高压动水环境侵蚀对多孔沥青混凝土损伤效应的多尺度分析

With the construction of Sponge City and the requirements of drainage, anti-skidding and noise reduction on highway, porous asphalt pavement is of wide popularization and application prospects. However, under the influence of environment erosion, aging and load hydrodynamic scouring, porous asphalt concrete and its pavement structure can present multi coupling effect under high hydrodynamic pressure and environment erosion.By using theories and methods such as porous media, fluid mechanics, damage mechanics, chemistry and mesomechanics, in this project, physical indexes , compression, tension, tri-axial and fatigue experiments are employed under different conditions such as chemical environment erosion, aging and high pressure dynamic water. Then, with the application of both micro-analysis techniques such as Computed Tomography, Scanning Electron Microscope, Infrared Spectroscopy, X-ray Diffraction, Digital Image Processing and microstructure simulation analysis, the evolution law of component structures, pavement performances and mechanical performances of porous asphalt concrete and its composition materials under the effect of high hydrodynamic pressure and environment erosion are studied systematically. What’s more, the influence on them is also comparatively analyzed among factors such as salt liquid simulating acid rain, sea salt water and its concentration, their variation cycle, aging, hydrodynamic pressure and its loading cycle, temperature, gradation and porosity. In the end, the impact factor or damage factor of environment erosion, aging and hydrodynamic pressure concerning porous asphalt concrete and its composition materials as high viscosity asphalt and aggregate are supposed to be put forward. Whereby corresponding damage mechanism of porous asphalt concrete under the influence of high hydrodynamic pressure and environment erosion can be established.

随着海绵城市建设和公路排水防滑降噪的使用要求，多孔沥青混凝土路面应用前景广阔。在环境侵蚀、老化和动水冲刷作用下，多孔沥青混凝土及其路面会呈现出高压动水环境侵蚀耦合损伤效应。项目运用多孔介质、流体力学、损伤力学、化学和细观力学等理论与方法，通过环境侵蚀、老化、高压动水等不同条件下的物理指标、渗透、压缩或拉伸、三轴及疲劳等试验，结合CT扫描、电镜扫描、红外光谱、X射线衍射和数字图像处理等微细观分析技术，以及细观结构模拟分析，系统地研究多孔沥青混凝土及其组成材料在高压动水环境侵蚀作用下的组分结构、路用性能和力学性能的演化规律，对比分析模拟酸雨和海盐水的盐液及其浓度、变化周期，老化，动水压力和加载周期，以及温度、级配、孔隙率等因素对它们的影响，提出多孔沥青混凝土及其组成材料高粘沥青、集料的环境侵蚀、老化和动水作用的影响因子或或损伤因子，构建相应的高压动水环境侵蚀下多孔沥青混凝土损伤机制。

多孔沥青路面特有的大孔隙结构特征，使得诸多环境因素（如：阳光、空气和水等），更容易侵入沥青混凝土的内部结构，造成集料松散，影响透水沥青路面使用寿命。本项目研发了一种高黏度改性沥青、可模拟沥青-集料界面的小尺寸“三明治”夹心试样成型装置和可模拟透水沥青路面高水压冲刷养护车工作的高水压力冲刷试验系统，提出了相应的试验方法。模拟了多种环境因素（酸、盐）侵蚀、老化、动水冲刷等工况，对比分析了多孔沥青混凝土及其组成材料高黏沥青（胶浆）、集料和沥青-集料界面等被处理前后的物理力学性能指标和路用性能指标，结合微观结构测试和细观结构数值模拟分析，提出了酸雨和海盐水及其浓度、变化周期，动水压力和加载周期、老化周期等因素对多孔沥青混凝土耐久性的影响规律，以及多孔沥青混凝土动态模量预估模型。建立了高压动水环境下多孔沥青混凝土损伤效应机制，进一步揭示了多孔沥青混凝土路面破坏机理。为科学地评价多孔沥青混凝土及其路面结构设计、排水设计、施工工艺及质量控制、耐久性评价及改善等一系列工作，提供了坚实的理论基础。