Effects of Steel Slag Powder as A Cementitious Material on Compressive Strength of Cement-Based Composite

Abstract

The utilization rate of steel slag in China is far behind that of developed countries. The annual output of steel slag is still increasing, resulting in a large amount of accumulation, causing environmental pollution. This paper summarizes and analyzes the relevant research on steel slag powder (SSP) as a cementitious material, studies the effect of SSP replaces cement as single or multiple admixtures, with different specific surface areas, and the amount of activator on the compressive strength of cement-based material. The results show that due to the lower content of active substances in SSP compared to cement, the strengths decrease with the increase of the replacement ratio R, which is the ratio of SSP to cement. R = 30% is important for replacing cement with single SSP. When replacing cement with the mixture of SSP and slag/fly ash, the strengths of most groups decrease with the increase of the mix replacement ratio Rc. The decreasing trend is not obvious due to the pozzolanic effect. There is an optimal dosage for using a single activator to activate SSP. The effect of using multiple activators in combination is better than that of single one. The strength increases with the increase of the specific surface area (SSA) of SSP. However, if the SSA is too high, it will not only increase the preparation cost, but also reduce the increase in strength due to the agglomeration effect of SSP. The optimal range of specific surface area SSA is 400 m2/kg~500 m2/kg. With the increase of age t, the compressive strength increases. The effect of the curing methods on the compressive strength is hot and heat curing > standard curing > natural curing.