CONICET | Buscador de Institutos y Recursos Humanos

This work presents a basic physical characterization of coarse and fine aggregates that take part in the preparation of concrete. Specifically, we deal with arids coming from a quarry next to the city of San Luis, in Argentine. We characterize the material taking into account its origin, i.e., if its grading curve is the result of natural degradation (natural aggregate) or it comes from a grinding process (crushed aggregates). Apparent and real densities, shape and compacity are some of the parameters measured as a function of size and origin. We discuss the differences found when the origin of the material is taken into account. Once the material is characterized, we prepare several mixtures using different ratios of natural and crushed aggregates to add to concrete. Six cores for each mixture ratio were prepared and uniaxial compression tests were performed over the cores. We obtain a non monotonic behavior of the material resistance as a function of the percentage of crushed aggregates present in concrete. We discuss and justify this behavior on the basis of the previous physical characterization of the aggregates.