沥青—集料界面剪切力学性能试验研究

发布时间：2019-06-05 11:25

【摘要】：由于具有强度高、噪音低、成型和维护简单,而且行车平稳舒适等特点,沥青混凝土在道路工程中得到了特别广泛地应用。众所周知,我国沥青混凝土路面的早期破坏现象严重,剥落、松散、坑槽等病害层出不穷,很大程度上降低了沥青混凝土路面的使用寿命和行车的舒适性。大量研究者普遍认为,沥青与集料界面间的粘聚作用和粘附作用是沥青混凝土材料强度形成的关键因素,并且对沥青混凝土的各种路用性能有着直接影响。实践表明,沥青与集料的界面是沥青混凝土结构的薄弱环节,各种破坏形式往往都起源于界面的破坏,界面之间力学性能的优劣成为决定沥青混凝土材料性能的关键因素。因此,对沥青与集料的界面力学行为进行深入的试验研究,探索其破坏规律,对沥青混凝土的设计、成型与养护都至关重要。本研究从沥青混凝土的基本结构着手,在分析现有的沥青混合料剪切力学行为的成果和沥青与集料界面的力学行为的成果的基础上,对沥青与集料表面的粘聚粘附特性和破坏机理进行深入而系统地研究。为了研究沥青与集料界面的剪切力学性能,采用自行设计的剪切夹具,配合万能试验机与环境箱,对集料-沥青-集料三明治试件进行剪切试验,得到每个试件在剪切荷载作用下的应力-位移全曲线。对剪切破坏面进行观察分析发现,该条件下的界面破坏模式为粘聚粘附混合破坏,而纯粹的粘附破坏和粘聚破坏则很少发生。试验还发现,在同样试验条件下重复该试验,沥青-集料界面的剪切应力-位移曲线呈现出不同的模式,可以明显地区分为当波峰曲线和双波峰曲线。随后改变试验条件,分析不同试验条件对该剪切试验的影响。结果表明,集料表面粗糙度、成型压载和试验荷载加载速率等因素对该试验都有显著影响,并且这些试验因素对不同模式的应力-位移曲线有不同的影响。波峰应力与波谷应力以及它们所对应的位移和剪切刚度指数等参数被用来描述这些应力-位移曲线。另外,分析发现,双波峰曲线的第二峰值与其出现位置呈现线性递减关系。
[Abstract]:Asphalt concrete has been widely used in road engineering because of its high strength, low noise, simple molding and maintenance, and smooth and comfortable driving. As we all know, the early failure phenomenon of asphalt concrete pavement in our country is serious, spalling, loose, potholes and other diseases emerge in endlessly, which greatly reduces the service life and driving comfort of asphalt concrete pavement. A large number of researchers generally believe that the cohesion and adhesion between asphalt and aggregate interface are the key factors for the formation of asphalt concrete material strength, and have a direct impact on the various road properties of asphalt concrete. The practice shows that the interface between asphalt and aggregate is the weak link of asphalt concrete structure, and all kinds of failure forms often originate from the failure of interface, and the mechanical properties between interfaces become the key factors to determine the properties of asphalt concrete materials. Therefore, it is very important for the design, molding and maintenance of asphalt concrete to carry out in-depth experimental study on the interfacial mechanical behavior of asphalt and aggregate and to explore its failure law. Based on the analysis of the existing shear mechanical behavior of asphalt mixture and the mechanical behavior of the interface between asphalt and aggregate, this study starts with the basic structure of asphalt concrete, and on the basis of analyzing the existing shear mechanical behavior of asphalt mixture and the mechanical behavior of asphalt and aggregate interface, The adhesion characteristics and failure mechanism of asphalt to aggregate surface were studied deeply and systematically. In order to study the shear mechanical properties of the interface between asphalt and aggregate, the shear test of aggregate-asphalt-aggregate sandwich specimen was carried out by using a self-designed shear fixture, combined with a universal testing machine and an environmental box. The stress-displacement curve of each specimen under shear load is obtained. By observing and analyzing the shear failure surface, it is found that the interfacial failure mode under this condition is cohesion adhesion mixed failure, while pure adhesion failure and cohesion failure rarely occur. It is also found that when the test is repeated under the same test conditions, the shear stress-displacement curves of the asphalt-aggregate interface show different modes, which can be obviously divided into the wave peak curve and the double wave peak curve. Then the test conditions were changed and the effects of different test conditions on the shear test were analyzed. The results show that the aggregate surface roughness, molding ballast and test load loading rate have significant effects on the test, and these test factors have different effects on the stress-displacement curves of different modes. Wave peak stress and wave valley stress, as well as their corresponding displacement and shear stiffness indices, are used to describe these stress-displacement curves. In addition, it is found that the second peak value of the double-wave peak curve shows a linear decreasing relationship with its occurrence position.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U414

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