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

Abstract

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${}^{\circ }$C) and three long-term thermo-oxidative aging durations (3, 6 and 9 days at 85${}^{\circ }$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 $|G^{\ast }|$, the aging index (AI=$I_{S0}$ + $I_{C0}$) and a decrease in the penetration grade with the aging duration. Some correlations between the viscoelastic transition parameters ($T_{VET}$, $G_{VET}$ and ${\omega }_{VET}$) of the recovered asphalt binders and the aging index have been established. At the mixture scale, the results show that the stiffness modulus ($|E^{\ast }|$) increases with the aging duration, while the index of fracture resistance (IFR), the stripping resistance ($C_W/C_D$), the rut depth (P) and the fatigue deformation (${\epsilon }_6$) decrease with the aging duration. Finally, some correlations between the aging index and the rheological and the mechanical properties of binders and concretes ($|G^{\ast }|$, $|E^{\ast }|$, P, IFR, ${\epsilon }_6$) have been proposed.

Keywords:

• Asphalt concrete
• Aging
• stiffness modulus
• cracking and fatigue
• rutting
• stripping

Acknowledgments

The authors would like to thank Michel Liffraud at Cerema Toulouse, for its generous help in performing a part of the DSR tests on the asphalt binders.

Disclosure statement

No potential conflict of interest was reported by the author(s).