Carbonation-induced corrosion of alkali-activated binary concrete based on natural volcanic pozzolan

•AABC presented the best performance under carbonation (natural and accelerated).•The compressive strength of AABC was not affected by the severe CO2 attack.•AABC and OPC concretes’s pH after carbonation (72 weeks) decreased by 12 and 22%.•Natural carbonation rates (96 weeks) of AABC and OPC were 3.20 and 5.04 mm/year0.5.•AABC reinforcement steel remained in a passive state for 360 days of CO2 exposure. The alkali-activated concretes have been attractive as an alternative material to Portland cement-based concrete (OPC), due to their low environmental impact and the good mechanical properties, however, regarding durability exist uncertainties. This article studies the performance to carbonation induced corrosion of the reinforcing steel embedded in an alkali-activated binary concrete (AABC) based on NP (70% by mass) and GBFS (30% by mass). According to the results, AABC has a better carbonation performance than OPC under natural and accelerated exposures (25 °C, 65% HR, 1% CO2). The structural steels embedded in AABC after the exposure to accelerated carbonation remained in a passive state up to 360 days.