Dynamic Modulus for Porous Asphalt and Its Master Curve

The triaxial compression tests of porous asphalt (PA) mixture under different conditions were conducted in the laboratory by using a simple performance tester with dynamic modulus as the mechanical index to further promote the engineering application of PA pavement. The influence of confining pressure, loading frequency, and temperature on the dynamic modulus was then studied. The master curve equations of dynamic modulus were constructed on the basis of the time-temperature superposition principle using nonlinear least squares method. Results show that the dynamic modulus of PA demonstrates obvious viscoelastic behavior. The dynamic modulus decreases with the increase in temperature and rises with the increase in confining pressure or loading frequency. The frequency characteristics at low temperatures and the stress dependency at high temperatures are strong. The existence of confining pressure reduces the temperature sensitivity of the dynamic modulus of PA, which is stable with the increase in confining pressure. The influence of confining pressure on dynamic modulus is relatively large under the condition of low frequency or high temperatures.