Modification method of steel slag, modified steel slag and method for reducing steel slag expansion rate

The invention relates to a modification method of steel slag, modified steel slag and a method for reducing the expansion rate of the steel slag. Comprising the following steps: mixing steel slag with a modification treatment solution, soaking, and drying to obtain modified steel slag with the water content of not more than 0.1%; wherein the modification treatment liquid comprises at least one even fatty acid salt with the carbon chain number of 10-18. According to the modification method of the steel slag provided by the invention, the water absorption expansion rate of the steel slag can be effectively reduced, the expansion of the steel slag can be inhibited, the deformation problem caused when the steel slag is used as concrete aggregate can be further inhibited, and the stability of the steel slag can be improved; the fluidity and strength of the concrete are not affected, and the concrete is the same as conventional concrete of common aggregate. Compared with concrete prepared from steel slag aggregate