Material and mix design aspects of hot recycled asphalt mixes: A review

Sustainability in road construction can be achieved by integrating recycled materials in the production of new pavement. One such approach is using reclaimed asphalt pavement materials (RAPM) in hot mix asphalt (HMA). Successful implementation of RAPM in HMA can only be achieved by having good comprehension of the essential material characterisation and design process. The main objective of this review is to summarise the literature and provide a keen understanding of the characterisation of materials involved (RAPM and rejuvenators) and mix design, by giving due consideration to the interaction of virgin and recycled materials. Widely used techniques for extraction and recovery of reclaimed asphalt pavement (RAP) binder have been reviewed. The advantages and disadvantages of different characterisation techniques are identified. The effect of various factors on the volumetrics of the recycled mixes is presented. Insight in to the requirements of a rejuvenator by taking into account the changes in binder after ageing is provided. Aspects that need further exploration to normalise and increase the confidence of RAPM in HMA are also highlighted as the future recommendations.