Insights to compressive strength, impermeability and microstructure of micro-expansion steel slag cement under constraint conditions

This work aims at evaluating the influence of steel slag as partial replacement of cement on the mechanical properties and impermeability of cement-based materials under constraint conditions. The results show that, compared with the raw steel slag, the setting time of the wet-grinding steel slag system is shortened, and the free expansion rate is increased. When the wet-grinding steel slag content is 10%, the compressive strength of the specimen (constraint) after 28 days of curing is the highest, reaching 68.5 MPa, which is 9.3% higher than that of the free curing specimen, and the impermeability is also the best. Under the constraint conditions, the expansion strain produced by steel slag leads to the compact sample structure and reduced porosity, which is conducive to the mechanical properties and compactness of the pore structure of cement paste.