Performance analysis of asphalt pavement on fractional viscoelastic saturated subgrade under moving loads

This paper investigates the performance analysis of asphalt pavement on fractional viscoelastic saturated subgrade subjected to moving loads. Firstly, the thermoviscoelastic constitutive equation of asphalt pavement is derived by using the fractional viscoelastic Zener model, time-temperature superposition principle (TTSP) and Williams-Landel-Ferry (WLF) equation. Subsequently, the dynamic governing equations of saturated subgrade are established by the Biot theory. These equations are further generalized to address viscoelastic behavior through the fractional calculus theory and the principle of dynamic elastic-viscoelastic correspondence. With the combination of the boundary and interlayer contact conditions of the pavement-subgrade system, the solutions of this system are obtained by using the double Fourier transform, extended precise integration method (PIM) and the Fourier inverse transformation technique. Finally, the impacts of fractional order, temperature, asphalt surface thickness and moving load speed are conducted based on the theoretical validation. The results show that the maximum pavement deflection increases by about 50 % with the temperature increasing per 10 °C. When the fractional order is 0, the peak pore water pressure is >30 % higher than that under other fractional order conditions. The maximum pavement deflection increases by about 10 % and the pore pressure decreases by about 4 % with the asphalt surface thickness increasing per 5 cm.