Experimental studies and thermodynamic analysis of calcium sulfoaluminate clinker under carbonation condition

The degradation of cement is a crucial factor leading to the failure of CO 2 sequestration. In this study, experiments and thermodynamic methods were conducted on the carbonation of calcium sulfoaluminate (CSA) clinker. The results indicate that a significant layered phenomenon and macroscopic cracks occurred after the carbonation of the CSA clinker sample. AFt, AFm, and C 2 ASH 8 react with carbon dioxide to form CaCO 3 and Al(OH) 3 . Furthermore, the corrosive fluid continuously dissolves the CaCO 3 on the surface layer of clinker samples, resulting in the continuous leaching of Ca and O elements from the samples. Thermodynamic simulation results revealed that with the addition of sufficient carbon dioxide, all minerals, excluding the inert phase and Al(OH) 3 , undergo complete degradation, leading to a mildly acidic aqueous solution. Elevated temperatures may impede the development of corrosive chemical reactions. Consequently, a greater quantity of carbon dioxide is required to fully react with the primary minerals present in the CSA clinker. Furthermore, monosulfate demonstrates inferior corrosion resistance in comparison to the solid solutions of stra <spacing diaeresis>tlingite and ettringite. Among the endmembers, C 2 ASH 8 exhibits greater corrosion resistance than C 2 ASH 7 , while C 6 AS 3 H 32 demonstrates superior corrosion resistance compared to C 6 AS 3 H 30 . In contrast, C 4 AcH 11 exhibits the worst corrosion resistance compared to the other minerals.