Curing behaviour effect of epoxy asphalt on the microstructure and physicochemical properties of a modified epoxy mastic asphalt mixture

To alleviate reliance on unsustainable Trinidad Lake Asphalt (TLA), a novel epoxy-modified MA binder was developed as a substitute for conventional binders. This study evaluated the impacts of curing temperature and duration on the multi-scale microstructural evolution and physicochemical properties of the binder and mixture. FTIR, LSCM, viscometry, and mechanical testing were deployed. Results demonstrate an exponential increase in curing degree over time. Both binder viscosity and phase morphology stabilized after 120 min, achieving a highly uniform polymer dispersion (average particle size: 0.2–0.3 µm) and lowered temperature susceptibility. At the mixture level, elevated curing temperatures enhanced the stiffness modulus and fatigue life but compromised permanent deformation resistance. This performance difference stems from temperature-induced epoxy particle refinement, which alters internal lubrication and healing mechanisms. The developed binder offers a sustainable, high-performance alternative to conventional TLA-MA systems.