In-situ detection on near-infrared spectra fingerprints of asphalt mixture after laboratory short- and long-term aging.

Although Fourier transform infrared spectroscopy has been widely used in research on the aging of asphalt binders, it is a cumbersome, time-consuming, and environmentally polluting process using toxic solvents to extract and recover asphalt binders from asphalt mixtures for spectral measurement and analysis. However, little effort has been devoted towards its non-destructive spectral measurement, which is important for intelligent monitoring of pavement deterioration conditions. This paper focused on the non-destructive investigation of comparative near-infrared spectra of asphalt mixture specimens designed using the Marshall method after laboratory short- and long-term aging with a portable near-infrared spectrometer. The near-infrared spectra showed that asphalt mixtures from different aging states appeared significantly different fingerprints. The near-infrared fingerprints and aging states were also statistically significantly different according to the analysis of one-way analysis of variance. These distinctive near-infrared fingerprints could be attributed to the varied amounts of chemical functional groups, mainly hydrogen-containing groups during oxidative aging. This study provided a non-destructive and in-situ detection of the aging of asphalt mixtures. • The portable NIR spectrometer is used for the measurement of asphalt mixtures. • Asphalt mixtures from four aging states have unique and distinct NIR fingerprints. • ANOVA indicates a statistical difference in NIR spectra from four aging states. • NIR spectroscopy is suitable for in-situ detection of aging of asphalt mixtures. [ABSTRACT FROM AUTHOR]