Rheological properties of RAP binder extracted from RAP aggregates of different sizes

Abstract

Reclaimed Asphalt Pavement (RAP) obtained from milling bituminous layers consists of aggregate and aged binder. Fractionating RAP into different fractions facilitates better control over the binder content, rheological properties of RAP binder and aggregate gradation. Existing research shows that the binder content varies across fractions with coarser fractions having lower binder content and the finer fractions containing higher binder content. However, a detailed understanding on the extent of variation in rheological properties across such fractions is necessary. In this study, RAP was separated into three fractions namely: coarse, medium and fine. The binder was extracted and recovered from each fraction. All the recovered binders were subjected to a systematic rheological characterization. The results indicate the manner in which the binder ages and how its subsequent rheological properties vary for individual fractions of RAP. In most cases, the RAP binder from coarse fraction was found to exhibit higher stiffness when compared to the other fractions. Also, the temperature susceptibility of the binder fractions is observed to be different with the Medium RAP binder exhibiting a higher temperature sensitivity.