Metal Organic Frameworks as Antiaging Agents for Bitumen: Investigating the Inhibition of Oxidation Reaction

Bitumen aging leads to increased brittleness and reduced flexibility, which significantly compromises the durability and long-term performance of pavements. This study investigates the potential of metal–organic frameworks (MOFs) as antiaging additives for bitumen, with an emphasis on their porous structures and selective adsorption behavior. Three representative MOFs, namely Metal–Organic Framework-5 (MOF-5), Zeolitic Imidazolate Framework-67 (ZIF-67), and Universitetet i Oslo-66 (UiO-66), were synthesized and characterized by scanning electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, and thermogravimetric analysis. Their performance was compared with that of carbon nanotubes, which served as a conventional nanomaterial benchmark. The influence of these materials on the physical and chemical properties of bitumen was evaluated through viscosity measurements, Fourier-transform infrared analysis, and standardized aging tests. The results demonstrate that MOF-modified bitumen exhibits improved high-temperature flowability and substantial suppression of carbonyl and sulfoxide formation during oxidative aging. Among the tested materials, ZIF-67 provided the most pronounced antiaging effect, whereas carbon nanotubes primarily increased viscosity but were less effective in mitigating oxidative degradation. Three potential inhibition pathways, including inert gas oxidation blocking, reductive gas-induced reverse aging, and targeted adsorption combined with catalytic degradation, are proposed to explain the observed antiaging behavior. These findings indicate that metal–organic frameworks, particularly ZIF-67, are promising and sustainable modifiers for extending the service life of asphalt pavements. Future work will include long-term field validation and further elucidation of the molecular mechanisms underlying MOF-induced antiaging effects.