ABSTRACT
Permanent deformation in bituminous concrete occurs as a combination of densification and shear flow. There already exists standardized testing protocols like flow number and flow time tests that are focused on the shear flow mechanisms of the binder, though they are conducted in triaxial stress state. In order to characterize the permanent deformation of bituminous concrete accurately, the volumetric deformation involved in the densification process needs to be studied as well. A laboratory investigation was conducted under triaxial conditions with the main objective of observing the volumetric changes in the compressible viscoelastic behavior of bituminous concrete. Bituminous concrete cylindrical specimens which were fabricated with an unmodified binder and binders modified with crumb rubber, plastomer and elastomer were subjected to pure confinement creep and recovery tests at different confinement pressures, without applying any deviatoric stress. The response obtained showed clear dependence on the binder type and confinement pressure.
