Influence of silica fume on corrosion behaviour of reinforced steel in different media

Abstract

The electrochemical and corrosion behaviours of reinforced steel embedded in cement pastes incorporating different amounts of silica fume as a partial replacement of cement have been studied in chloride and sulphate solutions by using different electrochemical techniques. The results indicate that, while the passivity degree of the steel is low in the control sample upon soaking in the corrosive media, it is high in the sample incorporating silica fume and increases with the increase of silica fume content. The improvement effect of silica fume may be attributed to the pore solution structure of cement paste, which limits the mobility of aggressive ions near the surface of the steel. The mechanism of steel corrosion due to chloride and sulphate attack and the passivation effect of silica fume are discussed.