Effect of Coupled Mechanical-Chemical Activation on Hydration Activity of Copper Slag Powder

Abstract

In order to investigate the effect and mechanism of coupled mechanical–chemical activation on the hydration activity of copper slag powder, copper slag powder with different grinding time and content was applied to prepare composite cement. The hydration heat and rate of the composite cement paste were tested for 120 h. The mechanical properties and microstructure of the samples were characterized by compressive strength activity index, XRD, and SEM. The findings revealed that the specific surface area of the copper slag powder increased by 27.84%, 20.14%, and 10.92%, respectively, when the grinding time increased from 30 min to 120 min. The particle size distribution of the copper slag powder after grinding for 90 min and 120 min was superior to that of cement. The compressive strength activity index of the paste specimen increased with the extension of the copper slag grinding time when the copper slag powder content remained constant. Chemical activator CaO further stimulated the hydration activity of copper slag powder, increased the hydration heat of copper slag powder-based composite cement paste, and promoted the compressive strength of composite cement-hardened paste at different ages. With the increase in copper slag powder content, the porosity of the hardened paste increased, resulting in a decrease in compressive strength at different ages.