Preparation and characterization of composite epoxy asphalt based on modified graphene oxide: Enhancements in toughness, thermal stability, and workability

To address the issues of insufficient toughness and challenging in construction of epoxy asphalt pavements, this study introduces amino groups (-NH 2 ) from γ-aminopropyltriethoxysilane onto the surface of graphene oxide through a condensation reaction which was then used to modify epoxy asphalt. This modified graphene oxide (APs-GO) is then incorporated as a modifier into the epoxy asphalt, resulting in a composite modified epoxy asphalt, which is further evaluated for key properties such as tensile toughness, low-temperature bending toughness, retention time, and high-temperature thermal stability. The results of tensile tests indicate that the modification of graphene oxide with γ-aminopropyltriethoxysilane introduces siloxane bonds and hydrogen bonds, enhancing its compatibility and interfacial adhesion with epoxy asphalt, which in turn improves both tensile toughness and low-temperature bending toughness. Viscosity-time behavior tests demonstrate that the addition of APs-GO effectively prolongs the curing process of the epoxy asphalt, providing proper working time for construction. Additionally, Soxhlet extraction method confirms that the incorporation of APs-GO leads to a more uniform cross-linking and polymerization of the epoxy molecular chains within the asphalt binder. Microscopic analyses, such as thermogravimetric analysis (TGA) and X-ray diffraction (XRD), show that the addition of APs-GO effectively improves the thermal stability of the epoxy asphalt. Furthermore, differential scanning calorimetry (DSC) results indicate that the incorporation of APs-GO lowers the glass transition temperature of the epoxy asphalt from 9.64 °C to −7.07 °C, significantly improving its low-temperature performance.