Creep & Creep Recovery Research On High Viscosity Rubber Modified Asphalt Binder

The creep properties of asphalt binder are the fundamental reason of the rutting,shoving,wave,uplift,bleeding,etc.permanent deformation.The shear stress of the material is a nonnegligible factor of these damages,so studying the influence of shear stress onto the creep viscoelastic parameters of asphalt material will have important meaning in researching pavement shear failure.In this paper,the creep viscoelastic properties of high viscosity rubber modified asphalt binder(HVRA),while general rubber asphalt binder(RA)and SBS modified asphalt(SBS)be contrasted,were studied.Not only studied the original viscoelastic creep index,but also put forward a parameter directly related to the shear stress called equivalent plastic shear strain(NAS?),creep viscoelastic indexs are characterized based on temperature and stress levels.And it also finds out the numerical reason why HVRA contains good creep viscoelastic performance.Finally,the paper makes a comparative analysis of the model fitting effects of HVRA.Because of the shear stress and creep process are the most important factors for the occurrence of pavement deformation,the paper will do some corresponding research on original and new creep viscoelastic parameters respectively through static creep test and cyclic creep recovery test under the new torsional shear tester,focusing on the analysis of HVRA creep viscoelastic indexes and parameters and exploring the creep viscoelastic properties.The results show that: under the same temperature conditions and stress level,the creep viscoelastic parameters of HVRA are better than those of the corresponding level of RA and SBS;compared with the stress level,temperature conditions plays a more destructive roal on the effection on asphalt creep properties;creep stiffness of viscous component has stress independence at a certain temperature;NAS? is more suitable for describing the road shear deformation by considering the amplitude of shear stress;although the Burgers model can accurately fit the experimental creep curves in creep loading stage,but it shows a lack of capacity in the prediction of creep recovery,the improved Burgers model can significantly improve the recovery stage prediction problem.