Multi‐Physical Properties of Epoxy Asphalt Under Component Variations: A Molecular Dynamics Simulation and Experimental Study

A lack of unified testing and evaluation methods for both thermoplastic and thermosetting epoxy asphalt (EA) impedes the characterization of its performance evolution across varying epoxy resin system (EPS) contents, thereby limiting its optimal design. To address this gap, this study constructed and validated molecular models reflecting different EPS contents and curing degrees. Key thermal, volumetric, and mechanical properties were calculated via simulation and comprehensively analyzed alongside experimental results to understand the evolution of the physical characteristics of EA. The findings indicate that the volumetric features and glass transition behavior of EA are significantly influenced by both EPS content and curing degree. A critical transition from an asphalt-dominated thermoplastic state to a cross-linked–network-controlled thermosetting state begins at 30 wt% EPS. While increasing EPS content enhances heat resistance, its higher thermal expansion adversely affects the volumetric stability of the material. Notably, EA40 (40 wt% EPS) demonstrates a superior balance between stiffness and damping performance over EA50. Moreover, MD simulations successfully overcame experimental limitations, revealing consistent trends in modulus evolution and the ductile-to-brittle transition with increasing EPS content. These results offer molecular-level insights into the performance evolution of EA, promoting its design for diverse and multi-scenario applications.