Epoxy‐ SBS Modified Asphalt With a Dual Synergistic Network: Microstructure, Rheological Performance, and Workability

ABSTRACT Styrene‐butadiene‐styrene (SBS) modified asphalt suffers from the susceptibility of its physical network to failure at extremely high temperatures, while epoxy asphalt (EA) is often brittle and exhibits poor compatibility with asphalt. These limitations restrict their application in high‐performance pavements. Combining epoxy resin (ER) with SBS to synergistically enhance the high‐temperature performance of asphalt presents a promising approach. In this study, ER/SBS composite modified asphalt (ESBA) with different ER contents was prepared. The rheological properties, high‐temperature rutting resistance, and workability were systematically evaluated. Fluorescence microscopy (FM) revealed a unique phase behavior in ESBA. The composite modified asphalt containing 3 wt% SBS and 7 wt% ER relative to base asphalt (7ESBA) exhibited the optimal high‐temperature performance. It possessed the highest complex modulus, a plateau in the phase angle at high temperatures, the lowest non‐recoverable creep compliance ( J nr = 0.0219 kPa −1 @ 3.2 kPa), and the highest recovery rate ( R = 89.66% @ 3.2 kPa), significantly outperforming conventional SBS‐modified asphalt (SBA) and pure EA. Furthermore, 7ESBA demonstrated a moderate viscous flow activation energy and construction viscosity, achieving a balance between pavement performance and workability. This work provides an important theoretical and experimental basis for developing high‐performance asphalt paving materials.