Experimental and molecular dynamics study on regeneration mechanisms of aged asphalt with DOA plasticiser

To promote the recycling of aged asphalt, the Dioctyl phthalate (DOA) plasticiser was utilised to restore the properties. The rheological properties of recycled asphalt and the mechanism of recycling were comprehensively investigated by bending beam rheometer (BBR) and dynamic shear rheometer (DSR) as well as molecular dynamics simulation. The research results indicate that a 3% dosage of DOA resulted in the long-term aged base asphalt having better high and low-temperature rheological properties than the unaged base asphalt. DOA can significantly reduce the binding energy between asphaltene and resin, enhancing the solvation of asphalt micelles by the aromatics. The inclusion of DOA enhances the diffusion coefficients of all four components within aged asphalt by an excess of 65%. DOA molecules can effectively get into the void of the asphalt micelles to weaken the spatial interaction between the resin and asphaltene and increase the proportion of free resin molecules in the asphalt.