Rheological characterisation of synthetic binders and unmodified bitumens

This paper deals with the characterisation of the linear viscoelastic and s teady-state flow properties of commercial pigmentable synthetic binders and unmodified bitumens. From the experimental results obtained, we may conclu de that both types of materials show a thermorheologically simple linear vi scoelastic behaviour in the temperature range studied (5 degrees C-50 degre es C), although synthetic binders are thermorheologically complex materials in steady-state flow. Both of them display a predominant viscous behaviour within the linear viscoelasticity region. Synthetic binders are characteri sed by an apparent shift of the terminal zone of the relaxation spectrum to lower frequencies, probably related to the development of entanglements am ong macromolecule components, and by the highest values of the zero-shear-r ate limiting viscosity. (C) 1998 Elsevier Science Ltd. All rights reserved.