Corrosion behavior of duplex stainless steel reinforcement in ternary binder concrete exposed to natural chloride penetration

•Effect of OPC and mineral additions in the formation of passive layer on DSS rebars.•Long term corrosion response of DSS in concretes during a natural transport of Cl.•Cl accumulation at rebar level in relation to concrete and DSS for corrosion onset. The corrosion behavior duplex stainless steel rebars embedded in concrete exposed to natural chloride penetration has been carried out. Three duplex stainless steels (DSSs) differentiated in the Ni, Mo and Mn content and two types of concretes elaborated with different binders, Portland cement and Portland cement blended with Slag and Limestone, were employed. The corrosion behavior was followed through Ecorr and Rp measurements along the exposure period. The tests were extended up to corrosion detection or to 2 years, and the chloride contents accumulated at the rebar level were determined. The DSS with lower Ni content has demonstrated to show lower corrosion resistance in presence of chlorides and pitting corrosion at lower chloride contents accumulated at the rebar level were detected. The DSSs embedded in OPC concrete resist better to corrosion in presence of chlorides than those rebars embedded in concrete containing blast furnace slag and limestone.