Utilization of municipal solid waste incineration ash in stone mastic asphalt mixture: Pavement performance and environmental impact

The objective of this study is to the use of municipal solid waste incinerator (MSWI) fly ash as a partial replacement of fine aggregate or mineral filler in stone matrix asphalt (SMA) mixture. For saving natural rock and reusing solid waste, basic oxygen furnace slag (BOF slag) was used as part of coarse aggregate. And this makes SMA mixtures contain more than 90% solid waste materials by mass. A comparative study of the performance of two mixes designed using superior performance asphalt pavements (SUPERPAVE) and Marshall mix design procedures was carried out in this research. Samples from both mixes were prepared at the design asphalt contents and aggregate gradations and were subjected to a comprehensive mechanical evaluation testing. These tests included Marshall stability, water sensibility, resilient modulus, fatigue life and rutting. In all the performed tests SUPERPAVE mixtures proved their superiority over Marshall mixtures. TCLP test for environmental impact indicated that asphalt is an effective stabilization and solidification agent for heavy metal in MSWI ash. The heavy metal leachates in TCLP tests have great positive correlation with their initial concentration in waste. But Ni is an exception that lower initial concentration leaded to higher cumulative leaching rate.