Local Calibration of the MEPDG Rutting Models for Ontario’s Flexible Roads: Recent Findings

This paper summarizes the recent efforts for and major findings from local calibration of the rutting models of the AASHTO Mechanistic-Empirical Pavement Design Guide (MEPDG) for Ontario’s practices in pavement design, construction and maintenance. Unlike many other local calibration studies for rutting models, this study took a new calibration method built upon the more recent rutting calibration results from NCHRP Project 9-30A. To reduce the indeterminacy because of the unknown layer contributions of total rutting, two of the five local calibration factors (the temperature and traffic exponents) were prefixed based upon statistical analysis of the data obtained from Project 9-30A. The remaining three scale factors were determined by using a two-objective optimization strategy that eliminates bias and reduces residual errors. It was concluded that although the Superpave and Marshall mixes share the same set of traffic and temperature exponents, the scale factors are very different. A set of local calibration factors were recommended for future flexible pavement design in Ontario.