Formation of calcium-aluminum-silicate-hydrate (C-A-S-H) in iron ore tailings ceramsite and its influence on cement hydration degree

This study explores the application potential of iron ore tailing (IOT) ceramsites in cement and concrete. It focuses on elucidating the pozzolanic reaction of ceramsite and its impact on the hydration kinetics of cement paste. The results showed that the active substances inof ceramsite dissolve in an alkaline environment and bind with Ca2+ in the cement solution to form a robust structure with needle-like C-A-S-H as the framework and layer-like C-A-S-H as the core-shell. Ceramsite slightly delayed the end of the induction period and significantly increased the total heat of hydration, thereby enhancing cement paste hydration. The compressive strength and degree of hydration exhibited a linear correlation. The C-A-S-H structure effectively enhances the strength of the cement paste within 100 μm of the ceramsite, with the strengthening effect extending up to 700 μm after 3 days. This study underscores the significant potential of IOT ceramsites in the concrete industry.