ABSTRACT

Fatigue cracking is one of the major distresses in asphalt pavements. Engineers have used many methods, from sophisticated numerical simulations to experience-based knowledge, to address fatigue cracking and deliver pavements that perform well. One strategy that has become increasingly widespread is the use of a fatigue index parameter that identifies the cracking potential of asphalt mixtures independent of the pavement structure. The use of such indices allows pavement engineers to make quick and targeted decisions with regard to mix design, mix acceptance, and mix quality assurance. This paper proposes a new fatigue index parameter, S_app, which represents the damage capacity of a mixture and is based on the viscoelastic continuum damage theory. Unlike other indices, this new index considers the effects of both material toughness and stiffness. S_app was employed in this study to evaluate 105 different asphalt mixtures with varied design factors. The results indicate that S_app is able to distinguish the fatigue resistance of asphalt mixtures with varied properties, including different binder contents, binder performance grades, reclaimed asphalt pavement contents, types of binder modifier, air void contents, aggregate gradations, and aging levels. This paper also presents a set of recommended S_app threshold values for different expected traffic volumes.

摘要

疲劳开裂是沥青路面的主要缺陷之一。工程师使用了许多方法，从复杂的数值模拟到基于经验的知识，来解决疲劳开裂问题并提供性能良好的路面。一种越来越普遍的策略是使用疲劳指数参数来识别沥青混合物的开裂潜力，而与路面结构无关。使用这些指数可以让路面工程师在混合设计、混合验收和混合质量保证方面做出快速和有针对性的决策。本文提出了一种新的疲劳指数参数，S _app，它表示混合物的损伤能力，基于粘弹性连续损伤理论。与其他指标不同，这个新指标同时考虑了材料韧性和刚度的影响。本研究使用S _app评估 105 种具有不同设计因素的不同沥青混合料。结果表明，S _app能够区分不同性能的沥青混合料的抗疲劳性能，包括不同的粘结剂含量、粘结剂性能等级、再生沥青路面含量、粘结剂改性剂类型、空隙率、骨料级配和老化水平。本文还针对不同的预期流量提出了一组推荐的S _app阈值。