Understanding Aging Behaviour of Conventional Asphalt Binders Used in India

Aging is one of the most important and dynamic characteristics of asphalt materials. Aging helps predict the life of a flexible pavement owing to the adhesive characteristics of binders with aggregate particles. With advancement in age, the asphalt mix components including binders oxidize, and volatilization of oils takes place, which render asphalt mixes higher stiffness, thus, increasing viscosity. Certain parameters are found to be essential in a comprehensive understanding of aging characteristics of asphalt binders such as asphaltenes. Thus, there is a need to investigate the effect of these parameters on aging in order to predict pavement life over its design period. The main objective of this research study was to understand aging behaviour of two conventional (virgin) asphalt binders commonly used and practiced in road construction activities in India at unaged and short-term aged conditions: viscosity graded VG-30 and VG-40 binders. The significant outcome of the study was that it gave an assurance that asphalt aging can be effectively scrutinized by mapping the chemical constituents of the binder and thus paves a way for future research in this area. In this study, the amount of asphaltenes was selected as the chemical parameter. The findings showed that this parameter was more perceptible in studying the aging behaviour of asphalt binder, and hence is certainly a promising performance indicator. Hence, future studies are envisioned to establish asphaltene as a rational and critical indicator to understand aging performance parameters of asphalt binders and mixtures.