Electrochemical behaviour of a novel alloy steel in alkali-activated slag mortars

The present paper aims to investigate the passivation capability and accelerated chloride-induced corrosion behaviour of a novel alloy steel (00Cr10MoV) and a conventional low-carbon steel (20MnSiV) in ordinary Portland cement (OPC) and alkali-activated slag (AAS) mortars. Both steels were embedded in mortars with intact mill scale. Compared with OPC mortar, AAS mortar resulted in the formation of less protective passive film for both 20MnSiV and 00Cr10MoV steels after passivation due to the presence of reducing sulphides. Despite this, the initial negative effect of AAS mortar on 20MnSiV steel can be well compensated by its denser interfacial microstructure after the occurrence of active corrosion induced by chlorides. As for 00Cr10MoV steel in AAS mortar, however, this compensating effect was less pronounced. Moreover, unexpected low passivation capability and corrosion resistance can be confirmed for 00Cr10MoV steel in both OPC and AAS mortars due to the presence of defective and Cr-depleted mill scale.