Electrochemical chloride removal from reinforced concrete

Studies were carried out to provide a deeper inside into the mechanismn of electrochemical chloride removal (ECR). They were aimed at determining the changes in (i) total chloride content and (ii) the Cl--and OH--concentrations of the pore solution at varying concrete depths during ECR. It was shown that the efficiency of chloride removal deceased in the concrete cover with increasing depth, and that it was least efficient near the reinforcement. The factor that was identified as being responsible for this was the changes in OH--concentration of the pore solution that had been caused by reactions at the electrodes. The OH--concentration of the pore solution decreased in the area close to the surface during treatment, while it rose dramatically around the reinforcement. This resulted in an increase of the Chloride Transference Number and thus the efficiency of chloride removal close to the concrete surface, and a drastic decrease close to the reinforcement.