Effect of rejuvenator addition location in plant on mechanical and chemical properties of RAP binder

Rejuvenators can restore the reclaimed asphalt pavement (RAP) binder for another service period. To achieve this, homogeneous distribution of rejuvenator and good diffusion into reclaimed asphalt binder film has to be ensured. Ten potential rejuvenator addition locations are summarised, and two most promising are compared in full-scale study: spraying of rejuvenator on cold reclaimed asphalt on the feeding belt before heating versus addition of rejuvenator to hot reclaimed asphalt in mixer. RAP samples were collected at various places in the production line to evaluate the effect of rejuvenator addition location on softening point, penetration, rheology and chemical composition of extracted binder. The results revealed that passing through the extreme temperatures in the RAP heating drum does not sacrifice mechanical performance or increase chemical ageing of the rejuvenated binder. A benefit of early rejuvenator addition is that it provides a longer residing time of rejuvenator on the binder and thus potentially may allow higher binder activation and better blending of RAP binder with rejuvenator and virgin binder. This has to be evaluated through mixture tests.