Decalcification resistance of alkali-activated slag

► The effects of decalcification on properties of alkali-activated slag were studied. ► Decalcification was performed by concentrated NH4NO3 solution (accelerated test). ► Portland-slag cement (CEM II/A-S 42.5 N) was used as a benchmark material. ► Decalcification led to strength decrease and noticeable structural changes. ► Alkali-activated slag showed significantly higher resistance to decalcification.