Heterogeneous Finite-Element Modeling of the Dynamic Complex Modulus Test of Asphalt Mixture Using X-ray Computed Tomography

Abstract

Asphalt mixture is a heterogeneous, composite material consisting of aggregate, mastic, and air voids. Analysis of laboratory tests such as the dynamic complex modulus assumes that this material can be dealt with as a homogeneous material while overlooking the particulate nature of this composite. Because of the limitations of the elastic continuum theory, pavement engineers have recently paid considerable attention to the use of advanced modeling techniques for simulating the realistic behavior of asphalt mixtures. The objective of this study is to develop a three-dimensional (3D), heterogeneous model to describe the response of asphalt mixtures in the dynamic complex modulus test using an X-ray computed tomography image–based finite-element (FE)-modeling approach. Experimental testing results for two superpave mixtures, including one conventional hot-mix asphalt and one warm-mix asphalt, were used to validate and calibrate the developed FE models. Acceptable agreement between laboratory-measured and model-predicted dynamic modulus test results was achieved. Results of the developed FE models at different temperatures indicated that most of the deformations during the dynamic modulus test are derived from the mastic. In addition, the asphalt mastic had more influence than the aggregates on the results of the dynamic complex modulus test.