Influence of solid waste gypsum and additives on the properties of sulfoaluminate cement-fly ash-gangue ternary binder

Abstract

With rapid economic and social development, significant amounts of coal-based and gypsum solid waste are generated daily. However, the high cost of sulfate aluminum cement has limited its widespread application. Notably, when the dosage of desulfurized gypsum reached 8%, the strength of the cementitious material at different ages approached or even exceeded that of pure sulfate aluminum cement. The sulfate aluminum cement-coal-based solid waste gypsum cementitious material prepared in this study demonstrated high compatibility with various admixtures. Specifically, when the proportions of sulfate aluminum cement, coal gangue powder, ultrafine coal ash, and desulphurization gypsum in the cementitious material were 67%, 15%, 10%, and 8%, respectively, and the dosages of the polycarboxylate water reducer, boric acid, and lithium carbonate were 0.25%, 0.25%, and 0.15%, respectively, with a water-to-binder ratio of 0.35, the strength of the cementitious material at different ages met the requirements of 425 sulfate aluminum cement. This study innovatively utilizes solid waste gypsum to enhance the strength of sulfate aluminum cement-coal-based solid waste cementitious material and employs an admixture ternary compound to enhance the performance of sulfate aluminum cement-coal-based solid waste-solid waste gypsum cementitious material. These approaches contribute to improving the utilization rate of solid waste gypsum and reducing the cost of sulfate aluminum cement.