Towards the classification of recycled concrete aggregates: influence of fundamental aggregate properties on recycled concrete performance

This study provides an in-depth evaluation of how fundamental aggregate properties affect mechanical properties of structural concretes produced using 100% coarse Recycled concrete aggregate (RCA) and constant mixture proportions. The key findings presented within this study will assist in developing a framework for classifying RCA sources for use in specific concrete applications. Fourteen mixture proportions were developed using three RCA types with compressive strengths of 30, 40, 50, and 60 MPa. Contrary to other studies, one RCA concrete type had compressive strengths up to 22% greater than the natural aggregate concrete. These results were confirmed by repeated batching and measured to be statistically significant. An analysis of the failure modes of RCA concrete and linking particular aggregate properties to the observed concrete failure mode were used to explain the results. Based on measured correlations, the modulus of elasticity of RCA concrete can be estimated based on the compressive strength and aggregate unit weight.