Relationships between recycled concrete aggregates characteristics and recycled aggregates concretes properties

This research aims to analyze the quality and suitability of recycled concrete aggregates (RCA) produced by crushing concrete blocks provided from building demolition waste by comparison to natural ones in providing concretes for building structures. For each granular type, sieving, water absorption, porosity, Los Angeles and Micro-Deval tests were conducted before and after their exposure to freezing/thawing. Results show that the rules of mixtures (Voigt's model) can be used to predict all the studied properties of granular mixes (natural gravels + recycled gravels) except for the prediction of Micro-Deval index. Relationships are established between physical and mechanical characteristics of aggregates. The analysis of the frost resistance performance show that recycled concrete gravels are less resistant to freeze/thaw than natural one but their degradation, estimated through water absorption, porosity and Micro-Deval index, is not significant. Furthermore, the influence of RCA on mechanical properties of recycled aggregates concretes (RAC) is investigated. It appears that porosity and young's modulus of RAC are significantly affected by the porosity of the granular mixture and consequently of RCA. The compressive strength of RAC is dependent on the Los Angeles coefficient of gravels while tensile splitting strength depends on the porosity of concretes related to that of the granular mixture.