The rheological transformation of bitumen during the recycling of repetitively aged asphalt pavement

This article explores changes in bitumen during the recycling of asphalt pavement and what consequences the observed rheology has on pavement performance in the short and long term in the Nordic environment. As the existing environment dictates the state of performance, this research focuses on the intermediate and cold temperature performance and requirements, especially transformation from ductile to brittle behaviour. An asphalt pavement, originally constructed by using conventional paving grade bitumen 70/100 and 50/70, was rehabilitated by hot in-place recycling (HIR) for the first, second and third time. The HIR yields the pavement surface consisting of more than 70% of the in situ recycled asphalt. Samples were taken prior to, during construction and in the service. The rheological evaluation of ageing and rejuvenation of bitumen was conducted to investigate the effect of repetitive recycling on bitumen properties. Contractors used soft bitumen 650/900 as a rejuvenator and admixture with the virgin...