–4), 511–520 (2004) 5. A. Tafreshi, Delamination Buckling and Postbuckling in Composite Cylindrical Shells under External Pressure. Thin-Walled Structures. 42(10), 1379–1404 (2000) 6. A. Tafreshi, Delamination Buckling and Postbuckling in Composite Cylindrical Shells under Combined Axial Compression and External Pressure. Compos. Struct. 72(4), 401–418 (2006) 7. A. Acharyya, D. Chakravorty, A. Karmakar, Bending Characteristics of Delaminated Composite Cylindrical Shells with Complicated Boundary Condition. International Journal of Material Research, Electronics and Electrical System. 1(1), 11–23 (2008) 8. A. Acharyya, D. Chakravorty, A. Karmakar, Bending Characteristics of Delaminated Composite Cylindrical Shells – A Finite Element Approach. Journal of Reinforced Plastic and Composites. 28(8), 965–978 (2009) 9. M. Rout, S. S. Hota and Amit Karmakar. Free vibration characteristics of delaminated composite pretwisted stiffened cylindrical shell. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science. 2018, 232(4):595-611 10. S.Kumari and D.Chakravorty. Bending Behaviour OF Delaminated Composite Full Conoids under Point Load. National Conference on Recent Advances in Fluid and Solid Mechanics, National Institute of Technology, Rourkela, India, 2010 11. H. Das, D. Chakravorty, Design Aids and Selection Guidelines for Composite Conoidal Shell Roofs - A Finite Element Application. Journal of Reinforced Plastic and Composites 26(17), 1793–1819 (2007) 12. P.K. Parhi, S.K. Bhattacharyya, P.K. Sinha, Hygrothermal Effects on the Dynamic Behavior of Multiple Delaminated Composite Plates and Shells. J. Sound Vib. 248(2), 195–214 (2001)

Effect of Steel Fibre on Mechanical Properties of Metakaolin-Mixed Concrete Vishal Rawat, Rakesh Kumar, A. K. Sachan, and Deep Tripathi

Abstract An experiment was done to study the effect of metakaolin (MK) used as mineral admixture and its impact on the mechanical properties of MK-mixed concrete (MKMC) with and without the use of hooked steel fibre (SF). The present investigation was performed on referral concrete of M30 grade mix concrete. MKMC was made using OPC alone as control cube and using MK in place of cement by 5, 10, 15 and 20%. The parameters of fresh properties of concrete such as slump of concrete and hardened properties of mixed concrete such as compressive strength (CS) at 7, 28 and 56 days, split tensile strength (STS) at 28 days and flexural strength (FS) at 28 days with partial replacement of cement by MK with and without the use of SF were studied. After optimizing, the effect of inclusion of SF was also studied for CS (7, 28 and 56 days), STS (28 days) and FS (28 days) in referral as well as the MKMC. SF is added to 0.0, 0.50, 0.75, 1.0 and 1.25% by volume. It was found that substitution of cement by MK and the inclusion of SF shows better performance than referral concrete. Keywords Metakaolin (MK) · Hooked steel fibre (SF) · Metakaolin mix concrete (MKMC) · Metakaolin mix steel fibre concrete (MKSFC) · Ordinary portland cement (OPC) · Mechanical properties

V. Rawat (B) · R. Kumar · A. K. Sachan · D. Tripathi Motilal Nehru National Institute of Technology, Prayagraj, U.P, India e-mail: [email protected] R. Kumar e-mail: [email protected] A. K. Sachan e-mail: [email protected] D. Tripathi e-mail: [email protected] © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021 S. Chandrasekaran et al. (eds.), Recent Advances in Structural Engineering, Lecture Notes in Civil Engineering 135, https://doi.org/10.1007/978-981-33-6389-2_11

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1 Introduction Concrete is a very versatile construction material. It is a heterogenous mix of cement, water and aggregates. The admixtures may be added in concrete in order to enhance some of the properties desired specially. Various materials, such as fly ash, rice husk, metakaolin (MK) and so on, are added with steel fibre (SF) to obtain concrete of desired properties, the key to achieving a strong, durable concrete with the careful proportioning, mixing and compacting of ingredients. Rahane et al. [1] reported that the compressive strength of normal concrete increased up to 8.70% by the addition of 5% MK and 1% SF. Somasekharaiah et al. [2] reported that inclusion of 1.25% combine (steel and polypropylene) fibre volume and 10% replacement of cement with MK shows better performance in compressive, split and flexural strength. Shikhare and Kulukar [3] reported that addition of SF in the concrete enhances brittle nature to more ductile one and improves the concrete ductility behaviour, and also the mechanical properties of concrete increased with the addition of fibre content. Nikhil and Vidhale [4] reported that the optimum inclusion of SF was 1.5%, and the addition of higher fibre content increased compressive, flexural abrasion resistance and crack arrester properties. Gaikwad and Ghugal [5] have reported that workability of concrete decreases with increase in inclusion of SF and MK in concrete mix. Reddy and Jagadeesh [6] have reported that percentage loss in weight of concrete with the addition of 2% crimped SF is less as compared with other proportions and have lesser % loss in compressive strength. Jatti and Birajdar [7] have reported that compressive strength has increased by 1.53% as compared to referral concrete by the addition of 2.5% fibre and 5% MK. The brittle behaviour of concrete improved with the inclusion of SF in it [8]. Jagtap et al. [9] reported that the mechanical properties of MKMC increased as compared to conventional concrete. Siddique and Klaus [10] had reported that MKMC enhanced resistance to sulphate attack. Dinakar et al. [11] reported that by the replacement of OPC with MK reduces water permeability, absorption and chloride permeability of concrete. Sanjeev et al. [12] reported that with the addition of fibre, surface hardness of the concrete enhanced up to some extent. Amulya et al. [13] reported that percentage increase in CS, STS and FS of metakaolin-mixed concrete was 15.06, 18.80 and 14.75%, respectively, in comparison with nominal mix. Karthikeyan et al. [14] reported that workability of concrete mixed decreases with increase in fibre content. Nitin Verma et al. [15] reported that strength of fibre-reinforced concrete is significantly higher than the referral concrete. The purpose of this work is to study the mechanical properties of MKMC and MKSFC. MK used as a partial substitution of cement incorporated with OPC to produce different mixes. The different mixes were cast and tested for CS at 7, 28 and 56 days. Specimens were tested for STS and FS at the age of 28 days. Workability of different mixes of fresh concrete was also carried out in this study.

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2 Experimental Study The concrete mixes were prepared using ordinary Portland cement (OPC) as binding material, coarse aggregate, fine aggregate, metakaolin, steel fibre, water and superplasticizer.

2.1 Raw Materials and Their Properties OPC of brand JAYPEE of grade 43 was used for this study. The cement test results were normal consistency = 30%; initial setting time = 55 min; final setting time = 470 min; specific gravity = 3.15; CS = 42.00 MPa (28 days). The test values satisfied the provisions of IS: 8112-1989 [16]. Natural FA of rounded shape was used (conforms to zone III, IS: 383-1970 [13]). It’s bulk density and specific gravity were found to be 1680 kg/m3 and 2.68, respectively. The CA of size 10 and 20 mm have specific gravities = 2.70 and 2.72 respectively; water absorptions = 1.0 and 0.85%, respectively, were used and satisfied IS 383-1970 [13]. The bulk density of 10 and 20 mm size aggregate was 1590 and 1560 kg/m3 individually. The FM, that is fineness modulus, of FA was 2.45, and its value for the CA of size 10 and 20 mm was 6.26 and 7.05 individually. Metakaolin (procured from M/S Kaolin Pvt. Ltd., Gujarat) of off-white colour having specific gravity 2.30. Steel fibre (procured from M/S Stewols India (P) Ltd., Nagpur) having density 7850 kg/m3 and length as well as least dimension are 36 and 0.45 mm individually. A polycarboxylic ether-based master superplasticizer with density approximately 1.08 was used. The chemical compositions of OPC and MK are shown in Table 1 as provided by suppliers. Table 1 Chemical properties of OPC and MK Chemical composition (%)

OPC

MK

Silicon dioxide

20.05

50–55

Calcium oxide

61.95

1–3%

Aluminium oxide

5.28

Iron oxide

4.12

38–42% 0.4

Magnesium oxide

2.78