Could high RAP mixtures be multi-recycled? Validation through long-term performance assessment

Reclaimed Asphalt Pavement (RAP) multi-recycling is a step forward in the circular economy by the reuse of materials in successive phases of the life cycle of infrastructures without downgrading their functionality. RAP application continues to be faced with some challenges and barriers that are yet to be overcome to enable its widespread use mainly for rates up to 100 %. With the increment of RAP mixtures use, the multi-recycling capacity will be a near future problem. This paper assessed the multi-recycling capacity of RAP in high incorporation rate (75 %) mixture for wearing courses, before and after ageing, using two recycling cycles. Both the short- and long-term performances of RAP mixtures were evaluated by mechanical and functional tests. In general, the second recycled RAP mixture showed similar or higher performance than the virgin asphalt mixture. It showed a 23 % lower stiffness modulus, a 37 % higher fatigue resistance and 62 % lower permanent deformation than virgin asphalt mixture. Moreover, it presented non-sensitivity to water damage and good functional performance. The RAP multi-recycling capacity was validated. Further studies can be developed for other types of asphalt mixtures.