Effect of montmorillonite-loaded CeO2 nanocomposites with different CeO2 contents on thermal-oxidative and ultraviolet aging properties of asphalt

This study investigated the effect of montmorillonite-loaded cerium oxide (CeO₂) nanocomposites with different CeO 2 contents on the thermal-oxidative and ultraviolet (UV) aging properties of asphalt. Nanocomposites were synthesized using a sol-gel method, varying the CeO₂ content in montmorillonite (MMT), and then these nanocomposites were incorporated into 70# base asphalt at different contents. The micro-characteristics of nanocomposites were evaluated through a series of characterization techniques, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV-Vis spectrophotometry, and field emission scanning microscope (FE-SEM). The impact of the nanocomposites on the thermal-oxidative and UV aging resistance of asphalt were assessed by measuring changes in softening point, ductility, penetration, and carbonyl index (CI) before and after aging. The results demonstrated that the CeO₂ content significantly influenced the nanocomposite structure, affecting its dispersion, interlayer spacing, and UV absorption properties. At the same time, CeO₂ significantly improved the UV shielding properties of CM, with an optimal CeO₂ to MMT ratio found to enhance the aging resistance of asphalt. This was attributed to the synergistic effect of the oxygen storage and UV absorption capabilities of CeO₂, combined with the thermal insulation and oxygen isolation properties of MMT. Additionally, the application of the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) method identified 1 % CMMA0.5 as the optimal modifier for improving the resistance of asphalt to thermal and UV aging.