Three-phase modelling of electrochemical chloride removal from corroded steel-reinforced concrete

摘要

Electrochemical chloride removal (ECR) is an efficient and curative way for treating reinforced concrete structures about to suffer or already suffering from chloride attack. In order to provide a deep understanding of the mechanisms of ECR, this paper presents a mesoscale numerical model, which considers the multi-species coupling in pore solution, electrochemical reactions taking place at electrodes, multi-species binding between solid and liquid phases, as well as the effect of applied current density and treatment time on the efficiency of chloride removal. The concrete presented in this model is treated as a heterogeneous composite material with three constituent parts, including not only mortar but also volume-controllable aggregates and interfacial transition zones; each as one phase. Through a further study on the different configurations of multiple reinforcing bars as cathodes, a quantitative discussion regarding the economic issue of different cathode configurations is highlighted. In addition, the present three-phase model reveals some important features of aggregate effects which could not be discovered from previous one-phase models.