Leaching of metals from asphalt pavement incorporating municipal solid waste incineration fly ash

Abstract

Rising municipal solid waste incineration (MSWI) makes it imperative to recycle the fly ash (FA). FA can be solidified by asphalt and then applied in the asphalt road. However, little information on the metal leaching and associated with risks from asphalt solidified forms for FA is available. In the present study, metal leaching characteristics and long-term leaching potential from the asphalt-based FA matrices was determined based on the national standard method and simulating the actual using of the solidified forms in highways, respectively. The immobilization effect of asphalt on MSWI FA is well. Leaching velocity was in the order of magnitude of 10^~10⁻⁶ cm h⁻¹ during the entire leaching period. At the early age, leaching velocity of metals is high, especially Zn, Cd, and Ba. Cumulative leaching concentration of metals and leaching time has positive correlation. Only considering the leaching of simulating acid, leaching of metals in asphalt-based matrices is very slow, and the leaching toxicity of metals is lower than the Chinese National Standard.