Five-phase composite sphere model for chloride diffusivity prediction of recycled aggregate concrete

Abstract

A five-phase composite sphere model for the matrix in recycled aggregate concrete (RAC) is proposed and a closed-form solution for chloride diffusivity is calibrated with available experimental data. Based on a parametric study, it is found that the chloride diffusivity of RAC with Fuller gradation is always smaller than that with an equal volume fraction gradation. Furthermore, the chloride diffusivity of RAC decreases with an increase in minimum aggregate diameter whereas it increases with the old residual mortar content, recycled aggregate replacement rate and thickness of the old interfacial transition zone.