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

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 = 11) and severe carbonation (pH = 9) conditions using various electrochemical measurements (OCP, LPR, EIS, M - S 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 corrosionresistant steels in carbonated concrete.

Automated summary

Carbonation can modify the passive film of corrosion-resistant steel in alkaline concrete, with different effects based on the content of carbonate/bicarbonate ions. This study provides insights into the application of corrosion-resistant steels in carbonated concrete.