Comparison of binder and mixture aging characteristics in binders from different sources

Laboratory simulation of RAP is essential to minimise the variability in the characterization of RAP. Different binder/ mixture aging procedures are available to age bituminous binder/ mixture in the labor-atory. The mixture aging is more representative of the field conditions but involves considerable variability associated with the aging, extraction, and recovery processes. On the other hand, binder aging is more repeat-able but does not capture the thin film aging observed in mixtures. The aging behaviour is thus different in a binder and mixture aging. Scarcely has any study quantified the magnitude of variability associated with such aging and ascertained the influence of parameters such as the type of base binder and the aging temperature. In this study, bituminous binder and mixtures prepared with two types of base binders were aged in a forced draft oven at two temperatures, namely, 100 and 120℃. The binder extracted from the aged mixture and the binders aged in the oven were compared through their rheological properties. It was observed that the mixture aging exhibited much higher stiffness compared to the binder aging. Also, the properties of the base binder, especially the history associated with the production process, were seen to influence the rate of aging. This was verified through the master curve generated for these binders.