Evaluation of complex Poisson's ratio of aged asphalt field cores using direct tension test and finite element simulation

The aims of this study are to determine the complex Poisson's ratio of asphalt mixtures based on linear viscoelastic theory and to evaluate the effect of the complex Poisson's ratio on critical responses of asphalt pavements using finite element (FE) models. Direct tension tests were conducted on field core specimens, and horizontal and axial strains at the top and bottom of the field cores were recorded with loading time. The elastic-viscoelastic correspondence principle was utilized to compute the complex Poisson's ratio including the magnitude and phase angle with loading frequency. It is shown that the magnitude and phase angle were time, temperature and aging dependent. To better illustrate the effect of the complex Poisson's ratio on asphalt pavement responses, FE models with user-defined materials were developed to compute and compare pavement responses at critical locations with a constant Poisson's ratio and a complex Poisson's ratio. Besides, the effect of the aging time on the complex Poisson's ratio was evaluated from pavement responses. The differences between these cases were highlighted, which indicated the importance of using the complex Poisson's ratio in pavement design and performance evaluation. (C) 2020 Elsevier Ltd. All rights reserved.