ABSTRACT
ABSTRACT: The phase angle of bituminous materials is often required when in-sufficient data exists to define this with a high degree of accuracy. In addition, the measurement of phase angle has a higher variability than that associated with the complex modulus (G* or E*). Often historical data consists only as complex modulus versus frequency with no phase angle information. To enable use of these data sets in current analysis procedures requires the use of the phase angle information that has to be obtained from mathematical and/or predictive methods. Phase angle can be calculated from the retardation and relation spectra. This approach is contrasted to the method developed from the relationship found between the log-log gradient of complex modulus versus frequency and phase angle. Data is presented for a range of materials that includes non-bituminous products. It is concluded it would be reasonable to analyze complex modulus vs. frequency and estimate the phase angle from numerical procedures.
