Comparison of Different DSR Protocols to Characterise Asphalt Binders

The use of Dynamic Shear Rheometer (DSR) has become a standard tool to characterise bituminous binders, either for research or specifications purposes. Testing with the DSR enables to cover a wide range of temperature and frequency conditions in a fast way by using limited amount of materials. Depending of the test type, DSR measurements provide different rheological parameters to characterise physically the materials either at low, intermediate or high temperatures. At the same time, different test protocols have emerged. While the preferred mode is running in frequency sweep at different temperatures, the test can also be run with a temperature ramping at a fixed frequency. In order to evaluate the validity of the DSR testing mode, four different test protocols were run, including a frequency sweep test at different temperatures and temperature ramping at a fixed frequency with different temperature rates. This experiment was applied to three different bituminous binders, two non-modified binders, soft and hard, and a standard Polymer modified Bitumen (PmB). The analysis was conducted on shear modulus and phase angle versus Temperature. The outcomes showed a reasonably good correlation between the different protocols in the common range of temperatures and demonstrated instrument limitations regarding geometry and control parameters.