ABSTRACT
The main objective of this study is to use Molecular Dynamics (MD) simulation to investigate the rejuvenating process of aged asphalt at the molecular scale. The penetration process of rejuvenator into virgin and aged asphalt was studied using three-layered diffusion models. The diffusion behavior of asphalt binder and rejuvenator was evaluated using inter-diffusion coefficients based on Fickian law. The MD simulation results show that adding rejuvenator increases inter-diffusion of virgin and aged asphalt, which indicates that rejuvenator can improve the blending efficiency of virgin and aged asphalt. At the same time, the calculated inter-diffusion coefficients indicate that the rejuvenator diffuses faster into virgin asphalt binder than aged asphalt binder. The application of MD simulation enables direct observation of molecular interaction in the rejuvenating process and helps better understand the interaction mechanisms between rejuvenator and asphalt binder.
