Analysis of Asphalt Aging Characteristics and Mechanisms Based on FTIR

To investigate the evolution mechanisms of functional groups in different grades of asphalt (30#, 50#, 70#) and SBS-modified asphalt during the aging process, Fourier Transform Infrared Spectroscopy (FTIR) was employed, with the technique being combined with short-term and long-term aging experiments. By analyzing changes in infrared spectral peaks and asphalt properties, characteristic functional group indices were calculated. Subsequently, the Pearson correlation coefficient was employed to analyze the correlation between asphalt functional groups and macroscopic properties, and regression equations were established. Results show that long-term aging induces more intense oxidation reactions than short-term aging, causing significant changes in characteristic peaks, functional group indices, and properties. As asphalt grade increases, the variation range of aliphatic groups decreases, while aromatic, carbonyl, and sulfoxide group indices increase (order:70#>50#>30#>SBS). SBS-modified asphalt exhibits the smallest variation range due to modifier presence, enhancing its anti-aging properties. Penetration is highly positively correlated with the intensity of asymmetric aliphatic group peaks (r=0.95). The softening point is highly positively correlated with the intensity of sulfoxide group peaks (r=0.89). Brookfield viscosity is highly positively correlated with the intensity of carbonyl group peaks (r=0.97). Non-recoverable creep compliance is highly negatively correlated with the intensity of carbonyl group peaks (r=−0.72). These findings provide valuable insights for developing high-performance asphalt materials and studying anti-aging properties.