Viscosity Characterization of Asphalt Cement

There exists an inherent relationship between the commonly used consistency tests (viscosity at 140 F (60 C), viscosity at 275 F (135C), and penetration at 77 F (25 C)) as applied to asphalt cements used in paving. Based on data accumulated from 84 worldwide crude sources of asphalt, it is shown that the viscosity at 140 F is related to each of the other two tests by power law logarithmic function, and that the overall relationship is represented by a nesting of lines. With the viscosity at 140 F as the independent variable, there exist significant differences in the penetration (77 F) and viscosity (275 F) levels but with only minor differences in the slope of the lines. Thus, the relationships between this viscosity and the other two consistency tests serve to identify the viscosity grade as well as to indicate the source of the asphalt, which in turn relates to temperature susceptibility properties.