Effect Of Steel Slag Powder On Performance Of Cement Based Materials

The application of slag powder and slag powder mixed as the replacement of cement is an important way to improve the utilization ratio of steel slag. Currently national standard "steel slag powder"(GB 28293-2012) gives the activity grades of different compound powder. However, there are no specific requirements for the proportion of steel and slag powder including the specific surface area of steel powder for each grade. In this paper, a systematic study has been carried out on the key technical problems in the development and application of steel slag powder in order to determine the specific surface area of slag powder, the proportion of steel and slag powder and provide the technical guidance of its application in cement-based materials.In view of the application of steel slag powder in cement based materials, a series of laboratory experiments has been conducted in this study. The effect of different specific surface area of steel slag powder on cement properties, including standard consistency water demand, setting time and soundness and fluidity ratio, compressive and flexural strength was investigated. At the same time, the different mixing ratio of steel to slag powder was designed to study its effect on cement properties and the G85 steel slag powder was prepared. Three kinds of concrete with different strength grade C30, C40 and C50 containing G85 powder were investigated. The main conclusions can be concluded as follows:(1) The appropriate specific surface area of steel powder is 2370 m2/kg(BET), while the grinding energy consumption of steel slag is relatively low, and the cementitious activity of steel slag is better. Steel powder has good effect on the late strength of cement. The toughness of the steel slag cement can be improved.(2) Cement standard consistency water and setting time increase with the increasing of steel slag in steel slag powder. The best ratio of steel and slag powder in steel slag powder is 1:4.This proportion of steel slag powder has high cementitious activity, and can meet the cementitious activity of G85 steel slag powder.(3) G85 steel slag powder was used to the preparation of C30, C40 and C50 concrete. The three different concretes have good working performance, steady growth of late strength, and good durability.To sum up, steel slag grinding is conducive to improving the activity, steel slag powder has good activity, for the preparation of the conventional grade of concrete and concrete working performance, mechanical property and durability. The results of this study have important significance for the popularization and application of steel slag powder in cement based materials.