Unsaturated Soil Modeling for Airfield Pavement Design

Abstract

This study presents results of one of the first in situ assessment studies on the use of the Mechanistic-Empirical Pavement Design Guide (M-EPDG) methodology applied to the design of airfield pavements. The M-EPDG’s Enhanced Integrated Climatic Model (EICM) introduces unsaturated soil modeling techniques into the prediction of moisture changes in the unbound materials throughout the life of pavements for highway conditions. Field soil moisture content changes measured at several Air Force bases in the U.S. were collected from historic studies and compared to MEPDG predictions. Details and outcomes from this comparative study are presented herein. Despite significant differences in structural dimensions and geometric design, this study showed that the EICM promises to be a suitable predictive methodology to be adapted for airfield pavement conditions and has the potential to become a tool for the incorporation of unsaturated soil modeling for the design of airfield pavements, provided that several enhancements are made to the model applied to highway design. Also, a discussion on possible sources of uncertainty in the predictions of the MEPDG and a series of alternative revisions and enhancements required to incorporate the EICM with current airfield pavement design methodologies are presented.