This paper presents a mesoscale numerical approach to investigate the chloride diffusivity in cracked concrete. Concrete is treated as a five-phase material, including cement paste, aggregate, interfacial transition zone (ITZ), crack, and damaged zone (DZ), for its heterogeneity. In the mesoscale model, the randomly distributed aggregates were treated as impermeable, whereas all other phases are assumed permeable but with different diffusion coefficients. It is assumed that the crack is located in the middle of the DZ, and there is a liner rela...