Assessment of the physicochemical properties of alkali-activated slag blended with belite-rich cement subjected to carbonation attack

The present study investigated the physicochemical transformation of alkali -activated slag (AAS) under CO 2 exposure. The belite-rich cement (BRC) used as an additive up to 30 wt% of GGBFS and Ca(OH) 2 was used for alkali activation. The threshold ratio of lime/slag and BRC/binder was 4.5% and 20%, respectively, for the improvement in strength and the physicochemical properties. The residual strength after CO 2 exposure was higher for an AAS mix prepared with 30% BRC/binder and a 6% lime/slag ratio. Due to the additive (BRC) in AAS, the unreacted beta-C 2 S and portlandite act as a buffer during CO 2 exposure. The additional supply of Ca 2 + ions provided via Ca(OH) 2 contributed to promoting the reactivity of AAS. The decrease in critical pore diameter by 51.6% as the prepared AAS with the higher BRC/binder ratio was exposed to CO 2 increased the solid -phase assemblage per unit volume, which also contributed to the physicochemical properties.