Comprehensive Review of Flexible Pavement Design Approaches

MaineDOT currently uses an in-house developed pavement design guidance which is based on the AASHTO 1993 design approach. This method was developed based on outdated traffic, limited soil type, and environmental conditions. Though MaineDOT employs engineering judgment to overcome these limitations, the decisions are often arguable and limited to individual experience. MaineDOT has been looking for an alternative design approach that can overcome these challenges. For example, MaineDOT had recently completed a preliminary study verifying the feasibility of using AASHTOWare Pavement Mechanistic Empirical Design (PMED) as an alternative approach. However, the results did not yield consensus among the practitioners for the Maine conditions. It is primarily due to insufficient data for accurate local calibration of PMED performance models. Also, given the low traffic volumes and a limited number of reconstruction projects each year, the PMED method has raised several concerns from a benefit-cost standpoint. This study reviews alternative design practices to provide recommendations to the DOT.