Unlocking the potential of epoxy binders for efficient reclaimed asphalt pavement recycling: an experimental and molecular simulation study

The efficient utilisation of reclaimed asphalt pavement (RAP) has emerged as a critical focal point within pavement recycling technology. High-performance epoxy binders show promise in achieving this objective. This study investigates the interaction mechanisms between epoxy systems and aged asphalt from three perspectives: macroscopic properties, microscopic phase structures, and molecular structure of the asphalt-epoxy system. Results reveal that the aged asphalt-epoxy system has increased elongation at break and decreased tensile strength. Microscopic assessments show that the phase structure of the aged asphalt-epoxy system is denser compared to neat asphalt-epoxy systems. The looser structure of neat asphalt-epoxy systems provides more space for epoxy system chemical reactions, leading to higher crosslinking compared to both pure epoxy and aged asphalt-epoxy systems. Additionally, the epoxy system exhibits better compatibility with aged asphalt than neat asphalt. At the molecular level, the epoxy system strongly adsorbs onto asphalt components, especially aged resin molecules. These findings contribute to the scientific application of epoxy binder in pavement recycling technology.