Experimental and molecular dynamics investigation of graphene oxide-modified bio-oil rejuvenated asphalt binder

Bio-oil, a waste material, has been increasingly used for rejuvenating aged asphalt, but ensuring the pavement durability of bio-oil rejuvenated asphalt remains challenging. This study employs graphene oxide (GO) to enhance the performance of bio-oil rejuvenated aged asphalt extracted from Reclaimed Asphalt Pavement (RAP). First, response surface methodology (RSM) was used to design the test plan. Then, penetration, softening point, and high- and low-temperature rheological tests were conducted, followed by microscopic characterization. Finally, molecular dynamics (MD) simulations were performed to reveal the enhancement mechanism of GO. Results indicate that incorporating GO enhances high-temperature performance and fatigue resistance. The optimized mix proportions are 0. 8 % GO, 7.3 % bio-oil, and 30 % virgin asphalt. Bio-oil replenishes light fractions and repairs microcracks in aged asphalt, while GO is uniformly distributed within the asphalt. The interaction energy between GO and asphalt depends on the surface functional group density of GO. These findings provide new insights into the application of bio-oil rejuvenated asphalt in pavement engineering, contributing to enhanced sustainability. • The optimal dosage of the bio-oil rejuvenator was determined using RSM. • The microscopic characteristics of the rejuvenated asphalt were revealed. • The enhancement mechanism of GO was explained from a molecular perspective.