Evaluation of the AASHTO Empirical and Mechanistic-Empirical Pavement Design Procedures Using the AASHO Road Test

Abstract

The American Association of State Highway and Transportation Officials

(AASHTO) adopted the Mechanistic-Empirical Pavement Design Guide (MEPDG) in 2008 and state agencies are now transitioning from the classical empirical procedures derived from the American Association of State Highway Officials (AASHO) Road Test. This thesis focuses on the practical implications of this transition: specifically, the changes to required pavement thickness. The AASHO Road Test pavement distress

histories are compared against the MEPDG and AASHTO 1993 performance predictions using several performance measures (PSI, IRI, rutting, and cracking). No existing relationships from the literature were found to fit the AASHO Road Test recorded data so new relationships were developed to relate measured PSI to MEPDG predicted distresses.

The findings, although somewhat inconclusive due to inherent difficulties in modeling the conditions at the Road Test for the MEPDG, suggest that the MEPDG predicts thinner pavement sections at higher traffic levels.