Molecular Dynamics Simulation of the Performance-Related Properties of RAP Binder

As a sustainable paving practice, there has been increasing interest in the use of reclaimed asphalt pavement (RAP) during pavement reconstruction and maintenance. The behaviors of RAP have been studied in many lab and field experimental programs, which aim to characterize the effect of RAP on performance of asphalt pavement. However, there are debates on the maximum amount of RAP allowable for paving without compromising its performance. Research on the mixture containing varied proportions of RAP is therefore crucial to optimize the application of RAP. Asphaltene, the main chemical component in asphalt binder, is mostly reactive to oxygen. In this study, aged asphaltenes in RAP were created based on chemical changes. The model system with low potential energy was created by employing Monte Carlo simulation. Molecular dynamics (MD) simulation was carried out to evaluate the thermodynamic properties of aged asphaltenes, compared with original asphaltenes. The analysis was conducted at -15, 5, 25, 45, and 65 °C. This preliminary study paved the way for further study on the behaviors of the blended asphalt binder with recycled asphalt binder.