Life Cycle Environmental Evaluation Framework for Mining Waste Concrete: Insights from Molybdenum Tailings Concrete in China

This study uses the case of substituting natural river sand with molybdenum tailings in concrete production in China to propose a methodological framework for evaluating the life cycle environmental impact of concrete materials. This approach addresses the mechanical performance adaptability and environmental friendliness, as well as the resource utilization of solid waste. The resource consumption, environmental impact, and economic costs are systematically analyzed using a life cycle assessment (LCA) approach, and the circular economy potential of tailings-based concrete is explored. A three-dimensional evaluation framework is constructed, encompassing raw material production, transportation, and construction stages. The environmental impacts of concrete with different molybdenum tailings replacement rates and strength grades are quantified using a willingness-to-pay (WTP) model. The results indicate that increasing the dosage of molybdenum tailings can significantly reduce environmental indicators such as global warming potential and acidification potential value. Specifically, C30 concrete with a 100% replacement rate shows an 8.5% reduction in total WTP compared to ordinary concrete, with a 2.85% reduction in energy consumption during the production stage. High-strength concrete further optimizes the environmental cost per unit strength through the “strength dilution effect,” with a 44.9% reduction in carbon footprint for 60 MPa concrete compared to 30 MPa concrete. Regional analysis reveals that the environmental contribution of the production stage dominates in short-distance transportation scenarios, while logistics optimization has a significant emission reduction effect in long-distance transportation scenarios. The study demonstrates that the proposed LCA methodology provides a scientific approach for the development of green building materials and the sustainable resource utilization of solid waste through case-informed generalization.