ABSTRACT

Fatigue cracking is the main type of distress in flexible pavements in Brazil. Numerical models that are based on viscoelastic continuum damage (VECD) theory can help to explain the damage evolution process in asphalt mixtures, thereby allowing the proper analysis of the fatigue phenomenon. This paper aims to characterise and verify the fatigue behaviour of four test sites constructed with dense asphalt mixtures in Santa Maria, Brazil, employing field monitoring, linear viscoelastic characterisation, uniaxial cyclic fatigue testing, the simplified VECD (S-VECD) model, and FlexPAVE^TM software. This study’s results are coupled with a cost/benefit analysis of the evaluated test sites. The constructed sites are compared to simulated optimal pavement designed using FlexPAVE^TM and fatigue damage transfer function. The results indicate that this study’s methodology can predict fatigue damage evolution by identifying early cracking in two of the test sites and capturing good fatigue resistance in the other two sites. Furthermore, in both cases of early cracking, the design requirements for fatigue resistance could be met by increasing the asphalt layer thickness (optimal pavements), which significantly reduced the US$/N_FATIGUE ratio. Thus, an improved cost/benefit ratio was realised for the pavements designed using this methodology and analysed using only an established fatigue criterion.

摘要

疲劳开裂是巴西柔性路面的主要故障类型。基于粘弹性连续损伤 (VECD) 理论的数值模型有助于解释沥青混合料的损伤演化过程，从而可以对疲劳现象进行适当的分析。本文旨在通过现场监测、线性粘弹性表征、单轴循环疲劳测试、简化的 VECD (S-VECD) 模型和 FlexPAVE 来表征和验证在巴西圣玛丽亚用稠密沥青混合料建造的四个测试场地的疲劳行为。^TM软件。这项研究的结果与评估的测试地点的成本/收益分析相结合。将建造的场地与使用 FlexPAVE ^{TM设计的模拟最佳路面进行比较}和疲劳损伤传递函数。结果表明，这项研究的方法可以通过识别两个测试地点的早期开裂并在其他两个地点捕获良好的疲劳抗力来预测疲劳损伤的演变。此外，在两种早期开裂的情况下，都可以通过增加沥青层厚度（最佳路面）来满足抗疲劳设计要求，从而显着降低 US$/N_疲劳比率。因此，使用该方法设计并仅使用已建立的疲劳标准进行分析的路面实现了改进的成本/收益比。