Study of Self Compacting Concrete

RIZVI COLEGE OF ENGINEERING
Bandra (W), Mumbai-400 050
UNIVERSITY OF MUMBAI
PROJECT (PART-B)
TITLE
STUDY OF SELF COMPACTING CONCRETE
BY
SA
SALMAN MUKKHIH
GOWDA KHAN MAQSOOD
B.E CIVIL
(SEM VIII)
DR.T.P.BANDIVADEKAR
(PROJECT GUIDE)
DEAPRTMENT OF CIVIL ENGINEERING
UNIVERSITY OF MUMBAI

RIZVI COLEGE OF ENGINEERING
Bandra (W), Mumbai-400 050
CERTIFICATE
This is to certify that the following students have satisfactorily completed the
project on,
“STUDY OF SELF COMPACTING CONCRETE”
In partial fulfillment of Bachelor’s degree in Civil Engineering
Course conducted by University of Mumbai
SALMAN MUKKHI
DINESH GOWDA
KHAN MAQSUD
Prof.T.P.BANDIVADEKAR
(PROJECT GUIDE) EXAMINER
Prof. T.P.BANDIVADEKAR
(HEAD OF DEPARTMENT) (PRINCIPAL)
SA
SALMAN MUKKHIH
GOWDA KHAN MAQSOOD

ACKNOWLEDGEMENT
We would like to take this opportunity to acknowledge the wholehearted support
extended to us by the CIVIL ENGINEERING faculty and staff of Rizvi college of
Engineering towards the project.
We would like to express our gratitude and sincere thanks to our project guide Prof.
T.P.BANDIVADEKAR for her valuable assistance and methodological approach
during the course of project. This project would not have been completed without her
valuable assistance and help.
We would also like to express our gratitude towards Mr. JAYANT BASU RAY,
Director, Constromat Consultancy & pvt. Ltd associated with project Palais Royale. He
gave us valuable suggestion and all the required facilities to perform our project. We are
also thankful to everyone at the construction site of Palais Royale who in their special
way helped us in our project.

INDEX
CHAPTER 1
INTRODUCTION-------------------------------------------------------
1.1 Background of self compacting concrete(SCC)-----------------------
1.2 Need for this research-----------------------------------------------------
1.3 Scope & objectives--------------------------------------------------------
CHAPTER 2
LITERATURE REVIEW---------------------------------------------
2.1 Development of SCC-------------------------------------------------------
2.2 Specifications----------------------------------------------------------------
2.2.1 Workability------------------------------------------------------------------
2.2.2 Durability--------------------------------------------------------------------
2.2.3 Mechanical characteristics-------------------------------------------------
2.3 Properties of hardened concrete ------------------------------------------
2.3.1 Compressive, tensile & bond strength----------------------------------
2.3.2 Modulus of elasticity-------------------------------------------------------
2.3.3 Shrinkage & creep----------------------------------------------------------
2.3.4 freeze/thaw resistance------------------------------------------------------
2.3.5 Water permeability----------------------------------------------------------
2.3.6 Rapid chloride permeability-----------------------------------------------
2.4 Test methods on SCC-----------------------------------------------------
2.4.1 Testing of wet SCC
2.4.1.1 Slump flow test & T50cm concrete--------
2.4.1.2 V funnel test & V funnel test at T5 mins--------------
2.4.1.3 L-box test------------------------------------------------
2.4.2 Testing of hardened SCC------------
2.4.2.1 Compressive strength test-----------------------------------------------
2.4.2.2 Flexural strength test-----------------------------------------------------
2.5.2.3 Tensile strength test------------------------------------------------------

CHAPTER 3
MIX DESIGN OF SCC-------------------------------------------------
3.1 General requirements in the mix design -----------------------------
3.2 Mixing procedure----------------------------------------------------------
3.3 Concrete mix design for Grade M40 (Self compacting Concrete)—
3.4 Rate analysis-------------------------------------------------
CHAPTER 4
TRANSPORTATION, CASTING ON SITE & FORM SYSTEM---------------
4.1 Transportation---------------------------------------------------------------
4.2 Casting on site---------------------------------------------------------------
4.2.1 Planning-----------------------------------------------------------------------
4.2.2 Filling of formwork----------------------------------------------------------
4.2.3 Finishing of formwork------------------------------------------------------
4.2.4 Curing--------------------------------------------------------------------------
4.3 Form system------------------------------------------------------------------
CHAPTER 5
ECONOMICS OF SCC -----------------------------------------------
5.1 Advantages of SCC---------------------------------------------------------
5.2 SCC v/s NCC----------------------------------------------------------------
CHAPTER 6
CASE STUDY------------------------------------------------------------
CHAPTER 7
CONCLUSIONS---------------------------------------------------------
BIBLIOGRAPHY--------------------------------------------------------

1
CHAPTER 1
INTRODUCTION
1.1 BACKGROUND OF SELF COMPACTING CONCRETE
Self compacting concrete (SCC) represents one of the most significant advances in
concrete technology for decades. Inadequate homogeneity of the cast concrete due to poor
compaction or segregation may drastically lower the performance of mature concrete in-situ.
SCC has been developed to ensure adequate compaction and facilitate placement of concrete
in structures with congested reinforcement and in restricted areas.
SCC was developed first in Japan in the late 1980s to be mainly used for highly
congested reinforced structures in seismic regions (Bouzoubaa and Lachemi, 2001). As the
durability of concrete structures became an important issue in Japan, an adequate
compaction by skilled labors was required to obtain durable concrete structures. This
Requirement led to the development of SCC and its development was first reported in 1989
(Okamura and Ouchi, 1999).
SCC can be described as a high performance material which flows under its own weight
without requiring vibrators to achieve consolidation by complete filling of formworks even
when access is hindered by narrow gaps between reinforcement bars. SCC can also be used
in situations where it is difficult or impossible to use mechanical compaction for fresh
concrete, such as underwater concreting, cast in-situ, pile foundations, machine bases and
columns or walls with congested reinforcement. The high flow ability of SCC makes it
possible to fill the formwork without vibration. Since its inception, it has been widely used
in large construction in Japan (Okamura and Ouchi, 2003). Recently, this concrete has
gained wide use in many countries for different applications and structural configurations
(Bouzoubaa and
Lachemi, 2001).
The method for achieving self-compactability involves not only high deformability of paste
or mortar, but also resistance to segregation between coarse aggregate and mortar.
Homogeneity of SCC is its ability to remain un segregated during transport and placing.
High flow ability and high segregation resistance of SCC are obtained by:
a) A larger quantity of fine particles, i.e., a limited coarse aggregate content.

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b) A low water/powder ratio, (powder is defined as cement plus the filler such as fly ash,
Silica fumes etc.) And
c) The use of super plasticizer
Because of the addition of a high quantity of fine particles, the internal material Structure of
SCC shows some resemblance with high performance concrete having self compactibility in
fresh stage, no initial defects in early stage and protection against external factors after
hardening. Due to the
Lower content of coarse aggregate, however, there is some concern that:
a)SCC may have a lower modulus of elasticity, which may affect deformation characteristics
of pre-stressed concrete members and
b) Creep & shrinkage will be higher, affecting pre-stress loss and long-term deflection.
SCC can be produced using standard cements and additives. It consists mainly of cement,
coarse and fine aggregates, and filler, such as fly ash, water, super plasticizer and stabilizer.
The composition of SCC is similar to that of normal concrete but to attain self Flow ability,
admixtures such as fly ash, glass filler, limestone powder, silica fume, Super-pozzolona, etc;
with some super plasticizer is mixed. Fineness and spherical particle shape improves the
workability of SCC.
Three basic characteristics that are required to obtain SCC are:
• High deformability,
• restrained flow ability and a
• high resistance to segregation.
High deformability is related to the capacity of the concrete to deform and spread freely in
order to fill all the space in the formwork. It is usually a function of the form, size, and
quantity of the aggregates, and the friction between the solid particles, which can be reduced
by adding a high range water-reducing (HRWR) admixture to the mixture. Restrained flow
ability represents how easily the concrete can flow around obstacles, such as reinforcement,
and is related to the member geometry and the shape of the formwork. Segregation is usually
related to the cohesiveness of the fresh concrete, which can be enhanced by adding a
viscosity-modifying admixture (VMA) along with a HRWR, by reducing the free-water
content, by increasing the volume of paste, or by some combination of these Constituents.
Two general types of SCC can be obtained:
(1)One with a small reduction in the coarse aggregates, containing a VMA, &
(2) One with a significant reduction in the coarse aggregates without any VMA.

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To produce SCC, the major work involves designing an appropriate mix proportion and
evaluating the properties of the concrete thus obtained. 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 honey combing of concrete. With these good properties,
the SCC produced can greatly improve the reliability & durability of the reinforced concrete
structures.
In addition, SCC shows good performance in compression and can fulfill other
construction needs because its production has taken into consideration the requirements in
the structural design.
1.2 NEED FOR THIS RESEARCH
Despite its advantages as described in previous section, SCC has not gained much local
acceptance though it has been promoted in the Middle East for the last five years.
Awareness of SCC has spread across the world, prompted by concerns with poor
consolidation and durability in case of conventionally vibrated Normal concrete. The
reluctance in utilizing the advantages of SCC are,
a) Lack of research or published data pertaining to locally produced SCC, b) The potential
problems for the production of SCC, if any, with local marginal aggregates and the harsh
environmental conditions prevailing in the region.
Therefore, there is a need to conduct studies on SCC.
1.3 SCOPE AND OBJECTIVES
The scope of this work was limited to the development of a suitable mix design to satisfy
the requirements of SCC in the plastic stage using local aggregates and then to determine the
strength and durability of such concrete exposed to thermal and moisture cycles.
The general objective of this study was to conduct an exploratory work towards the
development of a suitable SCC mix design and to evaluate the performance of the selected
SCC mix under thermal and moisture variations. The specific objectives were as follows:
1. To design a suitable SCC mix utilizing local aggregates, and
2. To assess the strength development and durability of SCC exposed to thermal and
moisture variations.

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CHAPTER 2
LITERATURE REVIEW
2.1 DEVELOPMENT OF SELF COMPACTING CONCRETE
The idea of a concrete mixture that can be consolidated into every corner of a formwork,
purely by means of its own weight and without the need for vibration, was first considered in
1983 in Japan, when concrete durability, constructability & productivity became a major
topic of interest in the country. During this period, there was a shortage of number of skilled
workers in Japan which directly affected the quality of the concrete.
In order to achieve acceptable concrete structures, proper consolidation is required to
completely fill and equally distribute the mixture with minimum segregation. One solution to
obtain acceptable concrete structures, independently of the quality of construction work, is
the employment of SCC. The use of SCC can reduce labor requirements and noise pollution
by eliminating the need of either internal or external vibration.
Okamura proposed the use of SCC in 1986. Studies to develop SCC, including a
fundamental study on the workability of concrete, were carried out by Ozawa and Maekawa
at the University of Tokyo, and by 1988 the first practical prototypes of SCC were produced.
By the early 1990’s Japan started to develop and use SCC and, as of 2000, the volume of
SCC used for prefabricated products and ready-mixed concrete in Japan was over 520,000
yard3 (i.e. 4,00,000 m3).
SCC has been used successfully in a number of bridges, walls and tunnel linings in
Europe.
During the last three years, interest in SCC has grown in the United States, particularly
within the precast concrete industry. SCC has been used in several commercial. Numerous
research studies have been conducted recently with the objective of developing raw material
requirements, mixture proportions, material requirements and characteristics, and test
methods necessary to produce and test SCC.
The latest studies related to SCC focused on improved reliability and Prediction of
properties, production of a dense and uniform surface texture, improved durability and both
high and early strength permitting faster construction and increased productivity.

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2.2 Specifications
2.2.1 Workability
A good SCC shall normally reach a slump flow value exceeding 60cm without
segregation.
• If required SCC shall remain flow able & self compacting for at least 90 minutes.
• If required SCC shall be pumpable for at least 90 minutes & through pipes with a
length of at least 100m.
2.2.2 Durability
• Should have freeze/thaw resistance
• No increased risk of thermal cracks compared with traditional vibrated concrete.
• Target values & acceptable ranges for the slump flow have to be design when the
mix design is decided.
The evidence in hand & data from other sources suggested that the durability performance of
SCC is likely to be equal or better than that of traditional vibrated concrete.
2.2.3 Mechanical Characteristics
• Characteristics compressive strength at 28 days shall be 25-60 MPa.
• Early age compressive strength shall be 5MPA - 20MPa at 12-15 hours.(equivalent
age at 20°C)
• Normal creep & shrinkage.
2.3 PROPERTIES OF HARDENED SCC
2.3.1 Compressive, Tensile, and Bond Strength
SCC with a compressive strength around 60 MPa can easily be achieved. The strength
could be further improved by using fly ash as filler. The characteristic compressive and
tensile strengths have been reported to be around 60 MPa & 5 MPa, respectively & 28-days
compressive strength values ranging from 31 MPa to 52 MPa. Compressive strength was in
the range of 28 MPa and 47 MPa & a compressive strength of up to 80 MPa with a low
permeability, good freeze-thaw resistance, and low drying shrinkage. SCC mixes with a high
volume of cement – limestone filler paste can develop higher or lower 28-day compressive
strength, compared to those of vibrated concrete with the same water/cementitious material
ratio and cement content, but without filler.
It appears that the strength characteristics of the SCC are related to the fineness and
grading of the limestone filler used.

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SCC with water/cementitious material ratios ranging from 0.35 to 0.45, a mass proportion of
fine and coarse aggregates of 50:50 with cement replacement of 40%, 50% & 60% by Class
F fly ash and cementitious materials content of 400 kg/m3 being kept constant, obtained
good results for compressive strength ranging from 26 MPa to 48 MPa.
The bond behavior of SCC was found to be better than that of normally vibrated concrete.
The higher bond strength was attributed to the superior interlocking of aggregates due to the
uniform distribution of aggregates over the full cross section and higher volume of cement-
binder matrix.
2.3.2 Modulus of Elasticity
Modulus of elasticity of SCC & that of a normally vibrated concrete, produced from the
same raw materials, have been found to be almost identical. Although there is a higher paste
matrix share in SCC, the elasticity remains unchanged due to the denser packing of the
particles.
The modulus of elasticity of concrete increases with an increase in the quantity of
aggregate of high rigidity, whereas, it decreases with increasing cement paste content &
porosity. A relatively small modulus of elasticity can be expected, because of the high
content of ultra fines and additives as dominating factors and, accordingly, minor occurrence
of coarse and stiff aggregates at SCC.
The modulus of elasticity of SCC can be up to 20% lower compared with normal vibrated
concrete having same compressive 34 strength and made of same aggregates reported an
average modulus of elasticity of SCC to be 16% lower than that of normal vibrated
conventional concrete for an identical compressive strength.
Results available indicate that the relationships between the static modulus of elasticity
(E) and compressive strength were similar for SCC and normally vibrated concrete. Average
28-days modulus of elasticity of SCC has been reported to be 30 GPa corresponding to
average 28-days cube strength of 55.41 MPa.
2.3.3 Shrinkage & Creep
Shrinkage and creep of the SCC mixtures have not been found to be greater than those of
traditional vibrated concrete. 0.03% for mixes with cement tested at 14 days, 0.03% to
0.04% for mixes with slag cement tested at 28 days, and 0.04 to 0.045% for mixes with

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calcined shale cement tested at 28 days. Shrinkage and creep of SCC coincided well with the
corresponding Properties of normal concrete when the strength was held constant.
The shrinkage and creep rates of SCC have been found to be approximately 30% higher
at an identical compressive strength; this is because of the high amount of paste. Since SCC
is rich in powder content and poor in the coarse aggregate fraction, addition of fiber will be
effective in counteracting drying shrinkage.
2.3.4 Freeze/thaw resistance
This property was assessed by loss of ultrasonic pulse velocity(UPV) after daily cycles of
18 hours at -30°C & 6 hours at room temperature . No significant loss of UPV has been
observed after 150 cycles for the SCC or higher strength concrete. The lower strength SCC
mix has performed less well than the reference in this freeze/thaw regime.
(Note: None of the concrete was air entrained.)
2.3.5 Water Permeability
SCC with high strength and low permeability can easily be produced. The permeability of
SCC significantly lower as compared to that of normally vibrated concretes of the same
strength grade have reported a water permeability value of 5 mm for SCC against 10 mm for
normal vibrated concrete.
The water permeability test is most commonly used to evaluate the permeability of
concrete. This test is useful in evaluating the relative Performance of concrete made with
varying mix proportions & incorporating admixtures..
Permeability tests, particularly those involving water penetration & chloride permeability,
are increasingly used to test concrete to evaluate its conformance with these specifications,
particularly for concrete exposed to aggressive conditions.
2.3.6 Rapid chloride permeability
Rapid chloride permeability of concrete is determined using a standard test method for
electrical indication of concrete’s ability to resist chloride ion penetration. The rapid chloride
permeability test evaluates the performance of various cementitious materials based on the
accelerated diffusion of chloride ions under the application of an external electric field.
For SCC against 1970 coulombs for normal vibrated concrete, obtained through the rapid
chloride permeability test.

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2.4 Test methods on SCC
It is important to appreciate that the test method for SCC has yet been standardized, &
the test described are not yet perfect or definitive. The method presented here are
descriptions rather than fully detailed procedures. They are mainly methods which have been
devised specifically for SCC. Existing rheological test procedure have not considered here,
though the relationship between the results of these tests & the rheological characteristics of
the concrete is likely to figure highly in future work, including standardization work. In
considering these tests there are number of points which should be taken into account:
• There is no clear relation between test results & performance on site.
• There is little precise data, therefore no clear guidance on compliance limits.
A concrete mix can only be classified as SCC if the requirements for all the following three
workability properties are fulfilled.
1. Filling ability,
2. Passing ability, &
3. Segregation resistance.
Filling ability: It is the ability of SCC to flow into all spaces within the formwork under its
own weight. Tests, such as slump flow, V-funnel etc, are used to determine the filling ability
of fresh concrete.
Passing ability: It is the ability of SCC to flow through tight openings, such as spaces
between steel reinforcing bars, under its own weight. Passing ability can be determined by
using U-box, L-box, Fill-box, and J-ring test methods.
Segregation resistance: The SCC must meet the filling ability and passing ability with
uniform composition throughout the process of transport and placing.
The test methods to determine the workability properties of SCC are described as
follows:
2.4.1 Testing of wet SCC
2.4.1.1 Slump flow test and T50cm test:
Introduction:
The slump flow test is used to assess the horizontal free flow of concrete in the absence
of obstructions. It was first developed in Japan for use in assessment of underwater concrete.
The test method is based on the test method for determining the slump .T diameter of the
concrete circle is a measure for the filling ability of the concrete.

9
Assessment of test:
This is a simple, rapid test procedure, though two people are needed if the T50 time is to
be measured. It can be used on site, though the size of the base plate is somewhat unwieldy
and level ground is essential. It is the most commonly used test, and gives a good assessment
of filling ability. It gives no indication of the ability of the concrete to pass between
reinforcement without booking, but may give some indication of resistance to segregation.
It can be argued that the completely free flow, unrestrained by any foundries, is not
representative of what happens in concrete construction, but the test can be profitably be
used to assess the consistency of supply of supply of ready-mixed concrete to a site from
load to load.
Equipment:
The apparatus is show in figure;
• Mould in the shape of a truncated cone with the internal dimensions 200 mm diameter at
the base, 100mm diameter at the top and a height of 300 mm.
• Base plate of a stiff none absorbing material, at least 700mm square, marked with a
circle marking the central location for the slump cone, and a further concentric circle of
500mm diameter
• Trowel
• Scoop
• Ruler
• Stopwatch(optional)

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Accessories for slump test Flow cone
Fig. 2.4.2 Slump flow test and T50cm test

11
Procedure:
About 6 liter of concrete is needed to perform the test, sampled normally. Moisten the
base plate and inside of slump cone, place base plate on level stable ground and the slump
cone centrally on the base plate and hold down firmly. Fill the cone with the scoop. Do not
tamp, simply strike off the concrete level with the top of the cone with the trowel. Remove
any surplus concrete from around the base of the cone. Raise the cone vertically and allow
the concrete to flow out freely. Simultaneously, start the stopwatch and record the time taken
for the concrete to reach the 500mm spread circle (This is the T50 time).floatable test, might
be appropriate. The T50 time is secondary indication of flow.
Results:
Flow table value = 750mm
& T50 time = 4 seconds
{For M80 grade of SCC, using admixture of poly corboxylate (PC), at room temperature}.
Interpretation of result:
The higher the flow value, greater its ability to fill the formwork, under its own weight. A
value of at least 650 mm is required for SCC. A T50 time of 3-7 seconds is acceptable for
civil engineering applications, and 2-5 seconds for housing applications. In case of severe
segregation, most coarse aggregate will remain in the center of the poll of the concrete and
mortar and the paste at the periphery of the concrete.
2.4.1.2 V funnel test and V funnel test at T 5 minutes
Introduction:
The equipment consists of a v shaped funnel as, show in Fig. 2.4.2. An alternative type of
V-funnel, the O funnel, with circular. The test was developed in Japan and used by Ozawa et
al. The equipment consists of V-shaped funnel section is also used in Japan. The described
V-funnel test is used to determine the filling ability (flow ability) of the concrete with a
maximum aggregate size of 20mm. The funnel is filled with about 12 liter of concrete and
the time taken for it to flow through the apparatus measured. After this the funnel can be
refilled concrete and left for 5 minutes to settle. If the concrete shows segregation then the
flow time will increases significantly.

12
Assessment of test:
Though the test is designed to measure flow ability, the result is affected by concrete
properties other than flow. The inverted cone shape will cause any liability of the concrete to
block to be reflected in the result-if, for example there is too much coarse aggregate. High
flow time can also be associated with low deformability due to a high paste viscosity, and
with high inter-particle friction. While the apparatus is simple, the effect of the angle of the
funnel and the wall effect on the flow of concrete is not clear.
Equipment:
• V-funnel
• Bucket (±12 liter)
• Trowel
• Scoop
• Stopwatch

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Fig 2.4.2 V Funnel test Apparatus

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Procedure flow time:
About 12 liter of concrete is needed to perform the test, sampled normally. Set the V-
funnel on firm ground. Moisten the inside surface of the funnel. Keep the trap door to allow
any surplus water to drain. Close the trap door and place a bucket underneath. Fill the
apparatus completely with the concrete without compacting or tamping; simply strike off the
concrete level with the top with the trowel.
Open within 10 sec after filling the trap door and allow the concrete to flow out under
gravity. Start the stop watch when the trap door is opened, and record the time for the
complete discharge (the flow time). This is taken to be when light is seen from above
through the funnel. The whole test has to be performed within 5 minutes.
Result:
Time taken by M80 grade of SCC with PC as admixtures at room temperature to empty a V
funnel is 12 seconds.
Interpretation of result:
This test measures the ease of flow of concrete, shorter flow time indicates greater flow
ability. For SCC a flow time of 10 seconds is considered appropriate. The inverted cone
shape restricts the flow, and prolonged flow times may give some indication of the
susceptibility of the mix to blocking. After 5 minutes of settling, segregation of concrete will
show a less continuous flow with an increase in flow time.
2.4.1.3 L Box Test
Introduction:
This test is based on a Japanese design for under water concrete, has been described by
Peterson. The test assesses the flow of the concrete and also the extent to which it is
subjected to blocking by reinforcement. The apparatus is shown in the figure. The apparatus
consist of rectangular section box in the shape of an ‘L’, with a vertical and horizontal
section, separated by a movable gate, in front of which vertical length of reinforcement bar
are fitted. The vertical section is filled with concrete, and then the gate lifted to let the
concrete flow into the horizontal section. When the flow has stopped, the height of the
concrete at the end of the horizontal section is expressed as a proportion of that remaining in

15
the vertical section. It indicates the slope of the concrete when at rest. This is an indication
passing ability, or the degree to which the passage of concrete through the bars is restricted.
The horizontal section of the box can be marked at 200mm and 400mm from the gate and
the times taken to reach these points measured. These are known as the T20 and T40 times
and are an indication for the filling ability. The section of bar con be of different diameters
and are spaced at different intervals, in accordance with normal reinforcement
considerations, 3x the maximum aggregate size might be appropriate. The bar can
principally be set at any spacing to impose a more or less severe test of the passing ability of
the concrete.
Assessment of test:
This is a widely used test, suitable for laboratory and perhaps site use. It asses filling and
passing ability of SCC, and serious lack of stability (segregation) can be detected visually.
Segregation may also be detected by subsequently sawing and inspecting sections of the
concrete in the horizontal section. Unfortunately there is no arrangement t on materials or
dimensions or reinforcing bar arrangement, so it is difficult to compare test results. There is
no evidence of what effect the wall of the apparatus and the consequent ‘wall effect’ might
have on the concrete flow, but this arrangement does, to some extent, replicate what happens
to concrete on site when it is confined within formwork. Two operators are required if times
are measured, and a degree of operator error is inevitable.
Equipment:
• L box of a stiff non absorbing material
• Trowel
• Scoop
• Stopwatch

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Fig.2.4.3 L Box test Apparatus

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Procedure:
About 14 liter of concrete needed to perform the test, sampled normally. Set the apparatus
level on firm ground, ensure that the sliding gate can open freely and then close it. Moisten
the inside surface of the apparatus, remove any surplus water, fill the vertical section of the
apparatus with the concrete sample. Leave it stand for 1 minute (60 secs). Lift the sliding
gate and allow the concrete to flow out into the horizontal section. Simultaneously, start the
stopwatch and record the time for the concrete to reach the concrete 200 and 400 marks.
When the concrete stops flowing, the distances ‘H1’ and ‘H2’ are measured. Calculate
H2/H1, the blocking ratio. The whole has tom performed within 5 minutes.
Readings:
H1 == 65mm, H2 = 65mm (For M80 grade of SCC with PC as an admixtures
At room temperature).
H2/H1 = 65/65 = 1
Interpretation of the result:
If the concrete flows as freely as water, at rest it will be horizontal, so H2/H1=1. Therefore
the nearest this test value, the ‘blocking ratio’, is unity, the better the flow of concrete. The
EU research team suggested a minimum acceptable value of 0.8. T20 and T40 time can give
some indication of ease of flow, but no suitable values have been generally agreed. Obvious
blocking of coarse aggregate behind the reinforcement bars can be detected visually.
2.4.2 Testing of Hardened SCC
2.4.2.1 Compressive strength test:
Introduction:
This method describes the procedure for making and curing compression test specimens
from fresh SCC and for determining the compressive strength of the SCC specimens.
Equipment and Materials:
• Moulds - cubic in shape (15cm×15cm ) made of non-absorbent material.
• Sampling Equipment – scoop, shovel, trowel and bucket.

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• Curing Equipment - a moist storage cabinet or room capable of maintaining
specimens at a temperature within ± 1 degrees of 23°C & capable of maintaining a moist
condition in which free water is maintained on the surfaces of the specimens.
• Compression Testing Machine - a machine of sufficient capacity which will apply a load
continuously without shock within a range of 0.140 to 0.350 MPa per second.
Fig.2.4.2.1 Mould & Automatic Compressive Testing Machine(ACTM)

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Procedure:
Place the mould on a firm, level surface. Form the test sample by placing concrete in the
mold in three layers of approximately equal volume. Move the scoop around the top edge of
the mold to ensure a symmetrical distribution of
the concrete within the mold. Store the specimen undisturbed for 24 hours in such a way as
to prevent moisture loss and to maintain the specimen within a temperature range of 15°C to
27°C.Remove the test specimen from the mold after 28 days with proper curing. Place the
specimen in the machine and slowly bring the blocks to bear on the specimen without shock
until failure occurs. Operate the machine at a constant rate within the range of 0.140 to 0.350
MPa per second.
Results:
Compressive strength of M80 grade of SCC at the end of 28 days is 99.68 MPa with the
loading rate of 5.2KN/sec. (at room temperature).
The mode of fracture of cubical SCC specimen should be in a dumbbell shape pattern.
2.4.2.2 Flexural strength test:
Introduction:
Flexural strength is one measure of tensile strength of SCC. It is a measure of an
unreinforced concrete beam or slab to resist failure in bending. Flexural MR (Modulus of
Rupture) is about 10-20 % of compressive strength depending on the type, size & volume of
the aggregate used.
Equipments & materials:
• Mould - 15cm ×15cm in cross section with the span length at least three times the depth.
• Sampling Equipment - scoop, shovel, trowel and bucket.
condition.
• Compression Testing Machine.

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Fig.2.4.2.2.1 Mould for beam for flexural strength testing
Procedure:
the concrete within the mold. Store the specimen undisturbed for 24 hours in such a way as
27°C.Remove the test specimen from the mold after 56 days with proper curing. Now the
time comes for the testing of beam in ACTM (Automatic Compressive Testing Machine).
1. Either before or after the beam is placed in the testing machine, draws a reference line on
the top and bottom of the beam, as cast, about 25 cm from the end of the specimen. The two
reference lines should be exactly opposite each other. A line drawn across the bottom of the
beam, as placed in the machine, will meet these two lines, and will be perpendicular to them.
The bottom of the beam as placed in the machine will be the side of the beam as cast.
2. Insert the stirrup pins in the slots at the bottom of the stirrups to prevent the stirrups from
swinging while the beam is being placed in the machine. This also assures that the support
bearings are in the correct position.
3. Place the beam in the testing machine so that the two reference lines on the side of the
beam are directly under the centerline of the center bearing. The maximum fiber stress
during application of the load will occur in the outer fiber in the line drawn across the
bottom of the beam, this line being directly under the load.

21
4. Apply a load with the loading rate of 0.07 KN/sec.
5. Stop the machine when loading beam fractures.
6. Always make sure the pointers on the gauge are set at zero before any loading begins.
Fig.2.4.2.2.2 failure of beam in flexural strength
Reading and calculations
Maximum flexural load, p = 46.11KN (Allowable Range is 40KN - 60KN),
Modulus of Rupture (MR) R (in MPa) = pL /bd²
Where,
p= Corrected load indicated, N. = 46110N
L= Span length, mm, between supports (600mm)
b = Width of beam at point of fracture, mm = 150mm
d = Depth of beam at point of fracture, mm = 150mm
Hence, R = 8.19N/mm².

22
Result:
Modulus of Rupture, R = 8.19N/mm² (for M80 grade of concrete after 56 days at room
temperature).
2.4.2.3 Tensile strength test:
Introduction:
This ASTM test method covers the determination of the splitting tensile strength of
cylindrical SCC specimens. This method consists of applying a diametrical compressive
force along the length of a cylindrical specimen. This loading induces tensile stresses on the
plane containing the applied load. Tensile failure occurs rather than compressive failure.
Plywood strips are used so that the load is applied uniformly along the length of the cylinder.
The maximum load is divided by appropriate geometrical factors to obtain the splitting
tensile strength.
Equipments & Materials:
• Moulds - The cylinder mould shall is of metal, 3mm thick. Each mould is capable of
being opened longitudinally to facilitate the removal of the specimen and is provided with a
means of keeping it closed while in use. The mean internal diameter of the mould is 15 cm ±
0.2 mm and the height is 30 +/- 0.1 cm. Each mould is provided with a metal base plate
mould and base plate should be coated with a thin film of mould oil before use, in order to
prevent adhesion of concrete.
• Sampling Equipment - scoop, shovel, trowel and bucket.
condition.
• Compression testing machine,
• Two packing strips of plywood 30 cm long and 12mm wide. The strips are placed
between the specimen and the upper and lower bearing blocks of the testing machine.

23
Fig.2.4.2.3.1 Cylindrical mould
Procedure:
The concrete within the mold. Store the specimen undisturbed for 24 hours in such a way as
27°C.Remove the test specimen from the mold after 56 days with proper curing. Now the
time comes for the testing of beam in ACTM (Automatic Compressive Testing Machine).
1) Draw diametric lines on each end of the specimen so that they are in the same axial plane.
2) Center one of the plywood strips along the center of the lower bearing block.
3) Place the specimen on the plywood strip and align so that the lines marked on the ends are
vertical and centered over the plywood strip.
4) Place the second plywood strip and the bearing bar so that they are lengthwise on the
cylinder, centered on the previously marked lines on the ends.
5) Apply the load continuously at a constant rate of 2.1KN/sec of splitting tensile stress until
failure occurs
6) Record the maximum load at failure.

24
Fig.2.4.2.3.1Testing of tensile strength of cylindrical SCC specimen in ACTM
Calculations:
Calculate the splitting tensile strength as follows:
Split tensile strength
P
Where P is the maximum load at failure in Newtons, and l and d are the length and diameter
of the cylindrical specimen respectively, in mm.
P = 367.8KN, l = 300mm, d = 150mm,
Hence, splitting tensile strength = 5.2N/mm²
Result:
Splitting tensile strength = 5.2N/mm²
Which is in the allowable range (3 – 6N/mm²) for M80 grade of concrete after 28 days at
room temperature.

25
CHAPTER 3
MIX DESIGN OF SCC
Before any SCC is produced at a concrete plant and used at construction site the mix has
to be designed and tested. During this evaluation the equipments and the local Materials used
at the plants have to be tested to find new concrete mixes with the right mixing sequences
and mixing times valid for that plant and material used and also suitable for the element to b
cast. Various kinds of fillers can result in different strength, shrinkage and creep but
shrinkage and creep will usually not be higher than for traditional vibrated concrete.
A flow-chart describing the procedure for design of SCC mix is shown in Figure 2 below,
Figure 2: SCC mix design procedure
3.1 General Requirements in the mix design
A high volume of paste: the friction between the aggregate limits the spreading and the
filling ability of SCC. This is the why SCC contains a high volume of paste (cement +
additions + efficient water + air), typically 330 to 400 l/m³, the role of which is to maintain
aggregate separation.
A high volume of the particles (<80µm): In order to ensure sufficient workability while
limiting the risk of segregation or bleeding, SCC contains a large amount of fine particles

26
(around 500 kg/m³). Nevertheless, in order to avoid excessive heat generation, the Portland
cement is generally partially replaced by mineral admixtures like fly ash (cement should not
be used as a filler). The nature and the amount of filler added are chosen in order to comply
with the strength & durability requirements.
A high dosage of super plasticizer: Super plasticizers are introduced in SCC to obtain the
fluidity. Nevertheless a high dosage near the saturation amount can increases the proneness
of the concrete to segregate.
The possible use of viscosity agent (water retainer): these products are generally cellulose
derivatives, polysaccharides or colloidal suspensions. These products have the same role as
the fine particles, minimizing bleeding and coarse aggregate segregation by thickening the
paste and retaining the water in the skeleton. The introduction of such products in SCC
seems to be justified in the case of SCC with the high water to binder ratio (for e.g.
residential building). On the other hand, they may be less useful for high performance SCC
(strength higher than 50 MPa) with low water to binder ratio. For intermediate SCC, the
introduction of viscosity agent has to be studied for each case. Viscosity agents are assumed
to make SCC less sensitive to water variations in water content of aggregates occurring in
concrete plants. Because of he small quantities of viscosity agents required, however it may
be difficult to achieve the accuracy of dosage.
A low volume of coarse aggregate: It is possible to use natural rounded, semi crushed or
crushed aggregate to produce SCC. Nevertheless, as the coarse aggregate plays an important
role on the passing ability of SCC in congested areas, the volume has to be limited. On the
other hand the use of coarse aggregate allows optimizing the packing density of the skeleton
of the concrete & reduction of the paste volume needed for the target workability. Generally
speaking, the maximum aggregate size (Dmax) is between 10mm &20mm. the passing
ability decreases when Dmax increases, which leads to decrease of the coarse aggregate
content. The choice of a higher Dmax is thus possible but is only justified with low
reinforcement content.
Admixtures added to SCC can have a retarding effect on the strength and the temperature
development in the fresh concrete, & this will have to be borne in mind in the construction

27
process. Suppliers of admixture can produce various admixtures suitable for different
weather conditions & temperatures.
3.2 Mixing procedure
The coarse and fine aggregate contents are fixed so that self compatibility can be achieved
easily by adjusting the water/powder ratio and super plasticizer dosage only.
Procedure: The following sequence is followed
• Determine the desired air content
• Determine the coarse aggregate volume
• Determine the sand content
• Determine the paste composition
• Determine the optimum water to powder ratio & super plasticizer dosage in
mortar
• Finally the concrete properties are assessed by standard test
(Explained in section 2.4)
Air content:
Generally air content may be assumed to be 2%. In case of freeze/thaw condition in cold
weather concreting higher percent of air content may be specified.
Determination of coarse aggregate volume:
Coarse aggregate volume is defined by bulk density. Generally coarse aggregate
(D>4.75) should be between 50% & 60%. Optimum coarse aggregate content depends on the
following parameters.
• The lower the maximum aggregate size, the higher the proportion.
• The rounded aggregate can be used at higher percentage then crushed aggregates.
Determination of sand content:
Sand, in the context of mix design procedure is defined as all particles bigger than 125
microns & smaller than 4.75mm. Sand content is defined by bulk density. The optimum
volume content of sand in the mortar varies between 40-50% depending on the past
properties.

28
Design of paste composition:
Initially the water/powder ratio for zero flow (ß) is determined in the paste, with chosen
proportion of cement & additions. Flow cone test with water/powder ration by volume are
performed with selected powder composition. Fig. 2.1 shows the typical results. The point of
intersection with “Y” axis is the ß value. These ß are used mainly for quality control of water
demand for new batches of cement & fillers.
Fig.3.2 Determination of water/powder ratio ß for zero slump flow
Determination of optimum volumetric water/powder ratio & super plasticizer dosage in
mortar:
Test with flow cone & V-funnel for mortar are performed at varying water/powder ratio
in the range of (0.8 to 0.9) ß & dosage of super plasticizer is used to balance the rheology of
the paste. The volume content of the sand in mortar remains the same as determined above.
The target values are slump flow of 24 to 26 cm & V-funnel time of 7 to 11 seconds.
At target slump flow, where V-funnel time is lower than 7 secs, then decrease the
water/powder ratio. For largest slump flow & V-funnel time in excess of 11 seconds
water/powder ratio should be increased.
If these criteria cannot be fulfilled, then the particular combination of material is
inadequate. One can also change the type of super plasticizer. Another alternative is a new
additive, and as a last resort is to change the cement.

29
3.3 Concrete mix design for Grade M40 (Self compacting Concrete)
Stipulation of proportioning:
1) Grade Designation M40
2) Type of cement (client’s
requirement)
OPC 53 grade conforming
to IS 12269:1980
3) Maximum Cement content 320 kg/cu.m
4) Maximum nominal size of the aggregate 20mm
5) Maximum Water Cement Ratio 0.45
6) Workability @ placement (for one hou
retention time) As per European Guideline Fo
SCC
V-funnel in secs
(9-25)
L-Box in %(80-100%)
T 500 in %(2-5 Secs)
7) Exposure Condition Severe
8) Method of Concrete Placing Pumping
9) Degree Of Supervision V.Good
10) Type Of Aggregate Crushed aggregate from
Jaw Crushers
11) Maximum Cement Content 450 kg/cu.m
12) Chemical Admixture type Viscosity Modifier

30
Test data of materials:
Cement used Ultratech 53 Grade
Specific Gravity of Cement 3.15
Specific Gravity of Flyash 2.25
Specific Gravity Of
1) Coarse Aggregate
2) Fine Aggregate
20mm 12.5mm
2.95 2.94
Gujarat sand : 2.65
Water Absorption
1) Coarse Aggregate
2) Fine Aggreagate
20mm 12.5mm
1% 1.56%
Gujarat : 1.6%
Target strength for mix proportioning:
Fck=fck + 1.65 s
From clause 3.2.1.2 assumed standard deviation ‘s’ is 5,hence the target strength is
Fck= 40 +1.65*5=48.25
Selection of water cement ratio:
Adopted Water cementatious ratio =0.236 & water cement ratio=0.45
Selection of water content:
Free water content of 135 lts/cum could satisfy all the fresh concrete properties for Self
Compacting Concrete.
Calculation of cement & flyash content:
Water Cement Ratio = 0.45
Water Cementatious Ratio = 0.236
Cementatious Content = 135/0.236=572 Kg/cu.m
Cement Content = 300 Kg/cu.m
Fly Ash Content = 272 Kg/cu.m (47.5% by weight of cementatious material)
(High Fly Ash Content is used in order to produce SCC without bleeding & segregation)

31
Proportion of volume of coarse aggregate and fine aggregate content:
Ratio of 20mm:10mm = 40%:60%
Mix calculations:
Volume Of Concrete 1 cu.m
Volume Of Cement (300/3150)=0.0952 Cu.m
Volume Of Flyash (272/2250)=0.1209 Cu.m
Volume Of Water (135/1000)=01.35 Cu.m
Volume Of P. Based admixture
@ 1.0% by Weight of Binder
(Structro 100M of M/s Fosroc)
(5.72/1030)=0.0056 Cu.m
Volume Of viscosity modifier
@.3% by weight of binder
(Structro 480 of M/s Fosroc)
(1.7/1010)=0.0017 Cu.m
Volume of All in aggregate 1 – (0.0952+0.1209+0.135+0.0056+0.0017)
=0.642 Cu.m
Mass Of Coarse Aggregate =0.642*0.60*2.94*1000=755 Kg/cu.m
Mass of fine aggregate =0.642*60*2.67*1000=1029 Kg/cu.m
Ratio of C.A to F.A by weight is =766:1029=42.35:57.7%

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Quantities of material per cum of concrete:
Free water 135kg/cu.m
Cement Content 300Kg/cu.m
Flyash 272Kg/cu.m
Gujarat Sand 1029Kg/cu.m
20mm down 302Kg/cu.m
10mm down 453Kg/cu.m
Chemical admixture(P.C BASED) of M/s FOSROC:
Structro 100(M)
(1.0% by weight of total binder content)
5.72 Kg/cu.m
Structro 480 (Viscosity Modifier)
(0.3% By weight Of Total Binder Content)
1.7Kg/cu.m
NOTE : Values denote aggregates for saturated surface dry condition.
Adjustments shall be made in the saturated quantities based on the moisture contents in
the aggregates during production of concrete.

33
Fresh concrete properties:
V-funnel Flow Time in secs : Initial/After 1
1 hr
16.8/18.6 secs
L-Box i.e Passing Ability Initial/After 1 hr 100/100%
T 500 i.e Time required for 500 mm
spread Initial/After 1 hr
2.9/3.9 secs
Flow in mm Initial/After 1 hr 740/710mm
3.4 Rate analysis for M40 grade of SCC:
Cost of Cementitious materials:
Cost of cement = 5780 Rs/tonne
Cost of fly ash = 1910 Rs/tonne
Cost of gujrat sand = 2310 Rs/tonne
Cost of aggregate (20mm) = 800 Rs/tonne
(10mm) = 800 Rs/tonne
Cost of Chemical admixtures ( P.C based) of M/s Fosroc
PC structuro 100(M) = 159500 Rs/tonne
VMR structuro 480M(viscosity modifier) = 48500 Rs/tonne
Calculations:
Consider 10m for calculations,
Cost of cement = ×300×10 = 17340 Rs.
Cost of fly ash = ×272×10 = 5195.2 Rs.
Cost of gujrat sand = ×1029×10 = 23770 Rs.
cost of aggregate(10mm) = ×453×10 = 3624 Rs.
cost of aggregate(20mm) = ×302×10 = 2416 Rs.

34
cost of PC structuro 100(M) = ×5.72×10 = 9123.4 Rs.
cost of VMR structuro 480M(viscosity modifier) = ×1.7×10 = 8245 Rs.
cost of water = ×135×10 = 67.5 Rs.
total ingredient cost = 69781.1 Rs/10m
cost of labour:
Labour No. of labour Cost of labour
(Rs/day)
Total cost of
labour(Rs)
Head mason ½ no. 400 200
Mason 2 no. 300 600
Mazdoor 20 no. 150 3000
Overall cost of labour = 3800 Rs/10m
Hence, total cost = total ingredient cost + overall cost of labour
= 69781.1 + 3800
= 73581.1 Rs.
Contigencie cost @ 0.5% = 0.5 % of total cost
= 0.005 × 73581.1 = 367.9 Rs.
Profit @ 10% of (contigencie cost + total cost ) = 0.1 × ( 73581.1 + 367.9 )
= 7394.9 Rs.
Therefore, Total cost/10m os SCC = 7394.9 + 367.9 + 73581.1
= 81343.9 Rs/10m
Cost of SCC per m³ =
.
= 8134.39 = 8135 Rs.
In the same manner,
the cost of normal concrete per m is around 4000 Rs to 5000 Rs.

35
CHAPTER 4
TRANSPORTATION, CASTING ON SITE
& FORM SYSTEM
4.1 Transportation
SCC can be delivered either by truck mixer or truck agitator. The mixing/agitating bowl
should be free from remains of the previously delivered concrete and remains of wash-out
water, and it should not be dry. Truck mixers should be distinguished from truck agitators. In
simple words, truck mixers are able to adequately produce, deliver, and discharge concrete
while truck agitators can not adequately produce concrete. Often properties of SCC need to
be adjusted on the job site and for some SCC producers this is a part of production/delivery
process. At such circumstances truck agitators shall not be used. Great care should be taken
if SCC is to be delivered by tip trucks due to the risk of static segregation.
The limitations to the delivery load size would be only dictated by the road conditions, i.e.
driving uphill. SCC can be safely transported over the reasonably hilly roads if the load size
of SCC is not exceeding 80% of the full capacity.
During transportation the transit mixer drum must rotate at a low speed (not less than 1
RPM)
• But before the drum actually delivers the SCC at site it has to rotate at full speed (10-
20 RPM)
• Care must be taken for long haul delivery sites.
• The driver must not add admixtures or any kind of fibers on his own.
• However if the mix is too hard super plasticizer can be added on site at the time of
delivery by the driver after obeying the note of instructions given to him.
• Also this has to be handed over to the site engineers about the report of how the SCC
has been handled before, during the haul duration n the expected handling after the
mix has been delivered.
• The addition of water has to be avoided in order to avoid segregation. The addition of
water is a very usual n cheap practice to make the mix workable.
• A Slump test can be worked out at the site to check the workability if the mix, also to
check that there is no segregation.
• In addition to the basic information provided, the following details will add to the
perfection of the work carried out

36
1. Slump Flow – target value and acceptance range
2. Production time (Time when it was produced)
3. Remarks if any admixture that shall be added at site
4.2 Casting on site
It is divided into 4 following sections,
4.2.1 Planning
4.2.2 Filling of formwork
4.2.3 Finishing
4.2.4 Curing
4.2.1 Planning:
The process of casting SCC can be mechanized to a great extent. Increased productivity,
lower cost and improved working environment is achieved. A minimum of manual
interaction in the process is however necessary. Based on formwork configuration,
reinforcement, temperature, casting equipment, casting speed etc., the persons in charge of
the concrete supply and the form filling respectively have to plan and jointly agree on SCC
workability data, including accuracy, open time, casting speed etc. In more complex
industrialized casting operations, the planning of flow of concrete can be computer modeled
in order to optimize the rheological material data to the specific formwork, the reinforcement
configuration and the sequence and methods of casting.
The planning also includes agreement on the quality assurance procedure, test methods,
frequency of test as well as of actions taken as results of tests. The planning should also
address the corrections of the mix that might be done at the casting site through extra dosage
of plasticizer.
Even if there will always be options of buying SCC off the shelf as standard products, the
strongest benefits and highest profits will come from optimizing the fresh concrete as an
integral approach in an industrialized process designed for the specific situation at hand.
Even if there is a significant reduction in the needed skill for the actual casting when SCC is
applied, the need for skills in planning, preparation and quality assurance is raised.

37
4.2.2 Filling of Formwork:
SCC is a liquid suspension following the rules of fluid mechanics while vibrated concrete
is a granular mass requiring vibration to be compacted. SCC is well suited for pumping and
can be fed through valves under pressure into vertical formwork. This technique is
frequently used when casting complex enclosed volumes where release from above is not
possible or no limited entrance to the interior of the form work is possible, nor vibrating it by
hand tools. Pumping SCC into the form work from underneath has proven to be beneficial
when high demands of aesthetics are of importance. The problem with pores and pot-holes
also tends to be less when the concrete has been fed from underneath through valves.
Experience from pressurized castings of 30+ vertical meters exists from practice. If the pipe-
based feeding system used includes furcating, the concrete flow chooses the easiest way
through the piping system. This may result in parts of the concrete not moving, thereby
preventing the concrete to fill the form work uniform and symmetrically
Vertical formwork can also be cast by dropping from above using pumps or crane skips.
Experience from dropping heights of 8 meters exists but 1-3 meters will be more common.
Flat and shallow formwork such as slab and decks are most often filled from above even if in
certain situations, e.g. in industrial production, casting through valves by pumping might be
an attractive option. For flat and shallow structures the dropping height is about 0.5-0.8
meters. High dropping heights require a stable mix to counteract the risk of segregation and
damage of the air pore system.
To release the SCC from a pump hose submerged some decimeters under the concrete upper
surface tends to reduce the coarser air pore structure. The results are not fully consistent
depending probably on the fact that the specific workability features of used SCC have
differed.
The layer thickness should be kept as thin as possible, in order to prevent larger air
bubbles to get trapped in the concrete or at the form surface. It is also beneficial to let the
concrete flow horizontally some distance (how long is depending on the mix and local
circumstances as form work geometry, denseness of reinforcement etc.). On the other hand,
the concrete has to be prevented to flow a very long distance in the form. If this is not taken
care of, separation at the front might occur. This is the reason why the concrete should be
released at fixed distances along the form work. These points of release should be at a
maximum distance from each other of about 5-8 meters depending on the geometry of the
form and density of the reinforcement and other obstacles.

38
Due to the high amount of fines, SCC is suitable for pumping. The usually high viscosity
of SCC may require a slower pumping rate, in order to avoid high pressure built up in the
piping system. High pressure may cause aggregate separation and pump stops.
A possible negative effect of too high a feeding rate is a significant drop in slump flow
(and mobility) after the pump. The openings should be large enough to allow the pump hose
to pass inside the form in an inclined position and when the concrete level has reached the
opening (openings) the pump hose (hoses) is pulled out and moved to the next opening
above. The lower openings are thereafter closed. Horizontal distances of 4-6 meters between
the openings and correspondingly 2-3 meters in vertical direction, have been proven
successful.
Practical experiences have shown the importance of operating with several valves or
pipes, in order to fill the formwork evenly and symmetrically, and to prevent the concrete
from traveling a long horizontal distance in the formwork. The most common procedure is to
pump the concrete through two or more valves or pipes simultaneously.
It is important to visually observe the flowing concrete in the formwork. Especially
important is to notice its flow around obstacles, reinforcement bars and other objects in the
form. Even in sections with dense reinforcement, the surface of the flowing concrete should
be fairly even, without any significant differences between the levels of the upper surfaces
that might indicate blocking. Coarse aggregate should be visible on the upper surfaces. Foam
on the upper surface is likely to indicate segregation.
It is important to plan the casting sequence. Layers of fresh SCC should be given some
time for the release of air through the surface while on the other hand following layers
should not come too late, which might make an integration of the layers difficult.
SCC is not necessarily self-leveling. SCC can be so designed that it can be built up in a
slope of a few degrees from the release point. This is an important possibility when casting
e.g. a bridge slab requiring a limited slope from the centre to the edges.
4.2.3 Finishing:
Finishing operations can be more difficult for SCC due to the thixotrophy, sometimes sticky
behavior. The absence of bleeding makes it even more difficult and the finishing operations
should be related to the setting time of the mix in actual conditions. It is advisable to perform
an appropriate field trial in advance to improve planning and timing of finishing. The
characteristics of the SCC mix, and the skill and timing of the finishers during placement
affect the quality of the surface of slab cast.

39
The general experience seems to be that conventional tools and ways to finish the upper
surface can be used working with SCC but sometimes finishing tools with other surface
materials are used. It is wise to expect this operation to take a little longer in comparison
with the finishing of conventional vibrated concrete.
4.2.4 Curing:
SCC mixes are characterized by a moderate to higher amount of fines in the formulation,
including various combinations of powders such as Portland cement, limestone filler, fly-ash
or ground granulated blast furnace slag. Thus, there might be very little or no bleeding and
the concrete will sometimes be more sensitive to plastic shrinkage cracking. The tendency of
plastic shrinkage increases with the increase in the volume of fines. This situation is
sometimes more complicated if the setting time is delayed because of the admixture effect,
and the concrete remains many hours in the fresh state.
Curing to counteract longer term shrinkage is to be handled like what is done for vibrated
concrete. It should be observed that due to a lower permeability of SCC, the drying rate and
following from that also the shrinkage rate might be slower.
4.3 Form system
Fig. 4.3.1 Form System

40
SCC Definition:
Self Compacting Concrete (SCC) is an innovative concrete that does not require vibration
for placing and compaction. It is able to flow under its own weight, completely filling
formwork and achieving full compaction, even in the presence of congested reinforcement.
The hardened concrete is dense, homogeneous and has the same engineering properties
and durability as traditional vibrated concrete.
Formwork:
• When a contractor opts to use SCC on a project there will be an immediate impact on the
type of formwork system that can be used. This is primarily due to the higher pressures that
will occur during the casting period.
• If SCC is to be utilized this will generally negate the option for the contractor to use
traditional hand-built timber and plywood columns or walls as is sometimes still seen on
sites
• Due to the considerably higher design pressures created when SCC, as opposed to
traditional concrete, is poured into vertical forms, the contractor is advised to use high
quality system formwork
• SCC requires a very accurate assembly of the formwork, with no openings left and 100%
tightness to avoid possible leaks
• SCC easily flows around obstructions with no vibration needed.

41
Fig. 4.3.2
• Formwork should be designed for full liquid head. This means that there will be another
220 kg of pressure for each meter of height of the forms. This is a danger for SCC since it
places so rapidly and can develop pressures leading to blowouts.
• Steel and plywood are used as formwork materials for SCC.
• In winters or in colder areas there is a need to maintain the temperature of the SCC. In
such cases the temperature is maintained by providing insulations to the formwork itself
before actually pouring the concrete into the formwork.
• Due to the cohesiveness of SCC, the formwork does not need to be tighter than that for
conventional vibrated concrete.

42
CHAPTER 5
ECONOMICS OF SCC
Savings in labor costs might offset the increased cost related to the use of more cement
and super plasticizer, and the mineral admixtures, such as pulverized fuel ash (PFA), ground
granulated blast furnace slag (GGBS) or lime stone powder (LSP), could increase the
fluidity of the concrete, without any increase in the cost. These supplementary cementing
materials also enhance the rheological parameters and reduce the risk of cracking due to the
decreased heat of hydration, and therefore, improve the durability
5.1 Advantages of SCC
Why SCC should used?
Self compacting concrete that is able to flow under its own weight and completely
fill the form work, even in the presence of dense reinforcement, without the need of any
vibration, whilst maintaining homogeneity.
Financial & Environmental Benefits
• Minimal labor involved
• Rapid construction without mechanical vibration
• Low noise-level in the plants and construction sites
• Overcome problems arise with vibration.
• Safer working environment
• Accelerated project schedules
• Reduced equipment wear
• Allows for innovative architectural features
• Greater Range of Precast Productions
Engineering Benefits
• Better surface finishes
• Easier placing
• Improved durability
• Greater freedom in design

43
• Thinner concrete sections
• Ease of filling restricted sections and hard to reach areas
• Encapsulate congested reinforcement
• Allows for innovative architectural features
• Homogeneous and uniform concrete
• Better reinforcement bonding
5.2 SCC v/s NCC
• One of the practical advantages of SCC over NCC is its lower viscosity and, thus, its
greater flow rate when pumped. As a consequence, the pumping pressure is lower,
reducing wear and tear on pumps and the need for cranes to deliver concrete in
buckets at the job site.
• This also reduces significantly the construction period and the amount of personal
necessary to accomplish the same amount of work.
• SCC gives designers and contractors a solution for using concrete in special
problems, like casting of complicated shapes of elements, heavily congestion of
reinforcement, or casting of areas with difficult access. Compaction of NCC is
tedious and costly in such congested structures. Also the use of vibrators is time
consuming.
• In all these cases, the use of NCC compromises the durability of the structure due to
poor consolidation. SCC is also called a “healthy” and “silent” concrete as it does not
requires external or internal vibration during and after pouring to achieve proper
consolidation.
• Where the mechanical vibration is a noisy and demanding task for the members of
the casting team the reduction or total elimination of this assignment diminishes the
environmental impact as well as the overall cost.

5.3 PPie charts SSCC v/s NCC
A
Ad
41.20%
25.7
C
Admixture =
dmixture =0.
70%
1% of total c
.6 % of total
5.40%
30.30%
SC
6.80%
50.12%
NC
cementitious
l cementitiou
22.90%
CC
17.16%
CC
s materials
us materials
Wa
Cem
Coa
Fine
W
C
C
F
ter
mentitious con
arse aggregate
e aggregate
Water
Cementitious co
Coarse aggrega
ine aggregate
44
ntent
ontent
te

45
CHAPTER 6
CASE STUDY
CASE STUDY
Use of self compacting concrete for domes in Rajasthan Atomic Power Project. (Carried out
by HINDUSTAN CONSTRUCTION COMPANY LIIMITED)
The following trials were conducted:
TRIALS OF SCC AT RPP – M45 GRADE
Ingredients Present Mix Proposed SCC Mix
Cement 400 300
Fly Ash 0 200
(40%)
W/Cm 0.37 0.36
Water 148 180
20m 526 290
10mm 526 436
Coarse Sand 479 331
Fine Sand 305 539
Superplasticiser 8.5 4.0
VMA 0 0.75
Retarder 0 0.5
__________________________________________________________________________
Present Mix Proposed SCC Mix
Fresh Concrete Properties
Conforming to criterion given in EFNARC
Hardened Concrete Properties
3 Days 32Mpa 26Mpa
7 Days 45Mpa 38Mpa
28 Days 60Mpa 57Mpa
56 Days 62Mpa 64Mpa

46
TRIALS OF SCC AT RAPP – M25
Ingredients Present Mix Proposed SCC Mix
Cement 320 225
Fly Ash 0 225(50%)
W/Cm 0.5 0.4
Water 160 180
20mm 511 250
10mm 511 374
Natural Sand 219 426
Crushed Sand 627 562
Superplasticiser 5.2 3.8
VMA - 0.45
Retarder - 0.45
3 Days - 11.5
7 Days 31 19.5
28 Days 43 35.0
56 Days 41.5 41.5

47
USE OF SELF COMPACTING CONCRETE FOR PIERS IN BANDRA WORLI SEA
LINK PROJECT,
TRIALS OF SCC AT BWSL – M60
Ingredients Proposed SCC Mix
Cement 345
Fly Ash 150
Micro silica 49.5
W/Cm 0.30
Water 165
Coarse aggregate 540
Fine aggregate 1160
Superplasticiser 5.5
VMA 2.0
Retarder 1.0
3 Days 34.3Mpa
7 Days 52.8Mpa
28 Days 71.8Mpa
Permeability (DIN) 0

48
TRIALS CARRIED OUT AT RMC INDIA LTD. FOR SCC
TRIALS FOR SCC (ELKEM)
M35 M35 M35 M35
(With
RMC
aggs)
TM NO. 2437 2438 2439 2440
OPC (Coramandal) 225 280 445 320
PFA (Dirk 63) 225 165 0 180
Micro silica (Elkem) 35 35 35 0
Total Cemetitious 485 480 480 500
10mm (Elkem) 634 634 634 634
SAND (Elkem) 1009 1009 1009 1009
TOTAL AGG 1643 1643 1643 1643
% Fines 61.4 61.4 61.4 61.4
HWRA (supaplast) 1.5% 1.2% 1% 1%
WATER 176 176 175 227
DPD 2304 2299 2298 N.T.
APD 2339 2316 2252 0.33
F W/C RATIO 0.33 0.33 0.33 600
FLOW (mm) 700 700 700 20.93*
STR – 3DAY 10.6 11.21 22.09 26.86/2330
7 DAYS 20.33/2367 22.41/2331 27.94/2291 46.47
28 DAYS 40.54 44.18 43.37 47.46
28 DAYS 41.36 42.26 46.17 46.965
AVE.28 DAYS 40.95 43.22 44.77
*: 4 day strength

49
CHAPTER 7
CONCLUSIONS
SCC mixes requires superior quality material, admixtures, methods & supervisions. SCC
eliminates the requirement of compaction which reduces the time & cost of construction,
hence bringing a new phase in concrete manufacturing. Country to country even the normal
concretes are defined differently. From time to time even the definition of normal concrete
keeps changing in the same country. It is likely that concrete such as SCC will also be
regarded as normal & will be redefined in future.
The compressive strength of SCC specimens increased with the time of curing. A
considerable increase in the compressive strength of concrete specimens exposed to thermal
variations was noted compared to specimens exposed to wet-dry and normal exposures.
Further, compared to the compressive strength of specimens under normal
Exposure, the compressive strengths of specimens under wet-dry was higher.
The SCC specimens displayed better performances with regard to water absorption.
The chloride permeability of SCC was very low for all the specimens exposed to all the
conditions investigated in this study. The chloride permeability values obtained in this study
are in agreement with those reported in the literature.
Concrete technology is dynamic & always displaying new, interesting & often exciting
phases. The traditional approach to durability, i.e., minimum cement content, maximum w/c
ratio & type of cement is being questioned by researchers & technologists. Toda studies are
being done on concrete durability & new dimension such as particle packing, transport
mechanism, binding capacity are the hot topics being looked into.

50
BIBLIOGRAPHY
• “The European guidelines for self compacting concrete” by BIBM, CEMBUREAU,
ERMCO, EFCA, EFNARC.
• Quintessence Vol.1 & vol.2 by Constromat Consultance and Pvt. Ltd.
• ”Concrete technology” by M.S. Shetty.
• Japan society of Civil Engineers, “Recommendations for design & construction of
anti washout Underwater concrete”, concrete library of JSCE, 19(1992) 89p.
• EFNARC, U.K(2002) “Specifications & guidelines for Self compacting concrete”

Study of Self Compacting Concrete

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