Study on the properties of nano-Fe3O4 modified asphalt materials based on molecular dynamics

Abstract

Asphalt possesses the inherent ability to self-heal microcracks, with enhanced healing observed under active heating conditions. Nanomaterials have the capacity to alter the microstructure of asphalt blends, offering certain advantages in terms of asphalt performance. In this study, models of nano-Fe3O4 clusters and nano-Fe3O4/asphalt blending systems with varying particle sizes were established. Molecular dynamics simulations were employed to investigate the physical properties of nano-Fe3O4 and asphalt molecules at different temperatures, simulating the microwave heating process within a temperature range of 303 K to 373 K. The findings revealed that the diffusion coefficient of Fe3O4 clusters decreased with increasing particle size. Nonbonding interaction energy predominantly governed the binding between Fe3O4 clusters and asphalt molecules. The incorporation of nano-Fe3O4 was found to enhance the physical properties of asphalt. Peak values of the radius of gyration for asphaltene and aromatics indicated increased density, while asphaltene, colloids, and aromatics exhibited greater extensibility with the addition of nano-Fe3O4.