Synthesis of early-strength steel slag grinding aids and their effect on the properties of steel slag-based cementitious materials

This study addressed the issues of low grinding efficiency, insufficient early strength of cementitious materials, and poor volume stability in steel slag processing by developing four composite grinding aids. Through optimization of the synthesis process, grinding aid d - formulated with polycarboxylate polymer combined with sodium sulfate (71%), sodium carbonate (15%), and calcium chloride (4%) - demonstrated optimal performance. Experimental results revealed that the optimal grinding duration for steel slag was 45 minutes, with grinding aid d increasing the proportion of 0-30μm particles to 66.77%, showing significant improvement compared to the control group. This grinding aid enhanced the 3-day compressive strength of steel slag-based cementitious materials by 21.04%, while effectively reducing free calcium oxide content through mechanical activation to improve volume stability. Microstructural analysis indicated denser hydration product structures, increased ettringite and calcium hydroxide crystal formation, and reduced porosity in samples treated with grinding aid d. The research confirmed a positive correlation between the 0-30μm particle proportion and hydration degree of cementitious materials, providing theoretical support for steel slag resource utilization.