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IBRACON Structures and Materials Journal • 2012 • vol. 5 • nº 4
Self-compacting concretes (SCC) – comparison of methods of dosage
4.2.3 Modulus of elasticity for the same compressive strength
range at 91 days
The performance analysis done in all methods, which relates the
modulus of elasticity for the same compressive strength range at
91 days is shown in Fig. 9.
According to the data presented in Fig. 9, it is observed that the
Repette-Melo method, 2005 [2], presented a larger modulus of
elasticity, for a strength of 48.8 MPa at 91 days, which is 7.6%
higher than what was obtained by Tutikian & Dal Molin, 2007 [3],
and 22.7% higher than what was found by Nan Su et al., 2001 [1].
The higher results achieved by Repette-Melo, 2005 [2], for this
property are probably due to the larger amount of coarse aggre-
gate obtained in the mixture composition and the smaller amount
of mortar promoted by the method of dosage.
When the amounts of mortar obtained by all methods are com-
pared, setting a compressive strength of 48.8 MPa at 28 days,
which was achieved by Nan Su et al., 2001 [1], it is possible to
demonstrate that the experiment conducted by the Repette-Melo
method, 2005 [2], the mixture presented an amount of mortar of
59.9%, while Tutikian & Dal Molin, 2007 [3], achieved 60.6% and
Nan Su et al., 2001 [1] presented 67.4%.
It should be noted that in the Repette-Melo method, 2005 [2], the
amount of coarse aggregate used was 50% in relation to the ag-
gregate total, in mass, compared to 48% used by Tutikian & Dal
Molin, 2007 [3], and 40% used by Nan Su et al., 2001 [1].
4.2.4 Propagation of velocity of the ultrasound wave for the
same compressive strength range at 91 days
The propagation velocity of the ultrasound wave measurements
were taken using the same samples from the modulus of elasticity
test, therefore the same compressive strength ranges for the com-
parison were defined, as well as the test age, at 91 days.
Fig. 10 shows the comparisons made for all methods of dosage,
relating the ultrasound wave velocity for the same strength range
at 91 days.
As can be seen in Fig. 10, the method which presented the best
results was Repette-Melo, 2005 [2]. It is important to highlight that
the difference between the results found by Repette-Melo, 2005 [2]
and those found by Tutikian & Dal Molin, 2007 [3], is small, namely
0.4%, while the results found by Nan Su et al., 2001 [1] were 8.3%
higher.
The difference between the values found by those two methods
to assess this property is too small, therefore it can be said that
Tutikian & Dal Molin, 2007 [3], and Repette-Melo method, 2005
[2], reached similar values for the propagation velocity of the ul-
trasound wave.
4.2.5 Chloride ions penetration for the same compressive
strength range at 91 days
Lastly, Fig. 11 shows the values obtained by all concretes regard-
ing chloride ion penetration.
Figure 9 – modulus of elasticity comparison
for the same range of compressive
strength of 91 days for all methods
Figure 10 – ultrasound wave speed
comparison for the same range of
compressive strength of 91 days for all methods
Figure 11 – chloride ions penetration comparison
for the same range of compressive
strength of 91 days for all methods