Study of Temporal Change in Chloride Diffusion Coefficient of Concrete

The chloride diffusion coefficient (D-t) is an important parameter that measures chloride penetration of concrete and characterizes the chloride diffusion rate in concrete. A larger value of D-t indicates that chloride can more easily penetrate concrete. In this paper, chloride concentration data collected from 2207 marine exposure stations and practical projects in 20 countries were investigated. The D-t values were recalculated according to different chloride diffusion models. For the ordinary concrete and high-performance concrete data, the exposure times ranged film 7 days to 91 years. The temporal change in D-t was systematically studied and a universal time-dependent index (m) value was proposed. In addition, other targeted values were proposed for different types of concrete or exposure zones.