基于有限厚度试件的沥青混合料疲劳试验开发及评价方法研究

发布时间：2018-10-13 15:43

【摘要】：疲劳破坏是沥青路面的主要破坏形式之一。现有的沥青混合料疲劳试验方法虽能在一定范围内模拟沥青路面的疲劳破坏,但相关试验设备昂贵、试件制备费时费力、试验操作较为繁琐,因试验成本限制而难以得到大范围的推广使用。此外,由于沥青路面厚度的有限性,现有疲劳试验方法不能以现场芯样为疲劳试件进行施工后路面疲劳性能的评价。基于此,开发一种成本低、省时节力且操作简便的新型沥青混合料疲劳试验方法是必要的。本文通过计算机数值模拟与室内试验相结合的途径,开发了一种基于有限厚度试件的圆盘弯曲沥青混合料疲劳试验方法,并将其与间接拉伸疲劳试验进行了对比分析,验证了该试验方法的可行性和可靠性,最后采用该方法测试评价了四种典型沥青混合料的疲劳性能。首先,借助Abaqus软件平台建立了圆盘弯曲疲劳试验的有限元模型,而后对其进行数值模拟优化。通过比较不同压头尺寸、试件厚度以及夹具约束形式下模型的力学响应后,确定了合适的试验模型尺寸范围以及适宜的夹具约束形式。其次,通过MTS-810加载系统并配备自主加工的疲劳夹具进行了圆盘弯曲疲劳试验方法的建立。基于室内试验优化确定了试验的尺寸参数:加载压头半径为12.5mm,圆盘形疲劳试件半径为75mm、厚度为30mm;通过平行试验和弃差处理验证了圆盘弯曲疲劳试验方法的可靠性和试验结果的有效性,并给出了圆盘弯曲疲劳的试验方法与步骤。再次,选用间接拉伸疲劳试验进行了相同试验参数下混合料的疲劳对比试验。对两种试验模式下混合料疲劳变形演变规律、不同加载频率和应力比下的劲度模量衰减曲线、疲劳损伤曲线以及疲劳曲线进行对比分析后,验证了圆盘弯曲疲劳试验评价沥青混合料疲劳性能的可行性。最后,基于圆盘弯曲疲劳试验测试了四种典型沥青混合料的疲劳性能,通过对试件变形曲线、疲劳曲线和疲劳损伤曲线的对比分析,评价了各混合料的疲劳性能,并初步分析了不同材料疲劳特性差异的原因。本文开发的圆盘弯曲疲劳试验主要针对有限厚度沥青混合料的疲劳性能评价,并有效弥补了现有试验方法的不足,为沥青路面疲劳破坏的研究提供了技术支持。
[Abstract]:Fatigue failure is one of the main failure forms of asphalt pavement. Although the existing fatigue test methods of asphalt mixture can simulate the fatigue failure of asphalt pavement within a certain range, the related test equipment is expensive, the preparation of the test piece takes time and effort, and the test operation is more complicated. Because of the limitation of test cost, it is difficult to be widely used. In addition, due to the limited thickness of asphalt pavement, the existing fatigue test methods can not be used to evaluate the fatigue performance of pavement after construction. Based on this, it is necessary to develop a new asphalt mixture fatigue test method with low cost, low time saving force and simple operation. In this paper, a new fatigue test method of circular bending asphalt mixture based on finite thickness specimen is developed by combining computer numerical simulation with indoor test, and the fatigue test is compared with indirect tensile fatigue test. The feasibility and reliability of the test method are verified. Finally, the fatigue performance of four typical asphalt mixtures is tested and evaluated by this method. Firstly, the finite element model of bending fatigue test of disk is established with the help of Abaqus software platform, and then it is numerically simulated and optimized. By comparing the mechanical responses of the models with different die sizes, specimen thickness and fixture constraints, the appropriate size range of the test model and the appropriate clamping constraint form are determined. Secondly, the bending fatigue test method of disk is established by MTS-810 loading system and self-machined fatigue fixture. Based on the laboratory test, the dimension parameters of the test are determined: the radius of the loading head is 12.5 mm, the radius of the disk fatigue specimen is 75 mm, the thickness is 30 mm, and the reliability of the bending fatigue test method is verified by parallel test and abandonment treatment. And the validity of the test results, The test methods and steps of bending fatigue of disk are also given. Thirdly, indirect tensile fatigue test was used to carry out the fatigue contrast test of mixture under the same test parameters. The fatigue deformation evolution law, stiffness modulus attenuation curve, fatigue damage curve and fatigue curve under different loading frequency and stress ratio under two test modes are compared and analyzed. The feasibility of evaluating the fatigue performance of asphalt mixture by disk bending fatigue test was verified. Finally, the fatigue properties of four typical asphalt mixtures are tested based on the disk bending fatigue test. The fatigue properties of each mixture are evaluated by comparing and analyzing the deformation curves, fatigue curves and fatigue damage curves of the specimens. The reasons for the difference of fatigue properties of different materials are analyzed. The disk bending fatigue test developed in this paper is mainly aimed at evaluating the fatigue performance of asphalt mixture with limited thickness, and effectively makes up for the deficiency of existing test methods, which provides technical support for the research of asphalt pavement fatigue damage.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U414

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