Abstract
The aim of this paper is to propose a model for simulating the chloride ion movement at the surface layer of hardened concrete. The model is to be combined with the analytical method for movement of chloride ion in hardened concrete to construct a complete model which is applicable to different environmental condition. Regarding the chloride ion movement at the surface layer, two models are introduced. One is the surface condensation model, that explains the phenomenon of higher chloride ion concentration in the surface layer than that of the submerged environment, by the concept of quasi-adsorption. The other is the cyclic wetting and drying model that explains the mechanism of chloride ion migration into concrete by the concepts of capillary suction and evaporation.
