Predictive relationships for HMA fracture properties based on mixture component characteristics

This study was mainly focused on identifying appropriate relationships between asphalt mixture component characteristics and asphalt mixture properties known to control cracking performance. The current lack of material property models that can accurately describe the changes in material properties over time in the field is probably the greatest deficiency in our ability to accurately predict pavement performance. Therefore, there is a need to evaluate existing material property models, and develop improved models for use in the prediction of pavement performance. Relationships able to predict initial fracture energy and creep rate, which are the properties known to govern the change in material property over time and are also required for performance model predictions, were developed in this study. In addition, conceptual relationships were identified to describe changes in these properties over time (aging) by including the effect of the non-healable permanent damage related to load and moisture. This can serve as the foundation for further development of improved models to predict mixture properties as a function of age in the field based on additional field data and laboratory studies using more advanced laboratory conditioning procedures. The verified relationships will also serve to provide reliable inputs for prediction of service life using pavement performance prediction models.