Performance characterization of long-term aged bitumen: Field and laboratory investigation

Aging of binder affects the service life of flexible pavements. Binder’s aging involves changes in its physical, rheological, chemical, and morphological characteristics, making it hard and brittle and resulting in pavement deterioration. Oxidation and volatalization are two main mechanisms involved in aging. Aging stiffens the binder as it increases the viscosity of binder resulting in pavement distresses like fatigue cracking, ravelling, and thermal cracking. Hence, it is obligatory to examine the aging effects on binder to predict the service life of flexible pavements. In this study, core samples are collected from 15 years aged in-service pavement section, and fresh binder was aged for varying aging duration in the laboratory to simulate field aging condition. Field aged and laboratory aged binders were subjected to physical, chemical, rheological, and morphological investigations for evaluating the variation of these properties with long-term aging (LTA). It is evident that the traffic speed influences the dynamic viscosity of binders. With aging, the rutting resistance of binders improved, and fatigue resistance of binders diminished considerably. 15 years field aging condition is simulated in the laboratory, and the results showed that the severity of aging in binder increases with the pavement depth in the field.