Establishing Default Dynamic Modulus Values For New England

The primary objective of this research is to test commonly used Hot Mix Asphalt (HMA) mixtures throughout New England to determine their respective dynamic modulus master curves. Four mixes were requested from each of the New England states for modulus testing. Physical testing consisted of two replicates of each mix, outfitted with 3, linear variable differential transformers (LVDTs). AASHTO TP 62 was followed for the testing of these samples. Comparisons of plant produced mix vs. lab produced mix shows no significant difference between the two methods. Thus indicating lab produced samples are analogous to real-world pavements for dynamic modulus testing. Furthermore, the results of physical modulus testing were compared to predicted modulus values from three different theoretical modulus models. Comparisons of Predicted |E*| values from the Mechanistic-Empirical Pavement Design Guide (MEPDG) and physical testing indicates the predicted |E*| values may be off by as much as 100% for New England Mixes. Through this research scaling factors were developed for all the mixes tested to allow state DOTs to forgo expensive and labor intensive physical testing. Furthermore, the minimal range and standard deviation of scaling factors for the Hirsh and Witczak models indicates there is potentially a constant scaling factor that could be applied to all New England mixes, regardless of aggregate source, and binder type. However, further testing may be required to determine if a uniform scaling factor for our region is truly valid.