Insights into the microstructure and mechanical properties evolution of hydration products in cementitious materials incorporating GGBFS

Previous studies show that the incorporation of ground granulated blast-furnace slag into PC (Portland cement) paste increases the complexity of hydration products. However, the relationship between microstructure and mechanical properties of hydration products in PC-slag paste is still unclear. Backscattering electron imaging, energy-dispersive X-ray spectroscopy and nanoindentation were applied to understand the relationship between microstructure and mechanical properties of hydration products in pure PC, PC-Slag blended and pure slag paste. It is found that the composition may not be the main factor determining the mechanical properties of hydration products in pure PC, PC-slag blended and pure slag system. In dual-component cementitious system (PC-slag blended system), the continuous generation of C-A-S-H in the long-term hydration contributes to the densification of Op, resulting in the improvement in the overall elastic modulus of Op, which narrows the gap between the elastic modulus of Ip and Op with the increase of curing age.