Characteristics of the corrosion products of steel bars in modified magnesium oxysulfide cement containing chloride salts

Abstract

The effects of chlorides on the corrosion of steel bars within a matrix comprising modified magnesium oxysulfide (MMOS) cementitious materials was investigated in this study, containing the phase composition, morphology, and distribution of steel corrosion products. The results showed that there was basically no corrosion of the steel bars in MMOS cement without chlorides. The presence of high chloride content and a high water-cement ratio in MMOS matrix had adverse effects on the corrosion of steel bars. The primary product of steel corrosion in MMOS was FeOOH and Fe2O3, while FeO was only observed at low water cement ratios, indicating a lower degree of oxidation. Moreover, the presence of Fe2(CO)9 at high water cement ratios suggests a higher degree of oxidation. At lower water-cement ratios, rust products readily diffused; Conversely, at higher ratios, these products accumulated in proximity to the steel bars, forming a compact structure.