Practical Method to Determine the Effect of Air Voids on the Dynamic Modulus of Asphalt Mixture

This study presents a practical method for estimating the effect of air voids on the dynamic modulus of asphalt mixture. Dynamic modulus was predicted for mixes with a large range of air void contents using the construction mix volumetric and binder rheological data from 10 accelerated loading facility (ALF) lanes, following the Witczak and Hirsch methods. A large variety of plant-produced and laboratory-prepared mixtures, including hot- and warm-mix asphalt (HMA and WMA), reclaimed asphalt pavement, and recycled asphalt shingles, was tested for dynamic modulus at different air void contents. The experimentally measured and normalized correction factors were found to be more dependent on test temperature than the frequency. The predicted correction factors were found to match with the experimental data at lower temperature but to be clearly lower at high temperature. A set of correction factors for each test temperature is recommended to practitioners correcting dynamic modulus with variation in air voids in asphalt pavement.