Influence of the nature of fraction unbound natural aggregates on the durability of recycled aggregates stabilized with cement

Abstract

In the study of the application of recycled aggregates produced in Spain for its stabilization with cement and use in road pavement bases, it was observed that the mechanical and durability behaviour of the Mixed Recycled Concrete Aggregate (MRCA) is worst compared to the Mixed Recycled Masonry Aggregate (MRMA). In the production of the MRCA, the aggregate producers tried to improve its quality adding stones of diverse types coming from the construction and demolition waste. The effect of the sulfate attack on recycled aggregates is specifically studied. This study has revealed the responsibility of certain metamorphic rocks, such as shales, in the bad behaviour of the MRCA in sulfate environments. The behaviour gets even worse when the recycled aggregate of concrete is contaminated by construction gypsum. The conclusion is that the characterization of the nature of the fraction unbound natural aggregates (Ru) must be included in the quality assessment of recycled aggregates in relation of his influence in durability of the application.