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InfraRed spectrometry is a powerful technique to characterise bituminous binders. The methodology is not fully harmonised and may lead to variability. The RILEM-272-PIM-TG1, evaluated seven complex bituminous, for which eleven laboratories performed FTIR. While, the spectra showed similar trends, further analysis was needed to improve comparison. A specific approach was applied on two binders, unmodified and polymer modified bitumen, and two ageing conditioning. Combining a Gaussian distribution and derivative analysis confirmed a good alignments of laboratory results. A two-step model was developed improving further interpretation. It consists of a baseline adjustment with eight points and normalisation over the maximum aliphatic peak. Furthermore, a specific fingerprint model was determined with the main absorption peaks defined by their location and shape. Only the intensity varies from laboratory to laboratory and binders. This general approach can be used as a platform to characterise aging or binder complexity.

Ageing has long been recognised as a major distress mechanism for asphalt concrete and, by extension, asphalt pavements. Ageing causes the material to stiffen and embrittle, which leads to a high potential for cracking. Although a significant amount of effort has been placed on understanding the ageing process of asphalt binder, less effort has been put forth to develop laboratory ageing procedures for producing aged mixture specimens for performance testing. An optimal laboratory conditioning procedure to simulate long-term ageing for performance testing and prediction is required in order to integrate the effects of long-term ageing in pavement prediction models and other mechanistic design and analysis methods. In this study, oven ageing and pressure ageing vessel ageing are applied to both loose mix and compacted specimens in order to evaluate and select an ageing method to simulate long-term ageing for performance testing and prediction. The selected method must be able to maintain specimen integrity in order to be used for performance testing and prediction. Efficiency, practicality, and versatility also are considered in evaluating the ageing methods. The results demonstrate that loose mix ageing in an oven is the most promising ageing method to produce mixture specimens for performance testing in terms of efficiency, specimen integrity, versatility, and cost.