Designing asphalt mixes containing reclaimed asphalt pavement (RAP)

Repairs and reconstructions of asphalt roads and paved areas generate large amounts of construction debris in the form of reclaimed asphalt pavement (RAP). The material milled from the upper layer contains aggregate and asphalt with deteriorating performance parameters as a result of long-term service under variable weather conditions. Since the debris is mostly composed of non-renewable materials, attempts have been made to recycle and utilise it in the preparation of new asphalt mixtures. This study investigates the design of an asphalt mix containing recycled RAP and summarises the testing of its performance parameters. By lowering the mixing temperature and using a two-stage method of RAP heating, it was possible to design an asphalt mix with 90% RAP content; thus, the demand for virgin aggregate and the fuel consumption throughout the mixing process could be effectively reduced.