Review of the state-of-the-art techniques for enhancing the toughness of thermosetting epoxy asphalt

Epoxy asphalt is widely utilized for steel bridge deck pavement due to its excellent performance. However, its inherent brittleness makes the pavement layer prone to cracking under low-temperature loading conditions. Numerous studies have been conducted to explore singular modification methods, yet the issue remains unresolved. This review summarizes the research progress on multiple mechanisms and strategies for toughening epoxy asphalt materials. It discusses representative studies involving modifiers such as rubber elastomers, thermoplastic polymers, hyperbranched polyesters, and fibers introduced at various levels including epoxy resin, epoxy asphalt, and epoxy asphalt concrete. The review elaborates on multiscale mechanisms including enhanced damping, cooperative deformation, increased flexibility of the framework, and cooperative stress relaxation. The results indicate that while single modification methods contribute to enhancing the toughness of epoxy asphalt materials, multi-level, multi-mechanism modifications are superior to singular modifications. Looking ahead, the design of functionalized nano-reinforcement materials and multi-component interface-compatible adjustive materials holds promise for enhancing the performance of epoxy asphalt composites to meet increasingly stringent infrastructure demands. This research provides a new perspective for the comprehensive optimization of multifunctional composite materials.