基于加速加载试验的沥青混合料疲劳损伤特性研究

发布时间：2018-04-15 09:25

本文选题：沥青混合料 + 疲劳损伤规律　；参考：《长沙理工大学》2015年硕士论文

【摘要】：沥青路面是我国高等级公路的主要路面结构型式,疲劳裂缝是沥青路面普遍出现的主要破坏形式之一。对沥青混合料的疲劳性能进行研究,可以让我们了解和掌握沥青混合料的力学性能、疲劳损伤规律,进而改善沥青混合料的疲劳特性,提高路面的使用性能和使用寿命。国内外已有广大学者和科研人员对沥青混合料的疲劳性能进行了深入的研究,以室内试件疲劳试验为主,如拉-压疲劳试验、弯曲疲劳试验、间接拉伸疲劳试验等,这些疲劳试验方法都具有一定的局限性,不能较好的模拟实际路面的工作状态,对于评价沥青混合料的疲劳性能会有一定的偏差。因此,本文将借助小型加速加载试验设备,通过测试不同加载次数下试件的抗压回弹模量,建立沥青混合料的刚度衰变方程,从而揭示沥青混合料的疲劳损伤规律。从损伤力学的基本理论出发,定义模量的衰减为疲劳损伤变量,由此推导得到刚度衰变方程;过对六种不同级配类型的沥青混合料进行加速加载试验,通过软件以此方程对加速加载试验数据进行拟合,并得到了模型参数,拟合结果均呈现出很好的相关性,从而建立了基于加速加载试验的沥青混合料刚度衰变方程。分析了沥青混合料疲劳过程中的损伤演化规律,即沥青混合料将经历迁移阶段—稳定阶段—加速阶段三个阶段的演变过程。提出以刚度衰减速率从稳定阶段进入疲劳破坏阶段达到的最大值作为疲劳失效判据,并利用此疲劳失效判据得到的疲劳寿命与计算结果一致,验证了提出的疲劳失效判据的合理性。通过小型加速加载试验与传统的室内试件疲劳试验进行对比,体现出小型加速加载试验对于研究沥青混合料疲劳性能的科学性与合理性,研究成果可以为沥青混合料的疲劳寿命预估和沥青混合料疲劳损伤特性研究提供理论参考,对于改善沥青路面的设计方法、提高沥青路面的耐久性具有重要的参考价值。
[Abstract]:Asphalt pavement is the main pavement structure type of high grade highway in China. Fatigue crack is one of the main failure forms of asphalt pavement.The study on the fatigue performance of asphalt mixture can help us to understand and master the mechanical properties and fatigue damage law of asphalt mixture, and then improve the fatigue characteristics of asphalt mixture and improve the service performance and service life of pavement.Many scholars and researchers at home and abroad have carried out in-depth research on the fatigue properties of asphalt mixtures, such as tensile compression fatigue test, bending fatigue test, indirect tensile fatigue test and so on.These fatigue test methods have some limitations and can not well simulate the actual pavement working state, and there will be some deviation in evaluating the fatigue performance of asphalt mixture.Therefore, in this paper, the stiffness decay equation of asphalt mixture is established by measuring the modulus of resilience of the specimen under different loading times with the aid of small accelerated loading test equipment, thus revealing the fatigue damage law of asphalt mixture.Based on the basic theory of damage mechanics, the attenuation of modulus is defined as fatigue damage variable, and the stiffness decay equation is derived.The data of accelerated loading test were fitted with this equation, and the model parameters were obtained. The fitting results showed good correlation. Thus, the stiffness decay equation of asphalt mixture based on accelerated loading test was established.The law of damage evolution in the fatigue process of asphalt mixture is analyzed, that is, the evolution process of asphalt mixture will go through three stages: migration, stabilization and acceleration.The maximum value of stiffness attenuation rate from the stable stage to the fatigue failure stage is proposed as the fatigue failure criterion, and the fatigue life obtained by the fatigue failure criterion is consistent with the calculated results.The rationality of the proposed fatigue failure criterion is verified.The small accelerated loading test is compared with the traditional indoor fatigue test, which shows that the small accelerated loading test is scientific and reasonable for the study of asphalt mixture fatigue performance.The research results can provide a theoretical reference for the prediction of the fatigue life of asphalt mixture and the study of fatigue damage characteristics of asphalt mixture. It has important reference value for improving the design method of asphalt pavement and improving the durability of asphalt pavement.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U414

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