Mechanistic Evaluation of Second Generation Preservation Overlays

The application of hot mix asphalt (HMA) overlays of rigid pavements is a common pavement rehabilitation practice. This paper provides an evaluation of the effect of the second generation hot mix asphalt (HMA) overlay on a 16 km section of Interstate 79 in western Pennsylvania. The project was constructed to provide a comparison of two second generation overlay strategies; one consisting of leveling and wearing and the other of binder and wearing courses. The evaluation included monitoring of the construction process, and assessment of the effect of the new overlays on pavement condition as measured by distress, deflection, and roughness. Additionally, the predicted performance of the two comparison cross sections was modeled using the proposed AASHTO Mechanistic-Empirical Pavement Design Guide (MEPDG), and other mechanistic analysis tools. Results from the work include structural evaluation of the two different pavement sections, and associated performance predictions. A methodology for performing long term monitoring of pavement performance and evaluation of life cycle cost was also provided to the highway agency.