Thermal influence and stability of in-situ mixed CO2 in cementitious mineral phases

Concrete's potential for carbon capture and utilization (CCU) is underscored by its widespread global use and capacity for stable mineral carbonation. This study highlights the effectiveness of in-situ CO2 mixing technology for CCU application in concrete production, eliminating the need for additional facilities or chemical additives. Various mixing water temperatures were employed to understand their impact on mineral carbonation. Results demonstrated that elevated temperatures expedite cement dissolution, enhancing CO2 absorption and subsequent calcite (CaCO3) precipitation, thereby improving early compressive strength development. In CO2-rich sealed environments, a notable transformation of CaCO3 into monocarboaluminate was observed during the hydration process. Therefore, a comprehensive understanding of mineralogical changes is crucial for evaluating concrete's capacity as a CCUS medium. Consequently, a quantitative assessment of CO2 content in the cementitious phase was conducted, utilizing a combination of experimental and thermodynamic analyses.