Evaluating the sustainability of microwave pre-cured high-volume slag concrete: Mechanical properties, environmental impact and cost-benefit analysis

Microwave pre-curing, a novel method, offers numerous advantages including energy and time efficiency. The mechanical performance and durability of high-volume slag concrete (HVSC) subjected to microwave curing were experimentally investigated in this study. Additionally, the environmental impact and cost-effectiveness of microwave-cured HVSC were studied, and the ecological efficiency and cost efficiency were analyzed in conjunction with compressive strength and durability. Experimental results indicate that microwave curing significantly enhances the early-stage hydration reaction rate of concrete, increasing the yield of hydration products, especially AFm. Consequently, the early-stage porosity decreases, and the early compressive strength and electrical resistivity of the mortar increase significantly. Furthermore, microwave curing significantly improves the early-stage ecological efficiency and cost efficiency of HVSC. Although the ecological efficiency and cost efficiency of later-stage strength decrease slightly, the durability ecological efficiency and cost efficiency have increased by 12.41-24.6 % and 13.79-26.89 %, respectively, compared to the control group. Time-saving analysis indicates that microwave curing can significantly reduce the curing time for samples by quickly enhancing the early mechanical properties of the materials. Specifically, microwave curing can shorten the curing time by 2.09 days when the compressive strength requirement reaches 20 MPa, and by 2.62 days when the requirement is 30 MPa.