Visco-Elastic Analysis of the Elastomeric Binder Shear Resistance in Relation to Asphalt Rutting

ABSTRACT This paper presents a study into a simple laboratory assessment method of the binder shear resistance (as a key property on asphalt rutting). Based on a binder testing instrument called an “Elastometer” and a simple visco-elastic (Kelvin-Voigt) model, very different behaviours of bitumens and polymer modified binders were analysed. A range of binders comprising bitumens and modified binders (with a range of different polymer modifiers) were used to produce asphalt slabs and then tested in a wheel tracking device. A comprehensive correlation study was carried out and it was found that the shear resistance at low strains was closely related to the rut resistance. This suggested that a viscous property was a more important contributor to asphalt rut resistance. However, it was thought that, for highly modified elastic binders, the elastic property also contributed to the asphalt rut resistance. The Elastometer parameters were compared to parameters from other test methods with which non-Elastometer users are familiar. Of particular importance was the comparison of Elastometer and Dynamic Shear Rheometer (DSR) parameters which were derived from the same visco-elastic model. Satisfactory correlations were observed between corresponding parameters. This demonstrated that the use of the Elastometer for the rheological testing of binders (and the application of the rheological model) was a reasonable approach.