Utilizing municipal solid waste incineration (MSWI) fly ash as a calcium source to prepare Al‐substituted tobermorite

Abstract

Tobermorite is one of the main products of autoclaved curing concrete. Utilizing of municipal solid waste incineration (MSWI) fly ash as a calcium source to prepare solid waste-based Al-substituted tobermorite was explored. The effects of incorporation of MSWI on the reaction products, compressive strength, microstructure, and pore size distribution of solid waste-based wall materials were studied. The ratio of calcium to silicon (C/S) influenced the formation of Al-substituted tobermorite, and the optimum C/S of the sample without and with MSWI were 1.18 (sample FA-T-(1.18) (FA-T means that fly ash (FA), quick lime, cement, and desulfurization gypsum were used to hydrothermally synthesize solid waste-based Al-substituted tobermorite)) and 1.30 (sample FA-MSWI-T-(1.30) (FA-MSWI-T means that FA, quick lime, MSWI, and desulfurization gypsum were used to hydrothermally synthesize solid waste-based Al-substituted tobermorite)), respectively. Compared with the sample FA-T-(1.18), the compressive strength of FA-MSWI-T-(1.30) increased by 77.5%, the range of main pore size distribution became smaller, and the structure was compact.The microstructure of FA-MSWI-T-(1.30) was fibrous. This work will provide a new way for the utilization of MSWI, which can effectively reduce the pressure on the environment caused by hazardous wastes and provide reference for the basic research on green autoclaved wall materials and heavy metal solidification technology. K E Y W O R D SAl-substituted tobermorite, compressive strength, microstructure, municipal solid waste incineration (MSWI) fly ash, pore size distribution, ratio of calcium to silicon (C/S)