Understanding strengthening mechanisms of Ca-LDO on cementitious materials

The influence of CaAl-layered double oxide (Ca-LDO) on physical properties, mechanical properties, hydration process, and pore structure of cement-based materials was investigated systematically in this study. The results demonstrated that 0.5% and 1% of Ca-LDO contributed to the development of mechanical properties of mortar, which could be attributed to the integration of the seed effect, internal curing effect, and micro-filling effect. In contrast, more than 1% of Ca-LDO was deposited on the surface of cement hydration products. Besides, the polymerization degree of C-S-H gel was reduced and the growth of monosulfate (AFm) was inhibited, which hindered the cement hydration process. These findings are expected to provide theoretical guidance for the application of layered double hydroxides (LDHs) in cement-based materials.