Solid waste-based dry-mix mortar using fly ash, carbide slag, and flue gas desulfurization gypsum

Abstract

The hydration characteristics, performance, and economic feasibility of inorganic cementitious materials prepared using circulating fluidized bed fly ash (FA), carbide slag (CS), and flue-gas-desulfurization gypsum (FGDG) are investigated, focusing particularly on FA-CS binary and FA-CS-FGDG ternary cementitious systems. Experimental results show that the compressive strength of the binary system is less than that of the ternary one. The ternary cementitious material exhibits strong synergistic effects, as the 28 days compressive strength of the ternary system can reach 6.35 MPa, suggesting that it has good prospects for practical application. A dry-mixed mortar using the material has been manufactured and tested in a pilot project; it meets Chinese government quality standards and reduces cost and carbon emissions relative to traditional mortar. The 28 days compressive strength of dry mix mortar can reach 13.1 MPa, the production cost of solid waste-based dry-mixed mortar was reduced by approximately 48.8%, and the carbon dioxide emission reduction ratio was 82.9%.

Keywords

• Circulating fluidized bed fly ash
• Calcium carbide slag
• Desulfurized gypsum
• Hydration characteristics
• Cementitious materials