Abstract This study aims to quantify the fracture properties of asphalt mixes varying degrees of moisture and freeze-thaw damages. The frequent occurrence of moisture and freeze-thaw cycles are predominant environmental damages in asphalt pavement. These factors not only can cause distresses in asphalt mixes but also can accelerate damages caused by traffic loading and reduce the resistances of asphalt mixes against cracking. It is known that different asphalt mixtures can give different ranks of fracture properties under varying degrees of moisture and freeze-thaw damages. Thus, fracture characteristics at varying levels of environmental damage are needed to rank the fracture resistance. In this paper, to study the fracture properties of asphalt mixtures, the semi-circular bending (SCB) tests were conducted on neat and modified asphalt mixtures after experiencing varying cycles of moisture and freeze-thaw. Then, the load and displacement at failure, the mode I critical stress intensity factor (KIC), strain energy (U), critical strain energy release rate (Jc), and fracture energy (Gf) were calculated to identify the damage level at each cycle of moisture and freeze-thaw damages. To incorporate the impacts of moisture and freeze-thaw damages on the service life, we defined the area under the critical strain energy release rate (Jc) and fracture energy (Gf) versus the service time as an indication of the overall fracture resistance of asphalt mixtures. The results show that the area under the curve of the fracture property versus service time can offer a proper index to investigate the long-term fracture resistance of asphalt mixtures. The proposed approach can concurrently address the fracture resistances of the asphalt mixture to moisture and freeze-thaw damages at different environmental conditions and damage evolution rates over service time.

中文翻译：

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一种基于裂缝表征沥青混合料在潮湿和冻融条件下的长期性能的方法

摘要 本研究旨在量化沥青混合料在不同程度的水分和冻融破坏下的断裂特性。潮湿和冻融循环的频繁发生是沥青路面的主要环境破坏。这些因素不仅会导致沥青混合料出现故障，还会加速交通荷载造成的损坏，降低沥青混合料的抗裂性。众所周知，不同的沥青混合料在不同程度的水分和冻融破坏下会产生不同等级的断裂性能。因此，需要在不同环境破坏水平下的断裂特性来对断裂抗力进行排序。在本文中，为了研究沥青混合料的断裂特性，在经历了不同的水分和冻融循环后，对纯沥青混合料和改性沥青混合料进行了半圆弯曲 (SCB) 测试。然后，计算失效时的载荷和位移、I 型临界应力强度因子 (KIC)、应变能 (U)、临界应变能释放率 (Jc) 和断裂能 (Gf)，以确定每个损伤水平。水分和冻融破坏的循环。为了结合水分和冻融损伤对使用寿命的影响，我们定义了临界应变能释放率 (Jc) 和断裂能 (Gf) 下的面积与使用时间的关系，作为沥青整体抗断裂性的指标混合物。结果表明，断裂性能与使用时间的曲线下面积可以为研究沥青混合料的长期抗断裂性能提供一个合适的指标。所提出的方法可以同时解决沥青混合料在不同环境条件下对水分和冻融损坏的抗断裂性以及随使用时间的损坏演变率。