Investigating tricalcium silicate dissolution kinetics in cementitious materials through single-particle analysis

The dissolution kinetics of tricalcium silicate (Ca₃SiO₅, or C₃S), the primary component of ordinary Portland cement, are critical to cement hydration, which governs key properties, such as setting, hardening, long-term mechanical performance, and durability. Despite its importance, the lack of dissolution kinetic data for single C₃S particle hinders the development of accurate hydration models and a comprehensive understanding of hydration mechanisms. In this study, we employed a novel lab-on-a-chip technology integrated with confocal laser scanning microscopy to investigate the dissolution behavior of individual C₃S particles and obtain statistical insights under varying degrees of undersaturation and hydrodynamic influence. By examining each particle's dissolution behavior, we observed key phenomena, including the simultaneous occurrence of dissolution and fragmentation, and demonstrated that dissolution rates are independent of particle size. Furthermore, we found that single-particle dissolution evolves over time, closely tied to changes in surface defects under different undersaturation levels. Our findings provide a new statistical and mechanistic understanding of C₃S dissolution at the particle scale, offering critical data to refine cement hydration models. This work sheds light on the role of particle-level factors such as fragmentation, size, and surface defects in dissolution and hydration processes, enabling the design of more effective additives to optimize cement performance.