Influence of diffusion coefficient on chloride ion penetration of concrete structure

This paper proposes a modified diffusion coefficient that considers the effect of chloride binding and evaporable water on the diffusion coefficient. A finite element method (FEM) program based on the modified diffusion coefficient estimates chloride concentration according to concrete depth, and external and internal conditions. The predicted chloride concentrations were compared with experimental values.The modified diffusion coefficient, which is a function of chloride binding, evaporable water content and diffusion coefficient, varies greatly according to the water–cement ratio. Also, C3A content, which has an influence on the chloride binding content, changes the modified diffusion coefficient. The FEM program using the modified diffusion coefficient estimates experimental chloride concentrations within a good accuracy. The numerical analysis of the internal and external conditions shows that the most effective way to reduce chloride ion penetration is to decrease water–cement ratio.