空隙形态及分布对钢桥面沥青铺装层断裂行为的影响

Influence of Air Voids Morphology and Distribution on Fracture Behavior of Asphalt Pavement Used for Steel Bridge Deck

为了研究空隙的细观构造(整体空隙率大小、单个空隙大小和空隙空间分布)对钢桥面用沥青混合料断裂行为的影响,首先借助三维颗粒流程序(PFC3D)内置"Fish"语言,构建了包含粗集料、沥青砂浆和空隙在内的沥青混合料虚拟试件,采用离散元方法实施了单边切口小梁虚拟三点弯曲试验。虚拟试验结果揭示并理论验证了钢桥面环氧沥青铺装空隙率应小于3%这一技术要求,同时空隙的空间分布应相对分散、均匀,对接近铺装层表面的受拉区域应尽量避免空隙集中现象,为优化完善钢桥面环氧沥青铺装的抗裂设计提供了合理建议。

In order to research the influence of the air voids microstructures (porosity, single void size and void distribution) on the fracture behavior of the asphalt mixture used on the steel bridge deck. Firstly, an asphalt mixture virtual specimen including the coarse aggregate, the asphalt mastic and the air voids was reconstructed using the Fish language provided in the three dimensional particle flow code (PFC3D). Secondly, a single - edge notched beam virtual three - point bending test was implemented using the discrete element method ( DEM). The virtual test results indicate and theoretical validate the technical requirements, which the void ratio of the epoxy asphalt pavement used for the steel bridge deck should be less than 3 % . Moreover, the space distribution of the air voids should be dispersive and uniform, and the tensile zone approaching the surface of pavement must avoid to the air voids concentration phenomenon. The results provide the reliable suggestions to optimize the crack resistance design for the epoxy asphalt pavement used for the steel bridge deck.