Modification of the Resistivity-Rutting Model to Use Recoverable Creep Compliance

Abstract

The resistivity-rutting model was developed as part of NCHRP Projects 9-25 and 9-31 and later was improved as part of Airfield Asphalt Pavement Technology Program Project 04-02. The model was intended to provide insight into the effects of mixture composition and binder properties on resistance to permanent deformation, but the use of |G*|/sin δ to characterize binder flow properties did not accurately capture the performance of modified binders, so an empirical correction factor was needed to address this problem. The modified model presented in this paper incorporated Jnr from the multiple stress creep and recovery (MSCR) test, in place of |G*|/sin δ, as an indicator of binder resistance to permanent deformation. This adjustment provided a more theoretically correct and more accurate means to characterize asphalt binder flow properties for use in the resistivity-rutting model. Because a large number of pavement test sections does not yet exist to provide information on rutting, including MSCR test data, the approach used here was to develop an empirical equation that related Jnr to standard dynamic shear rheometer test data. This relationship was then used to estimate Jnr for a database that consisted mostly of the original data used to develop the resistivity-rutting model. The recalibrated model appeared to have an accuracy similar to that of the previous version of the model but properly predicted the performance of modified binders without empirical correction factors.