Accuracy of MEPDG Dynamic Modulus Predictions for Short-Term and Long-Term Aged Asphalt Mixtures

Abstract

This study examines the accuracy of dynamic modulus, |E*|, predictions made by the Mechanistic-Empirical Pavement Design Guide (MEPDG) for short-term and long-term aged hot mix asphalt (HMA) and foamed warm mix asphalt (WMA) mixtures. Four asphalt binders and one aggregate were used in the preparation of the asphalt mixtures. The American Association of State Highway and Transportation Officials (AASHTO) standard test method, AASHTO R 30, was used to simulate the short-term and long-term aging of laboratory-produced asphalt mixtures, while the National Cooperative Highway Research Program (NCHRP) 1-37A and NCHRP 1-40D prediction models, along with the Global Aging System that are incorporated into the MEPDG, were used to predict the dynamic modulus of the short-term and long-term aged HMA and foamed WMA mixtures. By comparing the dynamic modulus predictions obtained using the MEPDG to |E*| measurements obtained in the laboratory for short-term and long-term aged HMA and foamed WMA mixtures, it was observed that the NCHRP 1-37A model generally underestimated the dynamic modulus of the HMA mixtures (R2 close to 0.80) but provided a better quality of fit for the foamed WMA mixtures (R2 close to 0.90). As for the NCHRP 1-40D model, which generally resulted in higher |E*| predictions than the NCHRP 1-37A model, it had a better quality of fit for both HMA and foamed WMA mixtures with an R2 value close to 0.90 for both mixtures, with little difference observed between the R2 values for the short-term and long-term aged mixtures.