Evaluation of Electrochemical Treatment of Chloride Contaminated Mortar Containing GGBS

Abstract

The present study concerns the influence of cementitious binder on electrochemical treatment of steel embedded in salt contaminated mortar. As binder, ordinary Portland cement (OPC) and ground granulated blast furnace slag (GGBS) were used and the current density of 250-750 mA/m(2) was applied for 4 weeks to complete electrochemical chloride extraction. To evaluate the effect of electrochemical treatment the chloride profile and corrosion behaviour covering chloride concentration, galvanic current density, linear polarization resistance, open circuit potential, and mass loss were measured. An increase in the applied direct current density resulted in a decrease in the chloride concentration at the vicinity of steel, accompanying the mitigated corrosion damage. The performance of electrochemical treatment was more remarkable in mortar containing GGBS presumably due to binding mechanism. However, corrosion damage was more detrimental in GGBS rather than OPC at a given potential, while GGBS had superior corrosion resistance to a corrosive environment and treatment conditions. Therefore, the electrochemical treatment should be conducted prudently to evaluate the corrosion state of embedded steel depending on binder type.