ABSTRACT
In order to predict the field performance of asphalt binder, extensive researches have been conducted to simulate aging of asphalt binder in the laboratory and then measure the properties of Laboratory-aged Asphalt Binder (LAB). However, the effectiveness of laboratory aging methods simulate in simulating field aging of asphalt binder remains a concern, since the filed aging of asphalt binder is a complex process, which depends on both the material itself and external environment. This study aims to determine the effectiveness of the standard Superpave laboratory aging methods in simulating the field aging of asphalt binder in subtropical climate. To achieve this objective, the Rolling Thin Film Oven Test (RTFOT) followed by (Pressure Aging Vessel) PAV test were employed to prepare the LAB sample. Meanwhile, six Field-aged Asphalt Binder (FAB) samples were obtained from the reclaimed asphalt pavement (RAP) materials which had served for different years at local urban roads in Hong Kong. Then, both rheological and chemical properties of these samples were characterized and compared. The results of Dynamic Shear Rheometer (DSR) and Fourier Transform Infrared spectroscopy (FTIR) tests show that the aging levels of FAB samples were significantly higher than the LAB sample. It indicates that the standard Superpave laboratory aging method is even not capable of simulating 4 years of field aging of Stone Mastic Asphalt (SMA) in Hong Kong’s climate, while the traditional dense-graded asphalt mixture, which is locally coded as wearing course (WC), showed slightly lower aging extent than SMA in the field. However, the 5 years of filed aging of WC was not matched by the standard laboratory aging method.
