Advanced Rheological Characterization of Non-Reversible Deformation and Fatigue Behavior in Crumb Rubber Modified Asphalt Binders

Starting from the assumption that the characterization of damage behavior associates specific mechanical properties to the materials' resistance in condition of incipient failure, this paper deals with the use of different rheometrical approaches to assess the resistance to fatigue and non-reversible deformation in crumb rubber modified (CRM) asphalt binders, Damage-related properties of CRM binders at high service temperatures were studied by analyzing the mechanical response and the viscous deformation mechanism in conditions of repetitive and static creep loading. Results shown that the accumulation of non-reversible deformations and the distribution of delayed elastic and viscous components in binders delayed mechanical response strongly depend on the presence of the rubber particles. At the intermediate service temperature, the development of the complex modulus (G*) in cyclic shear tests (time sweeps) was recorded under different loading conditions and the binders fatigue resistance was evaluated according to the available failure criteria. Using both stress-controlled and strain-controlled testing mode, the relations between the stress/strain amplitude and the number of cycle to failure (S-N curves) were established. Results allowed to define some dynamics related to the contribute of the crumb rubber modification in binder damage resistance with regard to the considered loading conditions.