| The electrochemical chloride extraction is one of rehabilitation method for repairing chloride-contaminated concrete. During the extraction, while the chloride in RC structures is extracted, the alkali around the reinforcing steel bar is increased. Accordingly, the reinforcing steel bar is prevented from getting rusty.Firstly, using cylinder RC specimen, the ion profile in concrete after electrochemical chloride extraction has been studied. Based on the ion profile curve in concrete, the parameters such as chloride extraction current and time which influencing the chloride extraction efficiency have been analyzed.Secondly, the system research of mechanical property after ECE is presented. Effect of desalination parameters on mechanical property is analyzed by pull-out test and bending experiment. The results show that, the main cause that leads to the ultimate bond strength impairment of the steel bar-concrete interface is chloride extraction current, and then ECE time. The amount of charge during ECE is not the direct reason. Compared to other mechanical properties, effect of the ECE technique on deflection of bending members during the loading process is more obvious.Thirdly, the durability of ECE is studied. It is proved that, after desalination, back diffusion coefficients of chloride affect durability significantly. Based on this, theoretical model of chloride back diffusion is established and the coefficients are theoretically analyzed. Diffusion coefficients, durability lifetime and desalination efficiency are computed combining the theoretical formulation and experiment results. The best desalination time is determined and the problem in electronic chemical technique is solved.Finally, by applying electrochemical principle, the key factor during desalination is analyzed and ECE control theoretical models of concrete structures are established. Combining desalination experiments, the key steps in electrochemical construction are summarized in detail. |
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