Abstract:The effects of coarse aggregate content, interfacial zone and porosity on the chloride ion permeability of concrete were studied from a microscopic perspective by a combination of experimental research and numerical simulation. Firstly, the RCM chloride ion diffusion coefficient rapid determination test and mercury intrusion test were carried out, and the relationship between different coarse aggregate content, water-binder ratio, porosity and chlorine diffusion coefficient was analyzed. Then, the concrete meso-random aggregate model was established by programming. Furthermore, the numerical simulation of the diffusion performance of chloride ions was carried out, and the effects of coarse aggregate content and interface parameters on the permeation and diffusion of chloride ions were analyzed. The results show that the numerical simulation agreed well with the experimental results, and the validity of the meso-scale numerical model is verified. The chloride ion diffusion coefficient decreases with the increase of coarse aggregate content. The concrete porosity increased with the increase of water-to-binder ratio, and then increase the permeability of concrete. The permeability of concrete increased with the thickness of the interface zone and the diffusion coefficient of the interface zone.