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Research Article: Tawashi & AlAmoudi 66

affects one component or more of the three can explain the excess dose of the plasticizer
mentioned. Table 3. below shows the increase causes additional dispersion and scattering of
in the cylindrical compression strength the cement granules, due to the repulsion of
depending on the cement quantity, the the negative charges that enveloping them.
percentage of plasticizer, and W/C ratio. In the Thus, there was a lack of bonding of the cement
mixes with cement quantities 450 kg/m3, it is granules. Another reason that could occur was
noted that the compression strength takes the an increase in the additional air to the mixture.
same result with or without a plasticizer. This

Table 3. Compressive strength of SCC mixtures
Cement
Mixture quantity W/C Superplasticizer Compression Strength Strength Increase
(MPa)
(%)
Ratio (%)
3
(kg/m )
RS-550 550 0.448 - 33,572 -
SCC-HRW-550 550 0.39 2 37.616 12
RS-500 500 0.448 - 27.717 -
SCC-HRW-500 500 0.39 2.5 28.249 1.9
RS-450 450 0.448 - 24.680 -
SCC-HRW-450 450 0.39 2.5 24.890 0.01

Figure 5. shows the relation between the mathematical graphic curves are closest to our
strength and the plasticizer percentage used, experimental tests. It is clear from figure 6 that
according to the quantity of cement in the SCC the model known as the Rational Function gives
samples. the closest model with the best correlation
factor R closer to 1. Equation 8, the realistic

Strength MPa 40 33.572 x + 2.022 y = 40
35
30
27.717 x + 0.2128 y =
25 24.68 x + 0.084 y = 35 Strength(Mpa)
20 30
15 C550 25
C500
10 C450 20
Rational Function
5
15
MMF Model
0
0 0.5 1 1.5 2 2.5 3 Richards Model 10
Admixtures Ratio (%)
Lab Sample
5
Fig. 5. SCC Strength and Plasticizer Percentage Relation 0
425 475 525 575
Cement Grade
According to the previous data of the tests, and
by searching for the mathematical equation Fig. 6. The Closest Mathematical Curves
that is closest and most representative of the

relation between the strength of SCC and
behaviour of the SCC, and the most expressive
cement quantity and by using Curve Expert1.4
software program for processing curves, many of the relation between the cement quantity
and the strength of the self-compacting
mathematical curves were obtained. Figure 6.
concrete, on the axial compression for different
shows the closest curves to the study case with
correlation coefficient R. The below three plasticizer ratios. While the other curves show a

SJSI – 2023: VOLUME 1-1