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Cracking in asphalt concrete (AC) layers is among the driving modes of flexible pavement deterioration. Material properties, along with structural layer characteristics and external factors such as vehicular and environmental loading, govern cracking mechanisms in flexible pavements. Current practice of AC and pavement structural design methods does not allow for direct characterisation of AC impact on crack damage initiation and propagation. Asphalt concrete performance tests are the essential components of performance-related and performance-based specifications, for which they can be used either for screening AC to minimise deterioration risks or to directly predict specific modes of pavement deterioration. This paper evaluates commonly used performance tests intended to characterise AC fracture resistance. A multistep evaluation protocol was applied using various statistical techniques to determine the discrimination ability of each test method outcome criterion as well as strength of correlation to field performance. The results from full-scale accelerated pavement test (APT) sections were used to correlate with the results obtained from various laboratory performance tests. Mixes used in the study contained various levels of reclaimed asphalt pavement and recycled asphalt shingles with a recycled binder ratio up to 40%. It was shown that the flexibility index parameter obtained from the Illinois semi-circular bending (IL-SCB) test, also referred to as the Illinois Flexibility Index Test (I-FIT), resulted in the highest number of subsets and consistent ranking with APT field performance, indicating a high discrimination potential. Even though two of the overlay test's criteria resulted in fewer subsets, they also provided a consistent ranking with APT field performance. Composite scores indicate that the overlay test criteria and flexibility index from the I-FIT had the highest strength of correlation to field performance. [ABSTRACT FROM AUTHOR]

Fatigue cracking is a common form of pavement failure and is strongly tied to the properties of the asphalt binder used in the mix. The Superpave grading procedure is currently used in the United States and in other parts of the world to classify and select asphalt binders for the design of asphalt mixtures. The parameter, , in the Superpave grading system is used to control the quality of the binder at intermediate temperatures. It is also used by many as a metric to measure the inherent fatigue cracking resistance of an asphalt binder. It is widely recognised that while this parameter was a significant improvement over previous binder grading and selection methods, it does not accurately measure the inherent fatigue damage resistance of asphalt binders. This paper provides a review of several studies that have attempted to develop methods to measure the fatigue damage resistance of asphalt binders during the last two decades. The studies reviewed in this paper have been classified into four main categories based on the type of test method employed. The four categories include: time sweep performed using the Dynamic Shear Rheometer (DSR), amplitude sweep using the DSR or its variations, ductility-based test methods and strength-based tests. This paper focuses primarily on tests developed in the United States with an emphasis to improve the existing Superpave criteria along with relevant research from other parts of the world. [ABSTRACT FROM AUTHOR]