Preliminary Dynamic Modulus Criteria of HMA for Field Rutting of Asphalt Pavements: Michigan’s Experience

This paper presents a comparative study of laboratory results of both dynamic modulus testing and field rutting performances of hot-mix asphalt (HMA) in the state of Michigan. Fourteen field-produced mixtures at various traffic levels and aggregate sizes were evaluated and compared to those of field rutting. These mixtures were collected from job sites and compacted with a Superpave gyratory compactor to imitate the common air void level used in Mich., which is 7%. Dynamic modulus $E^{\ast }$ was measured at temperatures ranging from −5 to $39.2°\text{C}$ and frequencies ranging from 0.1 to 25 Hz. The results show that the dynamic modulus values increased when the designed traffic level for HMA mixtures increased. The field rutting performance was evaluated based on theoretical pavement rutting life index. Two parameters, $\left|E^{\ast }\right|$ and $\left|E^{\ast }\right|/\text{sin}\left(\phi \right)$ , were compared to the theoretical pavement rutting index. Based upon the preliminary study, it was found that $E^{\ast }$ was a suitable parameter in comparing the field and laboratory performance. Preliminary $\left|E^{\ast }\right|$ criteria for Mich. were prepared based upon the contractor’s warranty criteria consisting of the theoretical pavement rutting life index, and the collected traffic survey data. In addition, sigmoidal master curves were constructed using all minimum $\left|E^{\ast }\right|$ data in order to meet the practitioners’ needs.