HP-GPC characterization of rejuvenated aged CRM binders

The recycling of reclaimed asphalt pavement (RAP) is typically achieved by adding a rejuvenating agent into the mix. The addition of the rejuvenating agent leads to adjusting the compositions and consequently improving the physical and performance properties of the rejuvenated aged binders in the RAP. Many rubberized pavements, around the country, are over 15 years old and some of them are a candidate for recycling. Therefore, there is a need to study the effects of rejuvenating agents on aged crumb rubber modified binders (CRM binders). This paper presents a study characterizing the blends of laboratory-aged CRM binders and rejuvenating agents using gel permeation chromatography (GPC), resulting in the development of empirical models to predict selected properties of the blends. Three aged CRM binders and two aged control binders (PG 76-22) were mixed with either a rejuvenator or a softer binder at different concentrations to determine the influence of the various asphalt binders and the rejuvenating agents on the chromatographic profiles. The results indicated the compositional changes of the blends containing various percentages of either the rejuvenator or the softer binder are well reflected by the GPC profiles. The large molecular size (LMS) of the blends decreased and the small molecular size (SMS) increased as the percentage of the rejuvenator agents increased regardless of the type of aged binders or the rejuvenating agents. The empirical prediction models for Superpave binder properties (viscosity and high-failure temperature) were developed using LMS and SMS. The predicted values showed a high correlation with the viscosity and the high-failure temperature of binders.