Civil Engineering Reference
In-Depth Information
4.7.3.4 Resistance to Chemical Attack
Topcu and Demir (
2007
) reported that the effect on the decrease of compressive
strength of mortars with various amounts of rubber aggregates replacing natural
sand was stronger in sea-water curing than in normal curing. The authors therefore
recommended using sulphate resistant cement or high-strength cement in rub-
berized mortars to be used in sea-water environments.
4.7.3.5 Freeze-Thaw Resistance
Topcu and Demir (
2007
) also reported the effect of freeze-thaw cycles on the
performance of rubberized concrete. In this study, concrete specimens had a
cement content of 300 kg/m
3
, a w/c ratio of 0.5, and 0, 10, 20 and 30 %
replacement of fine aggregates by equal volume of rubber aggregates with size
1-4 mm. The results revealed that the concrete's compressive strength decreased
with the increment of rubber incorporation after the freeze-thaw test. However,
this reduction was slightly lower than the one observed for a similar concrete due
to increasing addition of rubber aggregates before the freeze-thaw test. These
reductions for all cylindrical specimens with 10, 20 and 30 % rubber incorporation
compared to cylindrical control specimens not exposed to freeze-thaw cycles
were, respectively, 16, 19 and 21 %. The reductions in cylindrical specimens with
10, 20 and 30 % rubber incorporation compared to control specimens, both
exposed to freeze-thaw cycles, were respectively 15, 16 and 16. A similar
behaviour was observed for cubic specimens. The authors also evaluated the
freeze-thaw durability according to weight loss where they found that concrete
prepared with 10 % replacement of fine aggregates by rubber aggregates exhibited
better performance than conventional concrete.
4.7.3.6 High Temperature Behaviour
Topcu and Demir (
2007
) reported that rubber incorporation in cement mortar did
not have significant effect on the compressive strength reduction due to increase in
temperature. The highest decrease was observed for rubberized mortar after
treatment at 400 C. Nayaf et al. (
2010
) reported that the addition of 5 % mi-
crosilica to cement and the use of fine rubber aggregates with a maximum size of
0.07 mm could improve the rubberized concrete's compressive strength behaviour
at high temperature. On the other hand, microsilica does not have any effect on
concrete with coarse rubber aggregates with maximum size of 20 mm. Both
aggregate sizes were used to replace coarse NA by 5-30 % in volume. Their
results are presented in Fig.
4.59
.
