Effect of carbonation curing on the mechanical properties of belite-rich cement mortar exposed to elevated temperatures

The present study aims to investigate the residual properties of carbonation-cured belite-rich cement mortar exposed to a high temperature. The mortar was carbonation-cured with a 10% CO₂ concentration for 28 days and was then exposed to elevated temperatures of 300 °C, 600 °C, 900 °C and 1200 °C. The findings revealed that the heat resistance of a cement mortar relative to that of standard water-cured sample was enhanced by carbonation curing. Moreover, it was noted that in comparison to Portland cement mortar, the residual mechanical performance was improved for the carbonation-cured belite-rich cement mortar sample. A physicochemical analysis revealed that the formation of thermally stable calcium carbonate due to carbonation curing was the primary cause of the enhanced residual properties. Furthermore, for samples exposed to 1200 °C, it was observed that the carbonation reaction products became thermally stable alite and belite phases.