Corrosion behaviour of a low-Ni austenitic stainless steel reinforcement in carbonated chloride-polluted alkali-activated fly ash mortars

This study concerns the corrosion behaviour of a low Nickel austenitic stainless steel embedded in 100% fly ash mortars, activated by two different solutions. The mortars were carbonated and exposed for 650 days to increasing amounts of chloride ions in order to simulate a highly corrosive environment. The corrosion resistance of AISI 304 in fly ash mortars and that of both stainless steels in ordinary Portland cement mortars were also evaluated for comparative purposes and, at the end of the 650 day exposure, polarization curves were recorded on selected steel bars. The results evidenced the excellent performances of low nickel stainless steel, even if its susceptibility to pitting corrosion was higher than that exhibited by AISI 304. Moreover, it was also found that the corrosion protection offered by fly ash mortars was always higher than that afforded by the traditional one.