Evaluation and molecular interaction of asphalt modified by rubber particles and used engine oil

This study investigates the molecular mechanism of used oil on improving the compatibility and viscosity reduction of rubberized asphalt (RA) using molecular simulations and lab tests. This validates the feasibility of producing waste oil modified RA while enhancing the sustainable use of resources and pavement performance. The model of RA with used oil was first built by Materials Studio software. Several molecular dynamics parameters were used to explore the molecular behavior, stability and viscosity of asphalt. Furthermore, the relevant experiments were employed to validate the results of molecular simulation. The results show that used oil molecules can promote the dispersion of macromolecules, including asphaltenes, resins and rubbers, making the system more in accord with the asphalt colloid theory. It supplements the light components in the system to provide a stable dispersion medium. FTIR spectra confirm the rubber activation with used oil and microwave radiation. The softening point difference of RA was reduced from 1.9 to 0.35 °C. Viscosity was even reduced by approximately 67.1%.