A comprehensive study on source dependency of conventional, chemical and rheological properties of asphalt binder

Abstract

Source of the asphalt binder has an important role to play in dictating the properties of a binder. The role is further exacerbated if the specification of binder relies on traditional properties of penetration, softening point, absolute viscosity and ductility. In case the binder supplied from different sources by manufacturers is expected to conform to same grade based on such traditional properties, the flexible nature of traditional grade assigning system may lead to an unwanted divergence in the expected properties. Hence, this study attempts to explore the source dependence of various conventional, chemical and rheological properties of asphalt binders. Five binder sources were adopted. The results indicated that only one binder source satisfied the penetration as per IS 73 specification. Such non-compliance with viscosity specification was also observed in one binder source. Different binder sources were observed to exhibit varying contents of asphaltenes. Age hardening evaluated based on retained penetration ratio (RPR), viscosity ageing index (VAI) and softening point increment (ΔS) differed for diverse binder sources. Similar variable observations for temperature susceptibility were perceived based on penetration index (PI), pen-vis number (PVN) and viscosity temperature susceptibility (VTS). Percent recovery (R) and non-recoverable creep compliance (Jnr) indicated the dependence of rutting characteristics on a binder source whereas linear amplitude sweep (LAS) accentuated the dependence of fatigue life on the source of the binder. Conclusively, statistical analysis indicated mixed results regarding the significance of differences in binders from different sources based on various evaluated parameters.