Modification of steel slag powder by mineral admixture and chemical activators to utilize in cement-based materials

摘要

Modification of steel slag powder by mineral admixture and chemical activators to utilize in cement-based materials was studied in this work. The results showed that for cement pastes with steel slag alone, the normal consistency water requirement and compressive strength were decreased significantly. Both of the initial setting time and final setting time were also retarded than that of the control sample. When a compound admixture of ground granulated blast furnace slag (GGBFS) -steel slag powder added the compressive strength was evidently improved. Modification of steel slag powder by "Gypsum-type" and "Sodium-type" chemical activators were further studied. Cement paste with the modified compound admixture by 1.5 % calcium sulfate hemihydrate or sodium sulfate, its 28 days compressive strengths could reach to 75.4 and 76.2 MPa, respectively. X-ray diffraction (XRD) patterns showed that the main hydration products mainly included Ca(OH)_2 and ettringite. It indicated that proper mineral admixture and chemical activators had a positive effect regarding early hydration of steel slag powder, and enhanced forming calcium silicate hydrate(C-S-H) gel and ettringite. This work contributes to understanding of how to sustainably manage wastes and byproduct materials and has the potential to provide several important environmental and economic benefits.