Predictive model for chloride penetration through concrete

Abstract

This work documents a numerical model, the objective of which is to predict the chloride penetration through saturated concrete. The model solves the Nernst–Planck/current law equations and accounts for the chloride interactions with the solid phase. In addition to boundary conditions, it requires a set of five experimental characteristics available from a single sample of material namely: density; porosity; pore solution composition; effective chloride diffusion coefficient; and chloride binding isotherm. The input data do not evolve with time; the exceptions are the ionic diffusivities, which are time dependent. The method used to obtain the input data is outlined. Particular attention is paid to the metrology of the unsteady state migration test, which makes it possible for the chloride diffusion coefficient to be measured. The manner in which the chloride binding isotherm is reached is emphasised. Finally, the method is validated by comparing the numerical simulations with experimental results made on a CEM-I-based concrete.