Correlation between PG Plus, Superpave PG Specifications, and Molecular Weight from GPC for Different Polymer Modified Binders

The purpose of this paper is to present a correlation of Multiple Stress Creep and Recovery (MSCR) parameters with elastic recovery and molecular weight of different polymer modified binders (PMB). The MSCR test which was recently developed by Federal Highway Administration (FHWA) enables one to correctly grade the field performance of polymer modified asphalts. The polymer modification of asphalts is one of the solutions to overcome the asphalt pavement defects such as rutting, thermal cracking, fatigue and stripping. However, the different polymer modified asphalts can behave differently even though they have the same performance grade. The MSCR test measures the high temperature binder specification parameter called non-recoverable creep compliance or J_nr, and percent recovery. In this study eight different polymer modified binders are measured. The molecular weights were determined using Gel Permeation Chromatography (GPC). The correlation of the MSCR results with the molecular weight will provide an insight into how modification effects mechanical response and the rutting potential as measured from MSCR.