基于耗散能量的沥青混合料疲劳破坏机理研究

发布时间：2018-01-16 16:40

本文关键词：基于耗散能量的沥青混合料疲劳破坏机理研究　出处：《华南理工大学》2014年硕士论文　论文类型：学位论文

【摘要】：沥青混合料的疲劳破坏是时沥青路面主要的病害形式，也是沥青路面结构层次设计要考虑的主要问题之一。深入地对沥青混合料的疲劳破坏机理进行研究将会为提升沥青混合料的疲劳性能、路用性能带来长足的促进作用。目前常用的研究沥青混合料疲劳性能的方法主要有三种，分别是：现象力学法、损伤力学法（包括力学近似法、连续损伤力学法）、能量法。考虑到现象力学法以及损伤力学法在传统研究过程中的一些限制，以及能量法的研究思想“关注状态，忽略过程”所带来的研究便利，本文将从能量法中耗散能量的角度出发，对沥青混合料疲劳破坏机理进行研究。本文基于能量法的基本原理，引用沥青混合料疲劳损伤阈值的概念，然后结合沥青混合料矩形梁的四点弯曲疲劳试验，设计了沥青混合料微损伤的愈合试验，以此说明沥青混合料能量的耗散与疲劳损伤阈值的存在，然后通过弯拉试验计算了普通沥青混合料以及改性沥青混合料的疲劳损伤阈值。论文接着从耗散能的角度切入，利用沥青混合料试件的四点弯曲试验耗散能以及相关的预测模型，，对沥青混合料的疲劳失效判据作了更细致地探讨和论证，提出了以耗散能相对变化率RCRDE的跃变为核心疲劳失效判据并给出了相应的拟合过程。然后将沥青混合料疲劳试验的耗散能与计算的损伤阈值进行比对，进一步阐述两者的联系。本文综合考虑当时的试验条件以及资源，主要做了以下工作： 1)为了论述沥青混合料在循环荷载作用下的损伤演化，引用损伤阈值概念，探讨了沥青混合料的疲劳损伤阈值以及评价方法。 2)结合试验条件和资源，对比了各类研究方法、各类试验方式、试件形式，确定了切合主题的试件类型、试验方式，并针对性地设计了试验方案。 3)结合前人的研究，以四点弯曲疲劳试验以及弯拉试验为基础，设计了沥青混合料微损伤的愈合试验，说明了沥青混合料疲劳损伤过程中的能量耗散与阈值的存在性和合理性。 4)由断裂统计理论可知，在分析材料的损失破坏行为时，需要先给予一个达到的损伤阈值。结合四点弯曲疲劳试验、弯拉试验和相关试验规范，计算了普通沥青混合料的疲劳损伤阈值。 5)通过改性沥青混合料的的蠕变试验，拟合了改性沥青混合料的黏弹性模型参数，并通过得出的模型参数和弯拉试验数据，计算改性沥青混合料的疲劳损伤阈值，对比性说明了计算的损伤阈值的合理性。 6)基于耗散能相对变化率RCRDE，通过四点弯曲疲劳试验以及数据分析，提出了以耗散能相对变化率RCRDE的跃变为核心疲劳失效判据。 7)结合领域内学者的疲劳性能预测模型，利用耗散能相对变化率RCRDE中的稳定状态值SPV进行模型的拟合，说明了以耗散能相对变化率RCRDE的跃变为核心疲劳失效判据的合理性，并从侧面论证了损伤阈值是一种能够作为评价沥青混合料疲劳性能的方式。
[Abstract]:The fatigue failure of asphalt mixture of asphalt pavement is the main form of the disease, but also the asphalt pavement structure to one of the main problems considered. Deeply fatigue on failure of asphalt mixture to study the mechanism of fatigue will improve the performance of asphalt mixture, the road to bring considerable role in promoting the performance of the commonly used methods for the research. Fatigue performance of asphalt mixture mainly have three kinds, namely: the phenomenon of mechanics, damage mechanics method (including mechanics approximation method, the continuum damage mechanics method), energy method. Considering some constraints method of mechanics and damage mechanics, the traditional method in the research process, and the thought of "energy law on state. The neglect process" of the research facilities, this paper from the perspective of dissipative energy method, the angle of research on failure mechanism of asphalt mixture fatigue.
In this paper, the basic principle of energy method based on the concept of reference for asphalt mixture fatigue damage threshold, and then the four point bending fatigue test of asphalt mixture with rectangular beam, the design of asphalt mixture micro injury healing test, in order to show the energy and dissipation of asphalt mixture fatigue damage threshold, and then through the bending test the ordinary asphalt mixture and modified asphalt mixture fatigue damage threshold is calculated.
Then, from the perspective of energy dissipation, the asphalt mixture of four point bending test piece and dissipation forecasting model, fatigue failure criterion of asphalt mixture made more detailed discussion and argumentation, put forward to the dissipation of the relative change rate of RCRDE jump as the core fatigue failure criterion and fitting the process was also given. Then the fatigue test of asphalt mixture material dissipation can be compared with the damage threshold calculation, further elaborated the link between the two. Considering the experimental conditions of the time and resources, mainly do the following work:
1) in order to expound the damage evolution of asphalt mixture under cyclic loading, we introduce the concept of damage threshold, and discuss the fatigue damage threshold and evaluation method of asphalt mixture.
2) combined with the test conditions and resources, various kinds of research methods, various test methods and test forms were compared, the types of subjects that met the theme, the test methods were determined, and the test plan was designed accordingly.
3) combined with previous studies, based on the four point bending fatigue test and flexural tensile test, the micro damage healing test of asphalt mixture was designed, indicating the existence and rationality of energy dissipation and threshold in the fatigue damage process of asphalt mixture.
4) from the statistical theory of fracture, we can see that when analyzing the damage and Breakage Behavior of material, we need to give a threshold of damage first. Combined with the four point bending fatigue test, bending test and related test specification, we calculate the fatigue damage threshold of ordinary asphalt mixture.
5) by modified asphalt mixture creep test, the fitting parameters of the viscoelastic model of modified asphalt mixture, tensile test data of the model parameters and bending and through the calculation of fatigue damage threshold of modified asphalt mixture, the contrast shows the rationality of the calculation of the damage threshold.
6) based on the relative change rate of dissipation energy RCRDE, through the four point bending fatigue test and data analysis, we put forward the criterion of fatigue failure based on the change of dissipation energy relative rate RCRDE.
7) combined with the fatigue performance in the field of scholars' prediction model, using energy dissipation relative change rate of steady state value in RCRDE fitting SPV model, description of the energy dissipation rate of relative change of RCRDE rationality as the core variable step fatigue criterion, and from the side proves the damage threshold is a can be used as evaluation the fatigue performance of asphalt mixture.

【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U414

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