Characterization of creep and recovery curve of polymer modified binder

The Multiple Stress Creep and Recovery (MSCR) curve was developed recently to better characterize polymer modified binders. The two parameters that are measured from the MSCR curve are the non-recoverable compliance (Jnr) and the percent recovery. The purpose of this study was to determine if the parameters of the entire creep and recovery curve rather than just the two parameters that are currently used would help to better understand the behavior of polymer modified binders. Eight in-house binders and six industry binders were tested in order to evaluate MSCR parameters. The creep and recovery calculated from the methodology developed in this study was within 15% of the measured creep and recovery curve. The linear, non-linear, and non-recoverable compliance was similar between cycles. The non-recoverable compliance was sensitive to base binder, Elvaloy, PPA, and SBS polymer modification. The permanent strain calculated from this procedure is significantly lower than the non-recoverable strain measured at the end of 10 s. The sensitivity of the different parameters to polymer modification should be evaluated to provide a better understanding on how a given polymer influences the mechanical behavior of a given binder.