Development and Validation of a Rutting Model for Asphalt Mixtures Based on the Flow Number Test

This study presents the development and validation of a rutting prediction model based on input of the Flow Number test. It was realized that such a model would require a very large laboratory testing program along with the construction of field test sections. Therefore, a Flow Number predictive equation, developed and published by the authors in a previous study, was one of the important tools used in this paper together with the Mechanistic Empirical Pavement Design Guide (MEPDG, now DARWin-ME). The MEPDG allowed the generation of hundreds of rutting values for different pavement structures, climatic locations, and traffic levels. A total of 1440 asphalt pavement sections were used in this analysis. For this rutting - Flow Number relationship, a power model form was recommended that also included traffic and layer thickness as input variables and had very good statistical goodness of fit. In addition, the model was validated using actual laboratory Flow Number testing and field rutting data from 10 test sections installed at the National Center Asphalt Technology (NCAT) Test Track in 2006. The results showed that the model had very good accuracy in predicting the field rutting of the NCAT test sections.