Properties in fresh state of mortars with recycled aggregate concrete and effect of c/a relation

Abstract

Construction and Demolition Residues have become a complex-to-manage

and expensive urban problem, so currently an environmental legislation is

innovated in order to promote activities to mitigate it being the recycling

one of the more accurate (it empowers the reintegration as second generation

material for new use in construction). Considering the previous

comments, some studies with mortars have been developed, where the

natural aggregates are replaced by different percentages of residues,

since there are not legislation or regulation that propose them. However,

there are few investigations about the behavior of these concretes in fresh

state, linked them with theirs properties in the posteriori hardened state.

In this investigation, tests of properties in fresh condition (consistency,

density and content of air) of mortars containing different percentages

of recycled concrete aggregates as substitution of natural aggregates (10,

20, 30, 50 and 100%) and with different cement/sand rates (1:3.25, 1:4

and 1:4.74), have been realized. The results obtained show that mortars

with recycled aggregates present a lower density, need more quantity of

water to achieve the required consistency, and have higher air content

than the reference mortars.