Effect of Curing Reaction Behaviors of Warm Mix Epoxy Asphalt Concrete on Its Field Compaction Characteristics Using Discrete-Element Method

The irreversible curing reaction of thermosetting epoxy asphalt mixture (EAM) brings challenges to the construction of epoxy asphalt concrete (EAC) on the steel bridge deck, and the curing reaction degree (CRD) of EAM before compaction has a great influence on the compaction quality. The objective of this study is to investigate the effects of excessive CRD condition and uneven CRD condition of warm mix EAC on its field compaction. To achieve this goal, a field compaction model for EAC on a steel bridge deck was developed using discrete-element method (DEM) first. In the DEM model, a two-stage contact model that combined Burges model with the parallel bond model was used to characterize the thermosetting and viscoelastic behaviors of EAM, and the values of the contact model's parameters under different CRDs were determined by a trial calculation method based on Superpave gyratory compaction test. Subsequently, the field compaction process of cured EAM with different CRDs was simulated by changing the contact parameters' value, and the effects of excessive CRD condition and uneven CRD condition on the compaction quality were analyzed. Results show that the highly cured EAM is hard to be compacted unless larger compaction loads are adopted in the repeated compaction. Uneven CRD of EAM is prone to generate the mixture agglomeration, and it has negative effects on the compaction quality of the surrounding EAM.