VDOT Research Council Publishes Pavement Rehabilitation Design Using Mechanistic-Empirical Concepts
The Mechanistic-Empirical Pavement Design Guide (MEPDG) was developed with an objective to provide the highway community with a state-of-the-practice tool for the design of new and rehabilitated pavement structures. The Virginia Department of Transportation (VDOT) officially adopted the MEPDG for new construction for interstate and primary routes effective January 1, 2018. For rehabilitation design, VDOT currently uses an earlier-generation AASHTO guide, the 1993 Guide for Design of Pavement Structures, but expects eventually also to implement the MEPDG for the most common scenarios. To ensure a more effective overlay design, it is imperative to conduct a local calibration/validation of design procedures and to determine the proper material inputs for both the existing and any new pavement materials that may be used in the rehabilitation.
The purpose of this study was to assist VDOT in the implementation of AASHTOWare Pavement ME Design software (hereinafter “Pavement ME Design”) for the design of overlays for existing flexible, rigid, and composite pavement. The study evaluated various input levels and the need for separate local calibration factors for rehabilitation of asphalt concrete (AC) over AC, AC over jointed concrete, and AC over continuously reinforced concrete pavements using Version 2.2.6 of Pavement ME Design. The study recommends implementation of the use of the current Version 2.2.6 for rehabilitation design only after a detailed sensitivity analysis with regard to various distresses using current calibration coefficients. Further, the study recommends the promotion of detailed forensic evaluation as part of rehabilitation design for restorative maintenance projects and that VDOT consider adopting V2.6 of Pavement ME Design for new and rehabilitation design.