Estimation and assessment of high temperature mix performance grade for select bio-based WMA additives

The Hirsch and Al-Khateeb models are commonly used to predict an asphalt mixture’s dynamic modulus (E*) at intermediate temperatures. However, G*b and the mix volumetrics are needed to make these predictions. The main objectives of this paper are to demonstrate how mix testing and binder results can be used to estimate the high temperature performance grade (PG) of warm mix asphalts (WMA) with and without bio-based additives and to compare dynamic modulus performance between different asphalt binders and select bio-based additives. The results indicate that prediction of high temperature performance grade for an asphalt mixture cannot be done using the Hirsch model, but is possible using the Al-Khateeb model and that the additives and non-modified binder were not found to be statistically different from one another overall as well as within each binder type.