Evaluation of the Composite Mechanism of Nano-Fe₂O₃/Asphalt Based on Molecular Simulation and Experiments

Asphalt, as an indispensable binder in road paving, plays an important role in transportation development. However, the mechanism of action between the modifier and asphalt cannot be fully explained by the existing test methods. This paper combines molecular simulations with experiments to provide a research and analysis tool to evaluate the "structure-performance" relationship of asphalt. From the trend of experimental results, the optimal content of Nano-Fe₂O₃ is 1% to 3%. The AFM micrograph of the asphalt material shows that at 3%, the Nano-Fe₂O₃ can be effectively dispersed in the asphalt and the unique " bee structures " of the asphalt can be adsorbed around the modifier. Molecular dynamics studies and results show that when Nano-Fe₂O₃ are incorporated into the asphalt and have a strong adsorption force on the colloidal structure of asphalt, the " bee structures " can be adsorbed around the Nano-Fe₂O₃. In the range of 208-543 K, the sol-gel structure of asphalt in the Nano-Fe₂O₃/asphalt composite system is gradually disrupted.