Development, Calibration, and Validation of a New M-E Rutting Model for HMA Overlay Design and Analysis

The purpose of this paper is to present a new mechanistic-empirical (M-E) rutting model developed for hot-mix asphalt (HMA) overlay thickness design and analysis. After reviewing existing rutting models in the literature, it was found that the well-known VESYS layer rutting model still is a rational choice and was adopted with minor modification to model HMA overlay rutting development. The main feature of the proposed M-E HMA overlay rutting model is to characterize layer specific permanent deformation properties rather than global rutting parameters used in the Mechanistic-Empirical Pavement Design Guide. For each specific layer, the proposed model requires rutting parameters alpha and mu; and these rutting parameters, which are two of the fundamental input parameters required in the proposed M-E rutting model, can be directly determined from the repeated load test following the test protocol discussed in the paper. Additionally, the proposed M-E HMA overlay rutting model was calibrated using 8 test sections of the National Center for Asphalt Technology (NCAT) Test Track 2006, and the calibrated model was further validated using two sets of independent rutting data: three test sections of the NCAT Test Track 2000 and four test sections of Special Pavement Study 5 on US175, Texas. Thus far, satisfactory results have been obtained. However, more field performance data are needed for further model improvement.