New Possibilities for Determining the Viscosity at 60 °C for Distillation Bitumen Types

Abstract

Szabolcs Rosta, Zita Szabo and Laszlo Gaspar

The precise determination of the rheological properties of road bitumen types is essential for the reliable prediction of long-term pavement behaviour. The aim of this study is to compare different viscosity determination methods – approximations, capillary viscosity, Brookfield measurement, and complex viscosity determined by dynamic shear rheometer (DSR) – and to analyse their relationships with each other. Furthermore, the European and Australian bitumen classification standards are compared in terms of dynamic viscosity and penetration, according to which Australian bitumen types show more stable results. The statistical evaluation of the results obtained with the different methods was based on Pearson correlation analysis and relative deviation analysis. The results obtained show that the DSR measurements at 1.6 Hz are most closely related to capillary viscosity and best correlated with the other measurements, while the Heukelom equation relationship overestimates the dynamic viscosity. The Brookfield method provided higher viscosities for all tests. The study highlights that the results of different measurement methods can only be compared under shear conditions, and that the DSR-based approach can be more suitable for the introduction of a new European bitumen classification.

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