Characterisation of Uniaxial Creep Deformation Behaviour of Asphalt Mixtures

Аннотация

Compressive uniaxial creep and creep recovery tests have been conducted on two generic UK asphalt mixtures over a range of temperatures and stress levels. Instantaneous elastic, viscoelastic (delayed elastic) and viscoplastic behaviour have been observed and volumetric changes have been studied. The elastic modulus of the DBM was found to be greater than that of the HRA. The viscoelastic strain was found to increase approximately in proportion to the total stain up to a certain point, above which it tends towards a constant level. The steady state viscoplastic deformation behaviour of the mixtures was found to be nonlinear with exponents of 2.5 and 5.4 for the HRA for the DBM respectively. Both mixtures were found to dilate under creep loading with more dilation exhibited by the DBM mixture due to increased aggregate interlock. The dilation ratio was found to be independent of stress level and dependent on the type of mixture and test temperature.