Characterizing Temperature Susceptibility of Asphalt Binders Using Activation Energy for Flow

The temperature-viscosity relationships for twenty two neat and modified asphalt binders were evaluated using conventional tests (CT) such as penetration, kinematic and absolute viscosities, and ring and ball softening point; rotational viscometer (RV); and dynamic shear rheometer (DSR). The temperature ranged from 25 to 135 °C, 100 to 185 °C, and 7 to 82 °C for conventional, RV, and DSR tests, respectively. Results from several binders studies have revealed that binders having similar penetration, viscosity and performance grade (PG) could show dissimilar rheological behaviors. Hence, there is a need to fully characterize asphalt binders to capture their rheology over a wide range of temperatures and loading frequencies. The activation energy (AE) concept was utilized in this study to characterize the temperature susceptibility of the asphalt binders. Correlations between AE and binder rheological properties (e.g., G*/sinδ and G* sinδ) were evaluated. In addition, a relationship between AE and useful temperature range (UTR) determined from the performance grades (PG) was developed. The advantages of characterizing the relative temperature susceptibility of the binders using AE are discussed. Finally, discussion on mixing and compaction temperatures, especially for polymer modified binders, by using AE is also included in this paper.