Civil Engineering Reference
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concretes have modules of deformation between a half and two-thirds of the
module of deformation of a similar strength conventional concrete.
It seems that the aggregate governs the behavior of concrete's module of
deformation. Thus, as recycled aggregate is more deformable than the natural
aggregate, the concrete produced with this aggregate is more deformable
than the concrete produced with natural aggregates.
14.4.6 Tensile strength
It seems that the replacement of natural aggregate by the recycled aggregate
also causes a reduction in the tensile strength, nevertheless, this appears to
be less intense than those that cause reductions in compressive strength.
Several authors (Dhir et al. 2004b; Ajdukiewicz and Kliszcczewicz, 2002;
Gómez-Soberón, 2002, 2003; Topçu and Sengel, 2004; Sagoe-Crentsil et
al., 2001; Evangelista and Brito, 2007; Fonseca et al., 2011; lovato et al.,
2012) state reductions in tensile strength from 6% to 30% for concrete made
with the recycled aggregate concrete.
According to Hansen (1986), the loss of tensile strength in concrete with
recycled aggregate concrete is less acute when only the coarse aggregates
are replaced. When both aggregates (coarse and fine) are replaced, usually
the loss is greater, up to 20%. Consistent with this, ravindrarajah and Tam
(1987a) observed a loss of 10% in the replacement of coarse aggregate, which
increased to 15% when both aggregates were replaced. However, lovato et
al. (2012) state that coarse aggregates have a greater negative influence on
this property.
The replacement of natural aggregates by the recycled red ceramic
aggregates also causes changes in the tensile strength in concrete. Brito et al.
(2005) state that replacing natural coarse aggregate by recycled red ceramic
coarse aggregate in contens of 33%, 66% and 100% achieves a reduction in
tensile strength of about 8.6%, 15.7% and 25.7%, respectively.
Therefore, it seems the reduction caused by the recycled aggregates on
tensile strength is not as strong as the reduction in compressive strength
(Brito and Alves, 2010). The tensile strength appears to take into account
the physical mechanisms of adhesion between particles. Once recycled
aggregates promote a good adhesion between the paste and the aggregate
due to its most irregular and rough form, the ITZ of recycled concrete is
very good (leite, 2001). Thus, based on the good performance of ITZ of
recycled concrete, the tensile strength of recycled concrete is not as affected
as the compressive strength.
14.4.7 Abrasion resistance
It seems that the abrasion resistance of recycled aggregate concrete is also
lower than that of conventional concrete although some authors (Evangelista
