This document provides an overview of a new book titled "New Materials in Civil Engineering". It discusses several new types of materials being used in civil engineering projects, including high-performance concrete, geopolymer concrete, fiber-reinforced concrete, lightweight concrete, ultrahigh-strength concrete, and bacterial concrete. It also discusses the use of computational intelligence for modeling pavement surfaces and distress, expanded polystyrene geofoam applications, recycling industrial wastes for clay ceramics, fiber-reinforced polymer composites, superplasticizer effects on self-compacting concrete, timber-derived building facades, piezoelectric composite plates, nanomaterials for self-healing concrete, sustainable concrete with waste fibers, alkali

2. New Materials in Civil Engineering

3. New Materials in Civil
Engineering
Edited by
Pijush Samui
Department of Civil Engineering, NIT Patna,
Patna, Bihar, India
Dookie Kim
Department of Civil and Environmental
Engineering, Structural System Laboratory,
Kongju National University, Cheonan,
Chungnam, Republic of Korea
Nagesh R. Iyer
FNAE Dean & Visiting Professor, Indian Institute
of Technology Dharwad, Dharwad, India
Sandeep Chaudhary
Discipline of Civil Engineering, Indian Institute
of Technology Indore, Indore, India

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5. Dedication
Dedication in memory of my father
Prof. G.R. Ranganatha Iyer
(June 26, 1922 October 30, 2019)
Chief Engineer & Joint Secretary (Retd), Govt. of Gujarat
Professor of Civil Engineering, L.D. College of Engineering, Gujarat
University & Technical Advisor, World Bank
He has been a fountainhead of knowledge, inspiration, philosophy,
and an excellent disciple of spiritual learning; a noble soul radiating
love and warmth; he has left behind a rich harvest of memories to
cherish, honor, and emulate. He was a magnanimous presence, an
endearing soul who spread happiness and love with his brilliant smile
and words of encouragement. We pray for his soul and salute him for
his foot prints on the sands of time! We will remember him in every
moment in every walk of our lives, as we continue to be inspired by
him, forever. People of his kind never die!

6. Contents
List of Contributors xvii
1 An overview of cementitious construction materials 1
Nagesh R. Iyer
1.1 Cement and concrete 1
1.2 High-performance concrete 10
1.3 Geopolymer concrete 13
1.4 Fiber-reinforced concrete 16
1.5 Fiber-reinforced concrete polymer composites 23
1.6 Lightweight concrete 25
1.7 Ultrahigh-strength concrete 40
1.8 Biomimetics and bacterial concrete 50
Acknowledgments 61
References 61
2 Computational intelligence for modeling of pavement surface
characteristics 65
Behrouz Mataei, Fereidoon Moghadas Nejad, Hamzeh Zakeri
and Amir H. Gandomi
2.1 Introduction 65
2.2 Computational intelligence methods 67
2.3 Conclusion 75
References 76
Further reading 77
3 Computational intelligence for modeling of asphalt pavement
surface distress 79
Sajad Ranjbar, Fereidoon Moghadas Nejad, Hamzeh Zakeri
and Amir H. Gandomi
3.1 Introduction 79
3.2 CI methods 80
3.3 Methodology and application 84
3.4 Application of CI frameworks in PMS 97
3.5 Conclusion 102
References 104

7. 4 Expanded polystyrene geofoam 117
S.N. Moghaddas Tafreshi, S.M. Amin Ghotbi Siabil and A.R. Dawson
4.1 Introduction 117
4.2 EPS properties 120
4.3 EPS in embankments 131
4.4 EPS in bridge abutments and retaining structures 138
4.5 EPS in utility protection 144
4.6 EPS in other uses 149
4.7 Conclusions 150
References 151
5 Recycling of industrial wastes for value-added applications
in clay-based ceramic products: a global review (2015 19) 155
M. Contreras, M.J. Gázquez, M. Romero and J.P. Bolı´var
5.1 Introduction 155
5.2 Industrial waste materials as aggregate in clay ceramics 158
5.3 Review of studies into the incorporation of waste materials
in brick making 164
5.4 Discussion 208
References 209
6 Emerging advancement of fiber-reinforced polymer composites
in structural applications 221
Kishore Kumar Mahato, Krishna Dutta and Bankim Chandra Ray
6.1 Introduction 221
6.2 Assessment of fiber-reinforced polymer composites by
mechanical, chemical, and thermal behaviors 224
6.3 Evaluation of special structural properties 233
6.4 Environmental durability of fiber-reinforced polymer
composites in civil structures 241
6.5 Conclusions and future perspectives 261
Acknowledgment 262
References 262
7 Fiber-reinforced concrete and ultrahigh-performance
fiber-reinforced concrete materials 273
Francesco Micelli, Angela Renni, Abdou George Kandalaft
and Sandro Moro
7.1 Fiber-reinforced concrete 273
7.2 Ultrahigh-performance concrete ultrahigh-performance
fiber-reinforced concrete 294
References 310
viii Contents

8. 8 The superplasticizer effect on the rheological and mechanical
properties of self-compacting concrete 315
Mouhcine Ben Aicha
8.1 Introduction 315
8.2 Chemical structure of superplasticizers 315
8.3 Action mechanisms of superplasticizers 318
8.4 Superplasticizer effect on cement paste 321
8.5 Superplasticizer effects on concrete rheology 324
8.6 Superplasticizer effect on concrete compressive strength 326
8.7 Conclusion 327
References 328
9 Trends and perspectives in the use of timber and derived
products in building façades 333
Anna Sandak, Marcin Brzezicki and Jakub Sandak
9.1 Introduction 333
9.2 Biobased façade materials 335
9.3 Trends and perspectives 348
9.4 Conclusions 369
Acknowledgment 370
References 370
10 Dynamic response of laminated composite plates fitted
with piezoelectric actuators 375
S.K. Sahu, A. Gupta and E.V. Prasad
10.1 Introduction 375
10.2 Formulation 378
10.3 Linear static analysis of cross-ply laminated plates 383
10.4 Dynamic and transient analyses 383
10.5 Nonlinear vibration analysis of composite plates
embedded with piezoelectric materials 384
10.6 Conclusion 392
References 392
11 Functional nanomaterials and their applications toward
smart and green buildings 395
Kwok Wei Shah, Ghasan Fahim Huseien and Teng Xiong
11.1 Introduction 395
11.2 Sustainability of traditional ordinary Portland
cement-based concrete 396
11.3 Self-healing concrete 398
11.4 Nanomaterials 410
11.5 Nanomaterial-based self-healing concrete 413
11.6 Sustainability of nanomaterial-based self-healing concrete 419
ix
Contents

9. 11.7 Advantages and disadvantages of nanomaterials for
self-healing concrete 420
11.8 Economy of nanomaterial-based self-healing concretes 420
11.9 Environmental suitability and safety features of
nanomaterial-based concretes 421
11.10 Conclusions 422
References 423
12 Production of sustainable concrete composites comprising
waste metalized plastic fibers and palm oil fuel ash 435
Hossein Mohammadhosseini, Mahmood Md. Tahir,
Rayed Alyousef and Hisham Alabduljabbar
12.1 Introduction 435
12.2 Waste metalized plastic fibers 437
12.3 Concrete incorporating waste metalized plastic fibers 439
12.4 Applications 454
12.5 Conclusions 454
References 455
13 Alkali-activated concrete systems: a state of art 459
R. Manjunath and Mattur C. Narasimhan
13.1 Introduction 459
13.2 Geopolymers and alkali-activated cementitious systems 460
13.3 Requirements for alkali activation of ground granulated
blast furnace slag 463
13.4 Alkali-activated slag systems 463
13.5 Effect of dosage and modulus of activator solutions 464
13.6 Workability and strength characteristics of geopolymers
and alkali-activated composites 465
13.7 Alkali-activated composites with alternative binders 469
13.8 Alkali-activated composites with different activators 471
13.9 Alkali-activated composites with alternative aggregates 472
13.10 Durability studies on alkali-activated composites 473
13.11 Elevated-temperature performance of alkali-activated
composites 475
13.12 Behaviour of alkali-activated composites incorporated
with fibers 477
13.13 Behaviour of rebar-reinforced structural elements made
from alkali-activated concrete mixes 479
13.14 Summary of alkali-activated composite systems 480
13.15 Future trends for AA composites—research needs 482
References 482
x Contents

10. 14 Porous concrete pavement containing nanosilica from black
rice husk ash 493
Ramadhansyah Putra Jaya
14.1 Introduction 493
14.2 Literature review 496
14.3 Materials 499
14.4 Experimental plan 501
14.5 Results and discussions 512
14.6 Conclusions 523
Acknowledgment 523
References 523
15 Porous alkali-activated materials 529
Priyadharshini Perumal, Tero Luukkonen, Harisankar Sreenivasan,
Paivo Kinnunen and Mirja Illikainen
15.1 Introduction 529
15.2 Porous alkali-activated materials 530
15.3 Characterization of porosity in alkali-activated materials 541
15.4 Properties of porous alkali-activated materials 546
15.5 Functional properties and applications 549
15.6 Conclusions 554
Acknowledgments 555
References 555
16 Lightweight cement-based materials 565
Teresa M. Pique, Federico Giurich, Christian M. Martı´n, Florencia
Spinazzola and Diego G. Manzanal
16.1 Introduction 565
16.2 Lightweight/low-strength aggregates 566
16.3 Lightweight/high-strength aggregates 575
16.4 Extenders 580
16.5 Outlook and future trends 586
References 587
17 Development of alkali-activated binders from sodium
silicate powder produced from industrial wastes 591
Parthiban Kathirvel
17.1 Introduction 591
17.2 Alternative for Portland cement 592
17.3 Alkaline activators 593
17.4 Waste glass 594
17.5 Silica fume 597
17.6 Rice husk ash 597
xi
Contents

11. 17.7 Sugarcane bagasse ash 602
17.8 Other materials 605
17.9 Cost analysis 606
17.10 Summary and conclusions 609
References 609
18 Innovative cement-based materials for environmental
protection and restoration 613
Hosam M. Saleh and Samir B. Eskander
18.1 Introduction 613
18.2 Innovative cement-based material 617
18.3 Conclusions 636
References 638
19 Comparative effects of using recycled CFRP and GFRP
fibers on fresh- and hardened-state properties of
self-compacting concretes: a review 643
M. Mastali, Z. Abdollahnejad, A. Dalvand, A. Sattarifard
and Mirja Illikainen
19.1 Introduction 643
19.2 Experimental plan 645
19.3 Results and discussion 647
19.4 Analysis 650
19.5 Conclusions 652
References 654
20 Corrosion inhibitors for increasing the service life of structures 657
B. Bhuvaneshwari, A. Selvaraj and Nagesh R. Iyer
20.1 Introduction 657
20.2 What is corrosion? 658
20.3 Severity of corrosion 660
20.4 Concrete corrosion inhibitors 661
20.5 Limitation of inhibitors 663
20.6 Mechanism of inhibition 664
20.7 Techniques to assess inhibitor performances 665
20.8 Concrete corrosion assessing techniques 666
20.9 Surface characterization of the metals/rebars after corrosion 668
20.10 Corrosion product analysis techniques 668
20.11 Durability studies of concrete with admixtures 670
20.12 Conclusion 673
Acknowledgments 673
References 673
xii Contents

12. 21 Use of fly ash for the development of sustainable construction
materials 677
Sanchit Gupta and Sandeep Chaudhary
21.1 Introduction 677
21.2 Sustainable development of fly ash utilization 678
21.3 Characterization of fly ash 679
21.4 Fly ash applications 681
21.5 Developments in industrial fly ash applications 682
21.6 Conclusions 686
References 687
22 An innovative and smart road construction material:
thermochromic asphalt binders 691
Henglong Zhang, Zihao Chen, Chongzheng Zhu
and Chuanwen Wei
22.1 Introduction 691
22.2 Three-component organic reversible thermochromic
materials 693
22.3 The performance characterization of thermochromic
asphalt binders 699
22.4 The adjustment of bituminous pavement temperature 713
22.5 Recommendations for future research and applications 714
References 715
23 Resin and steel-reinforced resin used as injection materials
in bolted connections 717
Haohui Xin, Martin Nijgh and Milan Veljkovic
23.1 Introduction 717
23.2 Computational homogenization 721
23.3 Experiments 722
23.4 Numerical simulation of resin 733
23.5 Numerical simulation of steel-reinforced resin 734
23.6 Conclusions 741
References 743
24 Swelling behavior of expansive soils stabilized with
expanded polystyrene geofoam inclusion 745
S. Selvakumar and B. Soundara
24.1 Effect of geobeads inclusion 745
24.2 Effect of the geofoam granules column 755
24.3 Conclusions 774
Acknowledgments 774
References 775
xiii
Contents

13. 25 New generation of cement-based composites for civil
engineering 777
Danna Wang, Wei Zhang and Baoguo Han
25.1 Introduction 777
25.2 Smart and multifunctional cement-based composites 778
25.3 Nanocement-based composites 784
25.4 Conclusions 789
Acknowledgments 790
References 790
26 Potential use of recycled aggregate as a self-healing
concrete carrier 797
Chao Liu and Zhenyuan Lv
26.1 Introduction 797
26.2 Self-healing concrete materials 802
26.3 Method and results 805
26.4 Effect of recycled aggregate in self-healing concrete 817
26.5 Outlook 820
References 821
27 Self-healing concrete 825
Xu Huang and Sakdirat Kaewunruen
27.1 Introduction 825
27.2 Materials and methods 828
27.3 Results 835
27.4 Discussion 851
27.5 Conclusion 853
Acknowledgments 854
Author contributions 854
Conflicts of interest 854
References 854
28 Equations for prediction of rubberized concrete compressive
strength: a literature review 857
Marijana Hadzima-Nyarko and Ivana Miličević
28.1 Introduction 857
28.2 Literature review 858
28.3 Database description 859
28.4 Expressions for compressive strength in the literature 864
28.5 Expressions for compressive strength of concrete 865
28.6 Comparison of existing expressions 869
28.7 Conclusion 872
Acknowledgment 872
References 872
xiv Contents

14. 29 Influence of cobinders on durability and mechanical
properties of alkali-activated magnesium aluminosilicate
binders from soapstone 877
Z. Abdollahnejad, M. Mastali, F. Rahim, Tero Luukkonen,
Paivo Kinnunen and Mirja Illikainen
29.1 Introduction 877
29.2 Experimental plan 878
29.3 Results and discussion 884
29.4 Conclusions 892
Acknowledgment 894
References 894
30 Fly ash utilization in concrete tiles and paver blocks 897
S.K. Sahu, S. Kamalakkannan and P.K. Pati
30.1 Introduction 897
30.2 Experimental procedure 900
30.3 Results and discussion 905
30.4 Conclusion 915
References 916
31 Problems in short-fiber composites and analysis of
chopped fiber-reinforced materials 919
Vahid Monfared
31.1 Introduction 919
31.2 Analytical methods 933
31.3 Numerical methods 954
31.4 Experimental methods 973
31.5 Constitutive and fundamental researches 990
31.6 Solved problems 992
References 1035
Index 1045
xv
Contents

15. List of Contributors
Z. Abdollahnejad Fibre and Particle Engineering Research Unit, Faculty of
Technology, University of Oulu, Oulu, Finland; Civil & Environmental
Engineering Department, University of Connecticut, CT, United States
Hisham Alabduljabbar Department of Civil Engineering, College of Engineering,
Prince Sattam bin Abdulaziz University, Alkharj, Saudi Arabia
Rayed Alyousef Department of Civil Engineering, College of Engineering, Prince
Sattam bin Abdulaziz University, Alkharj, Saudi Arabia
Mouhcine Ben Aicha National School of Architecture, Rabat, Morocco
B. Bhuvaneshwari Department of Chemical Engineering, Indian Institute of
Technology Kanpur, Kanpur, India
J.P. Bolı́var Department of Applied Physics, Faculty of Experimental Sciences,
University of Huelva, Natural Resources, Health and Environment Research Center
(RENSMA), Huelva, Spain
Marcin Brzezicki Wroclaw University of Science and Technology, Faculty of
Architecture, Wroclaw, Poland
Sandeep Chaudhary Discipline of Civil Engineering, Indian Institute of
Technology Indore, Indore, India
Zihao Chen Key Laboratory for Green & Advanced Civil Engineering Materials
and Application Technology of Hunan Province, College of Civil Engineering,
Hunan University, Changsha, P.R. China
M. Contreras Department of Applied Physics, Faculty of Experimental Sciences,
University of Huelva, Natural Resources, Health and Environment Research Center
(RENSMA), Huelva, Spain
A. Dalvand Department of Engineering, Lorestan University, Khorramabad, Iran
A.R. Dawson Nottingham Transportation Engineering Centre, University of
Nottingham, Nottingham, United Kingdom

16. Krishna Dutta Composite Materials Laboratory, Department of Metallurgical and
Materials Engineering, National Institute of Technology, Rourkela, India
Samir B. Eskander Radioisotope Department, Nuclear Research Center, Atomic
Energy Authority, Giza, Egypt
Amir H. Gandomi Faculty of Engineering & Information Technology, University
of Technology Sydney, NSW, Australia
M.J. Gázquez Department of Applied Physics, University of Cadiz, University
Marine Research Institute (INMAR), Cádiz, Spain
S.M. Amin Ghotbi Siabil Department of Civil Engineering, K.N. Toosi University
of Technology, Tehran, Iran
Federico Giurich Polymers for the Oil and Construction Industry, Engineering
Faculty, Universidad de Buenos Aires, Buenos Aires University, Argentina
A. Gupta Department of Civil Engineering, OP Jindal University, Raigarh,
Chhattisgarh, India
Sanchit Gupta Discipline of Civil Engineering, Indian Institute of Technology
Indore, Indore, India
Marijana Hadzima-Nyarko Josip Juraj Strossmayer Univеrsity of Osijek, Faculty
of Civil Engineеring and Architecturе Osijek, Osijek, Croatia
Baoguo Han School of Civil Engineering, Dalian University of Technology,
Dalian, P.R. China
Xu Huang Department of Civil Engineering, School of Engineering, University of
Birmingham, Birmingham, United Kingdom
Ghasan Fahim Huseien Department of Building, School of Design and
Environment, National University of Singapore, Singapore
Mirja Illikainen Civil & Environmental Engineering Department, University of
Connecticut, CT, United States; Fibre and Particle Engineering Research Unit,
Faculty of Technology, University of Oulu, Oulu, Finland
Nagesh R. Iyer Fellow, Indian National Academy of Engineering, Dean &
Visiting Professor, Indian Institute of Technology, Dharwad, India
Ramadhansyah Putra Jaya Department of Civil Engineering, College of
Engineering, University of Malaysia Pahang, Kuantan, Malaysia
xviii List of Contributors

17. Sakdirat Kaewunruen Laboratory for Track Engineering and Operations for
Future Uncertainties (TOFU Lab), School of Engineering, University of
Birmingham, Birmingham, United Kingdom
S. Kamalakkannan Department of Civil Engineering, NIT Rourkela, Odisha,
India
Abdou George Kandalaft BASF Construction Chemicals, Italy
Parthiban Kathirvel School of Civil Engineering, SASTRA Deemed University,
Thanjavur, India
Paivo Kinnunen Fibre and Particle Engineering Research Unit, University of
Oulu, Oulu, Finland; Civil & Environmental Engineering Department, University of
Connecticut, CT, United States
Chao Liu Xi’an University of Architecture and Technology, Xi’an, China
Tero Luukkonen Fibre and Particle Engineering Research Unit, University of
Oulu, Oulu, Finland; Civil & Environmental Engineering Department, University of
Connecticut, CT, United States
Zhenyuan Lv Xi’an University of Architecture and Technology, Xi’an, China
Kishore Kumar Mahato School of Mechanical Engineering, Vellore Institute of
Technology, Vellore, India
R. Manjunath Department of Civil Engineering, National Institute of Technology
Karnataka, Surathkal, India
Diego G. Manzanal National Univerity of Patagonia, Comodoro Rivadavia, Argentina;
ETS of Roads, Canals and Ports, Polytechnique University of Madrid, Madrid, Spain
Christian M. Martı́n Polymers for the Oil and Construction Industry, Engineering
Faculty, Universidad de Buenos Aires, Buenos Aires University, Argentina
M. Mastali Fibre and Particle Engineering Research Unit, Faculty of Technology,
University of Oulu, Oulu, Finland; Civil & Environmental Engineering Department,
University of Connecticut, CT, United States
Behrouz Mataei Department of Civil and Environment Engineering, Amirkabir
University of Technology, Tehran, Iran
Francesco Micelli University of Salento, Lecce, Italy
xix
List of Contributors

18. Ivana Miličević Josip Juraj Strossmayer Univеrsity of Osijek, Faculty of Civil
Engineеring and Architecturе Osijek, Osijek, Croatia
S.N. Moghaddas Tafreshi Department of Civil Engineering, K.N. Toosi
University of Technology, Tehran, Iran
Hossein Mohammadhosseini Institute for Smart Infrastructure and Innovative
Construction (ISIIC), School of Civil Engineering, Faculty of Engineering,
Universiti Teknologi Malaysia (UTM), Skudai, Johor, Malaysia
Vahid Monfared Department of Mechanical Engineering, Zanjan Branch, Islamic
Azad University, Zanjan, Iran
Sandro Moro BASF Construction Chemicals, Italy
Mattur C. Narasimhan Department of Civil Engineering, National Institute of
Technology Karnataka, Surathkal, India
Fereidoon Moghadas Nejad Department of Civil and Environment Engineering,
Amirkabir University of Technology, Tehran, Iran
Martin Nijgh Faculty of Civil Engineering and Geosciences, Delft University of
Technology, Delft, The Netherlands
P.K. Pati Department of Civil Engineering, NIT Rourkela, Odisha, India
Priyadharshini Perumal Fibre and Particle Engineering Research Unit, University
of Oulu, Oulu, Finland
Teresa M. Pique Polymers for the Oil and Construction Industry, Engineering
Faculty, Universidad de Buenos Aires, Buenos Aires University, Argentina
E.V. Prasad Department of Civil Engineering, OP Jindal University, Raigarh,
Chhattisgarh, India
F. Rahim Civil & Environmental Engineering Department, University of
Connecticut, CT, United States
Sajad Ranjbar Department of Civil and Environment Engineering, Amirkabir
University of Technology, Tehran, Iran
Bankim Chandra Ray Composite Materials Laboratory, Department of
Metallurgical and Materials Engineering, National Institute of Technology,
Rourkela, India
xx List of Contributors

19. Angela Renni Roughan & O’Donovan Consulting Engineers, Dublin, Ireland
M. Romero Department of Construction, Eduardo Torroja Institute for
Construction Science (IETcc-CSIC), Madrid, Spain
S.K. Sahu Department of Civil Engineering, NIT Rourkela, Odisha, India
Hosam M. Saleh Radioisotope Department, Nuclear Research Center, Atomic
Energy Authority, Giza, Egypt
Anna Sandak InnoRenew CoE, Izola, Slovenia; University of Primorska, Faculty
of Mathematics, Natural Sciences and Information Technologies, Koper, Slovenia
Jakub Sandak InnoRenew CoE, Izola, Slovenia; University of Primorska, Andrej
Marušič Institute, Koper, Slovenia
A. Sattarifard Faculty of Civil Engineering, Semnan University, Semnan, Iran
S. Selvakumar Department of Civil Engineering, Vel Tech Rangarajan Dr.
Sagunthala R&D Institute of Science and Technology, Chennai, India
A. Selvaraj CBM College, Bharathiar University, Coimbatore, India
Kwok Wei Shah Department of Building, School of Design and Environment,
National University of Singapore, Singapore
B. Soundara Department of Civil Engineering, Bannari Amman Institute of
Technology, Sathyamangalam, Erode, India
Florencia Spinazzola Polymers for the Oil and Construction Industry, Engineering
Faculty, Universidad de Buenos Aires, Buenos Aires University, Argentina
Harisankar Sreenivasan Fibre and Particle Engineering Research Unit, University
of Oulu, Oulu, Finland
Mahmood Md. Tahir Institute for Smart Infrastructure and Innovative
Construction (ISIIC), School of Civil Engineering, Faculty of Engineering,
Universiti Teknologi Malaysia (UTM), Skudai, Johor, Malaysia
Milan Veljkovic Faculty of Civil Engineering and Geosciences, Delft University
of Technology, Delft, The Netherlands
Danna Wang School of Civil Engineering, Dalian University of Technology,
Dalian, P.R. China
xxi
List of Contributors

20. Chuanwen Wei Key Laboratory for Green & Advanced Civil Engineering
Materials and Application Technology of Hunan Province, College of Civil
Engineering, Hunan University, Changsha, P.R. China
Haohui Xin Faculty of Civil Engineering and Geosciences, Delft University of
Technology, Delft, The Netherlands
Teng Xiong Department of Building, School of Design and Environment, National
University of Singapore, Singapore
Hamzeh Zakeri Department of Civil and Environment Engineering, Amirkabir
University of Technology, Tehran, Iran
Henglong Zhang Key Laboratory for Green & Advanced Civil Engineering
Materials and Application Technology of Hunan Province, College of Civil
Engineering, Hunan University, Changsha, P.R. China
Wei Zhang School of Civil Engineering, Dalian University of Technology, Dalian,
P.R. China
Chongzheng Zhu Key Laboratory for Green & Advanced Civil Engineering
Materials and Application Technology of Hunan Province, College of Civil
Engineering, Hunan University, Changsha, P.R. China
xxii List of Contributors

21. 1
An overview of cementitious
construction materials
Nagesh R. Iyer
Fellow, Indian National Academy of Engineering, Dean & Visiting Professor, Indian
Institute of Technology Dharwad, Dharwad, India
1.1 Cement and concrete
1.1.1 Introduction
The purpose of this chapter is to introduce different engineering materials of construc-
tion that have potential to be employed [13]. Considering various engineering attri-
butes such as durability, sustainability, enhanced performance, reduction of use of
natural resources, and low embodied energy, and the way forward, the reader is intro-
duced to the new materials, however no attempt is made to provide a treatise of each
material. The concepts introduced also give insight into the challenges and scope for
innovation that exist. The extraction, production, transportation, utilization, and recy-
cling of construction materials have impacts on the environment, sustainability, and
built environment. Generally, investment and rate of growth of infrastructure act as
one of the key indicators of economic growth and prosperity of any country. There are
reports of structures having suffered severe degradation. Investigations have revealed
that most of the distress, damage, or degradation are due to the combined effects of
aggressive environments, and increased live loads or altered function from the origi-
nal/intended design. Civil engineers face challenges of restoring the original design
life, and preserving and maintaining retrofitted structures [1] through technological
interventions. After water, concrete is the most commonly used building material in
the world. Concrete has been through different stages of development; the earliest was
conventional normal-strength concrete (NSC). Cement, water, fine aggregates, and
coarse aggregates are the four key ingredients to developing the concrete mix matrix.
For faster and leaner RCC construction of civil engineering infrastructure use of con-
crete with very high compressive strength is the preferred solution today. Civil infra-
structure referred to here is concerned with urban infrastructure, development of smart
cities, high-rise buildings, and long-span bridges, etc. In the next stages of develop-
ment, (1) high-strength concrete (HSC), (2) high-performance concrete (HPC), and (3)
ultraHSC (UHSC) have been successfully developed and deployed. It may be noted
that HSC has compressive strength over 50 MPa, whereas HPC and UHSC have
exhibited compressive strengths of over 100 MPa and high tensile strength (more than
10% of the compressive strength). There are also reports of achieving over 140 MPa
compressive strength. The range of applications of such UHSCs is far and wide.
New Materials in Civil Engineering. DOI: https://doi.org/10.1016/B978-0-12-818961-0.00001-6
© 2020 Elsevier Inc. All rights reserved.

22. To substantiate, successful uses have been reported in the construction of strategic sec-
tors (for example, blast shelters, impact-resistant structures, nuclear structures, etc.),
high-rise buildings, structures/infrastructures in coastal areas for corrosion resistance,
pavements, etc. In cases where one wants to achieve higher axial compressive
strength, the watercement ratio is reduced. This is done by adding a water-reducing
agent or superplasticizer (SP). In contrast to NSC, two other ingredients, namely,
admixtures and additives, are added to the mix. Silica fume (SF), fly ash (FA), and
blast furnace slag are preferred as admixtures. These are waste materials and are
industrial by-products. Therefore, HPC is considered as a green HPC (GHPC).
Considerable studies were reported on the behavior and applications of HPC toward
the end of the 20th century. UHSC thus has a clear advantage and is preferred in a
wide range of engineering applications such as, to improve strength, deformability,
and toughness of UHSC, short steel fibers are introduced during mixing to restrain
cracks. Introduction of steel fibers in the matrix improves the toughness and deforma-
tion of UHSC, thereby avoiding high brittleness [2,3].
Ordinary Portland cement (OPC) is an energy-intensive material and is also asso-
ciated with high CO2 emissions. Stricter regulations and proactive actions of major
cement manufacturers have reduced the emission levels and experiments on alter-
nate fuels to replace coal are on-going. The best way to reduce the carbon footprint
is to use supplementary cementitious materials (SCMs) like FA, ground slag, rice
husk ash, metakaoline, etc. The use of SCMs not only reduces the OPC content in
concrete, but also enhances the durability, which is one of the foundations of sus-
tainability. The use of blended cements in which the right kind of SCM of right
quality is used would obviate all apprehensions about using SCMs. Emphasis
should also be on optimizing the use of cement by applying mix proportioning. In
India, the majority of “normal” concrete of grades M20 and M25 is still manufac-
tured by volume batching. Use of appropriate construction chemicals judiciously to
reduce the watercement ratio and thus obtain a dense and durable concrete is
imperative.
Concrete that is made well, transported carefully, cast properly, and cured suffi-
ciently would last a very long time, making concrete an extremely sustainable mate-
rial. The absence of large-scale mechanization, absence of weigh-batching
facilities, improper shuttering, inadequate compaction, and virtually no curing are
the bane of concrete construction. There is a need for extensive training of masons
and construction workers to inculcate in them this level of professionalism.
1.1.2 Proportioning
Concrete is a composite heterogeneous material substantially influenced by the con-
stituent materials and the proportional distribution in the mix. Well-developed mix
design methods form the nucleus of concrete technology for sustainable develop-
ment. A good concrete mix should lead to strong and durable concrete as the end-
product. This can be attained by a well-established procedure of mixing of the
ingredients. Much depends upon how the voids are filled and packed in a concrete
mix, otherwise it will result in rough, honeycombed, and porous concrete.
2 New Materials in Civil Engineering

23. A mix is easy to handle and can produce a better and smoother finish when it
has an excess amount of cement paste. However, at the same time the mix would
shrink more and turn out to be uneconomical. Thus, optimum workability of con-
crete through a “magic” mix becomes the key. The most desired attributes in the
mix after it is hardened and is prepared with acceptable quality of paste are durabil-
ity and strength. The watercement ratio used to produce the mix determines the
strength and quality of the paste. The watercement ratio is the weight of the water
used for a given weight of the cement. This optimum and “magic” mix of cement,
aggregate, and water is generally in the range of 1015:6075:1520, respec-
tively. The numbers mentioned are percentages by volume. The air that is trapped
could be anywhere between 5% and 8%. This is the reason for vibrating the mix, so
that there are virtually no voids in the mix after it hardens. One can thus obtain
high-quality concrete by lowering the watercement ratio.
1.1.3 Other ingredients
The type and size of the aggregate used to prepare the mix depends on the geometry
and final application or the intended purpose [4]. In addition, aggregates should be
clean and free from any matter that might affect the quality of the concrete. Almost
any natural water without impurities that is almost pH neutral or not acidic qualifies
to be used for concrete, otherwise this can disturb adversely the setting time and
concrete strength. Poor concrete can show symptoms of efflorescence, staining, vol-
ume instability, and reduced durability. Furthermore, it can also lead to corrosion in
rebars. A number of studies and investigations have helped in framing guidelines
and specifications to define the limits or amount of chlorides, sulfates, alkalis, and
solids permitted. For thin building sections, small coarse aggregates should be used.
For large structures such as large dams, aggregates up to 150 mm (6 inches) in
diameter have been used. A continuous gradation of particle sizes is desirable for
efficient use of the paste.
1.1.4 Hydration
The hardening process begins once the appropriate proportion of cement, aggre-
gates, and water is used to produce a mix. Obviously, because of the presence of
water, this starts a chemical reaction called hydration. There is a formation of a
node on each cement particle surface. This node starts growing and expanding and
becomes connected with either nodes from other cement particles or adheres to
adjacent aggregates. This process leads to progressive stiffening, hardening, and
strength development of the mix. After the concrete is mixed thoroughly and is
workable, it is placed in molds or within the formwork that is already created to get
the desirable form/shape, etc. At this time, the concrete is consolidated and com-
pacted using vibrator(s) to remove voids, air to avoid forming honeycombs.
Technologies, instruments, and tools are used to achieve a smooth surface and
desirable outcome with precision. Curing ensures progressive gain of strength and
3
An overview of cementitious construction materials

24. stiffness through continued hydration. There are a number of methods of curing
that are well developed today. Concrete continues to get stronger as it ages.
1.1.5 Cement
“Cement,” in general, can be defined as any material which has the property to
bind together different materials through different reactions. Commonly the reac-
tions that are involved are chemical reactions which are aided by the presence of
water. A great deal of literature is available in the form of textbooks, standards,
technical papers, etc. which discuss in details cement, types of cements, and the
various reactions that take place during the strength-gaining process. The intention
of this section is to give a very brief overview of the types of cement generally
available in the market and major properties of such cements.
1.1.5.1 Types of cement
OPC: OPC is by far the most common cement used in India. Depending upon the 28
days strength of the cement mortar cubes, as per IS 4031-1988, OPC is classified into
three grades, namely 33, 43, and 53 grades. It is expected that for a particular grade
of cement the test results of the mortar cubes do not fall below the specified value.
Rapid hardening cement (IS 8041-1990): Rapid hardening cement starts gaining
strength and develops strength at the age of 3 days that OPC achieves in 7 days.
Higher fineness of grinding and higher C3S and lower percentage of C2S increase
the rate of development of strength.
Extra rapid hardening cement: When calcium chloride (up to 2%) is intergraded
with rapid hardening Portland cement (PC), extra rapid hardening cement is pro-
duced. Although the strength of extra rapid hardening cement is about one-fourth
higher than that of rapid hardening cement at 1 or 2 days and 10%20% higher at
7 days, it is almost the same at 90 days.
Sulfate resisting cement (IS 12330-1988): During OPC production when tricalcium
aluminate (C3A) is added restricting it to the lowest permissible value, it results in
sulfate resisting cement. It also has low C4AF content. Use of this type of cement is
more beneficial for structural elements in contact with soils and ground water, where
there is significant presence of sulfates, seawater, or exposure to the sea coast.
Portland slag cement (PSC) (IS 455-1989): PSC is produced by intimate inter-
ground mixing in suitable proportions of PC clinker, gypsum, and granulated blast
furnace slag with permitted additives. Except for slowness in hydration during the
first 28 days, other attributes of this cement are similar to OPC. Therefore it can be
employed for mass concreting. It has very low diffusivity to chloride ions and there-
fore has better resistance to corrosion of steel reinforcements.
Quick setting cement: At the time of clinker grinding, reducing gypsum content
produces quick setting cement. This cement can reduce the pumping time, making
it more cost-effective.
Super sulfated cement (IS 6909-1990): This is a hydraulic cement produced by inter-
grinding or intimate blending mixture of granulated blast furnace slag, calcium sulfate,
4 New Materials in Civil Engineering

25. and a small amount of PC or PC clinker or any other lime in the proportions of
8085:1015:5, respectively. IS:6909-1990 (reaffirmed 2016) provides more details.
Low heat cement (IS 12600-1989): This type of cement has low heat of hydration
and displays a slow rate of gain of strength. However, the ultimate strength is the
same as that of OPC. The cement is produced by intimately mixing together calcar-
eous and argillaceous and/or other silica-, alumina-, or iron oxide-bearing materials
burnt at clinkering temperature and grinding them.
Hydrophobic cement (IS 8043-1991): Hydrophobic cement is obtained by inti-
mately mixing together calcareous and argillaceous and-or other silica-, alumina- or
iron oxide-bearing materials burnt at clinkering temperature and grinding them with
natural or chemical gypsum with a small amount (say 0.1%0.5%) of hydrophobic
agent, forming a film which is water-repellant around each cement grain. The film
is broken out when the mixing together of cement and aggregate breaks the film.
This exposes the cement particles for normal hydration. The film-forming water-
repellant material is expected to improve workability and also protect from deterio-
ration due to moisture during storage and transportation.
Masonry cement (IS 3466: 1988): Masonry cement is made by intimate grinding
and mixing of PC clinker and gypsum with pozzolanic or inert materials and in
suitable proportions air entraining plasticizer resulting normally in fineness better
than OPC. It finds use mainly for masonry construction.
Expansive cement: In this type of cement, there is a significant increase in vol-
ume (instead of shrinking) vis-à-vis PC paste when mixed with water. The key ele-
ment is the presence of sulfoaluminate clinker mixed with PC and stabilizer in the
proportions of 10:100:15, respectively. This process not only improves the density
but also the integrity of concrete.
Oil-well cement (IS 8229-1986): Oil-well cement is used by the petroleum indus-
try for cementing gas and oil wells at high temperature and pressure. There are
eight classes (A to H) defined by IS:8229 that are manufactured. Each class essen-
tially contains hydraulic calcium silicates. As per the IS code, no material other
than one or more forms of calcium sulfate are interground with clinker or blended
with ground clinker during production. The common agents, which are known as
retarding agents, are starch, cellulose products, or acids to prevent quick setting.
Rediset cement: Cement which yield high strengths in about 36 hours, without
showing any retrogression is rediset cement. It has similar 1- or 3-day strength as OPC.
High alumina cement (IS 6452: 1989): As per the IS specifications, high alumina
cement is obtained by either fusing or sintering aluminous and calcareous materials
and grinding the resulting clinker. Only water can be added during the grinding pro-
cess. One of the key features of high alumina cement concrete is its very high rate
of strength development. In 1 day it can gain about 20% of the ultimate strength.
1.1.6 Cement composition
A complicated process known as hydration is caused due to chemical reaction dur-
ing mixing of cement and water in suitable proportions [2]. This gives strength to
PC. Lime, silica, alumina, and iron oxide are the chief raw materials used to
5
An overview of cementitious construction materials

26. produce cement. The four major oxides of cement, CaO, SiO2, Al2O3, and Fe2O3,
in decreasing order, interact in the kiln at high temperature, forming complex com-
pounds. The relative proportions of these oxide compositions influence various
attributes/properties of cement, including the rate of cooling and fineness of grind-
ing. Table 1.4 shows the oxide composition range of OPC. Oxides in smaller quan-
tities that are important for cement behavior include SO3, MgO, Na2O, and K2O.
PC is manufactured by crushing, milling, and proportioning the following
materials:
G
lime or calcium oxide, CaO: from limestone, chalk, shells, shale, or calcareous rock;
G
silica, SiO2: from sand, old bottles, clay, or argillaceous rock;
G
alumina, Al2O3: from bauxite, recycled aluminum, clay;
G
iron, Fe2O3: from clay, iron ore, scrap iron, and FA;
G
gypsum, CaSO4.2H2O: found together with limestone.
During the process of cement manufacture, the following methods are generally
used to determine the oxide composition of cement:
1. chemical analysis;
2. X-ray diffraction (XRD);
3. optical microscopy;
4. scanning electron microscopy (SEM) with energy dispersive X-ray analysis;
5. electron microprobe analysis;
6. selective dissolution;
7. thermal analysis.
The materials, without the gypsum, are proportioned to produce a mixture with the
desired chemical composition and then ground and blended by one of two processes:
a dry process or a wet process. The materials are then fed through a kiln at 1428
C
(2600
F) to produce grayish-black pellets known as clinker. The alumina and iron act
as fluxing agents, which lower the melting point of silica from 1650
C (3000
F) to
1428
C (2600
F). After this stage, the clinker is cooled, pulverized, and gypsum
added to regulate the setting time. It is then ground extremely fine to produce cement.
Because of the complex chemical nature of cement, a notational form as given
below is used to denote the chemical compounds.
CaO 5 C; SiO2 5 S; Al2O3 5 A; Fe2O3 5 F; H2O 5 H; MgO 5 M; Na2O 5 N; SO3
5 S; CO2 5 C
The following compounds contribute to the properties of cement.
Tricalcium aluminate, C3A: This generates considerable heat during the initial
hydration stages but has little strength contribution. The presence of gypsum delays
the hydration rate of C3A. A lower quantity of cement makes it sulfate resistant.
Tricalcium silicate, C3S: This compound hydrates and hardens rapidly. It is
largely responsible for PC’s initial set and early strength gain.
Dicalcium silicate, C2S: C2S hydrates and hardens slowly. It is largely responsi-
ble for strength gain after 1 week.
6 New Materials in Civil Engineering

27. Ferrite, C4AF: This is a fluxing agent which reduces the melting temperature of
the raw materials in the kiln [from 1650
C (3000
F) to 1428
C (2600
F)]. It
hydrates rapidly, but does not contribute much to the strength of the cement paste.
By mixing these compounds appropriately, manufacturers can produce different
types of cement to suit several construction environments.
The thermodynamics of cement chemistry have long been studied and were first
applied by Le Chatelier in 1905. The use of thermodynamic methods in cement
hydration was often doubted, as the watercement system was considered to be too
complex. Thermodynamic modeling of the interactions between solid and liquid
phases in cements using geochemical speciation codes can be the basis for the inter-
pretation of many of the observed experimental results. Thus, there are many phases
possible through different combinations within the CaOSiO2Al2O3Fe2O3
system. This permits extrapolation of the same to longer time scales by varying
different parameters within the system. The phases that get formed in the
CaOSiO2 2 Al2O3 2 Fe2O3 system as a result of combinations of number of com-
ponents such as two, three, or four can be described as binary, ternary, and quater-
nary phase diagrams [57]. A typical phase diagram for this system is shown in
Fig. 1.1 [5], with an expanded view of the lime-rich part of the system. For exam-
ple, C3S and C2S compounds are formed as a binary system due to CaO and SiO2
phase relation and, similarly, C3A and C12A7 are formed due to CaO and Al2O3,
again as a binary phase relation.
1.1.7 Aggregates
Aggregates are the constituents which give the strength and mass to the concrete
[24]. Generally, aggregates are classified as coarse or fine aggregates. Usually
Temperature
o
C
Weight %Sio2
The CaO-SiO2
system The CaO-A12
O3
SiO2
system
Liquid Liquid
Liquid
Liquid
Two Liquids
Cristobalite - liquid
Cristobalite
Two
liquids
Tridymite - liquid
Tridymite
Tridymite
Quartz
Trioyhite
Anorthite
Mullite
Corundum
Genlenite
Lime
SiO2
A12
O3
CaO
Figure 1.1 The system CaOAl2O3SiO2.
Source: Reproduced with permission from ,https://www.cementequipment.org/home/
cement-chemistry-home/everything-you-need-to-know-about-cement-chemistry-from-ancient-
times-to-2019/. (under chemical clinker formation).
7
An overview of cementitious construction materials

28. aggregates less than 4.75 mm in size are described as fine aggregates and those
greater than 4.75 mm are coarse aggregates. Indian standard IS 383:1970 gives the
specifications for aggregates from natural sources that are used in making concrete.
Grading of aggregates is important in order to obtain good concrete. Based on the
particle size distribution, the aggregates can be classified as uniformly graded, well
graded, and gap/poorly graded. It is always recommended that well-graded aggre-
gates be used, since concrete produced with well-graded aggregates will have mini-
mum voids. The fine aggregates that are being used should have very low slit
content and preferably be free from organic materials.
1.1.8 Fine aggregates
Sand Natural river sand is the most commonly used fine aggregate in the construc-
tion industry. It is also the most suitable material as of today. However, the expo-
nential increase in the demand for sand has led to a supplydemand gap. More
excessive exploitation of river beds leads to many environmental issues. Hence
there is a growing need to find alternates to river sand.
1.1.8.1 Alternate fine aggregates
Sea sand This is available in abundance and, with the long shore line available in
India, it is a viable alternative [8]. The major problem that one faces when sea sand
is used is that it usually contains chloride in excess of the permissible level.
Generally, use of sea sand is not recommended. Hence, sea sand if used for con-
struction, especially in reinforced concrete, should be screened for its chloride con-
tent. Apart from this, the particle size of sea sand may also lead to problems, hence
one has to take care that the sand being used is well graded.
Coarse ash/bottom ash Coarse ash/bottom ash forms a major part of thermal
power plant waste. There have been some studies on replacing sand with coarse ash
in cement mortar used for plastering works. It has also been used to replace sand
during the making of hollow, paver blocks, etc.
Blast furnace/copper slag Blast furnace and copper slag are waste products pro-
duced during the extraction of iron and copper, respectively, from their ores. They
have pozzolanic properties and hence have been used as a cement replacement for a
number of years. However, due to the increasing demand for, and unavailability of,
sand, it is also being thought of as an alternative filler material. Studies have found
that replacement of sand with slag results in performance in terms of workability,
refractory properties, and resistance to alkalisilica reactions.
Manufactured sand This is sand that is obtained by crushing stones to the
required shape and size. The major factor involved here is the cost of production,
however, with the increasing scarcity of natural sand and places where other alter-
nate materials are not available, manufactured sand is emerging as a good
alternative.
In general, when an alternate material is used in making concrete, it has to be
ensured that the characteristics of the materials are thoroughly studied and
8 New Materials in Civil Engineering

29. suitable modifications are made to the mix design so that the performance of the
concrete is ensured.
1.1.8.2 Coarse aggregates
Coarse aggregates form the major volume of the concrete mass. In India, crushed
granite is mostly used as coarse aggregates, however other stones such as limestone,
basalt, and most igneous rocks are suitable to be used as coarse aggregate. It is
important to note that most of the strength contribution in a concrete mix is from
coarse aggregate, hence the stones used as coarse aggregates should be sufficiently
strong and inert to environmental factors. However, in some places even broken
bricks are used in making concrete. Special caution needs to be exercised while
using such materials as coarse aggregate. Use of stone, such as shale pumice, which
have very high water absorption capacity, should be avoided, as this can lead to
excessive cracking in the concrete. The other ingredients of concrete are discussed
separately in other chapters in this book.
1.1.9 Reinforcing bars
Concrete is strong in compression, but weak in tension. Normally, we use concrete
in applications in which the primary stresses will be compressive. However, this is
rarely the case, therefore we use steel reinforcement, because steel is equally strong
in both tension and compression. However, it is much more expensive than concrete
so we do not use it as the only building material, but use it in the form of reinfor-
cing bars, also called rebars. We use the amount of rebars as per design that will be
enough to take on any tensile force that the concrete is subjected to before the con-
crete would fail.
The reinforcing steel or rebar is used in different forms or compositions, such as
deformed bars and TMT bars. A deformed bar, a common steel bar, is used as a
tensioning device in reinforced concrete and reinforced masonry structures holding
the concrete in compression.
It may be noted that there can be several material candidates to be used as a rein-
forcement material to take the tensile force that may be used in concrete. However,
steel is the most preferred as the coefficients of thermal expansion of concrete and
steel are similar. This phenomenon produces minimal stress in the composite matrix
due to differential expansion.
However, the use of rebars also brings with it other challenges, such as corro-
sion. In concrete structures, corrosion is a large concern. The effect of corrosion on
structures can significantly deteriorate the physical integrity and progressively lead
to the destruction of property and loss of life. Corrosion of reinforcing steel is a
spontaneous irreversible electrochemical process [9] which is accelerated by the
presence of electrolytes, especially salt corrosion. Again, the chlorides initiate cor-
rosion and oxygen fuels the reaction. The concrete containing cement paste pro-
vides an alkaline environment around the rebar steel and helps to form a protective,
tenacious, and passive oxide film. The pH of the pore solution as well as the
9
An overview of cementitious construction materials

30. migration of aggressive species toward steel reinforcement plays a major role in
concrete corrosion. The use of inhibitors in protecting steel reinforcement from cor-
rosion is essential, not only for new structures to be constructed, but also for exist-
ing structures by means of repair. Researchers are now paying more attention
toward the synthesis of novel and efficient inhibitors and their proper usage in con-
struction applications [9].
1.1.9.1 Types of rebars
There are various types of reinforcing bars used in construction, such as [2]:
G
plain and ribbed (hot rolled) mild steel bars—the ribs improve the mechanical bond;
G
cold twisted deformed (CTD) bars—ribbed low-carbon steel bars, twisted to increase the
yield strength by work hardening. The resistance to corrosion decreases due to the residual
stresses caused by the work hardening;
G
thermomechanically treated (TMT) bars—bars with a hard high-strength surface and a
ductile core;
G
corrosion-resistant TMT bars—bars with small quantities of copper and chromium, and a
higher than usual percentage of phosphorus;
G
galvanized bars, epoxy-coated bars;
G
stainless steel bars.
1.1.9.1.1 High yielding strength deformed bars
These include grades Fe415, Fe500, and Fe550 (the number indicates the yield
stress). Grade Fe250 mild steel is also available but is used only as a secondary
reinforcement. One is advised to refer to the corresponding table provided in IS
1786-1985 for the (1) chemical composition of reinforcements and (2) mechanical
properties of reinforcements. The chemical composition is described by the consti-
tuents such as carbon, sulfur, phosphorous, and mix of sulfur and phosphorous for
all grades. The mechanical properties are characterized by (1) 0.2% proof stress or
yield stress, (2) percentage minimum elongation on gauge length 5.65OA, where A
is the cross-sectional area of the test piece, and (3) minimum tensile strength for all
grades, namely, Fe 415, Fe 500, and Fe 550. Further, the code (IS:1786, reaffirmed
in 2008) prescribes that (1) for Fe 415, the minimum tensile strength should be
10% more than the actual 0.2% proof stress but not less than 485 MPa, (2) for Fe
500, the minimum tensile strength should be 8% more than the actual 0.2% proof
stress but not less than 545 MPa, and (3) for Fe 550, the minimum tensile strength
should be 6% more than the actual 0.2% proof stress but not less than 585 MPa.
1.2 High-performance concrete
1.2.1 Introduction
The classification of HSC is straightforward, since it can be based on compressive
strength [2,3,1012]. This is not the case for high-durability concrete (HDC) as
strength can be a poor indicator of resistance to deterioration, particularly chemical,
10 New Materials in Civil Engineering

31. such as chloride attack. It is shown by considering the theoretical role of each mate-
rial that high performance can be approached as a whole technology, that is, from
the paste to the aggregate has to be taken into account. As the strength and durabil-
ity requirement increases, so the demands on all of the material components work-
ing together become more critical and pose ever greater demands on concrete
technology. Consideration is also given to the cost comparison of using HSC in
place of conventional-strength concrete in structures.
The durability of concrete has been a major concern for the past two decades,
when it was found that the structures built during the rapid expansion of infrastruc-
ture in the 1960s and 1970s were deteriorating significantly. Indeed, the legacy of
this is that more fiscal resources are now being spent on repair and rehabilitation
than on new construction. Thus, there has been a great deal of interest in the use of
both reactive and unreactive additional materials such as the pozzolanic binders and
rock flour to produce HDC. HDC can be defined as a concrete with enhanced resis-
tance to degradation, but not necessarily high strength. Frequently, higher strengths
necessary to achieve high durability are not possible, as it is difficult to give a pre-
cise requirement for the lifespan of a structure.
There are two distinct, but interrelated routes, to achieving HDC, these are to
reduce the continuity and spaces in the capillary pore system, until in an ideal situa-
tion, no fluid movement can occur. In practice, this is unlikely to be possible and
all concrete will have at least some interconnected pores, or else provide chemically
active sites to immobilize and retard passing aggressive ions (this is mainly for
chloride-bearing environments). This is an important factor for structures exposed
to chloride-bearing environments, since fluid movement is always likely to occur.
Chloride binding is a complex and not fully understood phenomenon. In HDC, high
levels of pozzolanic binders are used, increasingly in poly blends to provide both
chloride binding and reduced capillary pore size and their interconnection.
1.2.2 Characterization and design philosophy
Two complimentary but different indexes are usually used to describe high perfor-
mance, namely high strength and high durability. Depending upon the compressive
strength, post-set heat treatment and application of pressure before and during set-
ting may be necessary. The key characteristics of HPC can be summarized as:
G
low waterbinder ratio;
G
large quantity of fine mineral powder (e.g., SF);
G
aggregates containing fine sand;
G
high dose of SPs.
It is the use of mineral admixtures (MAs) acting as fine fillers in the production
of HPC that separates it from conventional concrete (CC). Pozzolanic materials like
FA and SF are used as MAs. Due to the presence of fine fillers in the mix, HPC has
a strong, denser, and hardened microstructure [2]. The low porosity and the stronger
transition zone of HPC result in its superior durability and strength characteristics.
However, quality control measures on the MAs are required basically to get HPC
11
An overview of cementitious construction materials

32. with low w/c ratios. Moreover, the pozzolanic action of MAs depends upon their
amorphous content as well as SiO2 content; the higher these contents the better will
be their hardened (hydrated) state. In fresh HPC mixes, the particle sizes and their
distribution in MAs play a major role. Finer and more spherical-shaped particles of
MAs are preferred in HPC. Thus, the tests for characterization of MAs are very
important requirements for HPC mix design.
Characterization of HPC is similar to that of conventional cement concrete, how-
ever, in view of low w/c ratios and generally high cement contents of HPCs, the
following characterizations are particularly important:
G
peak temperature reached in fresh concrete;
G
rate of retention of workability;
G
effect of methods/sequence of mixture of ingredients;
G
sensitivity to charge in small variations in dosages of admixtures;
G
ambient temperature/humidity conditions;
G
method of measurement of workability (compaction faction for stiff mixes, flow table for
highly workable mixes and slump cone for medium workable mixes, K-slump, Kelly
ball);
G
time of start of curing (to avoid self-desiccation problems);
G
curing method (curing compound, water ponding/spraying, etc.);
G
air content (entrained/entrapped air contents);
G
amount and type of vibration/compaction; and
G
mode of transportation of fresh HPC concrete mix.
Most of the above-stated characterization tests of HPC mixes are performance
oriented and, therefore, have to be conducted for each set of field conditions.
Hence, the laboratory in which the HPC mix is begin developed must have facilities
to simulate the field conditions so that the HPC mix can be appropriately developed
and the laboratory result can be more reliably used in the field. The conventional
cement concrete also requires generally similar considerations. However, the HPC
has to perform well from many considerations other than strength alone, in contrast
to conventional cement concrete whose performance is mostly measured in terms of
strength only and therefore more stringent quality control measures are required at
every stage of the production of HPC. HPC is usually designed to suit a particular
application. Therefore characterization of hardened HPC mixes should be with ref-
erence to its end-usage. The following characterization studies which are required
to be done on hardened HPCs are given as general guidelines.
G
strength properties at different ages such as 1, 3, 7, 14, 28, 56, and 90 day. HPC usually
contains pozzolanic admixtures and hence, the strength development beyond 28 days
would be substantial. In literature, both 56- and 90-day tests are reported (AASHTO T-22,
ASTM C39, IS: 516);
G
permeability to water (ISTST, AUTOCLAM, BS 1881 Part 5);
G
volume changes due to moisture movements (IS:4031);
G
creep, shrinkage, and long-term properties;
G
stressstrain relationship (IS:516);
G
electrical resistance;
G
pH and free lime content of hardened concrete;
12 New Materials in Civil Engineering

33. G
bond with steel reinforcement (IS:2770);
G
nature of transition zone between cement matrix and aggregate in hardened HPC;
G
air-void analysis and microstructure;
G
resistance to attack by sulfates and other aggressive agents;
G
resistance to abrasion, erosion, scaling, cavitation, etc. (IS:1234, ASTM C672);
G
ductility of RC structural elements;
G
permeability to chlorides (AASHTO T 277-831, ASTM C 1202);
G
permeability to CO2/resistance to carbonation;
G
permeability to air/oxygen;
G
electrochemical potential of steel-reinforced HPC;
G
corrosion current in steel-reinforced HPC subjected to accelerated corrosion cycles;
G
freezethaw test (ASTM C 666, AASHTO T 161).
It may be noted that the above characterization tests on hardened HPC can be
also performed on CC. In fact, it is essential to perform them both on CC and HPC
simultaneously so that the superior characteristics of HPC are brought out clearly,
for any particular set of ingredients. Some of the test methods available for CC are
mentioned in the above list. However, in view of the special nature of HPC and
also its high potential for use in important structures requiring a high degree of
durability combined with long service life, it is necessary to formulate standard test
methods so that the characteristics of HPCs developed all over the world can be
compared more meaningfully. This would also help in creating a database from
which the standard Codes of Practice can be prepared for use by field engineers.
Apart from the above, specific tests to study the performance of HPC with the
actual type and nature of structure need to be planned. Some examples in this con-
text are nuclear power plant structures, off-shore structures, marine structures, irri-
gation and hydraulic structures, highway applications, airport pavements, overlays
in factory floorings, and repair of chemically deteriorated or corrosion-damaged RC
structures.
1.3 Geopolymer concrete
1.3.1 Introduction
Geopolymer cements, eco-cements, and sulfoaluminate cements are considered as
three alternative cements holding high potential in recent years [2,13]. Geopolymer
cement concretes (GPCCs) are the most preferred among the new binder systems.
Geopolymer is a generic and broad term. It comprises nine classes of materials
representing a chain of inorganic molecules. However, Class F material consisting
of aluminosilicate materials qualifies for civil engineering applications as it has the
potential to replace partially at least OPC. However, its utility for structural and
nonstructural elements and its durability characteristics need to be established from
extensive RD studies [2].
The program on waste to wealth undertaken internationally to use the large
amount of industrial wastes and by-products by cleverly attempting to replace
13
An overview of cementitious construction materials

34. partially or substitute the ingredients of concrete mix mainly, cement and aggre-
gates have been the subject of research and applications. Some of these wastes
include FA, ground granulated blast furnace (GGBS), alkaline sludges like red
mud, and other materials. The wastes used are not necessarily pozzolanic.
Considering these aspects, deployment of GPC can provide significant environmen-
tal benefits. Over OPC, the setting process in GPC is much faster and does not
affect the hydration process. The polymerization takes place under alkaline condi-
tions on siliconaluminum minerals. This creates a three-dimensional polymeric
chain and ring structure. The ratio of Si to Al determines the final structure of the
geopolymer. This mix gains strength over different timescales. However, one disad-
vantage is that one needs over 30
C temperature scales for curing. This results in a
reduction of the extent of amorphous order within the binder. Aside from their
application as high-performance cements, GPCs find a range of niche applications
such as in automobile car parts, waste immobilization, thermal boards, roof tiles,
tooling materials, and decorated ceramics. GPCs result in a microstructure that is
more heat resistant, fire resistant, and that has superior thermal expansion, cracking,
and swelling properties compared to PC. They exhibit a smooth surface and can be
molded easily.
Several studies indicate that for geopolymerization, natural AlSi minerals are
most suitable. Due to the complexity of the reaction mechanisms involved, it is as
yet difficult to identify and assess the suitability of the specific mineral. So far, FA
and slags such as GGBS which are the by-products, have shown very encouraging
results for use as geopolymers in the studies conducted. Between FA and slag, FA
exhibits high reactivity—one of the reasons for this being that FA is finer than slag.
1.3.2 Development of structural grade geopolymer cement
concretes
There are no standard mix design approaches available for GPCs. As mentioned
earlier, the watercement ratio influences the strength of cement concrete. Studies
have been conducted for the formulation of the GPC mixtures on a trial-and-error
basis through liquid to binder (l/b) ratio and suitable composition of GPC solids
(GPS). This is done till it meets the workability and strength requirements through
a good cohesive mix. Recommended requirements for such mix are slump of
75100 mm and 28-day compressive strength of 2045 MPa [1416]. The mixes
were designed such that the test specimens cast were demoldable after 24 hours of
wet gunny curing and the required strength could be realized after 28 days.
Table 1.1 shows the typical mix composition of the geopolymer concrete.
The mechanical properties of the GPCC mixes, including the stressstrain char-
acteristics, were evaluated. Table 1.2 shows the strength characteristics of the
mixes.
The elastic modulus of high-volume GGBS-based GPCCs was slightly less than
that of conventional OPCCs but the high-volume FA-based GPCCs showed consid-
erably lower elastic modulus compared to OPCCs. The strain at peak stress ranged
14 New Materials in Civil Engineering

35. Table 1.1 Typical mix composition for GPCC [2].
Mix
ID
Binder Mix proportion
(B:S:CA)
Molar ratios l/b Na2O/
GPS%
SiO2/
GPS%
H2O/
Na2O
SiO2/
Na2O
SiO2/
Al2O3
Na2O/
(Al2O3 1 SiO2)
FAB-1 75% F
25% G
1:1.64:2.82 7.77 2.49 4.24 0.33 0.70 11.38 4.28
FAB-2 75% F
25%G
1:1.43:2.6 10.34 3.18 4.58 0.26 0.70 12.47 8.06
FAB-3 75% F
25% G
1:1.10:1.83 9.61 3.64] 4.43 0.22 0.55 10.18 6.58
GGB-1 0% F
100% G
1:184:2.82 11.96 5.36 4.30 0.15 0.70 9.18 3.45
GGB-2 25% F
75% G
1:1.78:2.82 9.42 3.78 4.16 0.21 0.70 9.18 3.45
GGB-3 50% F
50% G
1:1.64:2.62 6.80 2.72 3.97 0.29 0.70 9.18 3.45
CC1 OPC 1:2.35:2.95 0.55 35
CC2 OPC 1:1.95:2.58 0.48 41
CC3 OPC 1:1.49:2.15 0.40 52
B, Binder; CA, coarse aggregate; F, FA; G, GGBS; l/b, liquid/binder; S, sand.

36. from 3216 to 4516 μm/m for GPCCs, which is higher than that for CCs (around
2700 microstrains). The strain at failure ranged up to 6000 μm/m.
1.3.3 Geopolymer cement concrete building blocks and paver
blocks
With the scarcity in availability of fired clay bricks, concrete building blocks and
pavers are the most widely used concrete components other than structural concrete
[17]. Therefore the use of eco-friendly GPCCs in lieu of OPCCs for the production
of building blocks is an attractive proposal. Table 1.3 shows the engineering proper-
ties of some of the paver blocks with indigenous materials, the GPCC-based build-
ing blocks and pavers are feasible on a large scale and using the same tools and
plants as OPCC elements, and these blocks meet the relevant performance require-
ments. This technology was released by CSIR-SERC to AEON Construction Products
Ltd., Chennai, in 200809 [18].
1.4 Fiber-reinforced concrete
1.4.1 Introduction
It is well realized that concrete is essentially considered quasi-brittle or nearly brit-
tle. This brittleness can be significantly reduced by adding fibers to the concrete
mix. Historically, different materials were introduced as fibers in the mix such as
Table 1.2 Strength characteristics of the mixes [2].
Mix ID Binder σ
cu,
MPa
σft,
MPa
Ec,
GPa
σft, MPa
(IS-456)
Ec, GPa
(IS-456)
Ec, GPa
(ACI-318)
FAB-1 75% F,
25% G
17 2.35 11.2 2.07 14.79 14.7
FAB-2 75% F,
25%G
49 4.65 20.8 4.47 31.92 25.0
FAB-3 75% F,
25% G
52 4.81 22.4 4.63 33.07 25.8
GGB-1 0% F,
100% G
63 5.53 28.3 5.18 37.00 28.4
GGB-2 25% F,
75% G
57 4.84 26.5 4.89 34.91 27.0
GGB-3 50% F,
50%G
52 4.86 22.7 4.63 33.07 25.8
CC1 OPC 35 4.03 3.62 25.86 24.9
CC2 OPC 41 4.32 4.01 28.61 26.9
CC3 OPC 52 4.85 4.63 33.07 30.3
σcu, Compressive strength; σspt, split tensile strength; σft, flexural tensile strength; Ec, elastic modulus.
16 New Materials in Civil Engineering

37. Table 1.3 Engineering properties of GPCC building/paver blocks.
ID Average value of Suitable application Grade designation as per IS
code
Average value of
σcu
(MPa)
σspt
(MPa)
SD
(MPa)
Water absorption
(%)
SD (%)
GB1 18.2 4.85 2.2 Building block Grade Aa
3.3 1.0
GB2 36.4 6.33 4.3 Paver block M-30 1 2.4 0.47
GB3 57.2 8.15 4.9 M-50 1 1.2 0.29
GB4 58.0 6.14 4.9 M-50 1 0.7 0.23
GB5 53.8 5.44 4.3 M-50 1 1.4 0.8
FB1 22.6 3.77 2.8 Building block Grade Aa
4.3 1.0
FB2 18.3 3.66 3.3 Grade Aa
4.9 2.5
FB3 26.3 4.14 4.1 Grade Aa
4.0 1.4
FB4 28.8 5.14 4.6 Grade Aa
3.7 1.6
FB5 27.2 4.76 4.4 Grade Aa
3.1 1.9
LWG 23.2 - 4.6 Grade Ab
5.3 1.5
LWF 20.7 - 4.4 Grade Ab
5.8 1.6
LWC 19.9 - 2.0 Grade Ab
4.3 1.1
σcu, Compressive strength; σspt, split tensile strength; SD, standard deviation.
a
IS: 1185 -Part I(C M 8).
b
IS:1185-Part 2 (C M 9), 1 IS:15658 (C M 19).

38. steel, natural glass, polypropylene, asbestos, carbon, and polymeric fiber (kevlar,
aramid). Fibers with suitable aspect ratio of length to diameter and volume fraction
are introduced during the mixing process. Another advantage of the use of fibers is
that they act as a secondary reinforcement, thereby arresting cracking due to shrink-
age and improving the energy absorption capacity of the concrete. This makes the
product durable. Road pavements, industrial flooring, machine foundations, etc. are
some of the typical applications of fiber-reinforced concrete [2].
1.4.2 Steel fiber-reinforced concrete
Typically steel fibers are added to the concrete matrix in the range of 0.25%2%
by volume of concrete [2]. It has been noticed that if the fiber content is increased
beyond this range both the strength and workability of the concrete reduce drasti-
cally. Generally, a fiber dosage of 0.5%1% is found to perform very satisfactorily.
Again this depends on the type of fibers used and their sizes/dimensions. Fibers are
available in a variety of shapes; straight, crimped, hooked, etc., and the length of
the fibers can vary from 19 to 60 mm, fibers of length less than 19 mm are also
available and are generally referred to as microfibers. They are normally not used
in general concreting, however they find good application in UHSCs such as reac-
tive powder concrete (RPC). The shapes of fibers used are (1) straight, (2) crimped,
(3) hooked, (4) deformed, and (5) glued. The geometry of fibers used can be circu-
lar, square, or rectangular.
Some of the important features of SFRC are:
G
the weight density of concrete increases with the increase in the steel fiber content;
G
slump will decrease at a higher percentage of steel fiber and lower SF;
G
the workability of concrete improves when SF percentage increases;
G
the compressive strength increases significantly due to the addition of SF compared with
normal concrete;
G
the split tensile strength increases significantly due to the addition of steel fibers;
G
the flexural strength increases significantly due to the addition of steel fibers;
G
as the percentage of steel fibers increases, the percentage of tensile strength and flexural
strength properties increase more than the compressive strength.
In addition to the above, properties of FRC can be enhanced due to:
1. aspect ratio;
2. volume fraction;
3. fiber profile;
4. fiber efficiency factor; and
5. strength of matrix.
Thus, one can note that use of fiber can result in changes to the basic stress
strain characteristics. Further, it also turns out that while the slope of the stress
strain curve in the linear range will be similar or close to that of NSC, the slope in
the downward portion, that is, after reaching the fully elastic linear portion, is sig-
nificantly different. This can be seen from Fig. 1.2A where hooked fibers are used
and Fig. 1.2B where straight fibers are used. In both cases, the results are shown for
18 New Materials in Civil Engineering

39. different volume fractions of the fiber content against the control concrete [14].
Obviously, a higher fiber content in the mix makes it more ductile and improves
the toughness as there is an increase in strain at the peak stress. This results in a
strength improvement from 0% to 15% [14].
Direct tensile testing as carried out for metals, is not possible to be adopted for
quasi-brittle materials like concrete and FRC. Presently, there are no guidelines or
established standards for such tests. In view of this, a number of test schemes have
been attempted to conduct direct and indirect tensile tests. Similar to tensile tests,
flexural toughness is another parameter SFRC needs to be assessed. However, in
the case of flexural toughness there are established standards and guidelines:
ASTM C-1018, JCI-SF4, JSCE-S4, and ACI 544 are some that can be referred to.
The third parameter to assess the performance and behavior of SFRC is the impact
resistance. This determines the utility and range of applications of SFRC. Again,
testing procedures for impact resistance of SFRC members need to be established,
though considerable research has been reported. The tests involve investigation into
crushing, shear failure, and tensile fracturing. Charpy-type impact test, weighted
pendulum, drop-weight test, rotating impact test, blast impact test, projectile impact
test, and instrumented impact test are some of the tests used to investigate impact
resistance. The addition of fibers improves the impact resistance of the plain con-
crete. However, as already mentioned, the amount and the type of fibers used will
determine the extent of improvement.
From the various studies conducted, it is noted that [2,4,19]:
G
fibers near the surface corroded causing brown stains but the strength and toughness char-
acteristics of SFRC were not affected;
G
the SFRC shows better performance in beam column joints with enhancement of strength
by about 20%;
G
SFRC as shear reinforcement substitute has no effect on the shear capacity of joints;
G
the joints with SFRC provided better confinement of the concrete, showing less structural
damage of the joint both under static and cyclic loading;
G
in the case of exterior beamcolumn joints, addition of 1% steel fibers in the joint portion
spacing of stirrups at the beamcolumn joint can be increased by twice the normal rate;
Control Control
Smooth steel fibers Smooth steel fibers
Compressive
stress
Compressive
stress
Axial strain
(A) hooked steel fibers (B) straight steel fibers
Axial strain
Figure 1.2 Stressstrain response of FRC under compression [14]: (A) hooked steel fibers;
(B) straight steel fibers.
19
An overview of cementitious construction materials

40. G
addition of fibers, even in a small quantity, considerably improves the impact resistance
of concrete;
G
with an adequate fiber volume, the failure mode under repeated impact loading is trans-
formed from brittle failure to multiple cracking, concrete crushing, and disintegration.
1.4.3 Fiber-reinforced concrete with nonmetallic fibers
Nonmetallic fibers can be either natural or synthetic [2]. Coconut husk, sisal, sugar
cane bagasse, bamboo, akara, plantain, and musamba are some of the natural fibers
used in cement paste, mortar, and concrete. Glass, polypropylene, carbon, poly-
meric fiber, hybrid fiber-reinforced concrete, etc. are some of the examples of syn-
thetic fibers. A number of studies have been conducted to assess the performance
of the use of such fibers in concrete in terms of compressive strength, flexural
strength, etc. The results have been encouraging but, as of now, the applicability of
each of these is limited to specific applications. Durability, sustainability, and reli-
able composition are the key parameters to assess the performance to evolve
suitable test procedures, validation methods, and guidelines.
1.4.4 Applications of steel fiber-reinforced concrete
SFRC is generally used in repairs of abrasion, cavitation, or impact damage in vari-
ous components of structures and in new construction of some products. For new
constructions, these are presented in the following.
Precast products: There are a good number of manhole covers every kilometer
of road. These are manhole covers with frames that are needed to cover chambers
and there can be anywhere between 520 every kilometer. Cast iron manhole cov-
ers have been preferred in the past for such applications. However, cast iron covers
and frames/rings are susceptible to pilferage and work out costlier. They can crack
or break as the material is brittle. As a reliable and cost-effective substitute, SFRC
manhole covers with frames (Fig. 1.3) are employed for such applications. These
covers and frames are about 60% cheaper than cast iron ones. Having established
through a number of studies [2,4,19] for its ductility and high impact resistance,
SFRC is perfectly suitable for such applications. CSIR-Structural Engineering
Research Centre, Chennai (CSIR-SERC) [2] (https://www.serc.res.in) transferred
the technology on manhole covers and frames to more than 40 agencies in the coun-
try. Based on the intensity of vehicular traffic, these are produced as heavy-,
medium-, and light-duty. Similarly, SFRC has good potential for use in other pre-
cast concrete products such as lost forms, dolosses, and wall panels.
Another CSIR laboratory in India, CSIR-Central Building Research Institute
(CBRI), Roorkee, developed and transferred technologies to produce different building
components, such as, precast doubly curved roofing tiles (1000 3 10003 20 mm and
7003 7003 20 mm), precast lintels (120 3 2303 75 mm), and precast planks
(12003 4003 25 or 50 mm) using steel as well as vegetable fibers. In the early 1980s,
another product, namely, corrugated roofing sheets, made out of coconut fiber-
reinforced concrete was used in a major leprosy settlement in a village near Titilagarh
20 New Materials in Civil Engineering

41. in Orissa, India. There is no report of any damage till today, and after several years this
is evidence of its reliable and sustainable performance. In the neighboring state of
Andhra Pradesh, similar FRC roofing is also now being used in a number of villages.
SFRC for pavements and industrial floors: Cement concrete cannot provide ade-
quate wear resistance and quality/strength of concrete against impact, abrasion, etc.
needed for industrial floors. Further, pavements and industrial paved floors are
often in aggressive environments. In the changing scenario of industries where
material-handling equipment/machines/forklift trucks are deployed in high numbers
with frequent use, and use of robots in production, SFRC meets these stringent
requirements in full. SFRC is able to generate a finish that is very flat and provides
a smooth surface.
SFRC brings with it naturally several advantages and provides an ideal solution
as a replacement for plain concrete for the applications mentioned in above, as
listed here:
1. With the higher flexural strength of SFRC, it is observed that one can obtain a
reduction in the thickness of concrete floors of up to 30%, while at the same time
increasing the spacing of contraction joints by up to 50%;
2. Higher tensile strength minimizes shrinkage and warping cracks that might
occur due to thermal stresses;
3. Scaling in concrete is arrested due to higher abrasion resistance;
4. Because of its precrack and postcrack load-carrying capacities, it provides bet-
ter resistance to the development and propagation of cracks originating from under-
lying pavement. This delayed propagation of cracks provides a two- to three-fold
increase in the life of the overlay.
The above features and advantages make SFRC perfect for providing overlays
for pavements and industrial floors. There are also reported uses of SFRC in heavy
vehicle factories, boiler plants, and thermal power plants, where very heavy
machinery and tools are moved on tracked vehicles.
Figure 1.3 SFRC manhole covers and frames.
21
An overview of cementitious construction materials

42. One of the other important applications of SFRC is shotcrete, popularly known
as “steel fiber-reinforced shotcrete” (SFRS). SFRS is mortar or concrete containing
discontinuous discrete fibers that is pneumatically projected at high velocity on to a
surface. This process of shotcreting enhances its mechanical properties/attributes
significantly. Some of these are (1) flexural strength, (2) shear strength, (3) durabil-
ity, (4) ductility, (5) high fatigue and impact resistance, and (6) toughness. The
advantages of use of SFRS are: (1) increased load-bearing capacity, (2) homo-
geneously reinforced shotcrete layer, (3) increased crack control, (4) less energy
absorption, and (5) easy and simple to use. As stated here, increased crack control
allows, even after cracking, the material to continue to carry a higher load. This
permits failure to take place only after considerable deformation.
The properties and advantages mentioned in the above facilitate efficient design
of members, resulting in thinner or lighter sections. Substituting mesh reinforce-
ment by steel fibers, SFRS can offer considerable time savings and makes it less
labor intensive. Thus, there is no overconsumption of concrete as compared to tradi-
tional reinforcement. A reinforced shotcrete lining can be applied immediately after
excavation for immediate safety.
1.4.5 Slurry infiltrated fibrous concrete
Slurry infiltrated fibrous concrete (SIFCON) is a special type of fiber-reinforced
concrete and relatively recent material [2]. In FRC, 1%2% by volume fibers are
used, whereas in SIFCON between 6% and 15% fibers are used. The constituents
(Fig. 1.4) used to produce SIFCON are (1) cement paste or flowing cement mortar,
(2) sand (it is preferable to sieve it through a 1.18-mm sieve), (3) FA or slag or SF,
(4) SP, and (5) water. Because of the high fiber content, cement slurry needs to be
infiltrated into a bed of preplaced fibers. SFRC can be successfully employed to
Figure 1.4 Constituents of SIFCON.
22 New Materials in Civil Engineering

43. provide high impact resistance and high ductility where standard modes of rein-
forcement are not effective, such as precast concrete products, refractory applica-
tions, pavements and overlays and bridge decks, strategic applications, and
structures subjected to blast and dynamic loading.
Investigations [2] considering two mix proportions of volume and cement to sand
ratio (1:1 and 1:1.5) and two w/c ratios (0.40 and 0.35) revealed that a mix proportion
of 1:1 with a watercement ratio of 0.35 and polycarboxilic-based SP and viscosity-
modifying agent (VMA) exhibited better performance in terms of compressive and split
tensile strengths. Similarly, it was noted that with addition of 8% fibers, the compres-
sive strength achieved was in the range of 7080 MPa and the split tensile strength
was found to be between 15 and 18 MPa. The aspect ratio of straight and crimped
fibers used in the study was 66, whereas that for the hooked fiber was 48. Fig. 1.5 is a
typical stressstrain plot for the various types of fibers at 8% fiber volume.
1.5 Fiber-reinforced concrete polymer composites
1.5.1 Fiber-reinforced polymer composite laminates
Fiber-reinforced polymer (FRP) composite materials are produced from three main
fiber types, namely, carbon, glass, and aramid [2,7,19,20]. Each fiber has different
engineering properties and, therefore, selection must be made to suit the require-
ments of a particular application. Carbon fibers have great strength. Stresses at
Figure 1.5 Stressstrain plot in compression for 8% fibers.
23
An overview of cementitious construction materials

44. failure can be in excess of 3000 N/mm2
. However, they are very expensive.
Conversely, glass fibers are relatively inexpensive but have less strength and greater
elasticity. Aramid fibers, renowned for their high impact resistance, tread the mid-
dle ground and their true potential is yet to be exploited in structural engineering
applications.
The composite materials currently utilized for repair and structural applications
are produced in the form of laminate or wrap. Laminates consist of groups of unidi-
rectional fibers, referred to as rovings, which are pultruded through a bath of resin
into a dye before being baked in an oven. The resulting product is usually between
1 and 2 mm thick with a width of less than 150 mm and can be coiled for transpor-
tation. Laminates and wraps are produced from either one or a combination of the
fiber types. In the plane of the material, it can be woven with the fibers oriented in
almost any direction and with different percentages allocated to the wrap and weft.
The resulting fabric is then fully impregnated with resin. Figs. 1.6 and 1.7 show the
carbon fiber mat and typical execution procedure for CFRP mat used for repair and
strengthening of RC structural elements. Despite its higher cost than steel, the ultra-
lightweight and durability of FRP makes it one of the most preferred material/sheets
because of its reliability in the use of distressed infrastructure. Some of the fea-
tures/advantages of this material are:
G
durable;
G
better fatigue life;
Carbon fiber mat
Figure 1.6 Carbon fiber mat roll.
24 New Materials in Civil Engineering

45. G
corrosion resistance;
G
resistance to chemical attack;
G
high strength-to-weight ratios;
G
easy to handle on site;
G
sufficiently pliable to fit almost any shape and size of structure;
G
reduced labor cost.
1.6 Lightweight concrete
1.6.1 Introduction
Lightweight concrete contains an expanding agent that increases the volume of the
mix due to which the concrete becomes nailable and has low density or lower dead
weight. These qualities allow faster construction, with lower handling costs. This
suits high-rise buildings and large infrastructures, as the total dead load on founda-
tions is substantially reduced. Because of its relatively low thermal conductivity, it
facilitates maintaining comfortable conditions in buildings. Lightweight concretes
allows use of industrial wastes such as clinker, FA, and blast furnace slag in large
quantities. Finally, the traditional concrete materials, such as sand and coarse aggre-
gates, are becoming very scarce and thus lightweight aggregate concretes could
contribute immensely to consuming less of these depleting natural resources [2].
Lightweight concrete has the ability to hold its large voids without the formation
of cement films when placed on a wall. However, sufficient watercement ratio is
essential to produce adequate cohesion between the cement and water to maintain
Protective coating
2nd resin coat
Carbon fiber
1st resin coat
Epoxy putty filler
Primer
Concrete substrate
Figure 1.7 Typical sketch showing repair and retrofitting steps.
25
An overview of cementitious construction materials

46. good strength of concrete. Otherwise, too much water can cause cement to run off
aggregate to form laitance layers, leading to weakening of concrete strength
[15,16].
1.6.1.1 Types of lightweight concrete
Concretes can be produced with different densities of concretes varying from 300
to 2000 kg/m3
and can be produced with corresponding (1) compressive strength
from 1 to 60 MPa and (2) thermal conductivities of 0.21.0 W/mk. Concrete can
be made lighter by adding air in its composition. This can be done in the following
three ways [2]:
1. By introducing very fine bubbles of gas in a cement paste or mortar mix to form a cellular
structure containing approximately 30%50% voids (aerated concrete and foamed concrete);
2. By replacing either wholly or partially natural gravel or crushed aggregates in a conven-
tional mix with aggregates containing a large portion of voids (lightweight aggregate
concrete);
3. By omitting the finer fraction from normal weight aggregate grading to create air-filled
voids called no-fines concrete.
1.6.2 Foam concrete/cellular concrete
Foam or foamed concrete is also known as cellular concrete [2,15,16]. This is a ver-
satile material principally comprising a cement-based mortar or paste mixed with at
least 20% by volume of air in the form of preformed foam [2,15,16]. The material
generally contains no coarse aggregates. As the name suggests, it requires a foam-
ing agent. Hydrolyzed protein-based concentrated liquid that does not chemically
react with cement is used as a foaming agent in producing the foam. The foam
serves as a temporary wrapping material for the air bubbles till the cement mortar
develops its own final set and strength. The mix can be designed with high volumes
of industrial waste materials and recycled aggregates. In foamed concrete both
strength and density are normally specified as the constituents and the proportions
are flexibly used. This gives a wide band of densities and strengths for varied appli-
cations. Foam concretes with dry densities varying from 360 to 1550 kg/m3
and air
contents from 28% to 78% showing strengths ranging from 1 to about 30 MPa have
been reported [2]. Foamed concrete has been established as an accepted building
material. It finds application in many areas due to its relatively low cost, light
weight, ease of production, easy placement, simple compaction, etc. Some of the
features offered by foam concrete are (1) flowability, (2) self-compactability and
self-leveling nature, (3) ultra-low density, (4) excellent thermal and sound insula-
tion properties, (5) dimensional stability, (6) economical, and (7) eco-friendly.
1.6.2.1 Applications of foamed concrete
Internationally, the material has been used in low-cost housing in the Middle East,
where its good thermal insulation, ease of placing, and relatively nondemanding
26 New Materials in Civil Engineering

47. technical input are beneficial. It is used in a variety of applications such as void fill-
ing, floor construction, bridge decks, roofing insulation, road sub-base, sewer infill,
swimming pool infill, raising the levels of flooring, underfloor infilling, train plat-
form infilling/reprofiling, floor and roof screeds, wall casting, complete house cast-
ing, sound barrier walls, subsurface for sport arenas, aircraft arresting beds, road
crash barriers, floating barges, jetty platforms and floating homes, trench reinstate-
ment, storm drain infilling, bridge strengthening, culvert abandonment filling, cul-
vert or bridge approaches, subway abandonment filling, large-diameter shafts,
tunnel abandonment, bridge abutments, slope protection, basement infill vaults,
pipeline infill, tank infill, and fuel tank infill [2].
1.6.2.2 Material constituents
Foamed concrete is a blend of cement, sand, water, and prefoamed foam with the
vast majority of foamed concrete containing no large aggregates but only fine sand
(Fig. 1.8) [4]. The extremely lightweight foamed concrete contains only cement,
water, and foam. The raw materials used for the production of foam concrete are
binding agent, aggregates, foaming agent, and water. The OPC is used with contents
varying from 300 to 600 kg/m3
. In addition to OPC, rapid hardening PC, high alu-
mina cements can be used to reduce the setting times and improve early strengths.
Partial cement replacements with FA, GGBS, and other fine materials can be made.
SF can be added to improve the compressive strength of concrete. However, the com-
patibility of these admixtures with foaming agents should be ascertained. GGBS gives
the foamed concrete a cohesive, almost sticky, consistency. The use of FA tends to
make the mix fluidier. The key requirement here is to have stable foam.
Only fine sands with particle sizes up to 5 mm are used, as coarse aggregate tends
to settle in the lightweight mortar mix and causes collapse of the foam during mixing.
Very low-density sand with a fineness modulus of approximately 1.5 are preferred,
including FA, lime, calcium carbonate, crushed concrete granite dust, expanded
Figure 1.8 Materials used for foam concrete.
27
An overview of cementitious construction materials

48. polystyrene granules, sintered FA aggregate fines, rubber crumbs, recycled glass, and
foundry sand. Lightweight aggregates such as sintered FA aggregate and vermiculite
can also be used to produce foamed concrete.
The preformed foam is a mixture of foaming agent, water, and air, with a den-
sity of 75 kg/m3
. The addition of preformed foam lowers the density of the mix,
increasing the yield. The higher the quantity of foam added, the lighter the resul-
tant material. Two types of foam, wet foam and dry foam, are used in the produc-
tion of foamed concrete. Wet foam is produced by spraying foaming agent
solution and water over a fine mesh. The foam produced in this case is similar in
appearance to bubble bath foam, with a bubble size ranging from 2 to 5 mm.
However, the foam that is added must remain stable without collapsing during
pumping, placement, and curing. This factor becomes prominent when the quan-
tity of foam is greater than 50% of the base mix (that is, for a density of approxi-
mately 1100 kg/m3
). Foamed concrete below this density needs to be
manufactured and used with care. The watercement ratio typically ranges from
0.4 to 0.8, depending on the mix proportions and consistency requirements. When
extremely fine materials are used in large quantities the water demand increases,
lowering the strength of foamed concrete. Chemical admixtures such as SPs,
VMAs, and accelerators can be used in foamed concrete, however their effect on
the stability of the foam should be ensured. Addition of fibers such as polypropyl-
ene and polyester fibers can be used to limit both plastic and drying shrinkage
strains. The constituents of the base mix can react with certain foaming chemicals
resulting in destabilization of the mix.
1.6.2.3 Mix proportioning of foamed concrete
There is currently no standard or accepted method for designing a foamed con-
crete mix. However, foamed concrete is specified by its strength and density.
Similar to normal concretes, the higher the air content in the mix, the weaker the
resultant material. That is, the lower the density of the concrete, the less its
strength.
In addition to the watercement ratio, the volume of voids is an important
factor that decides the strength of concrete. Strength will also be controlled by
cement and fine aggregate content. Unlike in normal concretes, strength is
achieved purely by cementing action, rather than by consolidation and mechani-
cal interlocking of aggregate particles. To design foamed concrete, through
selection/assignment of casting density, sand/cement and FA/cement ratios, the
water requirement is determined. Using these ratios and the relative densities of
the materials, the mass of the cement and the volume of foam that should be
added to obtain the required density is determined.
Using the following equation, the foam quantity in the mix is calculated by add-
ing the mix quantities (per m3
) to the target plastic density value [9,10]:
Fm 5 Bm 3 Fd ½1=Td 2 1=Bd
28 New Materials in Civil Engineering

49. where
Fm 5 Mass of foam, kg (this may be converted in volume using foam density, typically
4060 kg/m3
);
Bm 5 base mix mass, kg;
Fd 5 foam density, kg/m3
;
Td 5 target density, kg/m3
;
Bd 5 base mix density, kg/m3
(this varies greatly depending on the aggregate type used).
The sum of the material weights equal to the required casting density will pro-
duce 1 m3
of foamed concrete and the sum of the volume of all the constituent
materials should be 1 m3
or 1000 L.
The flow table test can be used to determine the water demand of cement or a
mixture of cement and FA. The mix should not absorb water from the foam. No
visual breakdown of the foam should take place. The higher the water content in
the mix the less the density.
1.6.2.4 Strength ranges
The British Cement Association reported on work on a range of mixes with dry
densities varying from 360 to 1550 kg/m3
and air contents from 28% to 78.5%,
with strengths ranging from 1 to about 10 MPa. Concretes with densities at the
upper limit can produce roughly strengths in excess of 15 MPa.
1.6.2.5 Characteristics of foamed concrete
The characteristics of foamed concrete are generally constant across a range of mix
designs such as:
G
high strength to weight ratio;
G
low coefficient of permeability;
G
low water absorption;
G
good freeze and thaw resistance;
G
high modulus of elasticity (compared to soils);
G
a rigid well-bonded body;
G
low shrinkage;
G
thermal insulating properties;
G
shock-absorbing qualities;
G
not susceptible to breakdown due to hydrocarbons, bacteria, or fungi.
1.6.2.6 Experimental investigations
The following section details the investigations carried out to develop foamed con-
crete having a density of approximately 1000 kg/m3
for structural applications. A
pilot study undertaken to develop foamed concrete panels to be used as infill for
precast roof and floor systems is also described in detail.
29
An overview of cementitious construction materials