Search

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]

Asphalt binder represents the main constituent of asphalt paving mixtures. The functional performance and durability of asphalt pavements strongly depend on the rheological and mechanical properties of the binder. Asphalt binder is a highly temperature susceptible material that becomes brittle and more prone to failure at low temperature, which may ultimately result in thermal cracking at the mixture level. Significant effort was devoted over the years to reduce the occurrence of this distress. For this purpose, a number of experimental methods were developed to characterise asphalt binders at low temperature. At the same time, different models were formulated to better understand and predict the material behaviour while extrapolating more information from the testing measurements. In this paper, a comprehensive review on the behaviour of asphalt binders at low temperature is presented. First, a synthetic introduction and background on the development of the criteria for asphalt binder low-temperature behaviour are provided. Then, the current testing procedures for characterising asphalt binders are presented and the validity of the current PG specification is discussed. Finally, the most significant modelling developments are reviewed. [ABSTRACT FROM AUTHOR]