Preparation and characterization of epoxy vitrimer asphalt based on transesterification dynamic covalent bond system

Epoxy asphalt is renowned for robust performance in road engineering, yet difficulties persist in crack repair and sustainability due to its rigid, crosslinked structure. Our study addresses these issues by introducing a novel epoxy vitrimer asphalt (EVA) that incorporates transesterification to boost self-healing capabilities without sacrificing the intrinsic benefits of traditional epoxy asphalt. EVA was developed with dynamic ester bonds that facilitate self-healing, using zinc acetate as a catalyst and multi-organic carboxylic acids as curing agents. Our research showed that adding vitrimer can improve EVA's mechanical properties and high- and low- temperature performance. Among all samples, the epoxy asphalt containing 30 wt% vitrimer was found to exhibit the most balanced performance. Self-healing tests showed that more significant effects were observed under lower damage levels, higher healing temperatures, and longer healing times. For example, at 50 % damage, 60 min, and 60 degrees C, self-healing indices above 70 % were recorded for all EVA samples, indicating strong self-healing performance. This innovative approach extends the service life of epoxy asphalt surfaces. By enhancing the material's self-healing properties, sustainable road construction practices are promoted.