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self compacting concrete
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CHAPTER-I
INTRODUCTION
1.1 GENERAL
For the durability of the structure during its service life and
to withstand the high service loads, the high performance
concrete is needed this demand is the increasing with time. The
concrete which provides there requirement may be the need of
future the self-compacting concrete fulfil those basic
requirements.
For the development of any country it is required that
physical infrastructure and social infrastructure grow with same
pace. For developing good infrastructure which survive for a
longer time i.e. its service life period, we need robust and
durable civil engineering structure Primarily the civil engineering
structure are made up of concrete, steel, or combination of both.
In initial days ordinary or lean concrete had been in use. Later on
standard concrete where in use. These ordinary and standard
concrete require huge amount of compacting energy for proper
placement of concrete. Now a day’s we require high strength
concrete for durable civil engineering structure. Also we need
lesser compacting energy for placement of concrete. A self-
compacting concrete is the need of civil engineering construction
industries. The concrete which can be placed and compacted with
ease is the need of our. To control the quality of concrete certain
1
Indian standard guide lines are prepared. To control quality of
self-compacting concrete certain guide lines are required.
The study of different behaviour of self-compacting concrete
will help to formulate standard guide lines. This project is a study
on mechanical properties of self-compacting concrete. Now a
days self -compacting concrete is used in various project in
developed countries. They are using the self- compacting
concrete since 1990. This research proposal is dedicated to
investigate the flow ability of the concrete without segregation and
bleeding. Also to make it more durable and investigation on
strength parameters have been also recorded
1.2 SELF COMPACTING CONCRETE
The self-compacting concrete is defined as a concrete
which can be placed and compacted under its self-weight with no
vibration effort and easily to handle without segregation or
bleeding.
Development of self-compacting concrete (SCC) is a main
achievement which minimise the problems which comes during
the cast-in-place concrete. Which is free from worker skill, amount
of reinforcing steel bar or structure arrangement .it has very high-
fluidity and segregation resistance so it can be pumped longer
distances (Bartos, 2000).
The concept of self-compacting concrete was proposed in
1986 by Professor Hajime Okamura (1997), but the prototype was
first developed in 1988 in Japan, by Professor Ozawa (1989) at
the University of Tokyo.
2
Self-compacting concrete was developed at that time to
improve the durability of concrete structures. Since then, various
investigations have been carried out and SCC has been used in
practical structures in Japan mainly by large construction
companies.
Investigations for establishing a rational mix-design method
and self-compact using ability testing methods have been carried
out from the viewpoint of making it a standard concrete. Self-
compacting concrete is cast so that no additional inner or outer
vibration is necessary for the compaction. It flows like “honey” and
has a very smooth surface level after placing. With regard to its
composition, self-compacting concrete consists of the same
components as conventionally vibrated concrete, which are
cement, aggregates, and water, with the addition of chemical and
mineral admixtures in different proportions.
Usually, the chemical admixtures used are high-range water
reducers (superplasticizers), which change the rheological
properties of concrete. Mineral admixtures are used as an extra
fine material, besides cement, and in some cases, they replace
cement. In this study, the cement content was partially replaced
with mineral admixtures, e.g. fly ash, slag cement, and silica fume,
admixtures that improve the flowing and strengthening
characteristics of the concrete.
3
1.3 HISTORICAL DEVELOPMENT OF SELF-COMPACTING
CONCRETE
In many circumstances of construction there is a need of
vibration for compaction, but compaction of concrete by vibration
is impossible and hence we use self- compacting concrete at in
place of traditional concrete.
Early self-compacting concretes relied on very high contents
of cement paste and, once super plasticizers became available,
they were added in the concrete mixes. The mixes required
specialized and well-controlled placing methods in order to avoid
segregation, and the high contents of cement paste made them
prone to shrinkage. The overall costs were very high and
applications remained very limited.
The introduction of “modern” self-levelling concrete or self-
compacting concrete (SCC) is associated with the drive towards
better quality concrete pursued in Japan around 1983, where the
lack of uniform and complete compaction had been identified as
the primary factor responsible for poor performance of concrete
structures (Dehn et al., 2000).
Due to the fact that there were no practical means by which
full compaction of concrete on a site was ever to be fully
guaranteed, the focus therefore turned onto the elimination of the
need to compact, by vibration or any other means. This led to the
development of the first practicable SCC by researchers Okamura
and Ozawa, around 1986, at the University of Tokyo and the large
Japanese contractors (e.g. Kajima Co., Maeda Co., Taisei Group
Co., etc.) quickly took up the idea.
4
The contractors used their large in-house research and
development facilities to develop their own SCC technologies.
Each company developed their own mix designs and trained their
own staff to act as technicians for testing on sites their SCC
mixes.
A very important aspect was that each of the large
contractors also developed their own testing devices and test
methods (Bartos, 2000).
In the early 1990’s there was only a limited public
knowledge about SCC, mainly in Japan. The fundamental and
practical know-how was kept secret by the large corporations to
maintain commercial advantage. The SCCs were used under
trade names, such as the NVC (Non-vibrated concrete) of Kajima
Co., SQC (Super quality concrete) of Maeda Co. or the Biocrete
(Taisei Co.).
Simultaneously with the Japanese developments in the
SCC area, research and development continued in mix-design
and placing of underwater concrete where new admixtures were
producing SCC mixes with performance matching that of the
Japanese SCC concrete (e.g. University of Paisley / Scotland,
University of Sherbrooke / Canada) (Ferraris, 1999).
1.3 NEED OF SELF COMPACTING CONCRETE:
In 1988 it was desired to develop the prototype of self-
compacting concrete the use of self-compacting concrete in actual
structures has gradually increased. The main reasons for its
construction are as ` follows:
5
• To shorten construction period
• To assure compaction in the concrete structure specially in
that zones where vibrating compaction is difficult
• To eliminate noise due to vibration
• Reduction in site man power
• Easier placing
• Improved durability
• Safer working environment
By employing self-compacting concrete, the cost of chemical
and mineral admixtures is compensated by the elimination of
vibrating compaction and work done to level the surface of the
normal concrete (Khayat et al., 1997).
However, the total cost for a certain construction cannot always
be reduced, because conventional concrete is used in a greater
percentage than self-compacting concrete. SCC can greatly
improve construction systems previously based on conventional
concrete requiring vibrating compaction. Vibration compaction,
which can easily cause segregation, has been an obstacle to the
rationalization of construction work. Once this obstacle has been
eliminated, concrete construction could be rationalized and a new
construction system, including formwork, reinforcement, support
and structural design, could be developed.
6
1.4 AIM AND SCOPE 0F WORK
Aim of this research is to explore the mix proportioning of
self- compacting concrete for high strength. The scope of this
research included an examination of:
• The effect of water-cement ratio;
• The effect of mineral admixtures; and
• The effect of chemical admixtures on the compressive
strength of self-compacting concrete.
1.5 METHODLOGY
Mix proportioning to achieve high flow ability without
segregation and bleeding will be done. Use of HRWR to achieve
the flow ability in concrete will be recorded. The use of mineral
admixture as recommended by EFNARC, an European federation
dedicated to specialist construction chemicals and concrete
systems.
Use of mineral admixture as mentioned in British DOE method (
Department of Environment ) capturing the property of cementing
of mineral admixture is used in deciding the proportion of mineral
Admixture in the proportioning of self-compacting concrete
Further use of HRWR in different dosages will be used to study
the flow ability and strength of the mix proportion. The
selections of HRWR dosage are based on the EFNARC
guidelines.
7
1.6 LIMITATIONS
Mix proportioning requires a number of trial since the flow ability
of concrete without segregation and bleeding depends upon the
constituent elements of concrete, which are cement, fine
aggregates, coarse aggregate, chemical admixture and mineral
admixture. He properties of individual elements are going to
change the property of self-compacting concrete. The output
parameters like flow ability, segregation, bleeding, and strength
have temporal variation so a large of trial are needed for attaining
any conclusion.
The variation of physical & chemical properties of the constituent
element will definitely
1.7 THESIS ORGANIZATION
Have impact on self-compacting concrete. So the duration of
observation is also an important parameter w a major constrain in
this project.
8
CHAPTER-II
LITERATURE REVIEW
2.1 INTRODUCTION
Self-compacting concrete extends the possibility of use of
various mineral by-products in its manufacturing and with the
densification of the matrix, mechanical behaviour, as measured by
compressive, tensile and shear strength, is increased.
On the other hand, the use of superplasticizers or high
range water reducers, improves the stiffening, unwanted air
entrainment, and flowing ability of the concrete. Practically, all
types of structural constructions are possible with this concrete.
The use of SCC not only shortens the construction period but also
ensures quality and durability of concrete.
This non-vibrated concrete allows faster placement and less
finishing time, leading to improved productivity.
In the following, a summary of the articles and papers found
in the literature, about the self-compacting concrete and some of
the projects carried out with this type of concrete, is presented.
2.2 HISTORY
During the construction San marco dry dock at Trieste high
fluidity and high cohesiveness were desirable requirement for the
9
concrete at site. This can be achieve with large dosage of
sulfonated naphthalene type super plasticizer with high proportion
of sand this was done 1980. Also the similar concrete was used in
mass Transit Railway of Hong Kong.
The super plasticizer admixture was expensive at that time,
but still saving cost of poker vibrators. This has been reported in
ACI SP119. Some of the early works in Japan for development of
SCC mixtures has been described by Miura et al and Tanaka et al
(1980).
In Germany and the United State there was a considerable
interest in decreasing the viscosity of fresh concrete to make it
suitable for repairing work. Use of viscosity-modifying admixture
(VMA) had gained attention during 1980 to 1990. Use of VMA into
a concrete mixture enables it to become cohesive even without
use of high content of fine particle of cement and mineral
admixture. This is because the molecular structure of typical VMA
facilitates the removal of large amounts of water by physical
adsorption. The VMA containing concrete mixture exhibits
thixotropic behavior.
Use of VMA gained momentum in India. River sand and
coarse aggregate the necessarily ingredients for making SCC
included superplasticizer VMA and mineral admixture of fine
particle size. Due to superior rheological characteristics the SCC
was very much in demand.
This is also used in under water concreting as well as
concreting at excessively location. At the same time the SCC
required high degree of quality control.
10
2.3 LITERATURE REVIEW
Demand of super-workable concrete was started in late
sixties. The development of self-compacting non segregating
concrete in laboratory served the purpose. Later fine material like
fly ash, lime stone filler were used without changing the water
content and also compared with the conventional concrete it was
found that minor variation in proportions of constituent material of
concrete change the rheological behaviour of the concrete. So
the use of mineral admixtures increases the flow-ability of the
concrete and also producing self- levelling cohesive concrete.
Over the time new research were carried out to control the
rheological behaviour of concrete with the use of chemical
admixture. The demand was to generate a concrete which
requires minimal force to initiate flow but should have adequate
cohesion to resist aggregate segregation and excessive bleeding.
The advent of advanced synthetic high-range water
reducing admixture (HRWR) and a viscosity modifying admixture
(VMA). or by increasing the percentage of fines a new mix
proportioning has been established.
Later on self-compacting concrete is focused on high
performance, better and more reliable quality, dense and uniform
surface texture, high strength.
In Europe and Japan their use has been extensively used in
bridge, high rise building in accessible construction Site and also
in precast concrete industry the properties of concrete material of
11
concrete and their proportion or dosage have a greater impact on
the self-compacting concrete desire properties, such as the well
graded cubical or rounded coarse aggregate are desirable as they
minimise cement paste content as well as admixture dosage. The
maximum size of aggregate is generally limited to 20mm or less.
Fine aggregate should be of uniform grading. The particles finer
than 425 micron are considered as fines. To achieve a balance
between deformability or fluidity and stability, the total content of
fine has to be high usually about 1100kg/m3.
To achieve the balance between deformability or fluidity and
cohesion or stability the use of chemical admixture including
HRWR, VMA and mineral admixture including silica fume, fly ash
ground granulated blast furnace slag and lime stone powder are
recommended. The constituent materials improve rheological
properties and durability of SCC along with other parameters.
A European federation dedicated to specialist construction
chemical and concrete systems has been doing research is
known as EFNARC has set up a guidelines for self-compacting
concrete. However, EFNARC recognise that this is a technology
which is still evolving and further advances may require these
specification requirements to be modified or extended.
A number of researchers in japan developed the self-compacting
concrete technology based upon the earliear development of
superplasticizers. In Europe similar technology have been
developed with the use of silica fume, Ground granulated blast
furnace slag (GGBFS), and Fly ash. The contribution came from
the following researchers K. Ozawa, H. okmura, M. Rooney P.M.S
12
Bartos(1992),Petersson, Ö., Billberg, P., Van, B.K., (1996),
Bartos, P.J.M., (Japan, August 1998), Haykawa, M., Bartos,
(1993) Ozawa, K., Sakata, N., Okamura, H., (1995) Rooney, M.,
Bartos, P.M.J., (2001),Henderson N A, Baldwin N J R, McKibbins
L D, Winsor D S, & Shanghavi H B, (2002).
The composition of SCC mixes includes substantial
proportions of fine-grained inorganic materials and this gives
possibilities for utilization of mineral admixtures, which are
currently waste products with no practical applications and are
costly to dispose of (St John, 1998).
2.3 SUMMARY
Present-day self-compacting concrete can be classified as
an advanced construction material. It does not require to be
vibrated to achieve full compaction. This offers many benefits and
advantages over conventional concrete. These include an
improved quality of concrete and reduction of on-site repairs,
faster construction times, lower overall costs, facilitation of
introduction of automation into concrete construction. An
important improvement of health and safety is also achieved
through elimination of handling of vibrators and a substantial
reduction of environmental noise loading on and around a site.
13
CHAPTER-III
EXPERIMENTAL PROGRAM
3.1 THEORY AND FORMULATION
Since concrete is a three phase system containing volume
of solid, volume of water and volume of air it is mixture of so many
heterogeneous material like coarse aggregate, fine aggregate,
mineral admixture, chemical admixture, cement and water.
Establishing a rational mix proportioning of the above
mentioned material is the main aim to achieve self-compacting
concrete. Earlier the research had used different proportion of the
material keeping in mind the desirable property of the concrete.
ACI method, British DOE method, Indian standard method,
European method of mix proportioning had now been established.
The above mentioned methods are limited to standard concrete
only. For the self-compacting concrete more investigation are
required to achieve a rational mix proportioning. A comparative
study has been prepared with the above mentioned method. After
investigation it is found that Indian standard method of mixed
proportioning can be enhanced to achieve a mix proportioning of
self-compacting concrete.
Since the self- compacting concrete apart from there self-
compacting requirement , strength requirement of more than
14
55N/mm2 is explored , during which it is found in literature review
that the size of coarse aggregate lesser than 16 mm and the
zone of fine aggregate should not be less than zoneII and the the
mineral admixture should have low calcium content.
To achieve the desirable properties likes fluidity we need to
use HRWR along with VMA. The Indian standard mixed
proportioning guide line is mentioned in IS 10262:2009
3.2 MATERIAL PROPERTIES
3.2.1 CEMENT
The Cement used in high strength fiber reinforced
concrete was Ordinary Portland Cement (OPC) of grade 43. The
various laboratory tests confirming to IS: 4031-1996 specification
was carried out and the physical properties were found as such:
Fineness - 0.225 m2/g
Consistency - 30%
Initial setting time - 50 min
Final setting time - 520 min
Specific gravity - 3.12
3.2.2 FINE AGGRIGATES
Ordinary sand from Sone having the following
characteristics has been used
Specific gravity - 2.67
Fineness modulus - 2.60
15
Sand after sieve analysis (see table 3.1) confirm to zone II as per
IS 383-1970.
TABLE 3.1: SIEVE ANALYSIS OF FINE AGGREGATE
IS Sieve (mm)
Wt. Retained(Kg)
Cum. Wt.(Kg)
% Retained
% Passing
Remarks
4.75 0.034 0.034 3.4 96.6 Sand
Zone II
As per
IS: 383-
1970
2.36 0.026 0.060 6 94
1.18 0.140 0.200 20 80
600 0.162 0.362 36.2 63.30
300 0.425 0.787 78.7 21.30
150 0.185 0.972 97.2 2.30
3.2.3 FLY ASH
Fine low calcium fly ash samples taken from Kahalgaon
Thermal Power Plant, NTPC were used in this study. This fly ash
was of average quality formed with the combustion of lignite and
bituminous coal. The colour of the fly ash was light grey. The
sample satisfied the requirements of IS 3812(Part I).
Sl no. Physical Properties Observed values
1 Specific Gravity 2.4
2 Initial Setting 45 min
3 Final Setting 280 min
4 Consistency 35
16
The chemical characteristics are presented in table 3.2. The
chemical property of the fly ash has been presumed based on the
data made available from NTPC Kahalgaon Bihar.
Table 3.2: Chemical Properties of Fly Ash
Sl. No.
Test Conducted Observed Values (%)
Requirement as per IS:1320-1981
1 Loss of Ignition 2.32 5.0(max)
2 Silica as SiO2 42.04 SiO2+ Fe2O3+ Al2O3=70
3 Iron as Fe2O3 4.40 -
4 Alumina as Al2O3 33.60 -
5 Calcium as CaO 12.73 -
6 Magnesium as
MgO 0.00 5.0
7 Sulphate as SO3 0.40 3.0
8 Chloride -
9 Lime Reactivity 4 .00 4.5
3.2.4 COARSE AGGREGATE
Locally available crushed stone (PAKUR) with maximum
graded size of 16 mm have been used as coarse aggregate. The
physical properties for the coarse aggregate as found through
laboratory test resulted in
Aggregate crushing value = 24%
Aggregate impact value = 29%
17
Specific gravity = 2.74
Water absorption = 0.44
Sieve analysis of the locally available coarse aggregate is given in
table 3.3
TABLE 3.3 SIEVE ANALYSIS OF COARSE AGGREGATE
Sieve size(m
m)
Weight retained(K
g)
Cum.wt(Kg)
Percent
retained
Percentage
passing
Remarks
20 0.000 0.000 0 100
16mm
graded
16 0.470 0.470 9.4 90.6
12.5 3.461 3.931 78.62 21.38
10 0.463 4.393 87.88 12.12
4.75 0.562 4.956 99.12 0.88
3.2.5 CHEMICAL ADMIXTURES
Out of the large number of admixtures used in concrete to
obtain improve performance characteristics, the admixtures which
have significant effect on the rheology of concrete are plasticizers
and super-plasticizers, air-entraining agents, accelerators and
retarders. These admixtures are used in three ways:
(i) To give increased workability with the same long-term
strength and durability,
18
(ii) To give same workability with less water content and
hence higher strength, and
(iii) To give the same workability and strength with less
cement content; however, the reduced cement content
should be enough from durability consideration.
The plasticizer or super-plasticizers interact with cement
particles, introducing a membrane of absorbed charged molecules
around each particle, which prevent physically the particles
approaching each other so closely as to stick, so that flocculation
is prevented.
In the present study Super plasticizer (HRWR) as well as viscosity
modifying agent Master GLENIUM 51 with Chemical name
polycarboxylate super plasticizer as per IS 9103 shall be used to
enhance mechanical properties of self-compacting concrete. The
properties of GLENIUM 51 as given by the distributor is presented
in table 3.4
TABLE 3.4 PROPERTIES OF GLENIUM51
parameter Specification ( AS
PER IS 9103) Results
Physical stare Light brown liquid Light brown liquid
Chemical name of
active ingredient
Polycarboxylate
polymers
Polycarboxylate
polymers
Relative density
at 25oc 1.09 ± 0.01 1.124
PH Min.6 7.08
Chloride ion Max 0.2 <0.10
19
content (%)
OUT LINE OF THE EXPERIMENT:
The preamble of IS 10262-2009 is used along with EN-206 is
prcducing the self-compacting concrete in laboratory.
In this project we use the code IS 10262-2009, in place of
Europian code (EN-206). While all the information about SCC is
disscuss in the European code.
3.3 MIX-DESIGN CALCULATION
3.3.1 MIX PRORTIONING METHOD
Mix proportioning method for concrete is mostly based on
certain empirical relationships, charts nomographs, developed
from extensive experimental investigations. Preamble behind all
the methods is almost same only minor variation exists in different
Mix proportioning methods. The concrete Mix is usually dictated
by the desirable criterion such as durability condition of placing
and structural design conditions. Some of the commonly used Mix
proportioning methods for standard concrete are the following
• British DOE Mix design method
• Concrete mix proportioning-IS Guidelines.
• ACI Mix design method
In all the above mix proportioning method common steps mostly
used are as follows.
20
• The maximum nominal size of the aggregate as per the
specified requirements fixed
• The mean target strength is estimated from the specified
characteristic strength and the level of quality control.
• A suitable water cement ratio based upon strength and
durability criterion is adopted
• The degree of workability in terms of slump, compacting
factor or vee- bee time is selected as per job requirements
• The cement content is calculated and its quantity is checked
for the requirement of durability.
• The percentage of fine aggregate in the total aggregate is
determined from the characteristics of coarse and fine
aggregates.
• The trial batches obtained for the compressive strength test
on cube and cylinders.
• The mix which confirms the criterion of strength, working
and durability is approved.
In this present study the structural strength is taken
55N/mm2, where as the concrete placing criterion based on slump
is more than 300mm. Before arising a mix proportioning, the
above mentioned methods are explored.
As per BRITISH DOE method of concrete mix design the
following assumption are taken.
(1) The volume of freshly mixed concrete equals the sum of the
absolute volumes of its constituent material i,e the
water cement air content and the total aggregate.
(2) The compressive strength class of a concrete depend on
21
• water cement ratio
• type of cement
• type of aggregate
(3) workability of concrete depend on
• free water cement ratio
• type of fine aggregate
Stipulated value taken for the proportioning
Water cement ratio = 0.35
Exposure classes = XD3
( X- Exposure condition, D-Dry and wet condition, 3- Clorine ion
contain)
Water content taken as per working requirement = 225 kg/mm3
Reducing water in case of using additive and also HRWR.
Net Water = 157kg/mm3
Now using additive with cementing co-efficient = 0.3
FCFP
+=
100 or, P
PCF−
=100
where, F = fly ash content
C = cement content
P = percentage of fly ash in the total cementious
material
If k=cementing efficiency
Then total cementing material
= C+ KF
= C +
− PKPC
100
= P
KPCPC−+−
100)100(
22
= P
PKC−−−
100])1(100[
Free water cement ratio = KFC
W+
=}])1(100{[
)100(PKC
PW−−−
Therefore, the cement content is given by above equation
C =
+−−
−
KFCWPK
PW
])1(100[
)100(
=35.0]307.0100[
)30100(157XX−
−
= 397.46
= 398 kg
HWRW content is 1% weight of cement
WHRWR=3.98 kg/mm3
F= P
PC−100
= 301009830−
X
=170kg
Hence total cementing material,
C+F=398+170 =568
So watrer powder ratio , powderWater =
568175 =0.28
For water content of 157kg/m3 with average specific gravity of
2.65 of aggregate, the wet density of aggregate is 2450kg/m3
Hence total weight of aggregate= 2450 –(398-170-157-3.98)
= 1721 kg/mm3
23
As per the monographs percentage of aggregate and 40%
Mass of fine aggregate =688 kg/mm3
Mass of coarse aggregate=1033 kg/mm3
Cement
(kg/mm3
Water
(kg/m
m3
Fly ash
(kg/mm3)
FA
(kg/mm3
)
CA
(kg/mm3)
HRWR
(kg/mm3)
398 157 170 688 1033 3.98
1 0.39 0.43 1.73 2.6 0.01
The above trial was further improved with IS: Guideline
method. Since the above calculation proportion the structural
strength criteria was achieved but the workability Criteria was not
achieved since the flow ability of concrete is inhibited by the
coarse aggregate.
A guide line for self -compacting concrete is introduced by
EFNARC, the EFNARC is the European federation dedicated to
specialist construction in concrete systems. According to this
specification &Guidelines it is most useful to consider the relative
proportion of the key component by volume rather than by mass.
Indicative typical range of proportions and quantities in order
to obtain self-compact ability are as follows.
• Water powder ratio by volume of 0.8 to 1.10
• Total powder content.(160 to 240 litre)[400-600 kg/m3]
24
• Coarse aggregate content normally 28to35 percent by
volume of the mix
• Water cement ratio is selected based on requirements is
in EN206. typical water content does not exceed 200
litre/m3
• The sand content balances the volume of the other
constituents
Further modification will be necessary to meet strength and
other performance requirements. A viscosity modifying agent
should be included in the mix. The dosage of the super plasticizer
with VMA compliable with local materials should be used.
Keeping in mind the above guideline and Indian standard
guideline for standard concrete, a proportioning approach has
been adopted which is as follows.
MIX PROPORTIONING FOR TRIAL-1
Based upon the laboratory findings and researcher journals the
percentage of Fly Ash has been taken as 30 % of the weight of
cementitious material
We adopted Water Cement ratio as 0.35
As per code IS 10262:2009 maximum water content for size
16mm Graded is 208 kg
Weight of water=208 kg
For Self-compacting concrete slump would be 300mm & more
Hence increasing water 30%
Required water content for 300mm slump =208+30x208/100
=270kg
25
As superplasticizer is used, the water content can be reduced
upto 30 percent
Net water = 270-270x30/100
= 189kg
Superplasticizer used 2% by weight of cement
Consider water cement ratio=0.35
Weight of cement = 189/0.35
= 540kg
Powder combination: Increase powder by 15%( Taking into
account the cementing coefficient para meter of fly ash)
Weight of powder=540+540x15/100
=621kg
Let us consider 30%fly ash is used
Weight of fly ash = 621x30/100
= 186kg
Weight of cement = 621 - 186 = 435kg
Weight of cement = 435kg
Hence water powder ratio = 189/621
= 0.30
Weight of superplaticizer = weight of cement x2%
= 435x2/100=8.7kg
The mix calculation per unit volume of concrete shall be follows:
a) Volume of concrete=1 m3
b) Volume of cement = 1000
1cement ofgravity Specific
cement of Mass×
26
= 1000
115.3
435×
= 0.318 m3
c) Volume of fly ash = 1000
1ashFly ofgravity Specific
ashFly of Mass×
= 1000
11.2
186×
=0.0886 m3
d) Volume of water = 1000
1 waterofgravity Specific
waterof Mass×
= 1000
11
189×
= 0.189 m3
e) Volume of superplasticizer =1000
1icizersuperplast ofgravity Specific
icizer superplast of Mass×
= 1000
1124.1
7.8×
= 0.0077 m3
f) Volume of all in aggregate = 1— (0.189 + 0.138 + 0.0886
+ 0.0077)
= 0.5767
As per code IS 10262:2009 from table 3, volume of coarse
aggregate corresponding to 16 mm size aggregate and fine
aggregate (ZoneII) For water cement ratio of 0.5 =0.46
In the present case water-cement ratio is 0.35. therefore volume
of coarse aggregate is required to be increased to decrease the
fine aggregate content. As water-cement ratio is lower by 0.10,
27
the proportion of volume of coarse aggregate is increase by 0.02
ie water cement ratio is decrease by 0.5, the proportion of volume
of coarse aggregate is increase by 0.01
Therefore, corrected proportion of volume of coarse aggregate for
water-cement ratio of 0.35 =0.49
For pumpable concrete these values should be reduced by 10
percent
Therefore volume of coarse aggregate=0.49x0.9=0.441
Volume of fine aggregate=1-0.441=0.55
g) Mass of coarse aggregate=
= f x volume of coarse aggregate x specific gravity of fine
aggregate x1000
= 0.5767x0.441x2.73x10000
=694.3 kg
h) Mass of fine aggregate=
=f x volume of fine aggregate x specific gravity of fine aggregate
x1000
=0.5767x0.559x2.62x1000
=844.62kg
Cement
(kg)
Water
(kg)
Fly ash
(kg)
CA
(kg)
FA
(kg)
SP(HRWR)
(kg)
435 189 186 694.30 844.62 8.7
1 0.434 0.43 1.59 1.94 0.02
12 5.208 5.16 19.15 23.29 0.240
Water absorption:
water absorption by fine aggregate=1%
28
water absorption by coarse aggregate=0.5%
for 12kg cement
weight of cement=12kg
weight of coarse aggregate =19.15—0.09 = 19.06kg
weight of fine aggregate =23.29—0.23 = 23.06kg
weight of water =5.208+0.09+0.23=5.528kg
weight of fly ash =5.16kg
weight of superplasticize =0.240kg
final proportion given below in table
CEMENT WATER FLY ASH
CA FA SP(HRWR)
12 kg 5.528 kg 5.16kg 19.06 kg 23.06 kg 0.240 kg
Similar mix proportioning has been done for preparing other test
samples for different percentages HRWR concrete. Table 3.4
presents the mix proportioning for five different mixes.
TABLE 3.5, MIX PROPORTION FOR 12 KG CEMENT WITH VARIATION IN SP(HRWR) PERCENTAGE
Mix trial no.
Cemen
t
(kg)
Water
(kg)
Fly
ash
(kg)
CA
(kg)
FA
(kg)
SP(HRWR)
%
(kg)
1 12 5.528 5.16 19.06 23.06 2 0.240
2 12 5.528 5.16 19.04 23.05 2.1 0.252
3 12 5.528 5.16 19.03 23.03 2.2 0.264
29
4 12 5.528 5.16 19.01 23.02 2.3 0.288
5 12 5.528 5.16 19 23 2.4 0.300
6 12 5.528 5.16 19.06 22.98 2.5 0.300
TABLE 3.6, MIX PROPORTION FOR 1m3 CONCRETE
Mix trial no.
FACW+
Cement
(kg)
Water
(kg)
Fly
ash
(kg)
CA
(kg)
FA
(kg)
SP(HRWR)
% (kg)
1 0.30 435 189 186 694.30 844.62 2 8.7
2 0.30 435 189 186 693.82 844.03 2.1 9.134
3 0.30 435 189 186 693.34 843.45 2.2 9.57
4 0.30 435 189 186 692.86 842.86 2.3 10.005
5 0.30 435 189 186 692.38 842.28 2.4 10.44
6 0.30 435 189 186 691.18 841.69 2.5 10.875
CHAPTER-4 4.1EXPERIMENTAL RESULT AND ITS INVESTIGATION 4.1.1.SLUMP FLOW TEST: The usual slump cone having base diameter of 200mm, top
diameter 100mm and height 300mm is used.
30
• A stiff base plate sqare in shape having at least 700mm
side. Concentric circle are marked around the centre point
wherw the slump cone is to placed. A firm circle is drawn at
500 mm diameter. Fig given below
FIGURE 4.1
A FIRM CIRCLE IS DRAWN AT 500MM DIAMETER
4.1.2T50 SLUMP FLOW TEST:
31
The procedure for this test is same as for slump flow test. When
the slump cone is lifted, start the stop watch and find the time
taken for the concrete to reach 500mm mark. This time is called
T50 time. Thish is an indication of rate of spread of concrete. A
lower time indicates greater flowability. It is suggested that T50
time may be 2 to 5 second
FIGURE 4.2
32
SPREAD OF CONCRETE DURING 2T50 SLUMP FLOW TEST
FIGURE 4.3
MIXING OF SELF-COMPACTING CONCRETE
The slump values and T50 values for different mixes are shown in
table
TABLE-4.1 T50 Time of SCC with HRWR
Mix proportions (%)
T50 (Sec)
33
HRWR-2 7
HRWR-2.1 5
HRWR-2.2 4
HRWR-2..3 3.7
HRWR-2.4 3.5
HRWR-2.5 3
FIGURE 4.4 COMPRESSIVE STRENGTH TEST
34
TESTING CONCRETE CUBE INSERT IN THE MACHINE
FIGURE 4.5
35
DEVELOPING CRUSHING AFTER TESTING
FIGURE 4.6
CONCRETE FILL IN THE CUBE
36
4.1.3 COMPRESSIVE STRENGTH :The compressive strength of
the different concrete is shown in table for 7 day
TABLE-4.2
trial mix no
sl. no maximum load(KN)
compressive strength (N/mm2)
Average strength (N/mm2)
1
1 921.7 40.96
41 2 935.2 41.29
3 917 40.75
2
1 948 42.13
42.1
2 941.8 41.86
3 952 42.31
3
1 959 42.62
43.02
2 977 43.42
3
968 43.02
4
1 964.7 42.87
42.50
2 948 42.13
3
956 42.49
37
5
1 900 40
40 2 906 40.27
3
894 39.73
6
1 881 39.15
39.33
2 885 39.33
3
889 39.51
The compressive strength of the different concrete is shown in
table for 28 day
TABLE-4.3
trial mix no
sl. no maximum load(KN)
compressive strength (N/mm2)
Average strength (N/mm2)
1
1 1411 62.71
63.07
2 1419 63.07
3 1427.2 63.43
2
1 1456 64.71
64.76
2 1464 65.07
3 1451.3 64.50
38
3
1 1457 64.75
65.02
2 1463 65.02
3
1469 65.29
4
1 1448 64.35
63.99
2 1439 63.95
3
1433 63.69
5
1 1377 61.2
61.49 2 1382.5 61.44
3
1391 61.82
6
1 1355 60.22
60.51 2 1369 60.84
3
1361 60.49
TABLE-4.4, COMPRESSIVE STRENGTH
TRIAL NO
Mix proportion (%)
Compressive strength (N/mm2)
7day 28day
1 SP-2 41 63.07
2 SP-2.1 42.1 64.76
39
3 SP-2.2 43.02 65.02
4 SP-2.3 42.50 63.99
5 SP-2.4 40 61.49
6 SP-2.5 39.33 60.51
Graph between compressive strength & % superplasticizer for seven day FIGURE-4.7
Graph between compressive strength & % superplasticizer for twenty eight day FIGURE-4.8
40
Graph between T50 time & % Superplastisize
FIGURE-4.9
41
RESULT
In this present study, the fresh and hardened properties of self -
compacting conncrete were investigate for six trial mixes. In this
trial the percentage Of viscosity modified admixture was varied.
Fresh properties:
T50 & Slump flow test
The T50 test plays a major role to ensure the flowability of self-
compacting concrete the flowability without segregation and
bleeding is the main property of fresh concrete . the T50 value for
different mixes are shown in table
Through visual inspection the cohesive mix was observed for mix
no- 3 ,the coarse aggregate and fine aggregate move with ease
along with other constituent material. The flowability was as good
as of magma flowing through steep slope
Hardened properties
Compressive strength test at different ages were recorded and
are shown in table and figure
The 7 days compressive strength for mix-3 is highest the
variability in the strength is very less.
The 28 days compressive strength for mix no-3 is
highest and the value is 65.02 N/mm2
42
Conclusions
The mechanical properties of hardened concrete ie
compressive strength mdepends upon the cementious
material available in the mix. The consistency of the
strength indicate in the six trial.
In thish study keeping cementious material equal to 621 kg/m3
. in all the six trial mixes and varying the percentage of
viscosity modified chemical admixture. It is observed that as
the percentage increase the flowability of the concrete
increase upto 2.2 % by the weight of cement. After
increase the percentage of VMA flowability of the concrete
increase but segregation of the constituent materials also
started.
43
CHAPTER-5
Scope for Further Study :
Variation in chemical admixture is only done in this study other
variation of constituent material can also be done to conclude a
rational mix proportioning of self-compacting concrete . since the
mix specimen gain strength even after 28 days so the mechanical
properties should be checked after 90 days and 1 year. Variation
in grain size distribution can also be done to arrive a rational
approach of mix proportioning of self –compacting concrete
44
45