Abstract
The hydration mechanism of a mixture of rice husk ash and calcium hydroxide and the reaction product have been studied. It is shown that rice husk ash can react rapidly with saturated Ca (OH) 2 solution. The pH value and the electrical conductivity of saturated Ca (OH) 2 solution adding with rice husk ash decreased gradually with time, especially when ADR is added. Calcium hydroxide is consumed rapidly in the initial reaction period. The reaction mechanism of rice husk ash with calcium hydroxide is consistent with diffusion control and can be represented by both the Jander diffusion equation and Genstleng diffusion equation. The reaction rate constants of ADR and RHA with calcium hydroxide are 18.41×10-4 (KJ) and 14.46×10-4 (KG), 10.99×10-4 (KJ) and 9.180×10-4 (KG), respectively. The DTA and XRD results showed that the reaction product of the rice husk ash and calcium hydroxide was Ca1.5SiO3.5·xH2O.
