Correlation between multiple stress creep recovery (MSCR) results and polymer modification of binder

Nationwide traffic loads are increasing, pushing conventional asphalt to its limit, while in New Jersey matters are made worse by the heavy use of the Northeast Corridor. Polymer modification of asphalt, which can improve both low and high temperature performance, is already available; however, but in many cases traditional Superpave testing is not sensitive enough to quantify the impact of modification, dimensioning its use. Superpave Performance Grade Plus tests, are sensitive to polymer modification but are time intensive and costly, leading the New Jersey Department of Transportation to require styrene-butadiene or styrene-butadiene-styrene to be incorporated in all modified binder to ensure performance, causing supply shortages and rising cost in the state. A relatively new test developed by the Federal Highway Administration, Multiple Stress Creep Compliance (MSCR), offers a simpler procedure using the Dynamic Shear Rheometer (DSR), thus it does not require the expense of purchase additional testing equipment. The objective of this study is to determine the feasibility of using MSCR as a specification for binder testing. Upon testing a variety of binders it has been determined that MSCR binder testing is sensitive to flow time results. Binders with non-recoverable compliance value (Jnr) of less than 0.5 kPa-1 appear to show better high temperature performance. The guidelines set forth by AASHTO MP 19-10, in which the binders are graded according to traffic (ESALs) by using Jnr is recommended