Effects of steel slag on the early hydration of hydraulic lime

Steel slag inhibits the early hydration of cement, which limits its applications in cement-based materials. In this study, steel slag was used to prepare hydraulic lime, and steel slag was found to promote hydration in the hydraulic lime during the induction stage and inhibited hydration in the acceleration stage. As the steel slag content increased, hydration of hydraulic lime slowed and the yields of the hydration products C-S-H and Ca(OH)(2) decreased. The pore sizes of steel slag-hydraulic lime pastes were principally distributed in the range of 100-4000 nm. Hydraulic lime with a steel slag content of 10% had the highest peak heat release rate during the acceleration stage. When the steel slag content was 10%, the porosity of the matrix decreased, the compactness increased, and the three- and seven-day compressive strengths of the hardened paste also increased in comparison to the paste without steel slag.

Automated summary

Steel slag inhibits the early hydration of cement, but promotes hydration in hydraulic lime. With increased steel slag content, the hydration of hydraulic lime slows and the yield of hydration products decreases. The pore sizes of steel slag-hydraulic lime pastes are mainly distributed in the range of 100-4000 nm. Hydraulic lime with a steel slag content of 10% exhibits the highest peak heat release rate and improved compressive strength.