Retarding thermal-oxidative aging of anhydride-cured epoxy asphalt binder and mixture by incorporating antioxidant Irganox 1010

Abstract

ABSTRACT This research focused on the stabilisation of anhydride-cured epoxy asphalt (EA) over thermal-oxidative aging. EA binders with graduated Irganox 1010 antioxidant contents at 0, 0.3, 0.6, 0.9, and 1.2 wt% were prepared and then subjected to accelerated oven-conditioning aging at 85 and 100°C. The thermal stability, viscosity, mechanical parameters, and chemical structure of EA containing Irganox 1010 were evaluated during aging. The results showed that Irganox 1010 contributed to enhanced thermal stability, higher initial viscosity, and longer allowable construction time for EA. The 0.3–0.9 wt% Irganox 1010 had good compatibility with EA without weakening performance. During aging, Irganox 1010 effectively restrained degradation of the EA binder’s mechanical properties and the EA mixture’s low-temperature deformation. The variations of functional groups indicate that Irganox 1010 prominently restrained the oxidation of the asphalt phase and lightly affected the post-curing of the resin phase. There was a strong correlation between decreasing rate of bending strain of the mixture and increasing rate of sulfoxide in the binder. The mutual synergistic effect of resin and antioxidant improves the oxidation resistance of asphalt. Considering the aging improvement and economic cost, it is recommended to use 0.6 wt% Irganox 1010 as an antioxidant for anhydride-cured EA. Highlights Epoxy asphalt (EA) binder and mixtures incorporating antioxidant Irganox 1010 were analysed. Irganox 1010 plays a crucial role in aging protection effect of EA binder and mixture. Irganox 1010 antioxidant prominently restrains the oxidation of the asphalt phase and lightly affects the post-curing of the resin phase. There was a strong correlation between the bending strain of mixture and sulfoxide of binder. Addition of 0.6 wt% Irganox 1010 is recommended as an antioxidant for EA materials.