The increasing focus on existing hot-mix asphalt (HMA) pavement rehabilitation by State departments of transportation (DOTs) as HMA pavements are the predominant pavement type in the United States, State DOTs require local calibration of the Mechanistic-Empirical Pavement Design Guide (MEPDG) HMA overlay of existing HMA pavement methodology. Although this methodology is a great improvement on the 1993 American Association of State Highway and Transportation Officials (AASHTO) HMA overlay design procedure, it has significant shortcoming, such as: (1) The Level 1 procedure for characterizing existing HMA pavement structural capacity/condition based on falling weight deflectometer (FWD) deflection testing, coring, extraction of cores, and lab characterization of the HMA cores binder and volumetric properties has to date not been calibrated. (2) The Level 2 and 3 procedures, though calibrated, are based on pavement surface distress and condition rating making it at best highly subjective. The need to review, enhance as needed, and calibrate the MEPDG Levels 1, 2, 3 procedures for characterizing existing HMA pavement structural capacity/condition. The purpose of this research is as follows: (1) Develop and calibrate objective methodologies for characterizing existing HMA pavement damage for HMA and portland cement concrete (PCC) overlay design that will, as a minimum, be enhancements to current MEPDG Level 1, 2, and 3 methodologies. (2) The new methodologies must be compatible with the Interim AASHTO MEPDG Level 1, 2, and 3 methodologies. (3) The new methodologies must be practical and implementable within the current AASHTO Interim MEPDG framework.
Develop a new calibrated existing flexible (new hot-mix asphalt (HMA) and HMA overlaid HMA) pavement damage model for use in ME design. The new model will be based on objective deflection-based in situ measurement of pavement condition rather than current procedures that mainly consider only distress/condition at the pavement surface. By using a deflection-based model, the condition of the entire pavement structure prior to rehabilitation is assessed.