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

Abstract

Aging of binder affects the service life of flexible pavements. Aging involves change in physical, rheological, chemical and morphological characteristics of binder making it hard and brittle resulting in pavement deterioration. Oxidation and volatalization are the 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. 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. The severity of aging in binder increases with pavement depth in the field and 8 days of normal oven aging in the laboratory simulates 15 years field aging condition.