STUDY OF ELECTROCHEMICAL CHLORIDE EXTRACTION AS A NON-DESTRUETIVE REPAIR METHOD: PART 1. DISCRETE TEST SAMPLES

The representative parameters of ECE and the side effects were determined experimentally. The experimental program investigates chloride and alkali concentration, chloride removal efficiency, transference number, half-cell potential and possible bond strength degradation which is determined by pull-out test. Test variables were percentage of chloride concentration to mass of cement (i.e., 0%, 1%, 1.5% and 2%) and duration of application of constant electric current (i.e., 2, 4, 6 and 8 weeks). Tests results indicate that chloride concentration around rebars reduces to the threshold concentration level of about 0.4 after 6 to 8 weeks of treatment. Half-cell potential shows that corrosion activities of the steel reinforcement were stopped 8 weeks after the end of treatment. Chloride removal efficiency is hardly reached to 60% after 8 weeks of ECE treatment. Bond strength in specimens with and without transverse reinforcement was reduced by 30-44% and 19-27% at the end of the treatment, respectively. Bond strength in specimens with and without transverse reinforcement was increased by 10-16% and 8-10%, 8 weeks after end of treatment, respectively. Test results on a reinforced concrete slab will be presented in the subsequent paper.