More sustainable polymer modified binders - meeting existing specifications

Abstract

Tyre derived crumb rubber has been used as an elastomeric modifier for bitumen in Australia since the 1950s. Over the past years there has been a resurgence of interest in crumb rubber technology for use in roads, stemming from the need to recycle waste tyres. A number of initiatives are underway in Australia to increase the use of rubber in both sprayed seals and asphalt. This papers presents the development of a new generation of binders that contain both crumb rubber and SBS and comply with the existing Austroads polymer modified binder (PMB) specifications. The elastic properties of the rubber and SBS hybrid can be used to create binders that are equivalent to conventional A10E, A15E and A20E grade PMBs. The experimental work described in the paper include binder testing and asphalt performance testing. It also describes the first uses of the binder in Queensland and elsewhere in Australia. Site work included monitoring for potential harmful emissions. The results indicate that the hybrid crumb rubber/SBS binders are equivalent in every way to conventional PMB grades.