Development and evaluation of roadway-oriented epoxy-modified asphalt binders and mixtures

Epoxy asphalt (EA) is considered a highly promising solution for long-term asphalt pavement due to its excellent comprehensive properties. This study proposed a novel curing agent, which is a modified amine with an unsaturated fatty carbon chain. For the first time, this agent is suggested to be employed to generate roadway-oriented epoxy-modified asphalt (REA). The rheological characteristics, ductile failure resistance, and microscopic morphology of the REA binder were assessed. Additionally, the pavement performance of both semi-cured and fully-cured REA mixtures was analyzed. The substitution reaction occurring between the unsaturated CC bond in the curing agent and the C-H bond in asphalt considerably enhances the compatibility between epoxy and asphalt. Furthermore, the reactivity of the unsaturated CC bond in SBS with the curing agent facilitates the fusion of SBS phase and the epoxy phase. The presence of SBS reduces the critical epoxy content required for phase inversion in REA. The rheological properties of REA modified by SBS-epoxy exhibit substantial improvements in both high and low temperatures, outperforming the effects achieved by single epoxy or SBS modifications. The construction duration of REA mixtures is further extended to 5–6 h, fully satisfying the requirements for workability during construction. The co-modification of epoxy and SBS significantly enhances the high-temperature deformation resistance, low-temperature crack resistance, and fatigue resistance of REA mixtures. Specifically, the semi-cured REA mixtures possess a dynamic stability of 12115 times/mm, enabling immediate traffic opening after construction. The results of this study had a positive impact on the practical application of REA in engineering. •A novel curing agent was used to prepare roadway-oriented epoxy-modified asphalt (REA).•The substitution reaction between curing agent and asphalt enhances the compatibility between epoxy and asphalt.•The interaction between SBS phase and epoxy phase reduces the critical epoxy content associated with phase inversion.•The REA mixture perfectly solves the contradiction between construction duration and curing time.