Steady shear properties of a class of aged bitumens

Aging is the gradual changes in the properties of bituminous binders over time, mainly due to heat, oxidation, ultra-violet radiation and loss of volatile components. The most significant aging of bitumen takes place during mixing where the thin film is exposed to high temperatures together with increased airflow. Also, the bitumens continue to age throughout their in-service life. In this investigation, six modified bitumens with control unmodified bitumen were tested for their steady shear properties during their various stages of aging. The rolling thin film oven test (RTFOT) and pressure aging vessel (PAV) were used to simulate aging of bitumens during mixing and in-service respectively. It was found that long term aging has more severe effect on the steady shear properties of the bitumens than short term aging. © 2008 Taylor & Francis Group, London.