Structure-performance evolution on thermal-oxidative aging of CeO₂/SBS co-modified asphalt

ABSTRACT

Aging has a significant effect on the performance of asphalt, and the use of modifiers is the key to solving this problem. The mechanism of CeO₂ effect on the thermal-oxidative aging resistance of SBS modified asphalt was explored by studying the microstructure and macroscopic properties of asphalt. The melt blending method was used to prepare CeO₂/SBS co-modified asphalt, and the short-term thermal-oxidative aging process was demonstrated by a thin film oven test. Then, the effects of CeO₂ on the properties of SBS modified asphalt were investigated by using dynamic shear rheometry, nuclear magnetic resonance, and electron paramagnetic resonance spectroscopy tests. The results showed that CeO₂ increased the decomposition temperature of SBS modified asphalt and improved its thermal stability. The rheological results showed that the complex shear modulus aging index of CeO₂/SBS co-modified asphalt is lower than that of SBS modified asphalt, and the phase angle aging index increases. In addition, CeO₂ can make the internal molecular structure of asphalt produce more isomerisation and generate more long chains after aging. EPR results showed that CeO₂ can reduce the generation of free radicals during aging, thus slowing down the generation of oxygen-containing functional groups and improving the thermal-oxidative aging resistance of asphalt.

KEYWORDS:

• CeO₂
• co-modified asphalt
• thermal-oxidative aging resistance
• rheology
• free radicals

Disclosure statement

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

Additional information

Funding

This work was supported by the Transportation Science and Technology Development Plan of Tianjin (No. 2019-14 & No. 2022-12).