Evaluating Effects of Volumetric and Mechanistic Test Variability on Predicted Performance of Asphalt Pavement

The objective of this study is to evaluate, with the Mechanistic–Empirical Pavement Design Guide (MEPDG), the effects of volumetric and mechanistic variability on predicted performance of asphalt pavements. In addition, the effect of volumetric variability on predicted mechanistic properties of asphalt mixtures, as determined with the Fonseca–Witczak predictive model, was quantified with the use of a Monte Carlo simulation. Data collected from NCHRP Project 9–48, Field Versus Laboratory Volumetric and Mechanical Properties, were used to quantify the variability in volumetric and mechanistic properties. The effects of mechanistic variability on the design outcomes were evaluated with a sensitivity analysis of the MEPDG. According to the results, the average coefficient of variation (CV) in the dynamic complex modulus calculated from the Fonseca–Witczak model was 8.1%, which was less than the CV of 13.9% determined from the dynamic modulus test data presented in NCHRP Project 9–48. Predicted pavement distresses from the MEPDG indicated that a variability level in the dynamic complex modulus of 10% or less resulted in a change in the predicted level of performance of 10% or less. In contrast, variability in the dynamic modulus of 20% changed the design life of the pavement structures by up to 42% and the design hot-mix asphalt thickness by as much as 19%.