Predicting low temperature physical hardening in asphalt binders

The effect of the glass transition behavior on the rate and magnitude of physical hardening was studied for modified and unmodified asphalt binders. The analysis showed that the rate of physical hardening peaks at the glass transition temperature and becomes relatively insignificant beyond the limits of the glass transition region. ing the free volume concept, it was shown that physical hardening can be modeled as a function of isothermal time by a modified mechanical creep model. Such a model was developed in this study and used to predict physical hardening as a function of glass transition, conditioning time, and temperature.