1 January 2017
International studies have shown that gap graded asphalt with crumb rubber modified binders can provide improved resistance to crack reflection compared to conventional asphalt. These mixes are therefore commonly used in the USA when rehabilitating/overlaying existing pavements (especially concrete pavements) where improved resistance to crack reflection is required. It is envisaged that similar applications will apply in Australia.
However, currently there are no specifications available in Queensland and Western Australia for the use of crumb rubber modified binders in gap graded asphalt. As such, road owners cannot readily make use of the benefits provided by crumb rubber in rehabilitation treatments (such as asphalt overlays). The development of a technical specification for crumb rubber modified gap graded asphalt will therefore address this gap. This will overcome a significant barrier to its use in this application.