ABSTRACT

Mechanistic-empirical (M-E) fatigue models for asphalt concrete (AC) pavements often ignore damage induced-changes in the AC, although laboratory testing and field studies show that AC modulus deteriorates as the extent and severity of cracking accumulates. This study developed a pseudo fatigue cracking damage model that incorporated damage-induced changes in AC modulus and AC fatigue endurance limit (FEL) for a more realistic fatigue analysis. The model, based on layered elastic theory, implements incremental-recursive damage accumulation, and its goal is to further minimise empiricism in M-E fatigue modelling. Bending beam fatigue (BBF) test data from 20 AC mixtures constructed at the National Center for Asphalt Technology Pavement Test Track during several research cycles were used to formulate the model. The functional form of the model was identified through iteration and showed high potential in simulating BBF damage curve. The model inputs are AC modulus, FEL and applied strain level. In applying the model, a trial pavement cross-section is simulated in WESLEA, a layered elastic analysis programme, to generate a fatigue damage curve, where AC modulus degrades versus load applications. Suggestions for implementing the model in pavement design procedures are discussed. Field validation is recommended before the model is used for pavement design.

摘要

沥青混凝土（AC）路面的机械-经验（ME）疲劳模型通常忽略了AC中损伤引起的变化，尽管实验室测试和现场研究表明，AC模量会随着裂缝的程度和严重程度的累积而降低。这项研究开发了一个伪疲劳裂纹损伤模型，该模型结合了损伤引起的交流模量和交流疲劳耐力极限（FEL）的变化，从而可以进行更实际的疲劳分析。该模型基于分层弹性理论，实现了增量递归损伤累积，其目的是进一步最小化ME疲劳建模中的经验性。在几个研究周期中，使用了由美国国家沥青技术路面试验场中心建造的20种AC混合物制成的弯曲梁疲劳（BBF）试验数据，以建立该模型。通过迭代确定了模型的功能形式，并在模拟BBF损伤曲线中显示出很高的潜力。模型输入为交流模量，FEL和施加的应变水平。在应用该模型时，在WESLEA（分层的弹性分析程序）中模拟了试验路面的横截面，以生成疲劳损伤曲线，其中AC模量随载荷的增加而降低。讨论了在路面设计程序中实施模型的建议。建议在模型用于路面设计之前进行现场验证。交流模量相对于负载应用会下降。讨论了在路面设计程序中实施模型的建议。建议在模型用于路面设计之前进行现场验证。交流模量相对于负载应用会下降。讨论了在路面设计程序中实施模型的建议。建议在模型用于路面设计之前进行现场验证。