In-situ XRD study of the effects of amino acids on the carbonation kinetics of cementitious calcium silicates

The carbonation of cementitious calcium silicates, specifically tricalcium silicate (C3S) and dicalcium silicate (C2S), is crucial for Carbon Capture and Utilization (CCU) in reducing CO2 emissions in the cement and concrete industry. Controlling these reactions, including the rate and phase evolution necessary for producing desirable carbonated products, poses significant challenges. A lack of continuous kinetic data has impeded the understanding of the mechanisms behind carbonation and its optimization to enhance efficiency. This study explores the effects of four amino acids-glycine, L-arginine, sarcosine, and L-serine-on the carbonation of calcium silicate using in-situ XRD for real-time data collection. It identified a three-stage carbonation process starting with an induction period. The presence of specific amino acids encouraged the formation of stable vaterite and denser microstructures, indicating their potential to enhance the mechanical properties and durability of cementitious materials.