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Internal Curing of Concrete Using Localy Available Material in Bangladesh
by
Different materials have been used for internal curing or self curing in the form of saturated
lightweight fine aggregates, superabsorbent polymers, or saturated wood fibers such as super
absorbent polymers (SAP), crushed return concrete aggregates, pre-wetted lightweight
aggregates (LWA), expanded shale, clays, and slates, recycled waste porous ceramic coarse
aggregate, wooden fiber etc. In Bangladesh, Many of these materials are either unavailable or
costly.
For performance ease and economy, the material that will be used as internal curing material
should have high absorption capacity so that it can provide required water for curing of
concrete, at the same time should be readily available and cheap. The major challenge
associated with internal curing in Bangladesh or other developing countries is to select a
lightweight aggregate, which is cheap and available, and to select the proper percent
replacement. Availability, lightweight and high water absorption capacity of Burnt Clay
Aggregate (Brick) was prime factors to select it as a lightweight aggregate.
In this research different percent replacement is taken and is varied with water cement ratio,
stress-strain, modulus of elasticity, and age with a view to get the optimum percent
replacement of lightweight aggregate.
Research shows that use of brick as lightweight aggregate in internal curing does not
significantly reduce strength and for 20 percent replacement by brick, strength reduction is
minimum.
The research finds out can take a major role in cost elimination in construction especially in
areas having water scarcity
Keywords: Internal Curing, Modulus of Elasticity, Strength, Clay Burnt Aggregate, Brick,
LWA
Introduction
Introductory Remarks
Lightweight aggregate batched at a high degree of absorbed water may be substituted for
normal weight aggregates to provide internal curing in concrete containing a high volume of
cementitious materials. High cementitious concretes are vulnerable to self-desiccation and
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early-age cracking, and benefit significantly from the slowly released internal moisture. Field
experience has shown that high strength concrete is not necessarily high performance concrete
and that high performance concrete need not necessarily be high strength. A frequent,
unintended consequence of high strength concrete is early-age cracking. Blending lightweight
aggregate containing absorbed water is significantly helpful for concretes made with a low ratio
of water-to-cementitious material or concretes containing high volumes of supplementary
cementitious materials that are sensitive to curing procedures. This process is often referred to
as water entrainment. Time dependent improvement in the quality of concrete containing pre
wet lightweight aggregate is greater than with normal weight aggregate. The reason is better
hydration of the cementitious materials provided by moisture available from the slowly released
reservoir of absorbed water within the pores of the lightweight aggregate. The fact that
absorbed moisture in the lightweight aggregate is available for internal curing has been known
for more than four decades. The first documentation of improved long term strength gains
made possible by the use of saturated normal weight aggregates, was reported in 1957 by Paul
Klieger, who, in addition, commented in detail on the role of absorbed water in lightweight
aggregates for extended internal curing. In his 1965 report, Concrete Strength Measurement
Cores vs. Cylinders, presented to the National Sand and Gravel Association and the National
Ready Mixed Concrete Association. Holm (1984) cited the improved integrity of the contact
zone between the lightweight aggregate and the matrix. The improved quality was attributed to
internal curing, and better cement hydration and pozzolanic activity at the interface, and
reduction in stress concentrations resulting from elastic compatibility of the concrete
constituents. The benefits of internal curing go far beyond any improvements in long-term
strength gain, which from some combinations of materials may be minimal or non-existent.
The principal contribution of internal curing results in the reduction of permeability that
develops from a significant extension in the time of curing. Powers showed that extending the
time of curing increased the volume of cementitious products formed which caused the
capillaries to become segmented and discontinuous. It appears that in 1991, Philleo was the first
to recognize the potential benefits to high performance normal weight concrete possible with
the addition of lightweight aggregate containing high volumes of absorbed moisture. Reduced
sensitivity to poor curing conditions in concretes containing an adequate volume of pre wet
lightweight aggregate has also been reported. Since 1995 a large number of papers addressing
the role of water entrainments influence on internal curing and autogenous shrinkage have been
published of which Bentz, et al (1998), is typical. The benefits of internal curing are
increasingly important when supplementary cementitious materials, (silica fume, fly ash,
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metokaolin, calcined shales, clays and slates, as well as the fines of lightweight aggregate) are
included in the mixture. It is well known that the pozzolanic reaction of finely divided alumina-
silicates with calcium hydroxide liberated as cement hydrates is contingent upon the availability
of moisture. Additionally, internal curing provided by absorbed water minimizes the plastic
(early) shrinkage due to rapid drying of concretes exposed to unfavorable drying conditions.
The following Eq. is used to determine the volume of water that must be supplied from the
lightweight fine aggregate to reach complete curing.
Vwat=
(1)
where Vwat(m3 water/m3 concrete or ft3 water/yd3 concrete) is the volume of water that is
consumed during the hydration process due to chemical shrinkage, C fis the cement content,
CS is the chemical shrinkage of the concrete that occurs during the hydration process (usually
about 0.06 lb H2O per lb of cement hydrated or kg of H2O per kg of cement hydrated), max
represents the maximum degree of hydration and can be estimated as (W/C)/0.40 for W/C ratios
below 0.40, When the W/C ratio is greater than 0.40, the maximum expected degree of
hydration can be estimated as one and is the density of water.
This thesis is aimed at the following objectives:
To find out the best percent replacement by lightweight aggregate of concrete with respectto stress-strain, modulus of elasticity.
To observe the effects of percent replacement for different parameter i.e. stress, strain,modulus of elasticity.
To discuss the suitability of internal curing based on the research.Research Significance
Internal curing has been discussed as an added advantage in concrete research. It has wider
prospect and it is possible to get benefit from the internal curing instead of traditional external
curing. Lightweight aggregate are normally used in concrete for the internal curing which are
available, cheap and easy to transport. It has a significant contribution in shrinkage reduction,
enhancing durability, higher performance, improving contact zone, greater utilization of
cement, greater curing predictability, not adversely affect finishability, not adversely affect
pumpability, sustainability, lower maintenance, and hence improving overall concrete
performance. It can aid the construction process economically resulting into effective resource
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utilization. Also considering environmental impact analysis this technique is found as a
desirable one. Additionally introduction of internal curing can open doors for recycling and use
of other potential materials. In this regards, internal curing is expected to be beneficial in many
aspects.
Experimental Work
This Thesis includes the evaluation of several mixes to determine the effectiveness of
lightweight aggregates as an internal curing agent. Free shrinkage specimens and strength
cylinders are evaluated to determine the effects of the lightweight aggregates. The mixes have
water/cement ratio of 0.4, 0.45, and 0.50 with 10%, 20% and 30% of coarse aggregate
replacement. 3-day, 7-day and 28-days of curing period are evaluated for the specimens. A
total of four programs are described. In each program keeping the W/C ratio same the different
percentage of replacement of coarse aggregate were used, and a total of thirty six cylinders to
cast. In each program for each type of replacement three specimens have been made to have
more accurately representative conclusion. The first three programs included only coarse
aggregate replace but the last one was only fine aggregate replacement for w/c ratio 0.45, just to
compare with the earlier ones. The testing machines are also calibrated to ensure their
standards. The humidity and temperatures of testing days had been recorded for more
understanding the testing conditions.
Sieve Analysis of Fine and Coarse Aggregate
The analysis is conducted to determine the grading of materials proposed for use as
aggregates or being used as aggregate. The term fineness modulus (FM) is a ready index of
coarseness or fineness of the material. It is an empirical factor obtained by adding the
cumulative percentages of aggregates retained on each of the standard sieves and dividing
this sum arbitrarily by 100. No. 100, No. 50, No.30, No.16, No.8, No.4, 3/8 in, in, 1.5 in
are the ASTM standard sieves. This test method conforms to the ASTM standard
requirements of specification C 136.
The lab experiments were conducted for two different types of aggregate. These aggregates
are Stone chips (C.A), Burnt Clay Aggregate (brick chips), Sand (F.A), Fine aggregate
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prepared from Burnt Clay Aggregate (brick chips) aggregate. Test results are shown in Figure
1 to Figure 4.
Figure 1: Grain size distribution of coarse aggregate (Stone Chips)
Figure 2: Grain size distribution of coarse aggregate (Burnt Clay Aggregate)
0
20
40
60
80
100
1 10 100
PercentFiner%
Particle Size (mm)
Stone chips as
coarseagggregate
0
20
40
60
80
100
1 10 100
PercentFiner%
Particle Size (mm)
Burnt Clay
Aggregate as
coarse aggregate
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Figure 3: Grain Size Distribution for Fine Aggregate (Sand)
Figure 4: Grain Size Distribution of Fine aggregate (Burnt Clay Aggregate)
Specific Gravity and Absorption Capacity of Fine and Coarse aggregate
Aggregate generally contain pore, both permeable and impermeable, for which specific
gravity has to be carefully determined. With the specific gravity of each constituent known,
its weight can be converted into solid volume and hence a theoretical yield of concrete per
unit volume can be calculated. This test was conducted for determining the bulk and apparent
specific gravity and absorption of fine aggregate.
0
20
40
60
80
100
0.01 0.1 1 10
PercentFine
r%
Particle Size (mm)
Sand as fineaggregate
0
20
40
60
80
100
0.01 0.1 1 10 100
Percen
tFiner%
Particle Size (mm)
Burnt Clay Aggregate as
fine aggregate
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Bulk specific gravity is defined as the ratio of weight of aggregate (oven-dry or saturated
surface dry) to weight of water occupying a volume equal to that of solid including
permeable pores. This is used for
- Calculation of volume occupied by the aggregate in various admixtures containingaggregate on an absolute basis.
- The computation of void in aggregate.- The determination of moisture in aggregate.
Apparent specific gravity is the ratio of the weight of the aggregate dried in an oven at 100 to
C for 24 hrs. To the weight of water occupying a volume equal to that of solid excluding
permeable pores. This pertain to the relative density of the solid material making up the
constituent particles not including the pore space within the particles that is accessible to
water.
Absorption volume is used to calculate the change in the weight of an aggregate due to water
absorption in the pore spaces within the constituent particles, compared to the dry condition.
For an aggregate that has been in contact with water and that has free moisture on particle
surfaces, the percentage of free moisture can be determined by deducting the absorption from
the total moisture content. This test procedure conforms to the ASTM standard requirements
of specification C128. Test results are shown in Table 1.
Test Method: ASTM C128-88
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Table 1: Absorption capacity and Specific Gravity of aggregate
Material
Specific GravityAbsorption
CapacityBulkBulk
(SSD)
Appar
ent
Coarse
Aggregate
Stone 2.65 2.68 2.73 1.1Burnt
Clay
Aggrega
te
1.68 1.99 2.42 18.2
Fine
Aggregate
Sand 2.55 2.59 2.66 1.7
Burnt
Clay
Aggrega
te
1.6 1.95 2.49 22.3
Unit Weight of Fine and Coarse Aggregate
This test procedure covers the determination of unit weight in compacted or loose condition
of fine and coarse aggregates. Unit weight values of aggregates are necessary for use so many
methods of selecting proportions for concrete mixtures. They may also be used for
determining mass/volume relationship for conversions and calculating the percentages of
voids in aggregates. Voids within particles, either permeable or impermeable, are not
included in voids as determined by this test method. This test was conducted according to the
ASTM standard requirements of specification C29. Test results are shown in Table 2.
Table 2: Unit weight of aggregate
Material Type Unit Weight (gm/cm3)
Coarse Aggregate
Stone Chips 1.523
Burnt ClayAggregate
0.905
Fine Aggregate
Sand 1.531
Burnt Clay
Aggregate0.881
Parameters Considered
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Two parameters, water-cement ratio and percent replacement of lightweight aggregate were
considered for this experiment. For water cement ratio 0.40, 0.45, 0.50 three different percent
replacement of 10%, 20% and 30% were considered.
Test Procedure
Stone chips has used as course aggregate was brought to saturated surface dry (SSD)
condition. In the experiment it is done by wagging after pouring water on the coarse
aggregate. A same procedure was applied for the coarse aggregate. Wagging is needed to
make the aggregate homogeneously mixed. To avail internal curing, Burnt Clay aggregates
are used. 1st class bricks are used as a curing agent and coarse aggregate replacer. 3/8
downgraded coarse aggregate are used. Those crushed bricks are sunk under water with the
help of sacks (made of jute) for more than 24 hours to attain saturated condition. Thus, the
brick aggregate are allowed to fill its permeable pores filled completely by water.
Total sixteen mixes were designed for the experimental program. Four were normal mixes
and twelve mixes were to evaluate the effectiveness of using brick as lightweight aggregate
as internal curing agent. Twelve mixes have evaluated three different replacement levels,
10% replacement, 20% replacement and 30% replacement of lightweight aggregate for water
cement ratios 0.40, 0.45 and 0.50. Table 4 shows the concrete mixes of the experimental
program..
Table 4: Concrete mix
MixtureID
ReplacedAggregate
W/Cratio
PercentReplacement
A/CRatio
Water(kg/m3)
Cement(kg/m3)
CA(kg/m3)
FA,Sand
(kg/m3)
Stone(kg/m3)
Brick(kg/m3)
CA-1
CA
0.4
0% 3.34 252.3 628.6 1261.3 840.8 1261.3 0.0
CA-2 10% 3.34 252.3 628.6 1261.3 840.8 1135.1 126.1
CA-3 20% 3.34 252.3 628.6 1261.3 840.8 1009.0 252.3
CA-4 30% 3.34 252.3 628.6 1261.3 840.8 882.9 378.4
CA-5
0.45
0% 3.89 252.3 558.6 1301.3 872.9 1301.3 0.0
CA-6 10% 3.89 252.3 558.6 1301.3 872.9 1171.2 130.1
CA-7 20% 3.89 252.3 558.6 1301.3 872.9 1041.0 260.3
CA-8 30% 3.89 252.3 558.6 1301.3 872.9 910.9 390.4
CA-9
0.5
0% 4.45 252.3 502.5 1341.3 894.9 1341.3 0.0
CA-10 10% 4.45 252.3 502.5 1341.3 894.9 1207.2 134.1
CA-11 20% 4.45 252.3 502.5 1341.3 894.9 1073.1 268.3
CA-12 30% 4.45 252.3 502.5 1341.3 894.9 938.9 402.4
FA-1
FA 0.45
0% 3.89 252.3 558.6 1301.3 872.9 872.9 0.0
FA-2 10% 3.89 252.3 558.6 1301.3 872.9 785.6 87.3
FA-3 20% 3.89 252.3 558.6 1301.3 872.9 698.3 174.6
FA-4 30% 3.89 252.3 558.6 1301.3 872.9 611.0 261.9
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The summery of fresh concrete properties values are given in table 5.
Table 5: Summary of fresh concrete properties
Mixture ID Slump (mm) Unit Weight (kg/m3)
CA-1 114.3 2357.6
CA-2 65 2325
CA-3 55 2316.8
CA-4 78 2251.5
CA-5 190.5 2329
CA-6 205 2347.4
CA-7 215 2306.6
CA-8 220 2290.3CA-9 198 2306.6
CA-10 222.25 2314.8
CA-11 215.9 2308.6
CA-12 215.9 2306.6
FA-1 160 2445.4
FA-2 160 2376
FA-3 148 2337.2
FA-4 190 2335.2
The 0% (percent) replacement is kept under water for normal external curing. the other
%replacements are kept at almost constant humidity at normal temperature around 25 0c.
After 3, 7, 18 days, the cylinders are tested and Stress and corresponding strain are found
from it. Thus the experiment is ready for analysis
Specimen were made for the following tests.
Compressive strength development (ASTM C 39)
6 12 in normally cured cylinders without aggregate replacement . Three cylinderswere tested at 3 days, 7 days, 28 days. 6 12 in internally cured cylinders with aggregate replacement of 10%, 20%, 30%.Three cylinders were tested at 3 days, 7 days, 28 days
Modulus of Elasticity (ASTM C469)
6 12 in normally cured cylinders without aggregate replacement. Three cylinderswere tested 28 days.
6 12 in internally cured cylinders with aggregate replacement of 10%, 20%, 30%.Three cylinders were tested at 28 days.
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Result and Discussion
Required and Supplied Curing Water
Eq. 1 gives the amount of water required for complete curing. From the absorption capacity,
the amount of lightweight aggregate and the amount of water supplied by lightweight
aggregate is determined.
Table 6 shows that, curing agent (crushed brick) has the potential to provide concrete with
required curing water, which helps concrete to attain full due strength. Nevertheless, 10
percent replacement by lightweight aggregate (for both CA and FA) requires a huge amount
of water for complete curing. Due to this reason concrete cannot be cured properly. Thus,
cannot gain full strength. On the other hand, 30 percent replacement (for both CA and FA)
provides huge amount of excess water, which also prevents concrete from gaining due
strength.
water requred
for curing
internal curing is
working
wrto strength
wrto E
Reason to
choose CA Graph
& economy
% selection
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Table 6: Water requirement in curing according to Bentz and Snyder and the amount of water
supplied by lightweight aggregate
Replaced
Aggregate
W/CRatio
Percen
t
Replacemen
Brick
,
a(kg)
(kg
)
CS
Absorption
capacity
,b
Vwat
(fr
om
Eq2.9)
kg
supplied
throug
h
internal
curing
c
Extrawater
needed
(C-Vwat)
(kgperm
3)
CA
0.4
0% 0 628 0.07
18.2
44.0 0.0Normally
Cured
10% 126 628 0.07 44.0 22.9 -21.05D
20% 252 628 0.07 44.0 45.9 1.92
30% 378 628 0.07 44.0 68.8 24.87
0.45
0% 0 558 0.07 39.1 0.0 NormallyCured
10% 130 558 0.07 39.1 23.7 -15.42
20% 260 558 0.07 39.1 47.3 8.27
30% 390 558 0.07 39.1 71.0 31.95
0.5
0% 0 502 0.07 35.2 0.0Normally
Cured
10% 134 502 0.07 35.2 24.4 -10.79
20% 268 502 0.07 35.2 48.8 13.6330% 402 502 0.07 35.2 73.2 38.04
FA 0.45
0% 0 558 0.07
22.3
39.1 0.0Normally
Cured
10% 87.2 558 0.07 39.1 15.9 -19.63
20%174.
4558 0.07 39.1 31.7 -0.16
30%261.
6558 0.07 39.1 47.6 19.30
DNegative value indicates additional requirement of water for complete curing.
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Effect on Physical Properties
Effect of percent replacement of coarse aggregate as well as fine aggregate on internal curing
concrete has been observed from two points of views.
a) compressive strength and
b) modulus of elasticity.
4.3.1 Effect on Compressive Strength:
Figure 4.1 to figure 4.3 represent the variation of compressive strength for a particular W/C
ratio for different coarse aggregate replacement percent. Strength decreases with the increase
of replacement percent for internal curing concrete. For a particular W/C ratio with zeropercent replacement of coarse aggregate, normally cured concrete shows the higher strength
than internal curing concrete with higher replacement of coarse aggregate.
Figure 4.1: Figure: Strength Vs. Age for W/C ratio 0.40 (CA replacement)
0
1000
2000
3000
4000
5000
6000
0 5 10 15 20 25 30
Strength(psi)
Age (Day)
CA-1
CA-2
CA-3
CA-4
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Figure 4.2: Strength Vs. Age for W/C ratio 0.45 (CA replacement)
Figure 4.3: Strength Vs. Age for W/C ratio 0.50 (CA replacement)
0
500
1000
1500
2000
2500
3000
3500
4000
0 5 10 15 20 25 30
Strength(psi)
Age (Day)
CA-5
CA-6
CA-7
CA-8
0
500
1000
1500
2000
2500
3000
3500
0 5 10 15 20 25 30
Strength(psi)
Age (Day)
CA-9
CA-10
CA-11
CA-12
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Figure 4.4: Strength Vs. Age for W/C ratio 0.45 (FA replacement)
4.3.2 Effect on Modulus of Elasticity:
Figure 4.4 represents that modulus of elasticity varies linearly with percent replacement of
aggregate for a particular W/C ratio. Modulus of elasticity is higher in low percent
replacement on a certain W/C ratio. Comparing to the percent replacement of Coarse and
Fine aggregate keeping the W/C ratio same (0.45), Fine aggregate replaced concrete shows
higher Modulus of elasticity than the coarse aggregate replaced concrete. Modulus of
elasticity of different concrete mix for different aggregate replacement percentage is in
Appendix B.
0
500
1000
1500
2000
2500
3000
3500
0 5 10 15 20 25 30
Strength(psi)
Age (Day)
FA-1
FA-2
FA-3
FA-4
0
500
1000
1500
2000
2500
3000
3500
4000
0% 5% 10% 15% 20% 25% 30% 35%
ModulusofElasticity(ksi)
Replacement of CA, %
WC Ratio 0.4
WC Ratio 0.45
WC Ratio 0.5
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Figure 4.4: Modulus of elasticity Vs Replacement
Figure 4.5 represents that, variation of modulus of elasticity with strength of concrete with
aggregate having different percent of aggregate replacement. As replacement percentage
increases, strength of the concrete reduces as well as the modulus of elasticity. Brick chips
have lower strength than stone chips.
Figure 4.5: Modulus of elasticity Vs Strength
Reason to choose CA over FA
0
500
1000
1500
2000
2500
3000
3500
4000
0 5 10 15 20 25 30
Strength(psi)
Age (Day)
CA-5
FA-1
0
500
1000
1500
2000
2500
3000
3500
0 5 10 15 20 25 30
Strength(psi)
Age (Day)
CA-6
FA-2
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strength reduction percentage is minimum at twenty percent coarse aggregate replacement.
Specific percent replacement can be obtained from Fig. 4.7 for different W/C ratio.
Figure 4.6: Strength Vs Percent Replacement
Table 4.2: Percent strength reduction
%
Repacement
w
eihtbasis
CA FA
W/C
ratio 0.4
W/C
ratio
0.45
W/C
ratio 0.5
W/C
ratio 0.5
Strength
(psi)
Strength
reduc
tio
Strength
(psi)
trengt
reduc
tio
Strength
(psi)
Strength
reduc
tio
Strength
(psi)
Strength
reduc
tio
047
62
31
56
24
22
22
81
1
0
47
540.2
29
18
7.
5
18
03
25.
6
20
14
11.
7
2
0
48
88
-
2.6
29
85
5.
4
24
030.8
23
30
-
15.
7
3
0
43
50 8.7
29
45
6.
7
20
48
15.
4
21
03 9.7
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
18.0
0 5 10 15 20 25 30 35
StrengthReduction,
%
Burnt Clay Aggregate (CA), %
WC Ratio 0.4
WC Ratio 0.45
Wc Ratio 0.5
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Figure 4.7: Strength Reduction Vs. Percent Replacement (FA) for different W/C ratio
It will be recalled that, at a given degree of hydration, the w/c ratio determines the porosity of
the cement paste. Thus, the relation of equation accounts for the influence of the total volume
of voids on strength, i.e. gel pores, capillary pores and entrapped air. With an increase in age,
the degree of hydration generally increases so that strength increases. It should be
emphasized that strength depends on the effective w/c ratio, which is calculated on the basis
of the mix water less the water absorbed by the aggregate; in other words, the aggregate is
assumed to use up some water so as to reach a saturated and surface-dry condition at the
time of mixing.
4.3 Effect of water cement ratio
Effect of water cement ratio on internal curing concrete has been observed on two points of
view. Water cement ratio has an emerging effect on concrete compressive strength and
modulus of elasticity. Workability of concrete greatly depends upon water cement ratio as
seen in normal concrete. Higher the water cement ratio so the workability increases and vice-
versa. Effect of water cent ratio on concrete compressive strength and its modulus of
elasticity is discussed below.
4.3.1 Effect on Strength
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Figure 4.1 to Figure 4.3 represent the variation of compressive strength for a particular coarse
aggregate replacement percent for different W/C ratio at different age. Strength decreases
with the increase of water cement ratio for internal curing concrete. For a particular w/c ratio
with zero percent replacement of coarse aggregate, normally cured concrete shows the higher
strength than internal curing concrete with higher replacement of coarse aggregate. Maximum
strength is found for w/c ratio 0.40 both for normal curing and internal curing concrete.
Figure 4.3:Strength vs. w/c for 3days
500
1000
1500
2000
2500
0.35 0.4 0.45 0.5 0.55
Strength,(psi)
WC Ratio
CA 0% Replaced
CA 10% Replaced
CA 20% Replaced
CA 30% Replaced
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Figure 4.2:Strength vs. w/c ratio for 7 days
Figure 4.1: Strength vs. w/c ratio for 28 days
4.3.2 Effect on Modulus of Elasticity
1500
2000
2500
3000
3500
4000
0.35 0.4 0.45 0.5 0.55
Strength,(psi)
WC Ratio
CA 0% Replaced
CA 10% Replaced
CA 20% Replaced
CA 30% Replaced
2000
2500
3000
3500
4000
4500
5000
0.35 0.4 0.45 0.5 0.55
Strength,(psi)
WC Ratio
CA 0% Replaced
CA 10% Replaced
CA 20% Replaced
CA 30% Replaced
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