Comparative analysis of non-standardised aging methods for asphalt binder against standard laboratory aging and natural field aging

This research investigates non-standardised and natural field aging methods, in comparison with standardised ones. Aging in the Rotational Viscometer (RV) for 24 hours was studied. Pressure Aging Vessel (PAV) aging time and film thickness were changed and compared with standard rolling thin film oven (RTFO) and field-aged binders. Finally, a conventional binder preserved from external conditions was tested over 24 months. Results showed that PAV-aged binders may exhibit greater susceptibility to changes captured by RV. The study also noted a higher increase in viscosities at lower shear rates over time in the RV. However, rheological results did not align with RV findings across all binders. Altering asphalt film thickness in the PAV from 32.5 mm to 25 +/- 1 mm has a comparable effect to standard RTFO when the original binder is aged directly in the PAV for the same period of time. The recovered asphalt binder from a 15-year-old pavement showed similarities to 25-30 hours for high-temperature measures, and 55 hours for fatigue parameters indicating inconsistency between laboratory and filed aging. Finally, chemical changes indicated by carbonyl index showed that after 24 months of controlled environmental conditions, a conventional binder exhibited only 44% increase in the index compared to RTFO.