Page 116 - New Trends in Eco efficient and Recycled Concrete

90 New Trends in Eco-efficient and Recycled Concrete

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Uyguno˘ glu and Topcu (2010) partially replaced natural sand (size 0 4 mm)
with scrap tyre rubber (size 1 4 mm) in self-consolidating mortar mixes at up to
50%, by weight, at various water/binder ratios. They reported that the workability
of the mixes decreased by using rubber particles at both low and high volumes. The
workability of the rubberised mix dramatically decreased by 50% replacement of
sand with rubber particles.

4.3.1.2 Concrete with waste rubber aggregates
Crumb rubber may be used to replace a weight fraction of sand in the manufactur-
ing of concrete products. Khatib and Bayomy (1999) studied the workability of con-
crete mixes where natural sand was replaced with crumb rubber at 5% 100%, by
volume. Results showed that the workability decreased with increasing rubber sand
content.
Albano et al. (2005) partially replaced natural sand in concrete mixes with
recycled rubber from automobile tyres at 0%, 5% and 10%, by weight. The work-
ability decreased with increasing rubber sand content. The reduction in the slump
value was about 90%. They also reported that no segregation was observed in rub-
berised mixes.
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Topcu and Demir (2007) studied the workability of concrete mixes containing
rubber (1 4 mm particle size) at 0%, 10%, 20% and 30% sand replacement, by
volume. Results showed a reduction in the workability with increasing waste rubber
content.
The workability of concrete mixes containing crumb rubber was studied by
Batayneh et al. (2008) by replacing natural sand (size 0.15 4.75 mm) with crumb
rubber (size 0.15 4.75 mm) at 0%, 20%, 40%, 60%, 80% and 100%, by volume. A
reduction in the workability was observed when rubber sand content increased.
The reduction in the slump value was about 19%, 52%, 76%, 86% and 93% with
the addition of 20%, 40%, 60%, 80% and 100% of rubber sand, respectively.
Taha et al. (2008) replaced natural sand in concrete mixes with crumb rubber
(size 1 5 mm) up to 100%, by volume, maintaining a constant w/c ratio. Results
showed a reduction in the workability with the addition of rubber sand. The reduc-
tion in the slump value was approximately 13%, 40%, 66% and 80% with the
addition of 25%, 50%, 75% and 100% of rubber sand, respectively.
Raj et al. (2011) and Ganesan et al. (2013a,b) replaced natural sand with waste
rubber (maximum size 4.75 mm) in self compacting concrete (SCC) mixes up to
20%, by volume. They reported a reduction in the workability with increasing rub-
ber content. The average reduction in the flow value was up to 8% with the addition
of 20% waste rubber. The flow value decreased with increasing rubber content,
while the V-funnel time and L-box increased with increasing waste rubber amount.
The replacement of natural sand in SCC mixes with crumb rubber (size
0.15 4.75 mm) at 0%, 10%, 20% and 30%, by volume, was studied by Karahan
et al. (2012). Water to binder (W/b) ratio was kept constant at 0.32 and various con-
tents of high range water reducer were used. SCC mixes with the addition of rubber
sand exhibited a reduction in the filling and passing abilities. A reduction in the