沥青路面磨耗层与下卧层组合结构力学行为分析

Mechanical Behavior of Composite Structures of Wearing Course and Underlying Layer for Asphalt Pavements

路面结构的层间状态在服役过程中受到各种因素的影响会发生改变,层间结合状态的改变对路面结构的力学行为会产生很大的影响。该文通过组合结构试验与数值分析,探究不同磨耗层与下卧层组合结构在不同应力和黏结状态下的力学行为。作为对比分析,试验考虑3种目前常用的沥青路面磨耗层(面层)材料:AC-13、OGFC-13和SMA-13。试验结果表明:不同组合结构由于材料特性的差异表现出不同的层间黏结性能与疲劳特性;与AC-13+AC-20组合结构相比,OGFC-13+AC-20和SMA-13+AC-20的抗剪切疲劳性能较强,但是抗弯拉疲劳性能较弱。层间压-剪破坏主要发生在层间界面和界面过渡区,可以观察到材料空隙结构的压缩与黏结界面的嵌挤变形;局部界面会有集料在挤压和剪切过程中破坏,随着界面剪切变形和滑移。弯拉应力作用下组合结构的疲劳破坏行为与压-剪应力作用下明显不同,材料特性的差异对其抗弯拉变形能力有显著影响,且疲劳失效形态受到层间黏结与接触咬合状态的影响;随着材料损伤的开展,裂缝由组合梁试件底部沿着集料周边向上开展,到层间界面时会沿着界面向两侧横向开展造成局部脱黏,随后再向上开展直到组合结构试件失效。

The interlayer bonding state of pavement structures changes due to the influence of various factors under service conditions,and this change exhibits a significant influence on the mechanical behavior of pavement structures.Through the composite structure test and numerical analysis,the mechanical behavior of the composite structure of different wearing courses and underlying layers under different stresses and bonding states was studied.The test used three commonly used wearing course(surface layer)materials of asphalt pavements,namely AC-13,OGFC‑13,and SMA‑13 for comparative analysis.The test results show that different composite structures exhibit different interlayer bonding properties and fatigue characteristics due to the difference in material properties.Compared with the composite structure of AC‑13+AC‑20,OGFC‑13+AC‑20 and SMA‑13+AC‑20 have stronger shear fatigue resistance but weaker flexural and tensile fatigue resistance.The interlayer compression-shear failure mainly occurs at the interlayer interface and the interfacial transition zone.The compression of the void structure of the material and the interlocking deformation of the bonding interface can be observed.The local interface will have the aggregate destroyed during the extrusion and shear process,accompanied by shear deformation and slippage of the interface.The fatigue failure behavior of composite structures under flexural and tensile stress is obviously different from that under compression and shear stress.The difference in material properties has a significant effect on its flexural and tensile deformation resistance,and the fatigue failure mode is affected by interlayer bonding and interlocking.With the development of material damage,the cracks develop upward from the bottom of the composite beam specimen along the periphery of the aggregate.When the cracks reach the interlayer interface,they develop laterally along the interface to cause local deadhesion and then develop upward until the failure of the composite structure specimen.