Figures 4-5 through 4-10 show dynamic modulus and phase angle results for
mixture GAF1 for 100C, 250C, and 400C, which exhibited a typical response for the fine-
graded mixtures. Similarly, Figures 4-11 through 4-16 display typical dynamic modulus
and phase angle results at the 3 different testing temperatures for mixture GAC 1, which
also exhibited a typical response for the coarse-graded mixtures.
The degree of variability shown in the dynamic modulus and phase angle results for
mixtures GAF1 and GAC1 in Figures 4-5 through 4-16 are typical for the other mixtures
tested. The results also clearly show the expected rate dependence of the dynamic
modulus for asphalt mixtures, as the dynamic modulus increases with higher frequencies
(e.g., Sousa, 1987). As expected, a comparison of Figures 4-6 and 4-8 shows that the
phase angle also increases with higher testing temperatures. Also interestingly, a
comparison of Figures 4-6 and 4-8 shows how the phase angle decreased slightly
between 1 Hz and 4Hz, but increases with frequency up to 16 Hz. At higher
temperatures, the phase angle tends to increase with increased frequency, as shown for
example in Figures 4-8 and 4-10. The results for each specimen for the other mixtures
tested are provided in the Complex Modulus Microsoft Access Database, described in
Appendix B.
In summary, the dynamic modulus and phase angle results show the following
trends,
* Under a constant loading frequency, the dynamic modulus decreases with an increase
in test temperature for the same mixture.
* The phase angle increases with the increase of test temperature.
* Under a constant test temperature, the dynamic modulus increases with increased test
frequencies.