Design of SCC Mixes Based On Cement - SP Compatibility Studies
Design of SCC Mixes Based On Cement - SP Compatibility Studies
Design of SCC Mixes Based On Cement - SP Compatibility Studies
Post Graduate Student, 2Assiocate Professor, 3Assistant Professor, 4Research Professor, Department of Civil
Engineering, Siddaganga Institute of Technology, Tumkur.
ashar.ashu786@gmail.com, siddalingaiah.suresh@gmail.com, nanjundappa60@gmailcom, jk.dattatreya@gmail.com
Abstract
In this work 4 superplasticizers were used and on the basis of the workability test on cement paste two SPs were selected for further
studies and to compare their effects on mortar properties such as workability, compressive strength, water reduction and tensile
strength. Two different mortar mixes (1:1.5 & 1:2) were tested for three values of w/c ratio (0.3, 0.35, and 0.4) for varying SP dosage
i.e. from 0.6 to 2%. This paper presents an experimental investigation on strength aspects such as compressive, and split tensile
strength of self compacting concrete containing fly ash and workability tests (slump flow, T500mm, V-Funnel and T5min) are carried out.
The methodology adopted is that Portland cement is replaced by 0%, 35% and 50% of fly ash using two types of superplasticizers
(SNF, PCE) and performance is measured and compared.
Further Design of Self Compacting Concrete by replacing Fly ash is proposed and the studies on fresh and hardened properties were
conducted. The results showed that PCE type Superplasticizer is performing better than SNF type in terms of workability.
Keywords: Cement, Super plasticizers, mortar, SCC, Fly ash, fresh and hardened properties, compressive strength, split
tensile strength.
--------------------------------------------------------------------***------------------------------------------------------------------------1. INTRODUCTION
Concrete occupies unique position among the modern
construction materials, Concrete is a material used in building
construction, consisting of a hard, chemically inert particulate
substance, known as a aggregate (usually made for different
types of sand and gravel), that is bond by cement and water.
Self-compacting concrete is a fluid mixture suitable for
placing in structures with congested Self Compacting
Concrete is innovative concrete which can reduce the amount
of cementitious materials and total volume of concrete
required. It is a fluid mixture which can flow under its own
weight, completely filling formwork and achieving full
compaction in structures even with congested reinforcement.
Also the use of SCC increases the speed of construction and
reduces the noise. If the mineral admixtures replace a part of
the Portland cement, the cost of self-compacting concrete will
be reduced especially if the mineral admixtures are waste or
industrial by-product such as fly ash which is a by-product of
the combustion of pulverized coal in thermal power plants.
Therefore use of fly ash not only provides economical benefits
but also reduces heat of hydration Henceforth replacing of
Portland cement with fly ash can reduce the production of
CO2. Addition of SP reduces the water content of the concrete
which leads to higher durability, in addition to better
mechanical integrity of the structure. The successful
production of self compacting concrete (SCC) for use, is
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eISSN: 2319
2319-1163 | pISSN: 2321-7308
Conplast
ast 430) and other two were Polycarboxylate ether type
F (Auramix 400, Glenium 6100).on the basis of workability
test on cement paste two SPs were selected for further studies
as shown in figure 2 and figure 3.
3 In this study three types of
Sand were used i.e. Natural sand (N1), Natural sand (N2) and
Manufactured sand (M). The texture
text
of sand is shown in figure
6. Onn the basis of the workability test we shortlisted
Manufactured Sand for further studies as shown in table 5.
Results obtained
Fineness
Consistency
Initial
setting
time
Final setting time
9
28%
105 min >
IS:8112-1989
specification
10 mm
30 min
310 <
600 min
Specific gravity
3.15
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one is used aggregate in the SCC). Then all the materials were
mixed for 2 to 4 minutes. Several design procedure based on
scientific theories or (1) empirical experience have been
proposed for normal SCC [1]. In general, these procedures fall
into the following two categories: (1) combination of superplasticizer and high content of mineral powders and (2)
combination of superplasticizer. Table 3 gives the gradation of
sands and Table 4 gives the gradation of coarse aggregate.
Table 3 Fine aggregate gradation
Sl No
Properties
Results
silica
58.58
Iron oxide
3.42
alumina
28.2
CaO
2.23
MgO
0.32
SO3
0.07
Alkalies(K2O)
1.26
(Na2O)
0.58
3. TESTS ON MATERIALS
Constituents of the concrete mix namely the coarse aggregate
(granite), fine aggregate (sharp sand), and cement (Ordinary
Portland cement), water and chemicals. The granite used was
well graded, free from unwanted particles and of 12.5mm and
20mm sizes while the sharp sand consisted of 5mm sized
particles on average. The tests carried out include tests on the
coarse (granite) aggregates, sieve analysis of the fine (sharp
sand) aggregate, workability tests, and crushing test on the
concrete cubes. The sieve analyses of the coarse aggregates
and fine aggregates (sand) are given in Table 3. The size of
aggregates was between 4.75 to 9.5mm. The water absorption
of the aggregate was 18.02%, and the fineness modulus of the
sand was 2.76, specific gravity was 2.68, and absorption value
was 2.94. Type Portland cement was used in all mixes with
a specific gravity of 3.15. The 0%, 35% and 50% fly ash by
mass of cementitious materials as cement replacement was
used. A polycarboxylic ether (PCE) and sulphonated
napthelene formaldhyde (SNF) superplasticizer was
incorporated in all mixture; the PCE used was in the liquid
form with a specific gravity of 1.13 and solid content of
38.4%.where as SNF used was with specific gravity 1.22 and
solid content of42.8.To enhance the stability of SCC also filler
(lime stone powder) with the nominal particle size of 0.15 and
0.3mm was used. sand, lime stone powder, cement, and fly ash
were mixed first for 1 min, and then Superplasticizer that was
mixed in water was added (due to high value of water
observation. several attempts were made to find out the way of
adding SP and water content of the mixture, and finally it was
found that the SP mixed in total water is a good solution when
sieve size
20
10
4.75
% passing
20mm
91.84
2.62
0
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30
20
10
0
0
0.2
0.4
0.6
0.8
% sp/c
1.2
1.4
Time in sec
30
Glenium
20
auramax
rheobuild
10
conplast
0
0
0.25
0.5
0.75
1.25
% sp/c
Fig.2 Marsh Cone Test for different SPs
1.5
Spread in cm
W/c
Sp/C
N1 sand N2 sand M sand
0.4
1%
18
8
9
0.4 1.20%
19
8.8
10.1
0.4 1.40%
20.2
9.4
10.9
0.4 1.60%
21.4
10.1
12.6
0.4 1.80%
22.1
12.1
13.9
0.4
2%
23.5
14
15.2
Table 8: Results of Fresh properties of SCC
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Fig.5 V-funnel
N1- sand
N2-sand
M-sand
V-funnel test
circle.
T
500mm
and 3.96kg of granite) was used to produce the selfcompacting concrete. For mortar, total of 144 cubes were cast
comprising of control of cubes and cubes containing 0.6%
to2% SP by weight of cement. This was batched by weight.
After the mixing of the batched material, water was added and
mixed thoroughly with shovel to achieve a homogenous mix
and then the cubes were moulded (figure 9) and cured in a
curing tank for the durations as shown in Table 1.
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PCE
SNF
80
compressive
strength N/mm
compressive
strength N/mm
60
40
20
0
3
7
Curing Days
80
60
40
20
0
28
3
7
Curing Days
28
Figure 8: Compressive strength V/s curing days for mortar mix of 1:1.5 cement sand ratio
SNF
compressive strength
N/mm
compressive strength
N/mm
60
40
20
0
3 Curing Days
7
PCE
60
40
20
0
28
7
Curing Days
28
Figure 9: Compressive strength V/s curing days for mortar mix of 1:2 cement sand ratio
70
60
0% FA, Rb
50
35% FA, Rb
40
50% FA, Rb
30
20
0% FA, Au
10
35% FA, Au
50% FA, Au
3
28
Curing Days
Figure 10: comparison of compressive strength of concrete Vs curing days
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CONCLUSIONS
AND CONCRETE:
Tesnile strength
N/mm
Concrete
5
0% FA, Rb
35% FA, Rb
50% Fa, Rb
2
0% FA, Au
35% FA, Au
50% Fa, Au
% Variation of Fly ash
6. MIX-DESIGN
The Japanese concept for design of SCC is based on a method
proposed by Okamura and Ozawa [2] . The authors have
proposed a simple mix-proportioning system assuming general
supply from ready-mixed concrete plants. The coarse and fine
aggregate contents are fixed so that selfcompactability can be
achieved easily by adjusting the water to powder volume ratio
and superplasticizer dosage only. The mixed design as
proposed is:
Coarse aggregate content is fixed at 50% of the solid
volume;
Fine aggregate content is fixed at 40% of the mortar volume;
Water-powder ratio in volume is assumed as 0.9 to 1.0
depending on the properties of the powder; and
Superplasticizer dosage and the final water-powder ratio are
determined so as to ensure the self-compactability.
The value of water to powder volume ratio (Vw/Vp) is
optimized by mortar flow test and Mortar Funnel Test.
Takada [3] considered the slump flow value of 65030 mm
and the V-funnel time of 112 s as adequate value for the
workable SCC.
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REFERENCES
[1]
[2]
[3]
[4]
[5]
[6]
CODE REFERENCE
[1]
[2]
[3]
[4]
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