Effect of Different Treatment Processes on Expansion Stability of Steel Slag

In view of the poor stability in engineering application of steel slag caused by the volume expansion,the methods of acetic acid immersion and micro-silicon powder addition were adopted to reduce the volume expansion ratio of steel slag according to the hydration reaction mechanism of free calcium oxide（f-CaO）.The volume fraction of acetic acid solution was controlled at 10%,15% and 20%,and the proportion of micro-silicon powder was 0.6%,1.2%,2.4% and 4.8%,respectively.The results show that both of the methods can effectively reduce the volume expansion ratio of steel slag,and its effect is positively correlated with the reagent proportion.In the acetic acid immersion group,soaking for 3 h is enough for full function,and more than 76.1% of reduction for volume expansion ratio can be obtained for each experiment.In the group of micro-silicon powder addition,obvious difference on reduction of expansion ratio of the steel slag can be found for different micro-silicon powder addition.When the micro-silicon powder proportion is more than 2.4%,the volume expansion rate reduces to less than 2%,and an expansion ratio of 0.4% corresponding to 87.1% of reduction can be obtained with the proportion of micro-silicon powder at 4.8%.