Passive film modification by concrete carbonation: Re-visiting a corrosion-resistant steel with Cr and Mo

Abstract

Abstract Prior to natural carbonation, a protective passive film could be formed naturally on reinforcing steel when exposure to alkaline concrete environment. To evaluate the modification of passive films caused by carbonation on a corrosion-resistant steel containing Cr and Mo in alkaline concrete pore solution, the passivation capability and passive film composition were investigated in moderate carbonation (pH\xa0=\xa011) and severe carbonation (pH\xa0=\xa09) conditions using various electrochemical measurements (OCP, LPR, EIS, M\xa0−\xa0S and CV) and X-ray photoelectron spectroscopy (XPS). The results revealed that carbonation with various contents of carbonate/bicarbonate ions could exert different effects on naturally passivated corrosion-resistant steel by modification of the chemical composition of passive films, thus providing new insights into the field application of corrosion-resistant steels in carbonated concrete.