Modification of Dynamic Modulus Predictive Models for Asphalt ...

Figure 8: Master Curve Comparison for Cell 35 [29]
The master curve comparisons show that the Witczak model made relatively accurate
predictions at intermediate and low temperatures for cells 21 and 35. At the high temperature
range, the Witczak model did not fit the lab data. For mixtures from cells 33 and 34, the Witczak
predictive model is poor to fit the lab results. The 2000 Witczak model tends to predict lower
dynamic modulus values at high temperatures than those tested.
North Carolina State University Study [30]
This research performed by Y. Richard Kim et al. [30] studied dynamic complex modulus of
mixtures made from materials that were commonly used in North Carolina. The study includes
42 different mix designs with two types of asphalt binder. The laboratory results were compared
with the 2000 Witczak predictions as well as the Hirsch predictions. In the final report, accuracy
of the predictive model is quantified by the percent of error which is the difference between lab
result and model prediction divided by the lab result. Figure 9 and Figure 10 show the results of
comparisons.
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