Civil Engineering Reference
In-Depth Information
two different sizes of crumb rubber (0.6 and 1 mm), reporting an increase in
ductility performance of up to 90%. Those authors mentioned that crumb rubber
concrete columns can undergo twice the lateral deformation before failure
compared to the reference concrete columns. Mohammed (2010) confirmed
that concrete slabs containing crumb rubber with a finesses modulus of 2.36
shows a higher ductility behaviour which fulfils the ductility requirements
of en1994 - eurocode 4 (1994).
Thermal and sound properties
The replacement of fine aggregates by crumb rubber lowers the thermal
conductivity of concrete (Sukontasukkul, 2009). The replacement of up to
30% reduces the thermal conductivity by more than 50% to a minimum
of 0.241 W/mK. crumb rubber concrete also show high noise reduction
behaviour for high-frequency ranges (higher than 1000 hz) when compared
to the reference concrete. crumb rubber concrete shows a noise reduction
coefficient 36% higher. This reveals an ideal application for noise reduction
barriers. however, further investigations are still needed regarding the
aggregate characteristics and concrete mixes which could enhance soundproof
performance and at the same time can keep a minimum compressive strength
and durability.
Durability
Since rubber waste concrete has lower compressive strength and lower tensile
strength than reference concrete it is expected that its behaviour under fast
mechanical degradation actions would also be lower. Sukontasukkul and
chaikaew (2006) mentioned that crumb concrete blocks show less abrasion
resistance and also that increasing the crumb rubber content leads to a
reduction in the abrasion resistance. This result was confirmed by Ling et
al. (2009). Freitas et al. (2009) studied the abrasion resistance by immersion
of rubber waste concrete, reporting a lower degradation than the reference
concrete when only 5% rubber per mass was used to replace the coarse
aggregate. This result is quite interesting since the rubber addition leads to
a 30% compressive strength decrease. however, since the tensile strength
(Brazilian test) has been reduced by only 11% this helps to understand the
high abrasion resistance. The authors used this mixture in the rehabilitation
of a hydroelectric power plant.
Topçu and Demir (2007) mentioned that a high volume replacement of
sand by rubber waste (1-4 mm) has lower durability performance assessed
by freeze-thaw exposure, seawater immersion and high temperature cycles.
according to them, the use of a 10% replacement is feasible for regions
without harsh environmental conditions. The fact that these authors used
