Modelling capillary effects on the reactive transport of chloride ions in cementitious materials

The transport of chloride ions in concrete structures is not only due to diffusion but also to the advective effects of water movements and capillarity, mostly present with wet-dry cycles. These last two phenomena are currently very poorly modelled. A new system based on optical fibres was previously developed to measure the free chloride concentration in the pore solution without damaging the material. This work aims at developing a numerical model simulating the reactive transport of chloride ions by capillarity in a cementitious material, which considers the diffusion of chloride ions and water transport by capillarity, as well as the chloride adsorption by the material with chemical interaction. It led to the analysis of the main phenomena occurring during a capillarity test. In a larger perspective, this study improves the current understanding of the durability of concrete structures exposed to severe environmental conditions.