Thermal and mechanical properties of recyclable epoxy asphalt vitrimers

Epoxy asphalt has been extensively utilized in the construction of long-span steel deck bridges. Due to its thermosetting nature, however, the end-of-life epoxy asphalt cannot be reclaimed as thermoplastic polymer modified asphalts. In this paper, recyclable epoxy asphalt vitrimers (EAVs) were developed by introducing bond-exchange reactions into epoxy resin with fatty acids as curing agents. The existence of asphalt accelerated the bond-exchange reaction of the epoxy vitrimer (EV). Furthermore, the relaxation time of EAVs decreased with the asphalt concentration. The recycling enhanced the storage modulus of EAVs at the glassy stage. However, the glass transition temperature remained after recycling. The recycling lowered the mechanical properties of EAVs. However, both tensile strength and elongation at break of EAVs increased with the recycling time. For EAV containing 45% asphalt binder, the tensile strength and elongation at break after three-time recycling were onefold and twofold higher than those after only one-time recycling. The use of renewable epoxy resin in the development of epoxy asphalt not only reduces the dependence on petroleum resources but also makes the recycling of epoxy asphalt feasible.