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Development and evaluation of an HMA fracture mechanics based model to predict top-down cracking in HMA layers.

机译：基于HMA断裂力学的模型的开发和评估，以预测HMA层自上而下的开裂。

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摘要

It is well recognized that load-related top-down cracking commonly occurs in HMA pavements. This phenomenon has been reported to occur in many parts of the United States, as well as in Europe, Japan, and other countries. This mode of failure, however, cannot be explained by traditional fatigue mechanisms used to explain fatigue cracking that initiates at the bottom of the pavement. The primary objective of this research is therefore to identify the causes of top-down cracking and to develop mechanistic-based models for predicting this type of distress in HMA layers.The HMA fracture mechanics (HMA-FM) model developed at the University of Florida (UF) was determined as necessary to form the basis of this study because of its associated threshold concept that is suitable for developing rules for both top-down cracking initiation and propagation, and its ability to model the presence of macro cracks and their effect on response. However, the effect of aging and healing on top-down cracking performance during the entire service life of asphalt concrete pavement had not been considered. Also, the effect of transverse, as opposed to longitudinal, thermal stresses had not been addressed. Therefore, the framework of the existing HMA-FM model was modified by identifying and including appropriate sub-models to address these key factors, based on which the framework of the targeted model was formed. Consequently, the targeted model/system, which was termed the HMA-FM-based model, was completed by development and integration of several key elements into the finalized framework, including material property sub-models that accounts for changes in mixture properties (e.g., fracture energy, creep rate, and healing potential) with aging, and a thermal response model that predicts transverse thermal stresses.The HMA-FM-based model placed emphasis on the bending mechanism. A systematic parametric study showed that the model provided reasonable predictions and expected trends for both crack initiation and propagation. Furthermore, a full calibration of field sections indicated that the predictive system adequately represents and accounts for the most significant factors that influence top-down cracking in the field. The validation efforts using the prediction sum of squares (PRESS) procedure further established the viability of the predictive system. In conclusion, the work performed clearly indicates that the HMA-FM-based model developed and evaluated in this study should form the basis for a top-down cracking model suitable for use in the mechanistic-empirical pavement design guide (MEPDG). (Full text of this dissertation may be available via the University of Florida Libraries web site. Please check http://www.uflib.ufl.edu/etd.html)
机译：众所周知，与载荷相关的自上而下的开裂通常发生在HMA路面中。据报道，这种现象在美国许多地区以及欧洲，日本和其他国家都发生过。但是，这种失败模式无法用传统的疲劳机制来解释，该机制用来解释人行道底部引发的疲劳裂纹。因此，本研究的主要目的是确定自上而下的裂纹的原因，并开发基于机械的模型来预测HMA层中的此类应力。佛罗里达大学开发的HMA断裂力学（HMA-FM）模型（UF）被确定为构成本研究基础的必要条件，因为其相关的阈值概念适用于为自上而下的裂纹萌生和扩展制定规则，并且能够模拟宏观裂纹的存在及其对裂纹的影响。响应。然而，在沥青混凝土路面的整个使用寿命中，没有考虑老化和愈合对自上而下的开裂性能的影响。同样，与纵向相反的横向热应力的影响也没有得到解决。因此，通过识别并包括适当的子模型以解决这些关键因素，对现有HMA-FM模型的框架进行了修改，从而形成了目标模型的框架。因此，目标模型/系统（称为基于HMA-FM的模型）是通过将若干关键要素开发并集成到最终框架中而完成的，这些要素包括考虑混合物特性变化的材料特性子模型（例如，断裂能，蠕变速率和愈合潜能），并具有预测横向热应力的热响应模型。基于HMA-FM的模型着重于弯曲机理。一项系统的参数研究表明，该模型为裂纹萌生和扩展提供了合理的预测和预期趋势。此外，对田间断面的全面校准表明，该预测系统充分代表并解释了影响田间自上而下裂缝的最重要因素。使用预测平方和（PRESS）程序进行的验证工作进一步建立了预测系统的可行性。总之，进行的工作清楚地表明，在本研究中开发和评估的基于HMA-FM的模型应构成适用于机械-经验路面设计指南（MEPDG）的自上而下的裂缝模型的基础。 （可通过佛罗里达大学图书馆网站获得本文的全文。请检查http://www.uflib.ufl.edu/etd.html）

著录项

  • 作者

    Zou, Jian.;

  • 作者单位

    University of Florida.;

  • 授予单位 University of Florida.;
  • 学科 Engineering Civil.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 129 p.
  • 总页数 129
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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