Fractional derivative viscoelastic response of high-viscosity modified asphalt

To explain the dynamic viscoelastic characteristics of high-viscosity modified asphalt (HVMA) more compre-hensively and accurately, one type of finished HVMA and two types of laboratory-produced HVMA were chosen as the research objects. Firstly, a dynamic shear rheometer was employed for the strain sweep test to define the linear viscoelastic range of three different types of HVMA. Then, the frequency sweep test was performed in the linear viscoelastic range under different high-temperature conditions, and the viscoelastic properties of three different types of HVMA were analysed. Finally, an HVMA fractional derivative viscoelastic model was built and compared to the traditional Sigmoid function model. The results demonstrated that the traditional Sigmoid function model has limitations and cannot effectively illustrate the changes in the HVMA over a wide frequency range. The viscoelastic properties of HVMA can be fully described by the 1S1A1D fractional derivative model, including the storage modulus, loss modulus, complex shear modulus, and phase angle variations. For the 1S1A1D fractional derivative model, one Abel dashpot can illustrate the viscoelastic properties of HVMA, and increasing the number of Abel dashpots no significance on the performance.