Assessment of the 4-mm Diameter Parallel Plate Geometry of the Dynamic Shear Rheometer for Neat Asphalt Binder Characterization

Transverse cracks in flexible pavements are a result of excessive hardening of the binder and/or the material’s inability to dissipate stresses in response to a sharp drop in temperatures. This distress is closely associated with binder characteristics and current specifications use tests carried out in the bending beam rheometer (BBR) to grade the low-temperature performance of asphalt binders. Concurrently, researchers have explored the application of the 4-mm diameter parallel plate geometry in the dynamic shear rheometer (DSR) to obtain rheological parameters at low temperatures. This study aims to assess the 4-mm diameter parallel plate tool to classify 16 Brazilian binders based on their performance grade at low temperatures and to assess how the Δ T c parameter and the R -value obtained in the DSR compare with those obtained in the BBR. The results confirmed the effectiveness of the tool in determining the PG grade by adjusting the stiffness and relaxation rate limits (247 MPa and 0.301, respectively). The equivalence between the results was demonstrated by moderate-to-strong correlations obtained for the stiffness, relaxation rate, R -value, continuous grade, and Δ T c parameter. Only two binders showed discrepancies in PG grading between the techniques. In one case, the continuous grade was close to − 22 , a condition that makes the PG grade determination difficult even with the BBR. The DSR failed to scrutinize only one binder regarding R -value, and full equivalence between the Δ T c parameter obtained by both machines was observed in most cases, but not for all the materials.