Determination of creep compliance of asphalt mixtures at intermediate and high temperature using creep-recovery test

The linear viscoelastic (LVE) characterisation of asphalt mixtures in time domain is generally performed at temperature lower than 30°C to prevent the effect of permanent deformation. Although LVE properties in frequency and time domain can be mathematically interconverted, the determination of relaxation modulus and creep compliance through experiment is also necessary. This paper presents a method for determining the creep compliance of asphalt mixtures at intermediate and high temperature, at which permanent deformation takes place. Since the recovery of creep-recovery test is a pure LVE process, it was used to back-calculate the creep compliances (CCs) at various investigating temperatures. The results show that the CCs back-calculated from creep-recovery data achieve a good level of accuracy and repeatability. In addition, the obtained master curves of CCs agree well with those interconverted from dynamic modulus test data and the same shift factors are applicable for both creep compliance and dynamic modulus, phase angle.