Chloride-induced corrosion patterns of reinforcements in simulated pore solutions of calcium sulfoaluminate cement concrete: An analytical study

Abstract

The widespread use of calcium sulfoaluminate cement (CSA) for rapidly repairing marine structures exposed to high chloride levels has spurred limited investigation into the corrosion behavior of reinforcements in low-pH CSA systems. To address this knowledge gap, researchers conducted a comprehensive study on the impact of primary ions within CSA (OH−, SO42−, and Al(OH)4-) on steel rebars in simulated pore solutions (SPSs). The investigation employed various analytical methods such as Mott-Schottky/cyclic polarization curves, corrosion current, impedance spectrum analyses, and microstructural examinations. The results demonstrate that SO42− diminishes the corrosion resistance of reinforcements by depassivating them, consequently reducing the critical chloride concentration (Ccrit). However, this influence is mitigated with elevated OH− or Al(OH)4− concentrations. Furthermore, the presence of Al(OH)4- in the pore solution contributes to an increased Ccrit by stabilizing alkalinity via OH− hydrolysis. Based on the empirical findings, the researchers developed an empirical formula for Ccrit, offering insights into estimating the service life of CSA-based concrete structures in real marine environments.