Ingress of chloride ions with carbonation: parameter estimation and analytical simplification

Abstract

Presented is a series of estimating methods for the parameters in a comprehensive combined model which is developed recently. The calculation of numerous intermediate-process parameters is optimised or combined to simplify the expression. The effect of carbonation on the change of apparent diffusion coefficient of chloride is expressed by three polynomial functions. Furthermore, a new simplified analytical method is proposed for the approximate study of this combined action. With the assumption of linear diffusion, the analytical results for the carbonation depth and concentration of free chloride ions can be obtained from a function of exposure time and mix proportions of concretes; the coupling effect is included by introducing an empirical factor. Several sets of experimental data are used for the verification of our equations.