Abstract: Chloride diffusion coefficient in concrete is an important parameter for the durability of marine concrete structures,which characterizes the velocity of chloride penetrating into concrete.Based on the evolution of capillary in concrete during the long term service and electrochemical theory,a modified equation is derived in this paper to analyze the chloride diffusion in the real solution.Theoretical results show that the chloride diffusion coefficient of concrete increases with the depth.In addition,the c...