Anti-Aging potential of sulphur in terminal blend rubberized asphalt binder

Abstract

Terminal blend (TB) rubberized asphalt binder can be produced through the dissolution of crumb rubber modifier (CRM) in asphalt, meanwhile other modifiers, like styrene–butadienestyrene (SBS) polymer and crosslinking agent sulphur are supplemented to enhance the properties of modified asphalt. The effect of sulphur on asphalt oxidation and polymer degradation is not well documented for TB rubberized asphalt binder. This paper investigates anti-aging potential of sulphur in TB rubberized asphalt binder from chemical and mechanical perspective. Carbonyl index and butadiene/styrene ratio, which are derived from fourier transform infrared (FTIR) spectrums, are applied to analyse carbonyl growth and butadiene reduction. Gel permeation chromatography (GPC) based polymer retention index is used to detect the change of polymer molecular weight. The complex modulus |G*| is used to calculate hardening index and phase angle master curve is used to analyse the elastic contribution of sulphur. Crosslinking agent sulphur does not have definite positive or negative effect on the carbonyl growth of TB rubberized asphalt binders in this laboratory aging study. However, sulphur does help to alleviate the age hardening behavior. For miscible TB rubberized asphalt binders, 0.3% or 0.4% sulphur can improve the resistance to polymer degradation. In addition, sulphur can improve elastic response of TB rubberized asphalt binder even for pressurized aging vessel (PAV) aged asphalt.