基于集料形貌特性的动水压力下沥青-集料黏附机理研究

The adhesion failure of bitumen-aggregate interface caused by the hydrodynamic pressure is the main influence factor of the moisture damage in pavement structure. The surface morphology characteristics of the aggregate have a close relationship with the interfacial adhesion performance. Carrying out the research on bitumen-aggregate adhesion mechanism caused by hydrodynamic pressure based on the aggregate morphology characteristics is one important way to deepen the moisture damage theory of the asphalt concrete pavement. In this project, the 3-D laser scanner and environmental scanning electron microscope (ESEM) will be used to identify three-dimensional surface morphology characteristics of the aggregate in different scales based on fractal theory. One kind of adhesion test method using ultrasonic is recommended to simulate bitumen stripping from the aggregate surface under hydrodynamic pressure. A automatic digital image acquisition and processing system will improve the accuracy of adhesion test method. Evolution rule of bitumen-aggregate adhesion performance affected by hydrodynamic energy will be found. Base on the fluid mechanics numerical simulation technology, the analytical models describing the surface morphology of different aggregates affected by hydrodynamic pressure will be established. The effect of aggregate morphology parameters on the bitumen-aggregate adhesion performances will be simulated and analyzed. And the mechanism of stripping caused by hydrodynamic pressure will be ascertained. The research results of the project will provide a useful theoretical basis for the aggregate optimal selection, the optimization of the asphalt concrete design, and play a positive role in enhancing the anti-water damage performance of asphalt pavement, saving maintenance costs and prolonging service life.

动水压力作用下沥青-集料界面的黏附性破坏，是路面结构水损害的主要成因，而集料的表面形貌与界面黏附性能密切相关。开展基于集料形貌特性的动水压力下沥青-集料黏附机理研究，是深化沥青路面水损害理论的重要途径之一。本项目拟采用三维激光扫描仪及环境扫描电子显微镜，基于分形理论获取不同尺度范围的集料表面三维形貌特性参数。使用超声波模拟高速水流冲击产生的动水压力，构建新的沥青-集料黏附性能试验方法；开发自动数字图像采集处理系统，提高黏附性试验的精度。确立动水能量作用下沥青-集料黏附性演化规律。运用流体力学数值模拟技术，建立基于集料形貌参数的动水压力分析模型，模拟分析集料形貌参数变化对沥青-集料黏附性能的影响，确立动水压力作用下沥青沿沥青-集料界面剥落的机理。项目的研究成果，将为集料优选、沥青混合料的优化设计提供有益的理论依据，对提升沥青路面抗水损性能、节省养护费用、延长使用寿命起到积极的作用。

动水压力作用下沥青-集料界面的黏附性破坏，是路面结构水损害的主要成因，而集料的表面形貌与界面黏附性能密切相关。开展基于集料形貌特性的动水压力下沥青-集料黏附机理研究，是深化沥青路面水损害理论的重要途径之一。本项目构建新的沥青-集料黏附性能试验方法，使用超声波模拟高速水流冲击产生的动水压力，开发自动数字图像采集处理系统，提高黏附性试验的精度。基于该方法对不同种类粗集料与沥青进行黏附性能分析研究。从试验结果可以看出，该试验方法能够模拟动水压力作用下沥青从集料表面剥落的现象，并能够区分集料粗糙度对黏附性能的影响。采用三维激光扫描仪基于分形理论并基于原子力显微镜(AFM)分别获取细观、微观尺度的集料表面三维形貌特性参数，并验证集料表面形貌表征参数与沥青-集料黏附性的相关性。借助偏光显微镜从微观方面观测随时间变化沥青-集料界面剥落的现象，确立动水能量作用下沥青-集料界面黏附失效演化规律。利用AFM从微观角度观测水对沥青-集料界面的作用，通过分析水作用下沥青表面“蜂状结构”微观构造的变化规律，确立动水压力作用下沥青沿沥青-集料界面剥落的机理，为沥青-集料界面黏附性能失效提供了重要的理论依据。基于表面能理论，选择合理的参数指标表征沥青-集料界面的黏附功，建立其与沥青-集料黏附性能的相关性，并提出增强沥青-集料界面黏附性能的集料表面三维形貌特征指标。本项目的研究成果，将为集料优选、沥青混合料的优化设计提供有益的理论依据，对提升沥青路面抗水损性能、节省养护费用、延长使用寿命起到积极的作用。