Relationship between Chemistry and Mechanical Properties of RAP Binder Blends

Abstract

The present study aims to explain the dependency of different mechanical properties [penetration, softening point, viscosity, and dynamic shear rheometer (DSR) parameters] and chemical parameters of reclaimed-asphalt pavement (RAP) binder. Viscosity grade (VG30) and VG40 virgin binders, RAP binder, and different VG30 + RAP blends, were investigated. Complex shear modulus and phase angle were measured at different temperatures, and creep compliance and percent recovery were evaluated at 60°C. Functional groups were evaluated using Fourier-transform infrared spectroscopy. Aging parameters ICO, ISO, and ICC increased with RAP proportion, whereas ICH decreased. No trend could be observed for OH/CH. The ICO, ISO, ICC, and ICH parameters correlated well with the mechanical properties of the blends. This study will be useful for better understanding of the relationship between the mechanical and chemical properties of RAP binders. The demonstration of the applicability of the rule of mixes for different mechanical and chemical parameters will be useful in the design of RAP mixes.