Effect of Fly Ash Pre-Sintering Temperature on Adiabatic Foam Fabricated by Sodium Silicate

Adiabatic foam was fabricated successfully using sodium silicate as the raw material with pre-sintered fly ash as additive. Fly ash was pre-sintered at 500 to 900 oC and the effect of the pre-sintering temperature on the performance, including the thermal conductivity, density, compressive strength and microstructure, was researched. The results show that the pre-sintering process effectively reduces the density of the samples while the thermal conductivity and compressive strength are higher than those of the samples fabricated by the fly ash without being pre-sintered. Moreover, the samples exhibit tri-modal spherical pore structure with macropores and mesopores. The pore size remains unchanged until the pre-sintering temperature exceeds 700 oC, and then starts to increase.