High efficiency preparation of superfine steel slag particles and the effects on hydration of Portland cement

The promotion of hydration and high early strength in concrete holds vital significance for production efficiency of prefabricated concrete. Currently, how to prepare inexpensive early strength accelerators for component concrete is a current research hotspot. In light of the aforementioned objectives, superfine steel slag (SSS) with median size of 935 nm was produced by wet-milling technology in the research. The properties of SSS and its effects on paste/mortar were comprehensively investigated. Relevant data analysis confirmed that the phase composition of SSS was altered and the dissolution of ions was promoted due to hydration reaction. The 12 h compressive strength of the cement-based sample containing 8% SSS rose from 5.2 MPa of the blank group to 18.5 MPa, with an increase of 256%. The incorporation of SSS was found to promote the hydration rate and the growth of hydration products, as verified by hydration heat, XRD, and TG tests. These effects were attributed to the nucleation induction effect and the high-alkalinity liquid phase environment provided by SSS. This research provided a novel technical solution for the high-value-added utilization of steel slag in prefabricated concrete. • Superfine steel slag with median size of 0.935 μm was produced by wet-milling. • Superfine steel slag enhanced early mechanical property of cement-based materials. • An improvement of anti-permeability appeared when dosages of SSS was less 2%.