Improved Chemical System for Molecular Simulations of Asphalt

Molecular simulation methods have become popular to explore the micromechanical and thermodynamic properties of asphalt. The chemical components of the system are the key to accurate and reliable results. In this research, molecules to simulate fresh asphalt are collected from existing research, and molecules to simulate aged asphalt binders are generated according to the widely accepted aging chemistry of asphalt. Using these molecules, a new asphalt chemical system is proposed, in which three typical asphalt models and the corresponding aging models are established. The mass fractions of saturate, aromatic, resin, and asphaltene and of elements found with the model are very close to test results. The density of the stable model is calculated and compared to that of the real materials. The simulated atomic force microscopy force curve is used to calculate the maximum adhesion force, nanohardness, and modulus of the asphalt surface. The model characterizes the aging characteristics of asphalt binders well.