ABSTRACT

Reflective crack has been a major problem of asphalt overlay on existing concrete pavements. Joint or crack movements of concrete slab induce the concentrated stress in asphalt layer; thus producing this distress. Rainwater can then infiltrate into subgrade through this crack opening and the loss support is expected. In addition, the cohesive zone model has been steadily utilised to investigate the fracture behaviour of pavement materials. This method can characterise the crack propagation to the real-life phenomenon. Further, current prediction models of reflective crack have adopted the concept of uniform crack propagation to simplify their analysis. This assumption may misinterpret the crack estimation since nonuniformly propagation occurs over the cross-sectional area of asphalt overlay. Therefore, this study aimed to develop a cohesive-zone-based prediction model that can reasonably compute the amount of reflective cracks with the consideration of nonuniform crack propagation. Available data from LTPP database were also collected for reflective crack modelling and calibration. In addition, traffic- and thermal-induced reflective crack was evaluated by 3D finite element method and cohesive zone model. The mechanistic results were afterward correlated with measured the amount of reflective crack to form the prediction formulation. This model consequently generated the acceptable results with measured reflective crack.

摘要

反射裂缝一直是现有混凝土路面沥青覆盖层的主要问题。混凝土板的接缝或裂缝运动导致沥青层应力集中；从而产生了这种苦恼。然后雨水可以通过这个裂缝开口渗入路基，预计会有损失支持。此外，粘性区模型已被稳定地用于研究路面材料的断裂行为。该方法可以表征裂纹扩展到现实生活中的现象。此外，目前的反射裂纹预测模型采用了均匀裂纹扩展的概念来简化分析。这种假设可能会误解裂缝估计，因为在沥青覆盖层的横截面上会发生不均匀的扩展。所以，本研究旨在开发一种基于内聚区的预测模型，该模型可以在考虑非均匀裂纹扩展的情况下合理计算反射裂纹的数量。还收集了来自 LTPP 数据库的可用数据，用于反射裂纹建模和校准。此外，通过3D有限元法和内聚区模型对交通和热致反射裂缝进行了评估。随后将机械结果与测量的反射裂纹量相关联，以形成预测公式。因此，该模型通过测量的反射裂纹产生了可接受的结果。还收集了来自 LTPP 数据库的可用数据，用于反射裂纹建模和校准。此外，通过3D有限元法和内聚区模型对交通和热致反射裂缝进行了评估。随后将机械结果与测量的反射裂纹量相关联，以形成预测公式。因此，该模型通过测量的反射裂纹产生了可接受的结果。还收集了来自 LTPP 数据库的可用数据，用于反射裂纹建模和校准。此外，通过3D有限元法和内聚区模型对交通和热致反射裂缝进行了评估。随后将机械结果与测量的反射裂纹量相关联，以形成预测公式。因此，该模型通过测量的反射裂纹产生了可接受的结果。