Determining a Conservative Critical Chloride Concentration for Rebar Corrosion in Simulated Concrete Pore Solution Using Cyclic Potentiodynamic Polarization and Critical Pitting Temperature

Abstract

Critical chloride concentration (Ccrit) has been one of the most popular parameters for predicting rebar corrosion initiation in concrete. However, its large discreteness makes prediction challenging. Cyclic potentiodynamic polarization (CPP) and critical pitting temperature (CPT) were thus applied to detect the critical environmental condition for chloride-induced localized corrosion and to find a conservative Ccrit with lower discreteness. Results show that increased environmental aggressiveness decreases CPT's mean and minimum values. The discreteness of the CPP curve type and CPT are small when the exposure condition is noncorrosive and very aggressive. A new method based on CPT and CPP curves is then proposed to determine a conservative Ccrit. If the exposure condition is harsher than this concentration threshold, the minimum CPT will be lower than ambient temperature and nonnegative CPP curves will occur in repeated scans.