Properties of cemented phosphogypsum (PG) backfill in case of partially substitution of composite Portland cement by ground granulated blast furnace slag

摘要

The present study investigates the effect of the type of binder on the performance of cemented phosphogypsum (PG) backfill. Composite Portland cement (PC) and ground granulated blast furnace slag (GGBFS) were used as binder in various mixing proportions. The hydration characteristics, evolution of the strength and pore structure of backfill were studied. The results show that PG interfered in the hydration of binders, which led to a low rate of hydration, insufficient hydration products and a weak hardened structure. Applying PC-GGBFS as binder resulted in higher strength than that obtained for the pure PC. On the contrary, the sulfate of PG was conducive to the formation of ettringite due to its participation in the hydration of GGBFS. More hydration products were produced at the early stage of hydration, which accelerated the self-desiccation process and refined the pore structure. GGBFS showed high potential for application in cemented PG backfill.