Figure 2 Compressive strength test result of SCC with different percent Fly Ash
The compressive strength test is affected by percentage of fly ash. From the Figure 2 it is clear that there are differences on compressive strength test among all self-compacting concrete
mixtures. As shown in figure 2 self-compacting concrete 0 Fly Ash has the highest compressive strength value followed by SCC modified with 15, 35. Similarly Ganeshwaran et al. 2012
reported that compressive strength decreased with the increase in replacement of cement by fly ash.
Fly ash as filler can fill cavities in the concrete so that the concrete mix to more solid and strong, but the greater the level of fly ash will lower the value of the slump. This happens because
the fly ash absorb more water when compared with cement, so that the mixture becomes drier which subsequently affect slump concrete value becomes lower with increasing levels of fly ash
used Pujianto, A., 2010. The greater the levels of fly ash, the water content needed is also increasing, so this affects the value of FAS which resulted in concrete compressive strength
decreased while passing through the fly ash content of 15. Ankush 2014 investigate the effect of fly ash replacing cement on compressive strength
and concluded that an increase fly ash from 10 to 50 decreased compressive strength value from 53.17MPa to 39.25 MPa for 28 days of curing time. Mohamed 2011 reported that higher
amount of fly ash had higher values of compressive strength until 30 of fly ash. However, after the optimum amount of Fly Ash, the increase in Fly Ash decreased the compressive strength of
self-compacting concrete. The reason why there is difference in optimum percentage of Fly Ash from the current research is that due to mix design variation in which the amount of cement used
in research by Mohamed 2011 is 550 kgm
3
with WC of 0.42 whereas in this research it is 440 kgm
3
with wc of 0.47.
30,62 29,37
23,06
5 10
15 20
25 30
35
15 35
M axi
m u
m Load
M Pa
Flay Ash Replacement
3. Modulus of Elasticity
The modulus of elasticity MOE Young’s modulus E is a material property, that describes its stiffness. Mechanical deformation puts energy into a material. The energy is stored
elastically or dissipated plastically. To this study strength for modulus were determined at 28 day of specimens curing as per ASTM C 469. Three concrete cylinders were prepared with
dimensions of 150 mm x 300mm were molded and cured in accordance to standard description. The concrete were subjected to a slowly increasing longitudinal compressive stress and
readings were recorded and MOE were computed and beside it for comparison the modulus was also calculated using the formula
and all result shown in table 4. Table 4. Modulus of Elasticity MOE at 28 days as ASTM C 469
Fly Ash Modulus of
Elasticity MPa Decrease
MPa Decrease
26475 15
25960 1.945
2. 35
22955 13.295
The highest value of modulus of elasticity was found at 0 Fly ash modifier. Similarly Gencel et al. 2012 reported that self-compacting concrete with 0 Fly ash modifier had the
highest modulus of elasticity value of 36.9 GPa. Similarly, Turk and Karatas 2011 reported that modulus of elasticity of self- compacting concrete decreased with an increase in fly ash content
as replacement for cement.
Figure 3 Modulus of elasticity test result of SCC with different percent Fly Ash
4. Flexural Strength
Flexural test measures the force required to bend a beam under three point loading conditions, its data often used to select materials for parts that will support loads against bending
26475 25960
22955
21000 22000
23000 24000
25000 26000
27000
15 35
M o
d u
lu s
o f E
lasti ci
ty M
Pa
Flay Ash Replacement
load. Flexural modulus is used as an indication of a material’s stiffness. This test was done as specified by the ASTM D-790 and ASTM C 78 methods and procedures. The results are
presented in table 5. The dimension of the specimens was made in consideration of the size of coarse aggregate 19 mm 20 mm.
Table 5. Flexural Strength Kgcm2 or MPa at 28 days Fly Ash
Flexural Strength Kgcm2
Flexural Strength MPa
15 57.13
5.6 35
Figure 4. Flexural strength test result of SCC with different percent Fly Ash The Flexural strength value is affected by percentage of fly ash. From the Figure 4 it is
clear that there are differences on Flexural strength test among all self-compacting concrete mixtures. As shown in figure 4.10 self-compacting concrete 15 Fly Ash has the highest
Flexural strength value followed by SCC modified with 0, 35. In general the flexural strength observed to decrease as the amount of Fly Ash replacement was increased to 35. The optimum
value for flexural strength with Fly Ash replacement recorded at 15 as shown in figure 4.10. Vageesh and Reena 2014 reported the similar trend on flexural strength decrease as the Fly Ash
replacement increased to 30 as compared to 10 and 20 the optimum flexural strength was observed at 10 Fly Ash replacement at 28 days. In addition Gaywala and Raijiwala 2011
reported the same trend and similarly obtained maximum flexural strength at 15 Fly Ash replacement.
5,3 5,6
5,2
5 5,1
5,2 5,3
5,4 5,5
5,6 5,7
15 35
Fl e
cu ral
S tr
e n
g th
M Pa
Flay Ash Replacement
