Asphalt recycling is nowadays a requirement that accounts for demands on sustainability and energy efficiency. Despite being a minor component, the bitumen binder plays an important role in asphalt performance and also contributes for pavement deterioration. During its full lifetime bitumen faces different aging processes, mainly due to interactions with environment, which involve changes in chemical composition, in structure and microstructure and, by consequence, changes in rheological behavior (rheological material functions and material constants). From the perspective of bitumen regeneration, there are some relevant aspects like: (1) To what extent is it possible revert the ageing of bitumen? (2) To what extent can regeneration processes restore original bitumen properties? (3) What kind of response can we expect from regenerated bitumen when facing a new ageing cycle? There is no single answer to these questions, since several factors are to be considered such as the degree of ageing of bitumen in RAP (Reclaimed Asphalt Pavement), the RAP content and the properties of the new binder added to RAP. The methodology used to evaluate bitumen properties is behind those answer, since it provides the tools for understanding the phenomena that are taking place. The [ageing-regeneration-ageing] life cycle of bitumen used in Portuguese road construction was evaluated following a methodology based on chemical, structural and rheological characterization. Chemical analysis included the follow up of generic fractions (SARA, saturates+aromatics+ resins+asphaltenes) at different stages of the ageing and regeneration processes, as well as the pursuit of oxidation by infrared spectroscopic index. Structure and microstructure were assessed by using gel permeation chromatography (under extreme conditions) and atomic force microscopy. Furthermore, a rheological characterization was done, by measuring the relevant material functions in different regimes (dynamic and permanent (steady)).
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