New insights into the contribution of quartz powder byproduct from manufactured sand to the performance of cementitious materials

Quartzite stone powder (QP) is a mining and constructional byproduct that causes severe environmental problems. In this study, to realize its resourceful utilization, cement was partially substituted with four types of QP characterized with different fineness in preparation of an environment-friendly cementitious material. Mechanical properties, hydration heat releasing, hydration products, and porosity of blended materials were presented. The mechanism of the hydration process and microstructure evolution was discussed. The results show that the fineness of QP has a strong impact on the strength development as well as the hydration reaction. The addition of fine QP (600 and 800 m(2) kg(-1)) accelerates the hydration of cement by providing more nucleation sites for hydration products, and refines the pore structure via filling effect. Moreover, the incorporation of QP in binders could reduce cement usage and bring sustainability and economic benefits in reducing the energy consumption, carbon emission and cost of cementitious materials.