Evaluation of effects of short and long-term thermo-oxidative aging on chemo-rheological and mechanical properties of asphalt concretes

The effects of short and long-term thermo-oxidative aging on stripping resistance, rut depth, stiffness modulus, fracture and fatigue resistances of asphalt concretes have been assessed. A modified RILEM thermo-oxidative aging procedure on loose asphalt mixtures has been used to evaluate the gradual evolution of these properties with the aging duration. Two short-term aging durations (4 and 8 hours at 135∘C) and three long-term thermo-oxidative aging durations (3, 6 and 9 days at 85∘C) and a reference mixture (0 day aging) have been considered to this end. The impact of long-term thermo-oxidative aging on the chemo-rheological properties of recovered asphalt binders have been investigated. At the binder scale, the results show an increase in the Fraass temperature, the softening point, the shear modulus |G∗|, the aging index (AI=IS0 + IC0) and a decrease in the penetration grade with the aging duration. Some correlations between the viscoelastic transition parameters (TVET, GVET and ωVET) of the recovered asphalt binders and the aging index have been established. At the mixture scale, the results show that the stiffness modulus (|E∗|) increases with the aging duration, while the index of fracture resistance (IFR), the stripping resistance (CW/CD), the rut depth (P) and the fatigue deformation (ε6) decrease with the aging duration. Finally, some correlations between the aging index and the rheological and the mechanical properties of binders and concretes (|G∗|, |E∗|, P, IFR, ε6) have been proposed.