Fourier transform infrared spectroscopy characterization of aging properties of graphene oxide modified asphalt binder

Abstract

The fundamental reason why thermal-oxidative aging can greatly affect the physical properties, mechanical properties, rheological properties and durability of asphalt is that the molecular structure and colloidal structure of asphalt are changed due to volatilization, oxidation and spatial hardening. To study the possible chemical changes of graphene oxide (GO) modified asphalt after aging and reveal its action mechanism, this study analyzed how GO changes the process of thermal-oxidative aging of asphalt from the perspective of molecular structure, and evaluated the aging properties of GO modified asphalt by testing the content change of each characteristic functional group in asphalt after thermal-oxidative aging. The results show that GO can significantly increase the content of amide groups (0.0018 %) in the base asphalt, which in turn enhances the adhesion and toughness of asphalt, reduces the brittleness of asphalt and improves the bearing strength. The addition of GO effectively inhibited the increase of carboxylic acid and ketone content in asphalt caused by aging. Amide is the aging product of asphalt exposed to air, and the presence of amide promotes the formation of hydrogen bonds, which is more conducive to the miscibility of GO and asphalt. The modification effect of GO on base asphalt is better than SBS-modified asphalt. The results of AFM show that GO-modified asphalt has a better proportion of components and a more stable colloidal structure, and the adhesion performance of GO-modified asphalt is significantly improved. GO can obviously improve the aging resistance and slow down the aging rate of asphalt, indicating that GO can improve the pavement performance and extend the service life of asphalt pavement.