Interaction state and element leaching of waste incineration fly ash-asphalt mortar based on fillerization

•Adding fly ash and increasing the replaced amount could significantly improve the high-temperature rutting resistance and resistance to unrecoverable deformation of asphalt mortar, but the low-temperature performance was weakened.•Segregation had no discernible effect on fly ash-asphalt mortar's heavy metal dissolution concentration, and the mortar's storage stability was excellent.•Before and after segregation, the stabilization effect of asphalt on heavy metal leaching from fly ash was excellent, but the effect decreased with the increase of fly ash replaced amount.•When the replaced amount of fly ash was 25%-50%, the overall efficacy of fly ash-asphalt mortar was optimal.