Influence of weld seam on the compaction characteristics of steel bridge deck pavement asphalt mixture

Many weld seams are generated to connect the orthotropic steel bridge decks (OSBDs), which poses a potential threat to the compaction quality of steel bridge deck pavement (SBDP) asphalt mixture. To clarify the influence of weld seam on the compaction characteristics of SBDP asphalt mixture, the coupled finite element method-discrete element method (FEM-DEM) model with weld seam was established to simulate the SBDP asphalt mixture compaction process, and the simulation results were verified with the field compaction ones. Then, the influence of different weld seam heights on the compaction quality was analyzed and the coupling effect under different compaction speeds was also investigated. Moreover, the impact of weld seam on the particle bonding failure mechanism was further examined. Results show that the weld seam height has little effect on the SBDP asphalt mixture compaction quality under low compaction speed, while large compaction speed would reduce the SBDP asphalt mixture compaction quality, and the existence of weld seam would exacerbate this adverse effect and prompt the particle bonging failures. The SBDP crack propagation process above the weld seam is divided into the initiation, propagation, acceleration and stagnation stages. Furthermore, optimization suggestions for SBDP asphalt mixture compaction quality monitoring were given: for the 25 mm and 30 mm thick SBDP lower layer, the weld seam height is recommended not more than 2 mm and 3 mm, respectively; the compaction speed is recommended not more than 3 km/h and 4 km/h, respectively. The findings contribute to proving the theoretical guidance and technical support for the lean construction of SBDP.