Preparation and hydration process of copper slag-granulated blast furnace slag-cement composites

Abstract

Replacement of cement by solid wastes is an effective method to utilize secondary resources and reduce CO2 emissions. In this study, copper slag (CS) and granulated blast furnace slag (GBFS) were used to replace cement to address the low activity of CS, which limits its large-scale utilization. The dissolution characteristics, compressive strength, hydration products, and microstructure of the composite cementitious materials containing CS and GBFS were investigated. The results showed that adding GBFS into the CS-cement composites increased the compressive strength, and the 3-day and 28-day strengths could be increased by 112% and 90%, respectively. The CS acted as a diluting and heterogeneous nucleating agent, promoting the hydration of the GBFS and cement to produce more C−S−H gels. In addition, the number of pores decreased and the microstructure densification increased. This study provides a solution for the comprehensive utilization of CS, which contributes to the high-value green utilization of solid wastes.