Effect of Rubber Content and Digestion Time on the Properties of Crumb Rubber Modified Binder

The use of crumb rubber as a binder modifier in spray seals and asphalt applications is a mature technology that is generally well understood for high crumb rubber dosages. However, recent efforts to repurpose end of life tyres must also consider other applications. The use of crumb rubber as a low dosage binder modifier for local roads in Australia has been of significant interest in recent years. To determine their effectiveness as an alternative to more conventional unmodified binder grades, the performance of low dosages (5–15%) of crumb rubber modified binders, using both short and long blending durations, was assessed across several bitumen performance properties. While a higher (15%) dosage of crumb rubber, and using short blending processes provided the most significant performance improvement as an elastomeric modifier, the incorporation of any crumb rubber using either digestion duration was found to improve base binder properties, and may be suitable for use in local road asphalt surfacing.