A review of steel slag as a substitute for natural aggregate applied to cement concrete

Steel slag is the main by-product of steelmaking, and its stacking and burying cause serious pollution to soil and water. Meanwhile, the exploitation of gravel is restricted with the implementation of ecological environment protection, resulting in the lack of nature aggregate. Based on the good engineering properties of steel slag aggregate, many researches attempted to substitute natural aggregate with steel slag applied to concrete. Therefore, this article summarizes the composition and properties of steel slag and discusses the effect of steel slag on properties and microstructure of cement concrete. Extensive literatures verify the feasibility of steel slag substituting part of natural aggregate in concrete. Steel slag affects the workability and volume stability of concrete but improves compressive strength, frost resistance and wear resistance, whereas it is controversial in flexural strength and permeability. Finally, the future research trends of concrete with steel slag aggregate are put forward.