Modification of ultrafine blast furnace slag with steel slag as a novel high-quality mineral admixture to prepare high-strength concrete

Ultrafine blast furnace slag is a type of active mineral admixture used in high-strength concrete. However, it always causes ultrahigh temperature rise and autogenous shrinkage. In this study, the feasibility of modifying ultrafine blast furnace slag with steel slag as a novel high-quality mineral admixture preparing high-strength concrete to alleviate the temperature rise and autogenous shrinkage problems was systematically investigated. Results show that steel slag has a good effect on delaying the onset of main exothermic peak, reducing the peak value, and decreasing the cumulative heat release of cement-ultrafine blast furnace slag composite binder. Modification of ultrafine blast furnace slag with steel slag to prepare high-strength concrete effectively reduces the growth rate and value of the temperature rise and the autogenous shrinkage on the premise of ensuring the strength, workability and impermeability. This novel steel slag-ultrafine blast furnace slag high-quality mineral admixture efficiently realizes the optimization of high-strength concrete preparation.