Evaluation of empirical and theoretical models to determine asphalt mixture stiffnesses at low temperatures

A study is conducted with the aim to illustrate the relationship between binder and mixture stiffness measure at low temperatures in the log-log domain and to discuss the factors which influence the relationship. Selected empirical and theoretical binder-to-mixture stiffness relationship, including the one used in SHRP SUPERPAVE, is reviewed and the low-temperature mixture creep stiffnesses predicted by these models are compared to those obtained with the indirect tensile test at low temperatures. The suitability of existing binder-to-mixture stiffness model is assessed to develop alternate models. Single-function models are shown to lead to poor temperature shift factors and poor performance prediction or mixtures exhibiting discontinuous log-log stiffness behavior.