Investigation of Prony series model related asphalt mixture properties under different confining pressures

The objective of this paper is to investigate linear viscoelastic properties of asphalt mixtures measured under different confining pressures with respect to master curves of complex modulus, relaxation time and modulus of Prony series model. A modified collocation method is utilized to calculate the relaxation modulus of Prony series representation after the relaxation time is selected. The relaxation moduli of two asphalt mixtures under different confining pressures are compared at a wide range of reduced loading times. Finite element simulation is employed to fully investigate the effect of confining pressure on mechanical responses of asphalt pavement. The results show that the construction method of master curves of complex moduli is effective and reliable. The relaxation modulus calculated from the smoothed experimental storage and loss moduli of the same complex moduli are slightly different, and it is impossible to obtain the accurate relaxation time and modulus to well agree with the test data of storage and loss moduli simultaneously at the full range of reduced angular frequencies. As the confining pressure increases, the relaxation modulus does not always increase at the full range of reduced loading time due to the effect of phase angle. As the confining pressure increases, the tensile strains and shear strains in the asphalt layer decrease in the practical speeds of vehicular loading.