ABSTRACT
ABSTRACT: The dynamic complex modulus test for asphalt mixtures is conducted in the linear viscoelastic region and measurements assume that no damage is induced during the testing process. In contrast, the level of damage taking place in the flow number test is expected to be significant but it has not been quantified. The objectives of this study are to quantify the levels of damage in the dynamic complex modulus and flow number tests using x-ray Computed Tomography (CT) and to characterize the heterogeneous properties of asphalt mixtures under loading. Four asphalt mixtures, one conventional Hot-Mix Asphalt (HMA) and three Warm-Mix Asphalt (WMA) mixes, were evaluated. Two WMA processes (i.e., water foaming and RedisetTM additive) were used in the preparation of the WMA mixes. Results of the experimental program indicated that the damage taking place in the dynamic modulus test is minimal and homogeneous while the damage taking place in the flow number test is significant and heterogeneous. In addition, preparation procedure may significantly influence the three-dimensional air voids distribution in laboratory-compacted specimens.
