Volume 41, Issue 1 (January 2013)
Fatigue Analysis of Asphalt Concrete under Indirect Tensile Mode of Loading Using Crack Images
In this study, various fatigue criteria for indirect tensile (IDT) fatigue tests were evaluated and a new approach to identify the fatigue failure was proposed based on a crack-length criterion. The IDT fatigue tests were conducted to characterize the fatigue behavior of various asphalt mixtures, such as three warm mix asphalt mixtures and a polymer-modified asphalt mixture. During the IDT tests, digital cameras were mounted to monitor crack growth on the both faces of a specimen. Existing three fatigue failure criteria were evaluated regarding to fatigue-crack development. Then, a crack-length limit was proposed as a fatigue criterion. The IDT strength tests were also conducted to determine fracture energy of the mixtures. Based on the new fatigue criterion, a fatigue performance model was constituted with dissipated and fracture energy parameters. The fatigue model proposed in this study successfully predicted the fatigue lives of the mixtures with a high level of accuracy. The main advantage of this fatigue model is that it does not need a transfer function to convert the fatigue life to crack length or area, because fatigue-crack length is directly determined from the crack-length limit.