Preparation and Performance Evaluation of Warm-Mixed Epoxy Asphalt Ultrathin Overlay by Post-Doping Method

Abstract

Post-doping construction technology overcomes the difficulties of demanding construction requirements of warm-mix epoxy asphalt mixture (EAM) that limit its application, and it provides a new idea for the scaled application of EAM. To provide reliable support for the application of an epoxy asphalt ultrathin overlay (EAUTO), warm-mix EAM was prepared by simulating the post-doping method in the lab, and the Marshall molding method with reduced specimen thickness was considered. EAUTO moisture susceptibility, raveling resistance, and cracking resistance were evaluated to verify the feasibility of EAUTO molding. Furthermore, EAUTO long-term skid resistance and stripping resistance were analyzed in detail. The results showed that thin-layer molding solves the problem of the inappropriateness of conventional Marshall stability equipment for EAM and has cost-saving and efficiency advantages. The recommended molding parameters for the warm-mix EAUTO were 25 blows/face and a thickness of 30.0±0.6 mm. Despite the reduction in specimen thickness, moisture damage resistance and raveling resistance of the thin-layer EAM specimens were slightly attenuated compared with the original specimens but were acceptable, and the mechanical properties were still better than those of SBS-modified asphalt. Regarding cracking resistance, the evaluation results for the thin-layer specimens demonstrate consistency with those of the original specimens. Additionally, the cracking resistance of gap-graded mixes was better than that of dense-graded ones. The EAUTO showed excellent long-term stripping resistance and skid resistance durability compared with asphalt modified with styrene-butadiene-styrene (SBS). However, it is worth noting that the traditional texture depth was not suitable as a separate indicator for evaluating long-term skid resistance.