Properties of Self Compacting Concrete with Recycled Aggregate

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ABDULLAH PK – 01722094191 – engr.abdullahpk@gmail.com
ANALYZING THE PROPERTIES OF
SELF COMPACTING CONCRETE
MADE WITH DIFFERENT PROPORTIONS
OF RECYCLED AGGREGATE
A THESIS
SUBMITTED TO THE DEPARTMENT OF CIVIL ENGINEERING
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF
Bachelor of Science in Civil Engineering
BY
SHAHED ALAM
Roll:35,Batch: Eve.-2nd
, Registration no:280135,Session:2014-2015
In co-operation with
MD.MOSTAFIJUR
Roll:34, Batch: Eve.-2nd
, Registration no:280134, Session:2014-2015
MD.ASHIQUR RAHMAN
MD.ABDULLAH PK
MD.MARUF AHMED
Under the Supervision of
ANUPAM PAUL
Lecturer
Department of Civil Engineering
Submitted to the
DEPARTMENT OF CIVIL ENGINEERING
DHAKA INTERNATIONAL UNIVERSITY, SATARKUL, BADDA
NOVEMBER, 2018

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DEDICATED
TO OUR
PARENTS, FAMILY AND TEACHERS

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CERTIFICATION OF APPROVAL
This thesis titled “ANALYZING THE PROPERTIES OF SELF
COMPACTING CONCRETE MADE WITH DIFFERENT PROPORTIONS OF
RECYCLED AGGREGATE” submitted by Shahed Alam (Roll: 35; Batch:
Eve.-2nd
), Md. Mostafijur (Roll: 34; Batch: Eve.-2nd
), Md. Ashiqur Rahman
(Roll: 46; Batch: Eve.-2nd
), Md. Abdullah Pk (Roll: 50; Batch: Eve.-2nd
) ,Md.
Maruf Ahmed (Roll: 53; Batch: Eve.-2nd
) has been accepted as satisfactory in
partial fulfillment of the requirement for the degree of Bachelor of Science in
Civil Engineering on November, 2018.
APPROVED AS TO STYLE AND CONTENT
BY
OUR SUPERVISOR
ANUPAM PAUL
Lecturer, Department of Civil Engineering
DHAKA INTERNATIONAL UNIVERSITY
SATARKUL, BADDA
NOVEMBER, 2018

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DECLARATION
It is hereby declared that, except for the contents where specific references are
made, the work embodied in this thesis is the result of investigation carried out
by the authors under the supervision of Anupam Paul, Lecturer, Department of
Civil Engineering, Dhaka International University.
Neither this thesis nor any part of it is concurrently submitted to any other
institution in candidature for any degree.
Shahed Alam
Md. Mostafijur
Md. Ashiqur Rahman
Md. Abdullah Pk
Md. Maruf Ahmed

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ACKNOWLEDGEMENT
The preparation of the thesis was undertaken to meet the need for the partial
fulfillment of the Bachelor of Science Degree in Civil Engineering from DIU.
All praise to The Almighty ALLAH, who knows everything, for blessing with
potency and merit, to lead this thesis work towards completion. We would like
to express my deepest appreciation to all those who gave me the chance to
complete this thesis.
Foremost, we would like to express my sincere gratitude to my supervisor,
Anupam Paul, Lecturer, Department of Civil Engineering, DIU for the
continuous support unwavering guidance throughout the course of this work.
We greatly appreciate all the support that he has been given to me, both on this
thesis and during the entire period. We have learned a lot from him. The whole
work definitely needed the application of engineering judgment and thoughtful
logic along with information from textbooks or previous relevant publications.
Without his guidance and persistent help this thesis would not have been
possible. However, the entire research work has been carried out under the
auspices of the concrete laboratory in the Department of Civil Engineering of
DIU. Appreciate with the concrete lab assistants of Department of Civil
Engineering, DIU for their tire some efforts of performing lab work and
collecting data.
We wish to express our profound gratitude to MD.Hakimuzzaman Shah
,Coordinator, Department of Civil Engineering, DIU, who also support and
encouragement during this study.
Finally, we would like to thank Md. Masud Rana, Marketing Executive
(Admixture System), BASF Bangladesh Ltd. He helped us by providing
chemical admixtures for our work.
And finally, my special tribute goes to my parents, for their love and
encouragement.

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ABSTRACT
Self-compacting concrete (SCC) is a new kind of high performance concrete
(HPC) with excellent deformability and segregation resistance. It can flow
through and fill the gaps of reinforcement and corners of molds without any
need for vibration and compaction during the placing process. In practice, SCC
in its fresh state shows high fluidity, self-compacting ability and segregation
resistance, all of which contribute to reducing the risk of honeycombing of
concrete. With these good properties, the SCC produced can greatly improve
the reliability and durability of the reinforced concrete structures.The concepts
of sustainability and sustainable development are receiving greater attention
recently, as the causes of global warming and climate change are discussed in
various forums. Because concrete is the most widely used construction
material, sustainable technologies for concrete construction allow for reduced
cost, conservation of resources, use of waste materials, and the development of
eco-friendly durable concrete.One of the possibilities to enhance the
sustainability of SCC is to replace mineral aggregates in SCC using waste
materials such as recycled aggregates to produce sustainable concretes due to
their superior structural performance, environmental friendliness and low
impact on energy use.Considering these aspects, an attempt has been made to
develop a cementitious composite Self Compacting Recycled Aggregate
Concrete (SCRAC) where the waste material, such as recycled aggregate from
demolished concrete, have been added to SCC respectively.
The objectives of this research are to compare fresh and hardened properties of
Self Compacting Concrete with the recycled aggregate Self Compacting
Concrete.The course aggregate in concrete was replaced by 30%, 40% and
50% recycled coarse aggregate by weight. Concrete mixes were tested for
fresh properties (flowing ability, passing ability, segregation resistance) by
using Slump Test , L-Box Test,and V-Funnel Test and specimens were tested
for hardened properties such as splitting tensile strength,compressive
strength,water absorption,and modulus of elasticity. The mix design used for
making the concrete specimens was based on previous research work from
literature. All the concrete mixes were designed for 33MPa compressive
strength. The water – cement ratios varied from 0.287 to 0.30 while the rest of
the components were kept the same, except the chemical admixtures, which
were adjusted for obtaining the self-compactability of the concrete.

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LIST OF ABBRIVATION AND SYMBOLS
DIU Dhaka International University
SCC Self-Compacting Concrete
ASTM American Society For Testing And Materials
RCA Recycled Coarse Aggregate
CA Coarse Aggregate
PCC Portland Composite Cement
HRWRA High Range Water Reducing Admixture
VMA Viscosity-Modifying Admixture
BS The British Standard
SCFRC Self-Compacting Fibre Reinforced Concrete
EFNARC European Federation of National Associations Representing For
Concrete
NVC Normal Vibrated Concrete
HPC High Performance Concrete
JRMCA Japanese Ready-Mixed Concrete Association
LCPC Laboratory Central Des Pontset Chausses
CRI Concrete Research Institute
NCC Normal Compacting Concrete
HPMC Hydroxyl Propyl Methyl Cellulose
BFS Blast Furnace Slag
LFA Lignite Fly Ashes
DEPA Danish Environmental Protection Agency
EN The European Standard
FA Fly Ash
CRT Constant-Rate of-Traverse
SCRAC Self Compacting Recycled Aggregate Concrete

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TABLE OF CONTENT
Title page i
Dedication ii
Certification of Approval iii
Declaration iv
Acknowledgement v
Abstract vi
List of Abbreviations vii
Table of Content viii
List of Table xii
List of Figure xiii
CHAPTER- I, INTRODUCTION
1.1 General 01
1.2 Objectives of the Research 02
1.3 Scope of the Research 03
1.4 Research Methodology 04
CHAPTER-II, LITERATURE REVIEW
2.1 Introduction 07
2.2 Self Compacting Concrete 08
2.2.1 Self-Compacting Concrete Definition 08
2.2.2 Advantages and Disadvantages of using SCC 08
2.2.3 Fresh State Properties of Self-Compacting Concrete 10
2.2.4 Deformability (flow and filling ability) 10
2.2.5 Passing Ability 10
2.2.6 Segregation Resistance (homogeneity/cohesiveness) 11
2.2.7 Difference between SCC and Normal Vibrated
Concrete (NVC)
12
2.2.8 Mechanisms of Achieving SCC 12
2.2.9 SCC Applications 14
2.3 History of Development 15
2.3.1 Evolution of Self Compacting Concrete 16
2.3.2 Influence of Admixtures on Concrete Properties 28
2.3.2.1 Mineral Admixtures 28
2.3.2.2 Blast Furnace Slag 28

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2.3.2.3 Fly Ash 30
2.3.2.4 Chemical Admixtures 33
2.3.2.5 Super plasticizers 33
2.3.2.6 Viscosity Modifiers 36
2.3.3 Self Compacting Recycled Aggregate Concrete 39
2.3.3.1 Recycled Stone Aggregate Concrete 40
2.3.3.2 Use of Recycled Aggregate Concrete 47
CHAPTER-III, RESEARCH METHODOLOGY
3.1 Introduction 51
3.2 Constituents of Self Compacting Concrete 51
3.2.1 Cementitious Materials 51
3.2.1.1 Portland Composite Cement (PCC) 51
3.2.2 Aggregates 52
3.2.2.1 Fine Aggregates 53
3.2.2.2 Coarse Aggregate 55
3.2.3 Water 56
3.2.4 Chemical admixtures 57
3.2.4.1 Super plasticizers 57
3.2.4.2 Viscosity-Modifying Admixtures 58
3.3 Effect of Cement properties 59
3.4 Effect of Cement Replacement Materials (CRMs) 61
3.5 Effect of Aggregate Characteristics 62
3.5.1 Shape and Texture 63
3.5.2 Maximum Size of Aggregate 63
3.5.3 Grading of Aggregates 64
3.5.4 Effect of Absorption 66
3.5.5 Effect of Strength and Stiffness 66
3.5.6 Effect of Soundness and Toughness 67
3.6 Mix Design 67
3.6.1 SCC Mix Design 68
3.6.2 EFNARC Mix Design 69
3.6.2.1 Workability Criteria for the Fresh SCC 69
3.6.2.2 Mix Composition 70
3.7 Laboratory Mix Design 70
3.8 Laboratory Investigation & Test Procedure 71
3.9 Investigation of Materials 72

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3.9.1 Gradation 72
3.9.2 Combined Gradation 73
3.9.3 Aggregate Test Results 75
3.10 Steps of Investigation 75
3.10.1 Sieving of Aggregate 76
3.10.2 Mix design 76
3.10.3 Casting of concrete 77
3.10.4 Curing 78
3.10.5 Testing 79
3.11 Preparation of Specimen 79
3.12 Test Procedures 79
3.12.1 Slump Test 79
3.12.2 L-Box Test 80
3.12.3 V-Funnel Test 81
3.12.4 Compressive Strength Test 82
3.12.5 Split Cylinder Test 83
3.12.6 Water Absorption Test 84
3.12.7 Modulus of Elasticity Test 85
CHAPTER-IV, TEST RESULT AND ANALYSIS
4.1 Introduction 88
4.2 Gradation of Concrete Mix 88
4.3 Test of Fresh concrete 89
4.3.1 Slump Test 89
4.3.2 L-Box Test 90
4.3.3 V-Funnel Test 90
4.4 Test of Hardened concrete 90
4.4.1 Compressive Strength 91
4.4.2 Split Cylinder 91
4.4.3 Water Absorption 92
4.4.4 Modulus of Elasticity 94
4.5 Result Analysis 96
4.5.1 Gradation Results 96
4.5.2 Slump Test Results 97
4.5.3 L-Box Test Results 98
4.5.4 V-Funnel Test Results 99
4.5.5 Compressive Strength Results 100

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4.5.6 Tensile Strength Results 101
4.5.7 Water Absorption Results 103
4.5.8 Modulus of Elasticity Results 105
CHAPTER-V, CONCLUSION& RECOMMENDATION
5.1 Introduction 107
5.2 Conclusion 107
5.3 Recommendation 109
REFERENCES 111
APPENDIX A- Compressive Strength Results 113
APPENDIX B- Splitting Tensile Strength Results 114
APPENDIX C- Modulus of Elasticity Test Results 116
APPENDIX D- Sieve Analysis 122

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LIST OF TABLES
Table No Name of Table Page No
Table 3.1 Classification of Aggregates Based on Particle Size 53
Table 3.2 Mixtures Designation 68
Table 3.3 List of Test Methods 69
Table 3.4 Acceptance Criteria For Self Compacting Concrete 70
Table 3.5 Mix Composition 70
Table 3.6 Mixture Proportion 71
Table 3.7 Mix Ratio 71
Table 3.8 Combined Gradation 74
Table 3.9 Properties of Fine Aggregates 75
Table 3.10 Properties of Coarse Aggregates 75
Table 3.11 Fineness Modulus of Mixture 75
Table 4.1 Sieve Analysis of 30% Recycled Aggregate And 70%
Normal Aggregate (Mix 2)
88
Table 4.2 Slump Values of Different Mixes 89
Table 4.3 H2/H1ratio of Different Mixes 90
Table 4.4 Time Taken For Emptying of V-Funnel 90
Table 4.5 Compressive Strength Test (28 Days) 91
Table 4.6 Compressive Strength of Concrete Mixes 91
Table 4.7 Split Cylinder Test (14 Days) 92
Table 4.8 Tensile Strength of Concrete Mixes 92
Table 4.9 Water Absorption Test (28 Days 93
Table 4.10 Water Absorption Test (14 Days) 93
Table 4.11 Water Absorption of Concrete 93
Table 4.12 Modulus of Elasticity Test (28 Days) 95
Table 4.13 Modulus of Elasticity At 28days 96
Table 4.14 Determination of Gradation Type 97

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LIST OF FIGURES
Figure No Figure Name Page No
Figure 3.1 Gradation Curves of Normal Coarse Aggregates 72
Figure 3.2 Gradation Curves of Recycled Coarse Aggregates 73
Figure 3.3 Gradation Curves of Sand 73
Figure 3.4 Combined Gradation Curve 74
Figure 3.5 Sieving of Coarse Aggregates 76
Figure 3.6 Sieving of Fine Aggregates 76
Figure 3.7 Slump Tests 77
Figure 3.8 L-Box And V-Funnel Tests 77
Figure 3.9 Casting of Concrete 77
Figure 3.10 Curing of Concrete 78
Figure 3.11 Slump Test Apparatus With Upright Cone 80
Figure 3.12 L-Box Test Apparatus (All Dimensions Are In Mm) 81
Figure 3.13 V-Funnel Test Apparatus 82
Figure 3.14 Cylinder For Compressive Strength Test 83
Figure 3.15 Cylinder For Split Tensile Test 84
Figure 3.16 Water Absorption Test 85
Figure 3.17 Modulus of Elasticity Test of Concrete 87
Figure 4.1 Gradation Curve of Mix 2(30% RCA, 70% CA) 89
Figure 4.2 Modulus of Elasticity of SCC(28 Days) 96
Figure 4.3 Variation of Slump Value 97
Figure 4.4 Variation of L-Box Test Results 98
Figure 4.5 Variation of V-Funnel Test Results 99
Figure 4.6 Variation of Compressive Strength Test Results (28
Days)
100
Figure 4.7 Variation of Compressive Strength of Mixes With
Days
101
Figure 4.8 Variation of Tensile Strength Test Results (28 Days) 102
Figure 4.9 Variation of Tensile Strength of Mixes With Days 103
Figure 4.10 Water Absorption Test Results (28 Days) 104
Figure 4.11 Variation of Water Absorption of Mixes With Days 105
Figure 4.12 Variation of Modulus of Elasticity of Mixes
(28Days)
106

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CHAPTER I
INTRODUCTION
1.1 General
Cement is a composite material composed of aggregate bonded together with a
fluid cement which hardens over time .Cement is one of the many constituents
of concrete, part of the glue that holds the other materials together. It is made
by mixing cement, supplementary cementitious materials, water, fine aggregate
(sand), coarse aggregate (gravel or crushed stone) with or without admixtures,
reinforcement, fibres or pigments. The most popular artificial material on Earth
isn’t steel, plastic, or aluminum — it’s concrete. Concrete is easily and readily
prepared and fabricated in all sorts of conceivable shapes and structural
systems. Its great simplicity lies in the fact that its constituents are ubiquitous
and are readily available almost anywhere in the world. As a result of its
ubiquity, functionality and flexibility it has become by far the most popular and
widely used construction material in the world.
Over the years, technologies have improved greatly. A greatest innovation of
concrete is Self-compacting Concrete. Self-compacting concrete (SCC) is a
relatively new product that sees the addition of superplasticiser and a stabiliser
to the concrete mix to significantly increase the ease and rate of flow. By its
very nature, SCC does not require vibration. It achieves compaction into every
part of the mould or formwork simply by means of its own weight without any
segregation of the coarse aggregate. Developed in Japan and Continental
Europe, SCC is now being used in the Bangladesh where, apart from health and
safety benefits, it offers faster construction times, increased workability and
ease of flow around heavy reinforcement. Having no need for vibrating
equipment spares workers from exposure to vibration .No vibration equipment
also means safe construction site.
The future of concrete focuses on sustainability, the reuse of materials
alongside very high strengths. There is a growing interest in using waste

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materials as alternative aggregate materials and significant research is made on
the use of many different materials as aggregate substitutes such as coal ash,
blast furnace slag, fibre glass waste materials, waste plastics, rubber waste,
sintered sludge pellets and others. This type of use of a waste material can
solve problems of lack of aggregate in various construction sites and reduce
environmental problems related to aggregate mining and waste disposal. The
use of waste aggregates can also reduce the cost of the concrete production.
Concrete recycling gains importance because it protects natural resources and
eliminates the need for disposal by using the readily available concrete as an
aggregate source for new concrete or other applications. According to a 2004
FHWA study, 38 states recycle concrete as an aggregate base; 11 recycle it into
new Portland cement concrete. The states that do use recycled concrete
aggregate (RCA) in new concrete report that concrete with RCA performs
equal to concrete with natural aggregates. Most agencies specify using the
material directly in the project that is being reconstructed.
In Bangladesh, the volume of demolished concrete is increasing due to
deterioration of concrete structures as well as the replacement of many low-rise
buildings by relatively high-rise buildings caused by booming of real estate
business. Disposal of the demolished concrete is becoming a great concern to
the developers of the buildings. If demolished concrete is used for new
construction, the disposal problem will be solved, the demand for new
aggregates will be reduced, and finally consumption of the natural resources for
making aggregate will be reduced.
1.2 Objectives of the Research
The objectives of our research are :
To study the fresh properties (Slump, V-Funnel, L-Box) of the Self-
Compacting Concrete (SCC).

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To study the fresh properties (Slump, V-Funnel, L-Box) of the Self-
Compacting Concrete made with recycled coarse aggregate.
To study the mechanical properties of hardened concrete including
compressive strength, splitting tensile strength, water absorption and
modulus of elasticity of SCC and SCC with recycle course aggregate.
To investigate the results of SCC having different proportions of
recycled aggregate.
To compare the results among SCC and SCC with recycled coarse aggregate.
1.3 Scope of the Research
Concrete is the most consumed construction material for buildings at present.
The achievement of designed strength and durability of concrete relies largely
on sufficient compaction during placement. Inadequate compaction can
dramatically lower the performance of mature concrete in-situ. Therefore, to
ensure adequate compaction and homogeneity of the cast concrete and to
facilitate its placement especially in structures with congested reinforcement
and restricted areas, self-compacting concrete has been introduced.
It all started around 1988 at Tokyo University when Okamura et al. (1998)
established the basic description of SCC. The history of self-compacting
concrete (SCC) dates back to late 1980s. SCC concepts originally were thought
to be a tool to enhance long-term durability of structures having members with
congested reinforcements. It has generated tremendous interest since its
inception. It has been considered as the greatest breakthrough in concrete
technology for many decades due to the improved performance and working
environment.
SCC is a concrete that is capable of self-compacting, occupies all the space in
the formwork without any external effort (in the form of mechanical vibration,
floating, poking etc.). For the concrete to occupy the full space, flowing
through the formwork, without any external effort, it has to have an acceptable
level of passing ability, filling ability and stability. Because of the

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heterogeneous nature of concrete, its high fluidity and the fact that it contains
materials with different specific gravities, cohesiveness becomes an issue, as it
is very difficult to keep its constituents in a cohesive form where higher mass
particles tend to settle down. This problem however can be tackled by adding
larger amounts of finer material. Owing to its excellent user-friendly
characteristics, SCC is a highly attractive alternative today in traditional
construction industry.
Depending on its composition, SCC can have a wide range of different
properties; from a normal to an ultra-high compressive strength, from a poor to
an extremely high durability. The mixture of SCC is strongly dependent on the
composition and characteristics of its constituents in its fresh state. The
properties of SCC in its fresh state have a great influence on its properties in
the hardened state. Therefore it is critical to understand its flow behavior in the
fresh state. Since the SCC mix is essentially defined in terms of its flow-ability,
the characterization and control of its archeology is crucial for its successful
production.
1.4 Research Methodology
For the ease of research purpose, total work was divided into several phases.
Each of the phases had definite purpose, definite layout. All these together gave
us the required output which was expected to find our final result
Phase-1: Selection of the Suitable Aggregate Gradation
Large numbers of aggregate gradation are in practice for concrete mix design.
Various researcher, specification, codes have suggested different types of
aggregate gradations. Along with the conventional gradation procedures (i.e.
use two distinct portion – fine aggregate and coarse aggregate), recently many
researchers giving an extra emphasis on combined gradation (Crouch et al.
2000; Shilstone 1990; Taylor 1986). Primary objective of this phase is selection
of aggregate gradation that is suitable for available materials in Bangladesh.

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WardaBinte Ashraf (2012) proposed two aggregate gradations to give better
concrete properties compared to other aggregate gradation methodologies in
terms of concrete workability and compressive strength. These gradation band
are “5-10-14-18” and 5-10-1822” band gradation. These two gradation band
are selected from the aggregates found in the local market.
Phase-2: Collection of Aggregate Materials
Our main target was comparative analysis of fresh and strength properties of
concrete made from fresh aggregate and recycled aggregate that was easily
available around us. Fresh aggregate are to be collected from local market.
Local companies crush the stone for producing coarse aggregate of different
sizes. As the source of these stone is the mountains, hills of our hilly region and
also we have to import the stone from the neighboring countries, in some cases
these stone is not very economic. So it becomes costly and ineffective when
local companies cannot provide with the desired gradation of aggregates. In
most cases, it becomes hard to find the exact gradation we expect to have for
our work with the fresh aggregates. Recycled aggregates were collected from
the crushing of cylinders, beams that were found on the backyard of our
laboratory. Those beams or cylinders were made for the purpose research
works. We also collected the recycled aggregates from neighboring building
debris. We have used sylhet sand for the research work. Sylhet sand is costly
but not easily available throughout the country. This sand is good in
engineering properties and has good impact in the concrete mix..
Phase-3: Collection of Cementations Materials
Large amounts of powder materials are added to SCC to increase flow ability
and to facilitate self-compacting. However, an excess amount of concrete
added will greatly increase the cost of materials and dry shrinkage. To obtain
the required properties such as segregation resistance. So Cementitious
materials include Portland Composite Cement (PCC).We collected the PCC

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from Crown Cement (Bangladesh) Limited local dealer and used Crown PCC
in our research.
Phase-4: Collection of Chemical Admixtures
To impart better workability and viscosity to the mixture to avoid segregation
and to obtain a uniform slump flow of 750 mm, a naphthalene-based high range
water reducing admixture (HRWRA) and viscosity-modifying admixture
(VMA) calcium sulfate dehydrate were added. In our research we used Master
Glenium ACE 30 (JP) admixtures and VMA which was collected from BASF
Bangladesh Limited, Chemical Company.
Phase-5: Preparation of Test Equipments
To investigate the fresh properties of SCC and SCC with recycled aggregate we
built some equipments including L-box and V-funnel in standard dimension.
Phase-6: Laboratory Experiments
With the aggregates (coarse and fine aggregate) collected from our local
sources, we have carried out our laboratory experiments for finding our
required output. Comparative analysis of fresh (slump, L-box, V-funnel) and
hardened (compressive strength, split cylinder strength, water absorption,
flexural strength) properties of concrete was the main target of our laboratory
experiment. We have used cylinder to carry out our experiments such as
cylinder for compressive strength, split tension strength, water absorption and
modulus of elasticity test. All these were carried out for different mixer of fresh
aggregates and recycled aggregates. We have used the various proportions of
recycled coarse aggregate such as 30%, 40% and 50% by weight.

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CHAPTER II
LITERATURE REVIEW
2.1 Introduction
Reinforced concrete is one of the most versatile and widely used construction
materials. With the demand increasing for reinforced concrete structures in the
modern society to meet the needs of new developments, increasing population
and new ambitious structural design ideas, the reinforcement in concrete
structures is becoming more dense and clustered. The heavy and dense
reinforcement can raise problems of pouring and compacting the concrete. The
concrete must be able to pass the dense rebar arrangement without blocking or
segregating. The design of such concrete is very challenging because poor
placement and the lack of good vibratory compaction can lead to the inclusion
of voids and loss of long term durability of concrete structures. This has been a
concern for engineers for many years.
During the last decade, concrete technology has made an enormous advance
through the introduction of self-compacting concrete (SCC). Self-compacting
or self-consolidating concrete is a relatively new generation of high-
performance concrete that is able to achieve impressive deformability and
homogeneity in its fresh state, filling all the space around the reinforcement,
passing through dense reinforcing steel bars while compacting under its own
weight without any external vibration.
SCC with its outstanding properties, impressive deformability, gives designers
and architects more freedom of creativity that was not possible previously.
Lighter and slender members can be made from SCC, larger span bridges can
be developed, and underwater structures can be built, making SCC a highly
promising material for the future of the in-situ and pre-cast construction
industries. Since its early use in Japan, SCC has now started to be an alternative
to vibrated concrete across the world in such areas where normal vibrated
concrete is difficult or impossible to pour and vibrate. However those

21
applications are still few and vibrated concrete is still considered as the
standard concrete. As more and more investigations are done into SCC, it is
likely to move from being a fringe technology to becoming a concrete of
choice for construction because of reduced health concerns, i.e. no vibration-
induced noise.
In this chapter, a general overview of the properties and applications of SCC
will be given, highlighting the influence of materials used on its characteristics
in the fresh and hardened states.
2.2 Self Compacting Concrete
2.2.1 Self-Compacting Concrete Definition
The British Standard (BS EN 206-9, 2010) defines “SCC is the concrete that is
able to flow and compact under its own weight, fill the formwork with its
reinforcement, ducts, box outs etc, whilst maintaining homogeneity”.
Other researchers (Ozawa et al., 1989; Bartos and Marrs, 1999; Khayat, 1999)
have defined SCC in almost the same terms as a highly flow-able concrete that
should meet the following requirements:
Flow-ability: SCC should flow under its own weight and fill all
parts of form work without any external aid or vibration.
Passing ability: SCC should pass through heavy reinforcing steel
bars.
Segregation resistance: SCC should maintain its homogeneity without any
migration or separation of its large components (aggregates or fibres).
2.2.2 Advantages and Disadvantages of using SCC
The use of SCC on site offers many advantages:
Eliminating vibration and lower noise level: This will certainly put
less physical demands on site workers, something that is clearly a
desirable objective, including preventing “white finger” syndrome,
which is mainly related to the vibrating equipment.

22
Easy placement and filling: the impressive filling ability, flow-ability
and passing ability of SCC eases placement significantly even with very
complex shaped structures and where heavy reinforcement or very long
formwork is involved, and eliminate honeycombing, blow holes and
grout loss.
Better surface finish: SCC ensures a uniform architectural surface
finish with little to no remedial surface work.
Reduce manpower and construction time: SCC can be placed at a
faster rate with no vibration and less screeding resulting in reducing
manpower and saving construction time.
Improve durability: due to the dense matrix of SCC and the high
consolidation and bond around reinforcement, the structural durability is
improved.
Among sixty eight case studies of the applications of self-compacting concrete
(SCC), which were published from 1993 to 2003, the period of increasingly
widespread use of SCC in many countries, Domone (2006) reported that 67%
were using SCC for technical advantages where vibration is either difficult or
impossible due to the heavy reinforcement or inaccessibility, 14% were for
economical reason to reduce labour work and construction time, while 10%
were for new types of structure such as thin sections, pre-cast units and
steel/concrete composite. The rest of the cases involved environmental causes
including reducing noise level and improving working conditions.
We should however also mention the possible disadvantages of using SCC
compared with conventional concrete can include the high cost of materials
which can subsequently be overcome by the low cost of labour. Another
disadvantage can be related to the nature of SCC, because of its high fluidity,

23
handling and transporting SCC becomes a bit delicate, although the outstanding
results would definitely overcome these disadvantages.
2.2.3 Fresh State Properties of Self-Compacting Concrete
Deformability (flow and filling ability)
Passing Ability
Segregation Resistance (homogeneity/cohesiveness)
2.2.4 Deformability (flow and filling ability)
Deformability refers to the ability of SCC mix to deform and undergo changes
in shape with completely filling all areas and corners of the formwork
horizontally and vertically while maintaining its homogeneity. The
deformability of SCC is characterized by the concrete’s fluidity and cohesion,
and mainly assessed using the slump flow test described later in this Chapter.
Kennedy (1940) proposed the ‘Excess Paste Theory’ as a way to explain the
mechanism governing the workability of concrete. Kennedy states that there
must be enough paste to cover the surface area of the aggregates, and that the
excess paste serves to minimize the friction among the aggregates and give
better flow-ability. Without the paste layer, too much friction would be
generated between the aggregates resulting in extremely limited below
workability.
2.2.5 Passing Ability
Passing ability refers to the ability of SCC mix to pass through congested
reinforcement without blocking, whilst maintaining good suspension of coarse
particles in the matrix, thus avoiding arching near obstacles and blockage
during flow. The J-ring and L-box tests are the most common methods used to
assess this property. The probability of blocking increases when the volume
fraction of large aggregates and/or fibres increases. The size of aggregates,
their shapes and their volume fraction influence the passing ability of SCC,

24
moreover, the presence of fibres especially long and hooked or crimped ends
make self-compacting fibre reinforced concrete (SCFRC) more difficult to pass
through reinforcement.
Okamura and Ouchi (1999) reported that the potential of collision and contacts
between particles increases as the distance between particles decreases; which
therefore results in an increase in the internal stresses when concrete is
deformed, particularly near obstacles causing blockage. Research shows that
the energy required for flowing is consumed by the increase of internal
stresses. Limiting the coarse aggregate content whose energy consumption is
high can effectively reduce the risk of blockage. Highly viscous paste also
prevents localized increases in internal stress due to the approach of coarse
aggregate particles (Okamura and Ouchi, 1999) and therefore increases the
passing ability of SCC. Roussel et al. (2009) state that highly fluid SCC could
be more prone to have its coarsest particles blocked in highly reinforced zones,
which is related to the instability of the material, and to the increases in the
local volume fraction of coarse aggregates near an obstacle.
Blocking can be also increased as the gaps between steel bars are reduced. The
spacing between bars is typically recommended to be 3 times the maximum
aggregate size (EFNRC, 2005). For fibre-reinforced concrete, the bars should
be placed 1 to 3 times the maximum fibre length (Koehler and Fowler, 2003).
2.2.6 Segregation Resistance (homogeneity/cohesiveness)
Segregation resistance refers to the ability to retain the coarse components of
the mix and the fibres in suspension in order to maintain a homogeneous
material. Stability is largely dependent on the cohesiveness and the viscosity of
the concrete mixture which can be increased by reducing the free water content
and increasing the amount of fines (Khayat et al., 1999). Segregation resistance
is largely controlled by viscosity; therefore ensuring a high viscosity can
prevent a concrete mix from segregation and/or bleeding. Bleeding is a special

25
case of segregation in which water moves upwards by capillary action and
separates from the mix. Some bleeding is normal for concrete, but excessive
bleeding can lead to a decrease in strength, high porosity, and poor durability
particularly at the surface (Douglas, 2004). Two basic methods can ensure
adequate stability; the first approach is based on the Japanese method. It uses a
super-plasticiser (SP), low water/cement ratio, high powder content, mineral
admixtures, and low aggregate content. The second approach is based on
incorporating a viscosity-modifying admixture (VMA), low or moderate
powder content and super-plasticiser (Bonen, 2004).
2.2.7 Difference between SCC and Normal Vibrated Concrete (NVC)
SCC consists of cement, aggregates, water and admixtures which are quite
similar to the composition of conventional vibrated concrete, however, the
reduction of coarse aggregates, the large amount of fines, the incorporation of
super-plasticizer, the low water to cement ratio, is what led to self-compact
ability. What makes SCC unique is the migration of air bubbles to the surface
without any vibration which is mainly due to the dense matrix, mix proportion
and the material characteristics. The smooth passing ability through
reinforcement bars and the impressive filling ability of all the formwork
without any segregation or bleeding are remarkable, even in narrow structural
elements with complicated shapes and heavy reinforcement, thanks to the
balance between high fluidity and moderate viscosity. All these properties in
the fresh state would lead to a high strength and durable concrete in the
hardened state.
2.2.8 Mechanisms of Achieving SCC
In the fresh state, SCC should achieve high flow-ability as well as rheological
stability which means it must be as fluid as possible in the fresh state to fill
under its own weight all the far reaching corners in the form work and pass
through heavy reinforcement without segregation. The methodology of

26
selecting the right amount of materials and admixtures is crucial to achieve this
goal.
The following three main rules have been suggested by Okamura and Ouchi
(2003).
Limiting Aggregate Content.
Using Super-plasticiser.
Reducing Water-Powder Ratio.
Limiting Aggregate Content: The friction between the aggregates limits the
spreading and the filling ability of SCC. By reducing the volume and the
maximum size of coarse aggregates, and replacing crushed aggregates with
round ones the passing ability of SCC in congested areas can be increased, thus
improving the workability and optimizing the packing density of skeleton.
High Amount of Super-plasticiser: Achieving a highly flow able mix would
conflict with keeping the homogeneity at an acceptable level. The mechanism
of achieving this is by the dispersion effects of super-plasticiser on flocculated
cement particles, by reducing the attractive forces among them. An optimum
amount is necessary as a high amount would result in segregation and a low
amount would compromise the fluidity. Obtaining a good degree of
cohesiveness can guarantee a considerable improvement in the overall
performance (Kwan and Ng, 2010).
High Paste Volume: SCC contains a high volume of paste, the role of which is
to maintain aggregate separation (Tviksta, 2000). Okamura and Ouchi (2003)
indicated that the internal stresses can increase when concrete is deformed,
particularly near obstacles. The energy required for flowing is consumed by
those increased internal stresses, resulting in blockage. Also, paste with high
viscosity prevents localized increases in internal stresses due to the approach of
coarse aggregate particles. A high amount of fine particles increases the
workability and cohesiveness while simultaneously reducing the interlocking of
coarse particles which could result in a blocking behaviour (Khayat, 2000). The

27
necessity of including this large amount of fines requires that there should be
cement replacement materials such as GGBS, silica fume, fly ash...etc., in order
to avoid excessive heat generation.
Using Viscosity Modifying Agents (VMA): These products are generally
cellulose derivatives, polysaccharides or colloidal suspensions. The use of
VMA gives the same effect as the fine particles in minimizing bleeding and
coarse aggregate segregation by thickening the paste and retaining the water in
the skeleton. For normal strength SCC with high water to binder content, the
introduction of such products seems to be justified. On the other hand, they
may be less useful for high performance SCC with low water to binder ratio.
Viscosity agents are assumed to make SCC less sensitive to water variations.
Because of the small quantities of viscosity agents required, however, it may be
difficult to achieve accuracy of dosage (Tviksta, 2000).
2.2.9 SCC Applications
Following its success in Japan with more than 400,000 m3 of annual
production for bridges and buildings, other parts of the world have embraced
SCC.
At over 828 meters (2,716.5 ft) and 166 stories, Burj Khalifa (2010)
in Dubai holds the record of the tallest building and free standing
structure in the world with the largest number of stories. Self-
compacting concrete is playing a greater role in high-rise
construction to overcome the problem of congested reinforcement
and ease of placement. The groundwater in which the Burj Dubai
substructure is constructed is particularly severe, with chloride
concentrations of up to 4.5%, and sulfate of up to 0.6%. The chloride
and sulfate concentrations found in the groundwater are even higher
than the concentrations in seawater. Accordingly, the primary
consideration in designing the piles and raft foundation was
durability. The concrete mix for the piles which are 1.5 m in

28
diameter and 43 m long with design capacity of 3000 tonnes each
was a 60 MPa mix based on a triple blend with 25% fly ash, 7%
silica fume, and a water to cement ratio of 0.32. A viscosity
modifying admixture was used to obtain a slump flow of 675 +/- 75
mm to limit the possibility of defects during construction.
The 800 million dollar SodraLanken (1997) Project in Sweden
(notably was one of the largest infrastructure projects that used SCC.
The six kilometers long four-lane highway in Stockholm involved
seven major junctions, and rock tunnels totaling over 16 km partly
lined with concrete and over 225,000 cubic meters of concrete.
Incorporating SCC was ideal to cope with the density of
reinforcement required and the highly uneven rock surfaces.
Another example can be found in the UK at St George Wharf (2004),
London Docklands where SCC has been used to save time and
manpower (Figure 2.33). SCC was used in limited areas on two
floors in lift shaft walls, up stand beams and columns and for stairs
precast on site.
Dragon Bridge (2012), Alcalá De Guadaira, Seville, Spain (Figure
2.34). This spectacular 124 m long bridge, distributed in four spans,
stands out due to its unique shape. The concrete structure represents
a dragon that seems to emerge from the Guadaira river in the
province of Seville. The dragon’s body is made up of an egg-shape
section, 4 meters high and 2 meters wide, of self-compacting
reinforced concrete. Its shape was clad in “trancadis” using more
than 4,500 square meters of mosaic tiles.
2.3 History of Development
In the mid-1980s, research undertaken into underwater placement technology
within the UK, North America and Japan led to the development of concrete
mixes with a high degree of washout resistance. However, the creation of
durable structures from such mixes required adequate compaction by skilled

29
workers. At the same time in Japan, a gradual reduction in the number of
skilled workers in the construction industry was leading to a reduction in the
quality of construction work, with subsequent knock-on effects on concrete
durability (Okamura et al., 1998). One solution to overcome the durability
problems in concrete structures independently of the quality of construction
work was to use self-compacting concrete (SCC) (Okamura and Ouchi, 2003).
2.3.1 Evolution of Self Compacting Concrete
Self-compacting concrete (SCC), a new kind of high performance concrete
(HPC) with excellent deformability and segregation resistance, was first
developed in Japan in 1986. It is a special kind concrete that can flow through
and fill the gaps of reinforcement and corners of molds without any need for
vibration and compaction during the placing process. Though showing good
performance, SCC is different from the HPC developed in North America and
Europe, which emphasizes on high strength and durability of concrete. In terms
of workability, HPC merely improves fluidity of concrete to facilitate placing;
however, it cannot flow freely by itself to pack every corner of molds and all
gaps among reinforcement. In other words, HPC still requires vibration and
compaction in the construction process. Comparatively SCC has more
favorable characteristics such as high fluidity, good segregation resistance and
the distinctive self-compacting ability without any need for vibration during the
placing process. In 1993, Okamura proposed a mix design method for SCC.
His main idea was to conduct first the test on paste and mortar in order to
examines the properties and compatibility of superplasticizer(SP), cement, fine
aggregate and Puzzolanic materials, then followed by the trial mix of SCC. The
major advantage of this method is that it avoids having to repeat the same kind
of quality control test on concrete, which consumes both time and labour.
However, the drawbacks of Okamura’s method are that (1) it requires quality
control of paste and mortar prior to SCC mixing, while many ready mixed
concrete producers do not have the necessary facilities for conducting such

30
tests and (2) the mix design method and procedures are too complicated for
practical implementation.
The “Standardize mix design method of SCC” proposed by the JRMCA is a
simplified version of Okamura’s method. This method can be employed to
produce SCC with a large amount of powder materials, and a water/binder ratio
of <.30. On the other hand, the Laboratory Central Des Pontset Chausses
(LCPC), the Swedish Cement and Concrete Research Institute (CRI), research
groups in both Mainland China and Taiwan all have proposed different mix
design methods of HPC. The LCPC’s approach is developed on the basis of the
BTRHEOM rheometer and RENE LCPC software. It is difficult for others to
adopt their method without purchasing the software. CBI’s approach makes use
of the relationship between the blocking volume ratio and clean reinforcement
spacing to fraction particle diameter ratio. However, it is not clear how carryout
the critical tests because concrete mixed with the coarse aggregates and paste
only is susceptible to severe segregation. In Taiwan, the method proposed by
Hwang et al. involves a densified mixture design algorithm, which is derived
from the maximum density theory and excess paste theory. Nevertheless, there
is no information yet concerning the relationship between their method and
ability of concrete passing through reinforcement or its segregation resistance.
Hon’s group of Mainland China has not disclosed their mix design procedures,
but just offered some useful principles. They have also shown that too low a
paste volume not only impairs the passing ability of concrete, but also reduce
its compression strength if no vibration is used in the mixing process.
In 2002 EFNARC published their “Specification & Guidelines for Self-
Compacting concrete” which, at that time, provided state of the art information
for producers and users. Since then, much additional technical information on
SCC has been published but European design, product and construction
standards do not yet specifically refer to SCC and for site applications this has
limited its wider acceptance, especially by specifies and purchasers.

31
Goodie CI studied SCC is not expected to ever completely replace
conventionally vibrated concrete, the use of the material in both the precast and
ready-mix markets in the UK, Europe and the rest of the world is expected to
continue to increase as the experience and technology improves, the clients
demand a higher- quality finished product and the availability of skilled labour
continues to decrease.
Khayat et al (1999) published that By employing self-compacting concrete, the
cost of chemical and mineral admixtures is compensated by the elimination of
vibrating compaction and work done to the surface of the normal concrete.
Bertil Persson (2001) carried out an experimental and numerical study on
mechanical properties, such as strength, elastic modulus, creep and shrinkage
of self-compacting concrete and the corresponding properties of normal
compacting concrete. The study included eight mix proportions of sealed or air-
cured specimens with water binder ratio (w/b) varying between 0.24 and 0.80.
Fifty percent of the mixes were SCC and rests were NCC. The age at loading of
the concretes in the creep studies varied between 2 and 90 days. Strength and
relative humidity were also found. The results indicated that elastic modulus,
creep and shrinkage of SCC did not differ significantly from the corresponding
properties of NCC.
Nan Su et al (2001) proposed a new mix design method for self-compacting
concrete. First, the amount of aggregates required was determined, and the
paste of binders was then filled into the voids of aggregates to ensure that the
concrete thus obtained has flow ability, self-compacting ability and other
desired SCC properties. The amount of aggregates, binders and mixing water,
as well as type and dosage of super plasticizer to be used are the major factors
influencing the properties of SCC. Slump flow, V-funnel, L-flow, U-box and
compressive strength tests were carried out to examine the performance of
SCC, and the results indicated that the proposed method could be used to
produce successfully SCC of high quality. Compared to the method developed

32
by the Japanese Ready-Mixed Concrete Association (JRMCA), this method is
simpler, easier for implementation and less time- consuming, requires a smaller
amount of binders and saves cost.
Bouzoubaa and Lachemi (2001) carried out an experimental investigation to
evaluate the performance of SCC made with high volumes of fly ash. Nine
SCC mixtures and one control concrete were made during the study. The
content of the cementations materials was maintained constant (400 kg/m3),
while the water/cementations material ratios ranged from 0.35 to 0.45. The
self-compacting mixtures had a cement replacement of 40%, 50%, and 60% by
Class F fly ash. Tests were carried out on all mixtures to obtain the properties
of fresh concrete in terms of viscosity and stability. The mechanical properties
of hardened concrete such as compressive strength and drying shrinkage were
also determined. The SCC mixes developed 28-day compressive strength
ranging from 26 to 48 MPa. They reported that economical SCC mixes could
be successfully developed by incorporating high volumes of Class Fly ash.
Sri Ravindra rajah (2003) et al made an attempt to increase the stability of fresh
concrete (cohesiveness) using increased amount of fine materials in the mixes.
They reported about the development of self-compacting concrete with reduced
segregation potential. The systematic experimental approach showed that
partial replacement of coarse and fine aggregate with finer materials could
produce self-compacting concrete with low segregation potential as assessed by
the V-Funnel test. The results of bleeding test and strength development with
age were highlighted by them. The results showed that fly ash could be used
successfully in producing self- compacting high-strength concrete with reduced
segregation potential. It was also reported that fly ash in self-compacting
concrete helps in improving the strength beyond 28 days. Self-Compacting
Concrete.
Hajime Okamura and Masahiro Ouchi (2003) addressed the two major issues
faced by the international community in using SCC, namely the absence of a

33
proper mix design method and jovial testing method. They proposed a mix
design method for SCC based on paste and mortar studies for super plasticizer
compatibility followed by trail mixes. However, it was emphasized that the
need to test the final product for passing ability, filling ability, and flow ability
and segregation resistance was more relevant.
Paratibha Aggarwal (2008) et al presented a procedure for the design of self-
compacting concrete mixes based on an experimental investigation. At the
water/powder ratio of 1.180 to 1.215, slump flow test, V-funnel test and L-box
test results were found to be satisfactory, i.e. passing ability; filling ability and
segregation resistance are well within the limits. SCC was developed without
using VMA in this study. Further, compressive strength at the ages of 7, 28,
and 90 days was also determined. By using the OPC 43 grade, normal strength
of 25 MPa to 33 MPa at 28-days was obtained, keeping the cement content
around 350 kg/m3 to 414 kg/m3.
Girish (2010) et al presented the results of an experimental investigation
carried out to find out the influence of paste and powder content on self-
compacting concrete mixtures. Tests were conducted on 63 mixes with water
content varying from 175 l/m3 to 210 l/m3 with three different paste contents.
Slump flow, V funnel and J-ring tests were carried out to examine the
performance of SCC. The results indicated that the flow properties of SCC
increased with an increase in the paste volume. As powder content of SCC
increased, slump flow of fresh SCC increased almost linearly and in a
significant manner. They concluded that paste plays an important role in the
flow properties of fresh SCC in addition to water content. The passing ability
as indicated by J-ring improved as the paste content increased.
E. Todorova, G. Chernev, G. Chernev. The aim of the “influence of
metakaolinite and stone flour on the properties of self-compacting concrete”
was the manufacture and characterization of mixture for self-compacting
concrete with participation of powder additives (metakaolinite and stone flour)

34
and super plasticizers (viscocrete 5370 and viscocrete 5800). The influence of
chemical admixtures and powder additives on concrete properties was made by
the different methods: sorption ability; sем; ftir and potential. Physical and
mechanical properties as compressive strength; spreading and fluidity were
measured. Tests for mechanical and physical properties of self-compacting
concrete established, that the best appropriate mixtures were these with
metakaolinite and 1,25 % Viscocrete 5370, with stone flour and admixture of
1,2 % Viscocrete 5370 and viscocrete 5800. The strength pressure reaches 71
МРа, 65, 1 МРа and 63, 3 МРа, respectively. SЕМ micrographs proved
evenly distribution of fine fraction in concrete mixture. Metakaolinite and
stone flour showed excellent values for each test using for investigation
properties of prepared mixtures. They improve the characteristics of self-
compacting concrete. Better results showed mixtures with higher content of
powder materials and super plasticizers.
Cristian Druta (2003) carried out an experimental study on to compare the
Splitting Tensile Strength and Compressive Strength values of self-compacting
and normal concrete specimens and to examine the bonding between the coarse
aggregate and the cement paste using the Scanning Electron Microscope. In
this experiment used mineral.admixes Blast Furnace Slag, Fly Ash and Silica
Fume and chemical admixes Super plasticizers and Viscosity-Modifying
Admixtures, It has been using the slump flow and U-tube tests, that self-
compacting concrete (SCC) achieved consistency and self-compatibility
under its own weight, without any external vibration or compaction. Also,
because of the special admixtures used, SCC has achieved a density between
2400 and 2500 kg/m3, which was greater than that of normal concrete, 2370-
2321 kg/m3.Self-compacting concrete can be obtained in such a way, by
adding chemical and mineral admixtures, so that its splitting tensile and
compressive strengths are higher than those of normal vibrated concrete. An
average increase in compressive strength of 60% has been obtained for SCC,
whereas 30% was the increase in splitting tensile strength. Also, due to the use
of chemical and mineral admixtures, self- compacting concrete has shown

35
smaller interface micro cracks than normal concrete, fact which led to a better
bonding between aggregate and cement paste and to an increase in splitting
tensile and compressive strengths. A measure of the better bonding was the
greater percentage of the fractured aggregate in SCC (20-25%) compared to the
10% for normal concrete.
Subramanian and Chattopadhyay (2002) are research and development
engineers at the ECC Division of Larsen & Toubro Ltd (L&T), Chennai, India.
They have over 10 years of experience on development of self-compacting
concrete, underwater concrete with ant wash out admixtures and proportioning
of special concrete mixtures. Their research was concentrated on several trials
carried out to arrive at an approximate mix proportion of self-compacting
concrete, which would give the procedure for the selection of a viscosity
modifying agent, a compatible super plasticizer and the determination of their
dosages. The Portland cement was partially replaced with fly ash and blast
furnace slag, in the same percentages as Ozawa (1989) has done before and the
maximum coarse aggregate size did not Exceed. The two researchers were
trying to determine different course and fine aggregate contents from those
developed by Okamura. The coarse aggregate content was varied, along with
water-powder (cement, fly ash and slag) ratio, being 50%, 48% and 46% of the
solid volume. The U-tube trials were repeated for different water-powder ratios
ranging from 0.3 to 0.7 in steps of 0.10. On the basis of these trials, it was
discovered that self-compatibility could be achieved when the coarse aggregate
content was restricted to 46 percent instead of 50 percent tried by Okamura
(1997). In the next series of experiments, the coarse aggregate content was
fixed - at 46 percent and the sand content in the mortar portion was varied from
36 percent to 44 percent on a solid volume basis in steps of 2 percent. Again,
the water-powder ratio was varied from 0.3 to 0.7 and based on the U-tube
trials a sand content of 42 percent was selected. In order to show the necessity
of using a viscosity-modifying agent along with a super plasticizer, to reduce
the segregation and bleeding, the mixture proportion developed by the two

36
researchers was use to cast a few trial specimens. In these trials viscosity-
modifying agent was not used. The cast specimens were heavily reinforced
slabs having 2400x600x80 mm and no vibration or any other method of
compaction was used. However, careful qualitative observations revealed that
the proportions needed to be delicately adjusted within narrow limits to
eliminate bleeding as well as settlement of coarse aggregate. It was difficult to
obtain a mixture that was at the same time fluid but did not bleed. This led to
the conclusion that slight changes in water content or granular geometry of
aggregate may result either in a mixture with inadequate flowing ability, or
alternatively one with a tendency for coarse aggregate to segregate. Therefore,
it became necessary to incorporate a viscosity- modifying agent in the concrete
mixture. Viscosity-modifying agents can be a natural polymer such as guar
gum, a semi-synthetic polymer such as hydroxyl propyl methyl cellulose, or
water- soluble polysaccharides, including those derived from a microbial
source such as welan gum. Experiments involving three types of gums were
being carried out by the two researchers. One commonly used thickener in
cement- based systems, namely hydroxyl propyl methyl cellulose (HPMC), a
low-priced gum known as guar gum and a special product called welan gum
were selected for studying their suitability for use in self-compacting concrete.
On a first consideration, a1l these qualified as viscosity modifying agents.
However, some of these substances, with the exception of welan gum, had
shortcomings. Guar gum had to be made into a suspension in water after
heating to 60˚C and stirring for about one hour. This solution lost its
suspending power after twelve hours. HPMC was not compatible with the
naphthalene formaldehyde super plasticizer and entrained excessive air,
causing a reduction in strength (Fig.1) Welan gum is suitable for use in self-
compacting concrete because it combines with most types of super plasticizer
and has superior suspending power, compare to guar gum and hydro
xypropylmethy cellulose (HPMC). In order to arrive at an acceptable
combination of dosages of welan gum and superplasticizer, Subramanian and
Chattopadhyay (2002) ran several tests related to the tendency of the concrete

37
to bleed and its ability to pass the U-tube test. They discovered that with a
combination corresponding to 0.1 percent of welan gum and 0.53 percent by
weight of water acrylic copolymer type super plasticizer, a satisfactory self-
compacting mixture could be obtained.
Surabhi.C.S, Mini Soman, SyamPrakash.V Carried out an experimental study
on cement content in the SCC mix is replaced with various percentage of
limestone powder and the fresh and hardened properties were studied. It is
observed that limestone powder can be effectively used as a mineral additive in
SCC. Then conclude that result the 7 day and 28 day compressive strength
increases with increase in content of limestone powder up to 20%. The
improvement in compressive strength at 28 day is about 20% for a replacement
of 20% of cement with limestone powder. But further addition of limestone
powder reduces the strength. All the hardened properties like cylinder
compressive strength, split tensile strength, flexural strength and modulus of
elasticity improves with the addition of limestone powder.
Mayur B. Vanjare, Shriram H. Mahure (2012) carried out an experimental
study on to focus on the possibility of using waste material in a preparation of
innovative concrete. One kind of waste was identified: Glass Powder (GP). The
use of this waste (GP) was proposed in different percentage as an instead of
cement for production of self-compacting concrete. The addition of glass
powder in SCC mixes reduces the self-compatibility characteristics like filling
ability, passing ability and segregation resistance. The flow value decreases by
an average of 1.3%, 2.5% and 5.36% for glass powder replacements of 5%,
10% and 15% respectively.
Suraj N. Shah., Shweta S. Sutar, YogeshBhagwat carried out an experimental
study on to find out the effect of addition of red mud, which is a waste product
from the aluminum industries, and foundry waste sand, which is a waste
product from foundry, on the properties of self- compacting concrete
containing two admixtures and experimentation combinations of admixtures

38
which is taken Super plasticizer & VMA. It can be concluded that maximum
compressive strength of self-compacting concrete with the combination of
admixtures (SP+VMA) may be obtained by adding 2% foundry waste sand
which is a waste material of ferrous industry (foundry).
N. Bouzouba and M. Lachemi carried out an experimental study on producing
and evaluating SCC made with high- volumes of fly ash is presented. The high-
volume fly ash self-compacting concretes (except one) have a slump flow in
the range of 500 to 700mm, a flow time ranging from 3 to 7 seconds, a
segregation index ranging from 1.9 to 14%, and bleed water ranging from0.025
to 0.129 mL/cm2. The temperature rise of the self-compacting concrete was 5
to 10 C lower than that of the control concrete, and the setting times of the self-
compacting concrete were 3 to 4 hours longer than those of the control
concrete. The self- compacting concrete developed compressive strengths
ranging from 15 to 31 MPa and from 26 to 48 MPa, at 7 and 28 days,
respectively.
Manu santhanam and Subramanyam (2004) discussed the existing research
about various aspects of self-compacting concrete , including materials and
mixture design , test methods , construction-related issues, and properties. They
summarized that Self-Compacting Concrete is a recent development that shows
potential for future applications. It meets the demands places by requirements
of speed and quality in construction.
R.V(2003) found that use of fine fly ash for obtaining Self compacting concrete
resulted in an increase of the 28 day Compressive Strength Concrete by about
38%. Self-compacting concrete was achieved when volume of paste was
between 0.43 and 0.45.
Subramanian and Chattopadhyay (2002) described the results of trails carried
out to arrive at an approximate mix proportioning of Self compacting concrete.
Self-Compatibility was achieved for Water to Powder ratio ranging from 0.9 to

39
1.1 when Coarse Aggregate and Sand content were restricted to 46 % and 40%
of the mortar volume respectively.
Hardik Upadhyay carried out an experimental study on different mix design
methods using a variety of materials has been discussed, as the characteristics
of materials and the mix proportion influences self- compatibility to a great
extent. It can be a boon considering improvement in concrete quality,
significant advances towards automation and concrete construction processes,
shortened construction time, lower construction cost and much improvement in
working conditions as it reduces noise pollution. Properties of self-compacting
concrete with different types of additives.
ZoranGrdic (2008) carried out an experimental study on present’s properties of
self-compacting concrete, mixed with different types additives: fly ash, silica
fume, hydraulic lime and a mixture of fly ash and hydraulic lime. Due to test
results, the addition of fly ash to the mixture containing hydraulic lime is quite
beneficial, bringing a substantial improvement of the behaviour of SCC FAHL
concrete. Also, this mixture has smaller filling capacity and fluidity than other
mixtures.
Naik and Singh (1997) conducted tests on concretes containing between 15%
and 25% by mass Class F and Class C fly ashes to evaluate compressive
strength. The effects of moisture and temperature during curing were also
examined. The results of the research showed that concretes containing Class C
fly ash and were moist cured at 73°F (23°C) developed higher early age (1 to
14 days) compressive strengths than concretes with Class F fly ash. The long-
term (90 days and greater) compressive strength of concretes containing fly ash
was not significantly influenced by the class of fly ash. The air-cured concretes
containing Class F fly ash did not develop strengths equivalent to air-cured
normal concretes and air-cured concretes containing Class C fly ash developed
relatively greater compressive strengths than air-cured concretes containing

40
Class F fly ash. For concretes containing either class of fly ash, compressive
strengths at 7 days increased with an increase in curing temperature.
Safiuddin (2008) et al. observed that drying shrinkage occurs when concrete
hardens and dries out at the early age. It induces potential flow channels in the
form of micro-cracks. These cracks provide the access to deleterious agents,
and thus affect the durability of concrete. The drying shrinkage of SCC does
not differ very much from that of normal concrete. Several studies reported that
it could be even lower in SCC. In general, the reduced coarse aggregate content
and the increased amount of cementing material are expected to cause more
drying shrinkage in SCC. But the porosity also affects the drying shrinkage of
concrete. As the porosity is reduced in SCC, it compensates the negative effects
of aggregate and binder on drying shrinkage. In addition, the drying shrinkage
tends to decrease in SCC since a very small amount of free water is available in
the system. Also, SCC has minimum empty voids on concrete surface that are
largely responsible for drying shrinkage.
Felekoglu et al. (2005) has done research on effect of w/c ratio on the fresh and
hardened properties of SCC. According to the author adjustment of w/c ratio
and super plasticizer dosage is one of the key properties in proportioning of
SCC mixtures. In this research, fine mixtures with different combinations of
w/c ratio and super plasticizer dosage levels were investigated. The results of
this research show that the optimum w/c ratio for producing SCC is in the
range of 0.84- 1.07 by volume. The ratio above and below this range may cause
blocking or segregation of the mixture.
Nagataki, Fujiwara (1992) performed the slump flow test of SCC mix to find
out whether the concrete mix is workable or not. They also performed the
segregation test of SCC mix, by using locally available materials, the value
ranging from 500-700 mm is considered as the slump required for a concrete to
be self-compacted.

41
2.3.2 Influence of Admixtures on Concrete Properties
In the following are presented several papers, found in the literature, on the
effects of mineral and chemical admixtures on the fresh and hardened concrete.
The mineral admixtures referred to are blast-furnace slag, fly ash, and silica
fume. The chemical admixtures considered are high range water reducer or
superplasticizer and viscosity-modifying agent.
2.3.2.1 Mineral Admixtures
Mineral admixtures are added to concrete as part of the total cementitious
system. They may be used in addition to or as a partial replacement of Portland
cement in concrete depending on the properties of the materials and the desired
effect on concrete (Mindess et al., 2003). Mineral admixtures are used to
improve a particular concrete property such as workability, strength or compact
ability. The optimum amount to use should be established by testing to
determine (1) whether the material is indeed improving the property, and (2)
the correct dosage rate, as an overdose or under dose can be harmful or not
achieve the desired effect, because they react differently with different cements
(Kosmatka et al., 2002).
2.3.2.2 Blast Furnace Slag
Blast furnace slag (BFS), also called slag cement, is made by rapidly quenching
molten blast-furnace slag and grinding the resulting material into a fine
powder. BFS is classified by ASTM C 989 according to its level of reactivity.
Depending on the desired properties, the amount of BFS can be as high as 50
percent by mass, of the total cementitious materials content
(Ramachandran,1981). In his research, Russell (1997) found out that the use of
slag cement lowers concrete permeability, thereby reducing the rate of chloride
ion diffusion. Proper proportioning of slag cement can eliminate the need to
use low alkali or sulfate-resistant Portland cements. Russell’s results showed

42
that BFS can be used to enhance the strength gain at later ages than 28 days, it
replaces 20 to 30 percent by mass of the Portland cement.
Sobolev (1999) studied the effect of adding up to 50% by mass granulated
blast-furnace slag in the cementitious material that resulted in the increasing of
chemical and thermal resistance. The very low permeability of the concrete
obtained, provided high resistance to chemical attack and to freezing and
thawing cycles. There was no visible destruction of blast furnace slag concrete
samples after 140 cycles of freezing and thawing at -50ºC, and they also
demonstrated high resistance to elevated temperatures.
Ozyildirim (2001) studied three concrete mixtures placed in the jointed plain
concrete paving project in Newport News, Virginia. The main goal was to
reduce the shrinkage and improve the flexural strength of the concrete. Two of
the mixtures that he used contained ground-granulated blast furnace slag and
the third contained Class F fly ash. The content of blast-furnace slag in the two
mixtures was 30% by mass of the total cementitious material and the maximum
water-cement ratio was 0.50.
Flexural strengths at 28 days were similar for fly ash and blast-furnace slag
concretes, but after 60 days they were greater for those which contained slag.
The shrinkage values of concretes containing slag cement were slightly greater
than the values of concretes with fly ash. For freezing and thawing tests the
acceptance criteria at 300 cycles were a weight loss of 7 percent and less, a
durability factor of 60 and more, and a surface rating (ASTM C 672) of 3 or
less. Blast-furnace slag concretes complied with those requirements, but the fly
ash concretes had slightly higher weight loss than required.
Hale (2000) et al. investigated the effects of the cement replacement with 25%
by mass blast-furnace slag on fresh and hardened concrete properties. As a
result, compressive strengths were increased by approximately 25 percent at 28
days as compared to normal Portland cement mixtures. The use of 25 percent
blast-furnace slag led to minor to moderate reductions in slump and slightly

43
lower air contents as compared to conventional mixtures. Klieger and Isberner
(1967) have conducted a comprehensive study on the properties of pastes and
concretes made with Portland blast-furnace slag cements (ASTM Type IS).
Five commercial IS brands were included in these tests, in addition to a number
of Portland cements.
These IS type cements were made by inter grinding a mixture of Portland
cement clinker and granulated blast-furnace slag or by making an intimate and
uniform blend of Portland cement and fine granulated blast-furnace slag. The
amount of slag used in the mixtures was between 20% and 350% by mass of
the total cementitious material.
The compressive strengths of concretes made with type IS cements were
generally lower at early ages than the strengths of concretes made with Type I
cement. However, at 3 months, one year, and 3 years, the strengths were
generally equal to or greater than those of the Type I cement. Also, at the same
compressive strength, values of splitting tensile strength were essentially equal
for both types of cement.
2.3.2.3 Fly Ash
Gebler and Klieger (1983) studied concretes containing fly ash in order to
determine its effect on the air-void stability. 10% to 20% by mass of fly ash
was used in the total amount of cementitious material. The tests undertaken
indicated that air contents of concrete containing Class C fly ash appeared to be
more stable than those of concrete containing Class F fly ash. This occurred
primarily because Class C fly ashes have lower organic matter content and
carbon content values. The studies revealed that the higher the organic matter
content of a fly ash, the higher would be the air-entraining admixture
requirement for concrete in which the admixture is used. Practically, all
concretes containing fly ash required more air-entraining admixture than
concretes without fly ash and the concretes containing Class C fly ash tended to
lose less air than concretes with Class F fly ash.

44
Naik and Singh (1997) conducted tests on concretes containing between 15%
and 25% by mass Class F and Class C fly ashes, to evaluate time of setting,
bleeding, compressive strength, drying shrinkage, and abrasion resistance. The
effects of moisture and temperature during curing were also examined. The
results of the research showed that concretes containing Class C fly ash and
were moist cured at 73°F (23°C) developed higher early age (1 to 14 days)
compressive strengths than concretes with Class F fly ash. The long-term (90
days and greater) compressive strength of concretes containing fly ash was not
significantly influenced by the class of fly ash. The air-cured concretes
containing Class F fly ash did not develop strengths equivalent to air-cured
normal concretes and air-cured concretes containing Class C fly ash developed
relatively greater compressive strengths than air-cured concretes containing
Class F fly ash. For concretes containing either class of fly ash, compressive
strengths at 7 days increased with an increase in curing temperature. Concretes
with fly ash showed less bleeding than conventional ones. Further, concretes
with Class C fly ash showed less bleeding than concretes with Class F fly ash.
Also, drying shrinkage results for concretes containing fly ash were essentially
the same as for conventional concretes , regardless of initial curing
temperature. Drying shrinkage results for concretes with Class F fly ash were,
on the average, slightly less than for concretes with Class C fly ash. The
abrasion resistance of the concretes was essentially dependent on their
compressive strength and time of setting for most of the concretes containing
the two types of fly ash was retarded.
Dietz and Ma (2000) in their research, showed a possible application of lignite
fly ash (LFA) for the production of Self-Compacting Concrete (SCC). The
lignite fly ash has not only some characteristics of potential hydraulic
materials, it can also improve the rheological properties of the fresh concrete
because of its fineness, which is a primary advantage for SCC. Self-compacting
concrete with lignite fly ash shows a good flowing ability and high self
compact ability.

45
Lignite Fly Ashes (LFA) are fine residues of ground lignite burned in the
power plant industry. In comparison with fly ashes from coal, LFA contains
obviously more free lime and sulfate. The chemical and mineralogical
composition of the LFA shows wide variations and because of that, fly ash with
a free lime content of approximately 22% was chosen for the project. The
choice of this type of ash was due to its availability and its constant quality.
Two differently lignite fly ashes were used. One LFA, which was untreated
showed a high free lime content and was called Untreated Lignite Fly Ash (U-
LFA). The other fly ash, which was treated with water, was called Treated
Lignite Fly Ash (T-LFA). In the latter case, the free lime has changed into
calcium hydroxide. Cementitious material consisted of 75% cement and 25%
fly ash, by mass. It was discovered that, if the cement is replaced from 10% to
25% by U-LFA or TLFA, the water requirement is reduced. This is favorable
for the workability of the fresh concrete. The reduced water requirement
indicated that the grains of the cement - LFA mixture were more densely
compacted. The volume between the particles, which should be filled with
water, became smaller due to the denser packing. Furthermore, the spherical
LFA particles favorably affected the workability of the mixture. It was seen
that the U-LFA set very quickly. The setting and hardening of the cement-U-
LFA paste was clearly shortened by U-LFA. The higher the U-LFA proportion
was, the faster the paste hardened and, because of this, U-LFA was replaced by
T-LFA, which shortened the setting times only slightly. The slump flow and
funnel tests showed values within the ranges of other tests previously
undertaken. The compressive strengths of hardened concrete specimens
decreased with the increasing proportion of U-LFA over 25%, while they
remained approximately constant when T-LFA was used in percentages that
exceeded 25%. After 28 days, compressive strengths between 50 MPa and 60
MPa and splitting tensile strengths between 4 and 5 MPa were obtained for
self-compacting concretes, with w/c ratios ranging from 0.3 to 0.46.

46
2.3.2.4 Chemical Admixtures
Chemical admixtures represent those ingredients which can be added to the
concrete mixture immediately before or during mixing. The use of chemical
admixtures such as water reducers, retarders, high-range water reducers or
superplasticizers (SP), and viscosity-modifying admixtures is necessary in
order to improve some fundamental characteristics of fresh and hardened
concrete. They make more efficient use of the large amount of cementitious
material in high strength and self-compacting concretes and help to obtain the
lowest practical water to cementing materials ratio.Chemical admixtures
efficiency must be evaluated by comparing strengths of trial batches. Also,
compatibility between cement and supplementary cementing materials, as well
as water reducers, must be investigated by trial batches. From these, it will be
possible to determine the workability, setting time, bleeding, and amount of
water reduction for given admixture dosage rates and times of addition. Due to
the fact that this research dealt only with superplasticizers and viscosity
modifiers, papers found in the literature about these types of chemical
admixtures would be presented in the following.
2.3.2.5 Superplasticizers
A study of four commercially available superplasticizers used in type I
Portland cement concrete mixes was done by Whiting (1979). They represented
both melamine- and naphthalene-based formaldehyde condensation products.
Hardened concrete specimens were prepared and tested for compressive
strength development, drying shrinkage, freeze-thaw resistance, and resistance
to deicing scaling. From his research, Whiting found out that high range water
reducers were capable of lowering the net water content of concrete mixtures
from 10% to 20% when used in dosages recommended by the manufacturers.
Also it was found out that one- and three-day compressive strengths could be
substantially increased through use of high range water reducers. Compressive
strengths over 10,000 psi (70 MPa) were obtained after 28 days of curing. The

47
drying shrinkage was slightly reduced in the attempt to lower the net water
content of the concrete mixtures. Freeze-thaw durability and resistance to
deicer scaling of air-entrained concretes containing superplasticizer were equal
to or slightly better than air-entrained normal concretes prepared with equal
slump and cement content.
Ozkul and Dogan (1999) studied the effect of a N-vinyl copolymer
superplasticizer on the properties of fresh and hardened concretes. Workability
of concrete was measured by slump flow test and in situ tests were undertaken
to find out the pumping ability of superplasticized concrete. The coarse
aggregate was crushed stone with the maximum size of 25 mm. By using this
chemical admixture, which was a little bit different from the conventional ones,
the ability of water reduction was increased along with the retention of high
workability for a longer time.In situ test results obtained by Ozkul and Dogan
(1999) demonstrated that the superplasticized concrete could be pumped easily
from a height of about 13 m and the filling capacity was greater than 85%. The
pumping pressure was the same as for normal pumpable concrete and no
segregation was observed. For mixtures with water-cement ratios between 0.3
and 0.45, the slump diameters were between 500 mm and 740 mm and the
compressive strength varied between 53 MPa and 68 MPa at 28 days of age.
In their work, Roncero (1999) et al. evaluated the influence of two
superplasticizers (a conventional melamine based product and a new-
generation comb-type polymer) on the shrinkage of concrete exposed to wet
and dry conditions. Tests of cylinders with embedded extensometers have been
used to measure deformations over a period of more than 250 days after
casting. In general, it was observed that the incorporation of superplasticizers
increased the drying shrinkage of concretes when compared to conventional
concretes, whereas it did not have any significant influence on the swelling and
autogenous shrinkage under wet conditions. The melamine-based product led
to slightly higher shrinkage than the comb-type polymer.

48
Kasami (1978) et al. have investigated the pumpability of superplasticized
concrete under field conditions. In their experiment, about 2000 m3
of normal
and lightweight aggregate concrete, involving 14 mixes with and without
superplasticizers were pumped horizontally.
The pumping distance was 109 m and line diameter 125 mm. The dosage of the
naphthalene-based superplasticizer was in the range of 0.03% to 0.04% by
weight of cement and concrete mixing was done in ready-mix agitator-type
trucks. After the addition of the superplasticizer, the mixer was rapidly agitated
for one minute. Following this process, the concrete was pumped at rates of 10,
20, 30, 40, 50, and 60 m3
/h. Pump pressure and line pressure were measured at
each pumping rate. The tests data indicated that pumping pressure and line
pressure loss for normal weight concrete were reduced by about 30%, whereas
those for lightweight concrete were reduced by no more than 10%.
The effect of superplasticizer on the balance between flow ability and viscosity
of paste in self-compacting concrete was investigated by Ouchi (1996) et al.
From experimental results, the ratio of V-funnel speed to flow area of cement
paste with a fixed amount of superplasticizer was found to be almost constant,
independent of the water-cement ratio. A higher amount of superplasticizer
resulted in a lower ratio of V-funnel speed to flow area. The ratio was proposed
as an index for the effect of superplasticizer on cement paste flowing ability
and viscosity from the viewpoint of achieving self-compactability. However,
the relationship between high range water reducer amount and its effect was
found to differ depending on the type of cement or chemical admixture.
A rational mix-design method for self-compacting concrete was proposed by
Okamura (1997) et al. and the indexes for flow ability and viscosity were
defined as Γm and Rm, respectively. They were defined as follows:
Γm = (r1r2 – r20)/ r2
Rm = 10/t

49
Where r1 and r2 are the measured flow diameters perpendicular on each other;
r0 is the flow cone’s bottom diameter; and t is the measured time (in seconds)
for cement paste to flow through the funnel. These indexes are practical to use
because they are easy to obtain from simple test results. Larger Γm values
indicate higher flow ability and smaller Rm values indicate higher viscosity. A
cement paste with Γm = 5 and Rm = 1 was found to be the most appropriate
mixture for achieving self-compacting concrete.
2.3.2.6 Viscosity Modifiers
The viscosity modifiers or viscosity modifying admixtures (VMA) were
developed in order to improve the rheological properties of cement paste in
concretes (Khayat and Guizani, 1997). These admixtures enhance the viscosity
of water and eliminate as much as possible the bleeding and segregation
phenomena in the fresh concrete. Because not all types of viscosity modifiers
have showed satisfactory results, research has concentrated on only two types:
welan gum and anti washout admixtures.
In their research, Takada (1999) et al. investigated the influence of welan gum,
a kind of natural polysaccharide-based viscosity agent, on the water-
cementitious material ratio. It was found that the viscosity modifier raised the
value of the ratio due to its characteristics to make the mixture viscous. Welan
gum increased the viscosity of the free water in the fresh concrete by the ability
of its polymers’ characteristics to associate each other in water. The tests
results showed that a slump flow value of 650 ± 30 mm and a V-funnel time of
11±2 sec were achieved by using 0.01 to 0.02 percent viscosity agent and 0.025
to 0.035 percent superplasticizer from the total cementitious material. The
values were considered adequate for a workable self-compacting concrete.
Khayat (1997) et al. evaluated the properties of welan gum in achieving self-
compacting concrete for use in congested members and confined areas. The
viscosity-modifying admixture (welan gum) was used to ensure adequate
stability for concrete cast in deep structural members and wall elements in

50
order to avoid segregation and bleeding which can result in local structural
defects that can affect its mechanical properties. All the SCC mixtures had high
filling capacities ranging between approximately 60 and 70 percent, indicating
excellent deformability without blockage among closely spaced obstacles. No
external bleeding was observed on the top surface of any of the cast wall
elements and the settlement values of the self-compacting mixtures measured
on 150 cm walls ranged between 1.4 and 2.9 mm. This corresponds to 0.1 and
0.2 percent of the wall heights and is less than that for normal concrete, which
was around 0.4 percent. In order to verify the properties of self-compacting
concrete, Dehn (2000) et al. studied the interaction between the superplasticizer
and viscosity-modifying agent and the bonding between the reinforcing bars
and self-compacting concrete. They found out that the polymer in the viscosity
modifier (welan gum) and the polymer in the superplasticizer restrain each
other and this phenomena results in a higher segregation resistance and some
larger dosage of SP for a particular deformability. It was also seen that
depending on the mix design and chemical admixtures dosages the bond
behavior in self-compacting concrete was better than the bond in conventional
concrete.
Trial mixes with varying dosages of viscosity-modifying admixture (VMA)
and high range water reducing admixture (HRWR) to achieve a wide range of
flow behavior were investigated by Ferraris (1999) et al. In these mixes, the
VMA was incorporated in order to enhance the yield value and viscosity of the
fluid concrete, hence reducing bleeding, segregation, and settlement. The
enhanced cohesiveness could ensure better suspension of solid particles in the
fresh concrete and therefore good deformability and filling capacity was
achieved during casting. The HRWR used was a carboxylated copolymer-based
mixture and the VMA was a modified cellulose product. Even though the
dosages of chemical admixtures have been varied, the slump flow tests
undertaken, were not enough to determine whether a flowable concrete was
self-compacting or not.

51
Subramanian and Chattopadhyay (2002) carried out several trials to achieve an
approximate mix proportion of self-compacting concrete. At the initial stages
of development, mixtures were formulated without incorporating any viscosity-
modifying agents. After several trials, it was apparent that these admixtures
imparted exceptional stability to the mixture. The viscosity-modifying agent
was then required, because slight variations in the amount of water or in the
proportions of aggregate and sand would have made the concrete unstable, that
is, water or slurry might have separated from the remaining material. However,
not all VMAs were suitable for concrete applications, due to the fact that some
of them restricted the choice of superplasticizer. The welan gum that was used,
a well-known viscosity-modifying agent, was found incompatible with
melamine formaldehyde condensate-based type of superplasticizer, but after a
few trials, a naphthalene formaldehyde condensate and an acrylic polymer
superplasticizers were found to be suitable for application in self-compacting
concrete. Another two types of viscosity-modifiers, a hydroxy propyl methyl
cellulose (HPMC) and guar gum, were also selected for being used along with
the concrete, but they failed to react properly with the HRWR admixture. The
guar gum had to be made into a suspension in water after heating it to 60˚C and
stirring for about one hour, but it lost its suspending power after 12 hours. The
HPMC entrained excessive air, causing a reduction in strength. Subramanian
and Chattopadhyay (2002) found out that with a combination corresponding to
0.012 percent of welan gum and 0.036 percent acrylic polymer superplasticizer
by weight of cementitious material satisfactory self-compacting mixture could
be obtained. Investigations regarding the effects of viscosity-modifying
admixture (VMA) concentration, placement height, and mode of consolidation
on enhancing the stability of mixtures were done by Khayat and Guizani
(1997). In a first phase, bleeding and settlement were determined using 70 cm
high columns cast with concrete containing 0.035 and 0.07 percent viscosity
modifiers dosages. The water-cement ratios were between 0.50 and 0.70 and
the slump values from 140 to 200 mm. In the second phase, bleeding,
settlement, and segregation were evaluated for concretes with 200 mm slump,

52
cast in 50, 70, and 110 cm high columns. This time the mixtures had a water-
cement ratio of 0.50 and the same amounts of VMA, which was chosen to be
welan gum. The superplasticizer used was a liquid sulfonated naphthalene.
The studies showed that the addition of welan gum affected the aqueous phase
of the cement paste where chains of the water-soluble polymer could imbibe
some of the free water in the system, thus enhancing the viscosity of the
cement paste. As a result, less free water can be available for bleeding. The
enhanced viscosity of the cement paste can also improve the capacity of the
paste to suspend solid particles, process that reduces the sedimentation.
Mixtures containing a viscosity modifier exhibited a shear thinning behavior
whereas the apparent viscosity decreased with the increase in shear rate. The
mixtures incorporated 0.035 and 0.07 percent of viscosity-modifying admixture
and between 0.022 and 0.035 superplasticizer, by mass of cementitious
materials. All mixtures incorporating VMA exhibited lower rates of increase in
bleeding and settlement than those without VMA, regardless of water-cement
ratios. Also, concretes containing 0.035 and 0.07 percent viscosity- modifying
admixture had approximately 30 and 50 percent lower segregation coefficients
than conventional ones, regardless of the height of casting. As seen from the
above investigations, it is important to enhance the stability of fluid concrete
used to facilitate the casting in congested or restricted areas. The enhanced
cohesiveness of such concrete can reduce structural defects resulting from
increased porosity under aggregate and embedded reinforcement. This can lead
to improve tensile strength, impermeability, and bond strength with
reinforcement, especially in deep structural sections, which can contribute to
the reduction in congestion.
2.3.3 Self Compacting Recycled Aggregate Concrete
Recycled aggregate concrete is gaining its popularity because of its
environment friendly nature, its strength properties and easy availability.
Because of the fact that, in some countries, the natural aggregates are a scarce

53
resource, and also because the surface extractions destroy the landscape and
upset the biological balance, it is necessary to find a new source of aggregates
to guarantee the concrete production. The new source has accomplished two
main goals: on the one hand, to maintain the price of concrete, which until now
was the cheapest construction material; and on the other, to preserve the
environment, without creating piles of waste over the world. With the passage
of time, importance of using recycling materials is gaining popularity in all
context of our daily life. Construction and Demolition Wastes use is increasing
over time, proportionate with the development of the towns and the countries.
Reducing, reusing and recycling appear to be the best option, thus, also
increasing the lifetime of landfills and reduce exploitation of the natural
resources.
2.3.3.1 Recycled Stone Aggregate Concrete.
In a study by Limbachiya et al. (2000), concrete specimens made with up to 30
% RCA had equal compressive strengths for w/c ratios greater than
0.25.Exteberria et al. (2007) found similar behavior with tests using 25 %
RCA. They also performed the experiment with the same w/c ratio. This study
tested concrete made with 0, 25, 50, and 100 % RCA concrete mixes and
concluded that up to 25 % could be replaced without significant change in
compressive strength or a different w/c ratio; however, to obtain the same
strength with 50-100 %RCA, w/c ratio needed to be 4–10 % lower, and without
this alteration, the compressive strength for 100 % RCA mixes was reduced by
20–25 % (Exteberria et al. 2007).
Yang et al. (2008) attributed a reduction in compressive strength for RCA
concrete to the increased water absorption of the aggregate and found that at
relatively low water absorption (relatively low RCA fraction) concrete had
equivalent compressive strengths while higher RCA fraction sand absorption
compressive strengths were 60–80 % of that of conventional control concrete,
but that the compressive strength improved with age.

54
Several past and recent tests (e.g.,Kang et al. 2012) show that the splitting
tensile strength of RCA concrete is comparable to conventional concrete. In
some cases, RCA concrete performed superior to NA concrete with regards to
tension.
Singh and Sharma, in his paper “Use of Recycled Aggregate in Concrete- A
Paradigm Shift” states that recycled aggregate possess relatively lower bulk
density, crushing and impact values and higher water absorption as compared
to natural aggregate. The compressive strength of recycled aggregate concrete
is relatively lower up to 15% than natural aggregate concrete.Sudhir et al
(2013) experimented that the slump of the normal concrete is observed to be
less than the recycled one. The compressive strength of concrete containing
50% RCA has strength in close proximity to that of normal concrete. Tensile
splitting test shows that concrete has good tensile strength when replace up to
25-50%. The strength of concrete is high during initial stages but gradually
reduces during later stages.
As per the experiment conducted by Puri et al (2013), there is a considerable
increase in the compressive strength as well as flexural strength of concrete
when the aggregates are fully or partially replaced with construction debris.
However maximum strength was shown by concrete mix having 25% recycled
debris aggregates and 75% natural aggregates. In construction debris concrete,
there is a minor reduction in workability of the concrete mix.Murali et al
(2012), Compared to natural aggregate concrete the compressive strength of
recycled aggregate was decreased by 18.76%.The split tensile strength of
recycled aggregate was decreased by 9.55% than the natural aggregate. The
flexural strength of recycled aggregate was decreased by 17.39% compared to
natural aggregate.
By Gonculves et al, Full replacement of natural aggregate by recycled
aggregate leads to a decrease of concrete strength up to 16%. Replacements up
to 50% lead to concrete strength reduction less than 5%. The use recycled
concrete aggregate produces concrete with lower performances to durability

Properties of Self Compacting Concrete with Recycled Aggregate

Properties of Self Compacting Concrete with Recycled Aggregate

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