Ageing of rejuvenated bitumen in hot recycled bituminous mixtures: influence of bitumen origin and additive type

The present study aims at investigating the evolution of the rheological properties of a primary bitumen with ageing (first service life), hot recycling (50/50 blending of virgin and aged bitumen, without adding additives or adding with three different rejuvenators) and re-ageing (service life after RAP hot recycling). RTFOT and PAV equipment were used to simulate bitumen ageing in laboratory and DSR allowed analysing the rheological behaviour. Results show that the hot recycled bituminous blends including a properly selected and dosed rejuvenator can undergo a less severe oxidation than virgin bitumen and can be less stiff at the end of the service life. The comparison with the results obtained in a parallel research, using a bitumen produced through a visbreaking process, proved that the latter is more unstable and exhibits a more detrimental ageing.