Evaluating field performance: Case study including hot mix asphalt performance-related specifications

State highway agencies strongly desire to develop and use performance-related specifications (PRS) for highway construction. A PRS for hot mix asphalt (HMA) construction, titled HMA Spec, was recently developed as part of the WesTrack project. The beta version of HMA Spec was applied to compare pay factors and actual rutting performance to predicted performance for four Nevada Department of Transportation (NDOT) test sections on Interstate 80 (I-80) east of Reno, Nevada. Some of these sections were similar in terms of materials and construction techniques to coarse-graded sections constructed at WesTrack, so a comparison to performance at WesTrack was also made. NDOT placed the test sections on I-80 in an effort to assess the applicability of the Superpave mix design process and HMA Spec for Nevada's conditions. Sections were designed using both Hveem and Superpave mix design methods. Several interesting observations were made while evaluating the HMA Spec output. These observations and field performance data are described in this paper.