Preparation of sustainable and green cement-based composite binders with high-volume steel slag powder and ultrafine blast furnace slag powder

The mechanical properties and hydration mechanism of ultrafine ground granulated blast furnace slag powder (UFS)-cement-steel slag powder (SS) ternary cementitious material systems were studied. The chemical effects and contribution ratios of UFS and SS in ternary system at different hydration ages were also investigated. The results show that by adding UFS, the mechanical properties of concrete composites with high-volume SS conforming to the gap-graded particle size distribution are significantly enhanced. The close-packing effect between particles and the pore size distribution of hardened pastes are improved. The strength of cement matrix without any waste is still the highest. The SS has a negative impact on the hydration and strength development of the system at the early hydration ages, but it has a certain promoting effect at later hydration ages. UFS has a visible improvement effect on the hydration and the strength development of the system at both early and later hydration ages. The contribution ratio of UFS was analyzed and was found to be higher than that of SS apparently.