Simulation of nanoscale behavior and cross-scale correlation analysis of pyrolysis carbon black-based composite modified asphalt

Pyrolysis carbon black (PCB)-based composite modified asphalt is a new type of environmentally friendly material, yet the complex interactions between its components remain challenging to characterize. To elucidate the performance regulation mechanism of multi-component and multi-phase modifiers in asphalt, this study investigated the interfacial evolution of polyethylene (PE)/synthetic plant ester (SPE) modified asphalt (PE/SPE-A) on the PCB surface using molecular dynamics. Guided by the concept that macroscopic performance emerges from cumulative molecular diffusion and interfacial interactions at the microscale, a grey relational analysis was employed to establish a cross-scale connection. This approach identified highly correlated indicators, providing an experimental basis for precise macroscopic property prediction. Results show that the adhesion energy between PE/SPE-A and the PCB surface reaches 116.3% of the base asphalt, and the diffusion coefficient at construction temperature reaches 155.1% of the base asphalt. Additionally, the PCB surface exhibits strong selective adsorption toward asphaltenes. Correlation analysis reveals a significant correlation between the nanoscale behavior of the asphalt binder, naphthene aromatic components, and the conventional physical properties. These findings enable prediction and evaluation of the macroscopic properties of composite modified asphalt.