Development of high-temperature-resistant alkali-activated slag binders utilizing ceramic sludge waste

This study explores the impact of incorporating ceramic sludge waste on the structural and mechanical properties of an alkali-activated slag binder at elevated temperatures up to 1000°C. To this end, blast furnace slag (BFS) was partially substituted with 5-50% ceramic sludge waste (CSW) by weight. The investigation focused on compressive strength, crystalline phase development, and microstructural changes in the AAS blends after exposure to high temperatures. The results indicated that incorporating CSW up to 20 % improved compressive strength, with the best performance observed at room temperature for the 10% replacement level. At temperatures above 500°C, reaching up to 1000°C, the mechanical performance was enhanced by the incorporation of ceramic sludge waste, peaking at 30% replacement. This is due to the recrystallization of the geopolymer matrix and the formation of high-hardness minerals such as akermanite, gehlenite, and marlite. A cradle-to-gate life cycle assessment showed that the addition of ceramic sludge waste decreased the global warming potential of the alkali-activated slag binder by 5.50%, which was achieved when the replacement level was 30%. Thus, an optimum balance between environmental performance and high-temperature mechanical properties was reached. This study presents a promising method for producing highly thermally stable materials.