Austroads: Transport Research and Trends

A large proportion of the road networks in Australia and New Zealand consist of flexible granular pavements protected by sprayed sealing surfacings. An Austroads sprayed seal trial site was established in Coober Pedy in South Australia during 2011 to evaluate the relative performance of seals constructed with different grades of binders from their placement through to long‑term service. The site was constructed to predominantly compare the performance of different Austroads Technical Specification ATS 3110 polymer modified binder (PMB) grades when they were used in strain alleviating membrane (SAM) applications.

This webinar, presented by Steve Patrick and Dr Robert Urquhart, describes the findings obtained from an inspection of the trial site conducted 11 years after construction. The inspection included detailed visual assessments of the condition of each trial section by an expert team. Seal samples were also obtained from the trial sections so that binders could be extracted for rheological and chemical analysis tests. The test results obtained for the extracted binder samples have been used to gain insights into how the properties of the trial binders have changed over time.

The results of the visual assessment work indicated that all sections of the trial site were generally performing well after 11 years of service. Extracted binder sample tests indicated that all binders have become progressively harder over time. The control C170 bitumen section of the trial site has hardened more over time than the sections containing PMBs.