Meso-level numerical simulation on two-dimensional chloride diffusion in recycled aggregate concrete

Abstract:

According to the chloride diffusivity and geometric parameter of the five-phase recycled aggregate concrete (RAC), the chloride diffusion characteristics in modeled RAC is numerically simulated. The effect of relevant parameters, i.e., the replacement ratio of recycled coarse aggregate, the diffusivity of new and old hardened cement mortar and the interfacial transition zones, as well as the thickness of old hardened cement mortar on the diffusion properties of RAC is analyzed comparatively. The results obtained from the numerical simulation indicate that the distribution of chloride concentration is non-uniform within the modeled RAC; and the chloride concentration in recycled aggregate concrete declines wavelike along the diffusion depth. Furthermore, the influence of recycled coarse aggregate replacement ratio, cement mortar, ITZ, etc., on the chloride concentration is distinctly increased with the increase of the depth, and more obvious at the ITZ.