Pore structure and compressive strength of alkali activated mortar with sewage sludge ash (SSA) under optimal incineration conditions

Incineration is an effective way for sewage sludge reduction and recycle. To study the utilization of sewage sludge ash (SSA) for use in alkali activated cementitious material, optimal incineration conditions were investigated. Compressive strength, pore structure, and hydration of alkali activated mortar with SSA, SSA-ground blast furnace slag (GBFS), and SSA-metakaolin (MK) were explored. Generally, optimal incineration was at 800℃ for 1 h and annealing cooling. Alkali activated SSA mortar with 30% compound precursors and 5% alkali content showed great microstructure and compressive strength. Finally, a multivariate linear relationship model between compressive strength and pore structure was established and had a great correlation.