Investigation of rheological and fatigue properties of asphalt mixtures containing polyester fibers

The effects of polyester fiber on the rheological characteristics and fatigue properties of asphalt and its mixture are investigated in this paper. The viscosity, rheological and fatigue tests are conducted to characterize such related properties of asphalt binder and mixture with different fiber contents. Test results indicate that the viscosity of asphalt binder is increased with increasing polyester fiber contents, especially at lower temperature. With different polyester fiber contents, the complex modulus and loss modulus of asphalt binders are decreased at 15 °C and 0.1–100 rad/s frequency range. The dynamic modulus test results for asphalt mixture with 0.3% polyester fiber content also reveal that the dynamic modulus and phase angle are decreased at the same temperature, which leads to a decrease of fatigue parameter for asphalt mixture. When compared with the control asphalt mixture, the cycle numbers to fatigue failure of fiber modified asphalt mixture are increased with 1.9, 2.9 and 3.6 times at 0.5, 0.4 and 0.3 stress ratios, respectively. The parameters of fatigue functions for asphalt mixture with or without polyester fiber are obtained and compared, and it confirms that the fatigue property of asphalt mixture can be improved by fiber addition, especially at lower stress levels.