CRACK GROWTH BEHAVIOR OF ASPHALT MIXTURES AND ITS RELATION TO LABORATORY AND FIELD PERFORMANCE

A more complete understanding of the cracking behavior of asphalt mixtures and of the cracking mechanism associated with asphalt pavements has been gained through laboratory and field studies. The work has also led to the development of a viscoelastic fracture mechanics based crack growth law that is capable of fully describing both initiation and propagation of cracks in asphalt mixtures for any combination of loading and temperature conditions. The model requires the determination of only four fundamental mixture parameters that can be obtained from less than one hour of testing. These parameters can account for micro-damage, crack propagation, and healing for stated loading conditions, temperatures, and rest periods. The paper summarizes the developments that led to the model, and describes the model and its potential use in the areas of mixture design and optimization, performance based specifications, and pavement design.