Corrosion of steel bars in OPC mortar exposed to NaCl, MgCl2 and CaCl2: Macro- and micro-cell corrosion perspective

In North America, corrosion of the steel rebar commonly occurs due to chloride attack from deicing salts. In Canada, based on the severity and temperature of the ambient environment, three different deicing salts, or combination of them, are used: NaCl, MgCl₂ and CaCl₂. In this paper, the effect of each of these salts on the corrosion of steel rebar and their impact on the durability of the mortar have been investigated. The results show that CaCl₂ has the most negative effect on the steel and, in high concentrations, on the integrity of the mortar. MgCl₂ also deteriorates the mortar if used in high concentration, while NaCl has no apparent effect on mortar durability even in high concentration.