Electrochemical responses of carbon steel in ordinary Portland cement blended with calcium sulfoaluminate cement

This work investigated the passivation and chloride-induced corrosion of carbon steel exposed to an extract solution (PCSA) of ordinary Portland cement (OPC) blended with calcium sulfoaluminate (CSA) cement. As evaluated by EIS and XPS measurements, carbon steel gained inferior passivity by forming a thinner and less protective passive film in PCSA solution compared with that in the pure OPC solution. However, after chloride attack, comparable corrosion resistance was confirmed for steel exposed to both solutions. Furthermore, enhanced pitting corrosion resistance was identified for steel after 30 d of immersion in PCSA solution, which was mainly attributed to the formation of an Al-rich layer on the steel surface as well as the reduced chloride concentration in solution by the unreacted aluminum phase.

Automated summary

This study investigated the passivation and corrosion of carbon steel exposed to a blended solution of ordinary Portland cement (OPC) and calcium sulfoaluminate (CSA) cement. The carbon steel exhibited inferior passivity in the blended solution, but comparable corrosion resistance after chloride attack. Improved pitting corrosion resistance was observed in the steel immersed in the blended solution, attributed to the formation of an Al-rich layer and the reduced chloride concentration.