Development of Magnesium-Silicate-Hydrate Cement by Pulverized Fuel Ash

摘要

Magnesium silicate hydrate (M-S-H) gel can be fabricated via the reaction of MgO with silica fume in the presence of sodium hexametaphosphate (Na-HMP). In this study, in effort to reduce the cost of the M-S-H gel system, pulverized fuel ash(PFA) was utilized as a silica source to replace silica fume. The influence of various PFA quantities on the compression strength and other properties of the M-S-H system were investigated via XRD, SEM, and TG-RTG analysis. Compressive strength was optimal when 35 wt% of silica fume was replaced. The hydration products were relatively more complex when PFA was used, containing hydrated calcium silicate, hydrated magnesium silicate, and carbonate gel, among other products. Magnesium carbonate participated in the hydration reaction process, which generated carbonated gel to form a grid structure and promoted the initial strength of the material. Taken together, the results showed that PFA can be feasibly and effectively used to form M-S-H gel cement systems at low cost.