Overall material sustainability assessment of earthquake debris rca in pavement base layers using an entropy-weighted adaptive SAFE–fuzzy model

Abstract

The massive accumulation of debris following the 2023 Kahramanmaraş earthquakes necessitates sustainable resource recovery strategies for resilient infrastructure reconstruction. This study establishes a multi-criteria decision-making framework to evaluate the Overall Material Sustainability (OMS) of pavement base layers incorporating earthquake-induced Recycled Concrete Aggregates (RCA) at varying replacement ratios (0% to 100%). An adapted hierarchical Sustainability Assessment by Fuzzy Evaluation (SAFE) model was developed to overcome the limitations of traditional engineering thresholds. First, 30 primary engineering and ecological indicators, derived from standard testing and techno-economic analysis, were objectively weighted using the Shannon Entropy method. These were structured into five core dimensions: Mechanical Performance, Physical Durability, Environmental Safety, Economic Efficiency, and Social Impact. Subsequently, a Mamdani fuzzy inference system (FIS) aggregated these into Technical Performance and Socio-Eco Efficiency, yielding crisp OMS scores. The defuzzified results, mapped against the Prescott-Allen Sustainability Barometer, revealed a parabolic penalty mechanism for extreme designs. Mix-0 (100% natural aggregate) and Mix-100 (100% RCA) fell into potentially unsustainable zones with scores of 0.380 and 0.320, respectively, failing to balance ecological preservation with structural safety. Conversely, among the five investigated mixtures, Mix-50 (50% RCA) achieved the highest model-derived score (0.740) and the best-performing balance between load-bearing requirements, landfill diversion, and carbon reduction. This model-specific optimum depends on the selected indicators, Shannon Entropy weights, and fuzzy rule base and is not a universal RCA replacement ratio. Ultimately, this framework provides a robust, data-driven tool to optimize disaster waste management and accelerate sustainable urban recovery.