Abstract: The mechanism of chloride ion migrating from saline soil to concrete is simulated by Comsol Multiphysics. Based on Fick’s second law, the impact of electric field, binding and capillarity are analyzed. Binding impedes the chloride ion transport; whereas electric field and capillarity promotes the transport. With the increase of invasion depth, the function of binding decreases and electric field of initial stage first increases and then decreases. The effect of binding and electric field both decrease gradually over time. Capillary action is only obvious in the initial 1.5 hours of the invasion. The coupling model in consideration of diffusion, electric field transport, and binding action was established. The model was verified by experimental data.

Key words: concrete, Comsol Multiphysics, chloride ion, electric migration, binding, capillary action