Electrochemical performance of reinforcing steel in alkali-activated slag extract in the presence of chlorides

This study concerns the passivation behaviour and corrosion resistance of reinforcing steels in ordinary Portland cement (OPC) extract and alkali-activated slag (AAS) extract with chlorides. The electrochemical behaviour of steels in both extracts was monitored by various electrochemical measurements. Compared with OPC extract, less protective passive film was formed for steels in AAS extract without chlorides. However, much higher corrosion resistance was highlighted for steels exposed to AAS extract than OPC extract after the addition of 1 M NaCl. This was mainly attributed to the formation of gel-like substances in AAS extract, effectively suppressing the propagation of corrosion pits.