FACTOR ANALYSIS OF MATERIALS AND MARINE ENVIRONMENT ON CHLORIDE ION DIFFUSION PREDICTION BY FICK’S SECOND LAW

Abstract

 The chloride ion diffusion in marine concrete structures is predicted by using Fick’s second low with two parameters, the surface chloride ion concentration C₀ and the apparent diffusion coefficient D_ap, which are obtained from the measured chloride ion concentration distribution. This study investigated the influence of materials and environmental conditions on the prediction accuracy of this conventional method, and conducted factor analysis by numerical simulation. The result showed that D_ap varies with the time series behavior of C₀, and it affects the prediction accuracy of the method. In particular, in the case where C₀ gradually increases, it was found that the prediction may be underestimated. Furthermore, prediction method using the diffusion coefficient with considering the time-series behavior of C₀ was proposed and it could solve the underestimation by the conventional method.