Abstract: This study focuses on the performance and environmental safety of municipal solid waste incineration (MSWI) fly ash melt-derived products as aggregates in cement concrete pavement. Through a process of “electric furnace melting followed by forced washing” applied to a mixture of fly ash and quartz sand (at a ratio of 100.0∶17.6), vitrified slag was produced. This slag was subsequently sieved and its gradation optimized for use in mortar specimen preparation, followed by characterization of its fundamental physical and chemical properties. The results demonstrated that the mortar specimens prepared with the optimally graded vitrified slag achieved a 28-day compressive strength of 32.9 MPa and a wet density of approximately 2.5 t/m3, meeting the mechanical requirements for road construction materials. Under simulated acid rain conditions (pH = 4.32), the leached concentrations of Cr, Ni, Cu, Zn, As, Cd, Pb, and Mn were all significantly lower than the limits stipulated in the Technical Requirements for Solid Waste Vitrification Product (GB/T 41015—2021). Predictions based on the US EPA 1315 semi-dynamic leaching test indicated exceptionally low cumulative leaching amounts over 15 years, with Zn showed the highest value at 2.12 mg/kg and Cd the lowest at 0.001 mg/kg. The accelerated leaching method established in this study showed a deviation of less than 10% compared to the long-term predicted results, verifying its validity. The vitrified slag demonstrates strong potential for application as an aggregate in cement concrete pavement.

Key words: municipal solid waste incineration fly ash, vitrified valorization products, performance analysis, safety assessment