Effect of belite-rich cement on the micro/macro properties and sustainability of slag–oyster powder–cement-based ternary materials

Abstract

Against the backdrop of global urbanization, the production of cement materials continues to increase. The need to meet development needs also raises concerns about environmental pollution. The cement industry is confronting an increasingly serious challenge of reducing carbon emissions. Using supplementary cementitious materials to replace part of the cement is a direct way to reduce carbon dioxide emissions. In this study, ternary blended cement (TBC) was prepared using blast furnace slag (BFS), oyster powder (OSP), and belite-rich cement on the micro/macroscale, and ternary slag–oyster powder–cement-based materials were prepared by partially or completely replacing the Ordinary Portland cement (OPC) in TBC with more environmentally belite-rich cement (BRC).The surface resistivity, and ultrasonic pulse velocity (UPV), mechanical properties of the hybrid samples were assessed through macroscopic experiments. Microscopic characterization of the samples included heat of hydration, thermogravimetric analysis (TG), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). Finally, the sustainability of CO₂ emissions per unit volume and strength of the mixed samples was assessed. The results indicate that substituting BRC for OPC can effectively reduce the cumulative hydration heat and surface resistivity of the mixed sample. At 90 d, a BRC substitution ratio of one-third yields the highest compressive strength, while complete replacement results in the lowest compressive strength. BRC substitution decreases the CO₂ emissions per unit volume of the mixed sample. The lowest CO₂ emissions per unit strength occur with a one-third BRC replacement ratio, which is identified as the optimal substitution level.