Passive layer degradation of reinforced concrete steels in the marine environment: Thermochemical model

Abstract

This paper is interested in the modeling of the process of depassivation of reinforcement of a saturated concrete exposed to seawater. In particular, it attempts to describe the degradation of the passive layer of reinforcement and the conditions under which it provides more protection. In order to achieve this, a model coupling multi-species transport and Thermochemical is set up. The model takes into account the chemical imbalance involved in the diffusion transport of ions contained in seawater as well as the chemical reactions occurring and its consequences in terms of dissolution at the passive layer. It allows to study the thermodynamic equilibrium of iron oxide in a concrete polluted by sea water and to quantify the duration beyond which the initiation of the corrosion can begin according to the nature of the constituents of the passive layer. It shows, in addition, the kinetics of degradation of the passive layer.