Understanding aging across material scales is critical for predicting the long-term performance of bituminous materials. This study investigates the aging of binder, mastic, and asphalt mixture samples under various temperature, pressure, reactive oxygen species (ROS), and humidity. Chemical aging processes were analysed using attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR), principal component analysis (PCA), and Euclidean distance. Normalisation, baseline correction, and advanced ATR correction were used to enhance the accuracy of FTIR results. Hydrated lime in mastics enhanced the resistance to oxidative aging, particularly under hygrothermal conditions. PCA identified key spectral regions for understanding aging processes of bituminous materials. Porous asphalt (PA) mixtures aged more than stone mastic asphalt under field-like conditions. PCA identified distinct aging clusters at low and high pressure. Euclidean distance analysis indicated that binder-level aging can approximate mastic and mixture aging under certain conditions. The findings confirm that FTIR indices are effective for multi-scale aging studies.

Ageing of bituminous materials contributes to various forms of pavement failures, thus leading to the degradation of pavement performance. To understand the evolution of pavement performance, the development of a proper laboratory protocol to simulate long-term ageing process of asphalt mixtures is of uppermost importance. In this study, the porous and dense asphalt slabs with thickness of 5 cm were exposed to oven ageing at 85?C for 3 and 6 weeks in the laboratory. Cyclic Indirect Tensile tests were performed to investigate the effect of ageing on the mechanical properties of asphalt mixture. The results were used to correlate with the change in the mechanical properties of the porous and dense pavement in the field. Pavement test sections were constructed in 2014 and have been exposed to actual environmental conditions since then. To study the temporal changes in the mechanical properties of the pavements, asphalt cores were collected from the test sections annually. The results show that porous asphalt has a higher ageing rate than dense asphalt due to its high porosity. Porous asphalt aged at 85?C for 3 and 6 weeks in the laboratory have the same stiffness change as that aged 3 and 3.5 years in the field, respectively. Dense asphalt aged at 85°C for 3 weeks in the laboratory have the same stiffness change as that aged 4 years in the field.