A Prediction Method for the Corrosion Rate of Steel Rebar in Carbonated Mortar under Variable Environmental Conditions

This study investigated carbonation-induced corrosion behaviours with different water-to-cement (w/c) ratios and cover thicknesses under different environmental conditions. The relative humidity (RH) and temperature dependence of the corrosion behaviours were determined by considering the water content and electrical resistivity of the mortar and the corrosion rate of the steel reinforcing bar (rebar). Accordingly, corrosion controlling mechanisms were discussed and verified. Prediction methods for the corrosion process under resistive and cathodic control were proposed based on the water content, temperature, and cover thickness. Finally, the proposed corrosion rate prediction method was verified by a field survey on three carbonated reinforced concrete (RC) buildings. The general agreement between the measured and calculated corrosion rates of the steel rebar verified the reliability of the proposed corrosion rate prediction method, contributing to the soundness evaluation of RC members.