Study on the Activity of Filter Slag Powder in Concrete Batching Plants and Its Effect on the Properties of Cement Mortar
Addressing the resource utilization of filter slag powder in concentrate batching plants,this study analyzed its mineral composition,used chemical titration and thermogravimetric methods to estimate the content of unhydrated cement in the slag,and examined its effects on the water demand and mechanical properties of cement mortar.The results showed that the mineral types in the filter slag powder were stable,and its water demand was higher compared to cement.The mass fraction of unhydrated cement in the slag was about 27.7%after 18 days of storage,indicating low activity.Grinding treatment had a negligible effect on improving the activity of the filter slag powder.Compared to the original filter slag powder,the ground filter slag powder had a minimal effect on improving the compressive strength and flexural strength of cement mortar.The drying shrinkage performance of concrete mixed with finely ground filter slag powder was poorer than the control group,and the drying shrinkage rate reached its maximum at 28 days.After 28 days of standard curing,the surface of the filter slag powder concrete exhibited discontinuous fibrous C-S-H gel,which was disordered and not in a network structure.