Effectiveness and microstructure change of alkali-activated materials during accelerated carbonation curing

Abstract Alkali-activated materials (AAMs) have two major environmental benefits compared to traditional cement-based materials: reducing greenhouse gas emissions and recycling industrial by-products. To evaluate the possibility of using AAMs for well construction in carbon capture, utilization and storage (CCUS) projects, the carbonation resistance performance of AAMs was investigated under accelerated carbonation conditions. The results showed that the loss ratios of the AAMs compressive strength were 89.75% and 88.20% in the gas and liquid phase carbonation environments during the first 3 days, respectively. The structural damage in the AAMs was mainly caused by the leakage of Ca2+ from the calcium silicate hydrate (C-S-H) phase of the matrix, converting it into crystalline calcium carbonate after CO2 attack. From 7 days of the start of carbonation, the cumulative pore volumes of the AAMs samples increased from 0.97 to 5.02 ml/g and from 0.97 to 4.37 ml/g in the gas and liquid phase carbonation environments, respectively. The presented work indicates that under accelerated carbonation conditions, the rate of destruction of AAMs is too rapid for such material to be used for the construction of CCUS wells.