Effects of Rejuvenator on the Properties of Hot-Mix Recycled Epoxy Asphalt Binder Doped with RAP

Abstract

Asphalt pavement thermal recycling technology plays a crucial role in recycling waste road surface materials, offering a strategy for developing environmentally friendly pavements. The application of epoxy resin polymer (EP) and rejuvenator presents great potential in thermally regenerating reclaimed asphalt pavement (RAP) materials, promising to improve the toughness and reliability of road asphalt binders. This study systematically modeled the effect of rejuvenators on the hot-mix recycled epoxy asphalt binder, focusing on viscosity changes, tensile properties, rheological properties, chemical composition, and microstructural differences. The results indicate that aged asphalt doped with rejuvenator and epoxy resin (RAEA) effectively prolongs curing time and facilitates the construction allowance time compared with epoxy-modified aged asphalt (AEA) and epoxy asphalt (EA). Besides, the bond tensile elongation of RAEA can reach 200%, exhibiting that it meets the requirements for vehicle traffic repeated load. In rheological tests, the rejuvenator obviously improved the low-temperature cracking resistance and fatigue resistance of AEA. According to the Glover-Rowe (G-R) parameter and creep flexibility J(t), rejuvenator enhances the low-temperature rheology of AEA, reduces the risk of cracking, and results in a significant rejuvenation effect. In addition, the Fourier transform infrared (FTIR) and laser confocal microscopy (LSCM) analyses revealed that the rejuvenator can effectively reduce the carbonyl index (IC═O) and the sulfoxide index (IS═O), improving the compatibility of AEA. The RAEA structure changes considerably compared to AEA, undergoing a remarkable phase transition and forming a larger crosslinked network structure. Based on the tests, it was found that rejuvenators have a high potential for application in epoxy hot-mix recycled systems.