The deterioration of mechanical properties caused by asphalt ageing is the main cause of road surface damage, and regeneration aims to restore performance by reversing the ageing effect. However, the mechanism of how the regenerator restores the micromechanical properties of ageing asphalt is still not fully understood. This study uses molecular dynamics (MD) simulation to establish a molecular model of matrix asphalt, ageing asphalt and epoxy soybean oil (ESO) regenerated asphalt. Through the comparative analysis of uniaxial stretching and shear simulation, the mechanism of ESO to improve the mechanical properties of ageing asphalt is systematically clarified. The results show that ESO optimises the molecular arrangement in ageing asphalt, improves intermolecular interaction and hydrogen bonding, and improves the energy barrier of molecular movement, thus affecting the mechanical properties of regenerated asphalt. The ultimate tensile strain of recycled asphalt can reach 342% of its initial length, and the elastic modulus is reduced to 2.04 GPa (123.6% of the original asphalt), confirming the effectiveness of ESO in restoring tensile elasticity and extreme deformation ability. However, ESO also weakens the bearing stability in the later stage of asphalt stretching. Recycled asphalt exhibits an intermediate shear modulus of 141 MPa, so that asphalt changes from brittle rapid destruction to toughness slow damage while balancing fluidity and rigidity. This study deeply reveals the recovery mechanism of the tensile and shear properties of regenerated asphalt from the atomic perspective, which can be used as an evaluation index of the regeneration effect of different regenerative agents on the mechanical properties of asphalt.
Lin et al. (Mon,) studied this question.