A long-term trial into the performance of a polymer modified road seal continues on the Stuart Highway in Coober Pedy, SA, with updates now released on how it’s been faring.
The Austroads trial began in 2011, with this section of road chosen due to its high use by heavy vehicles and exposure to Australia’s harsh elements.
“We’re here in Coober Pedy because this gave us the opportunity to trial our polymer modified binders in a hot climate, but it also gave us the opportunity to test it in a low traffic environment but with very heavy commercial vehicle counts,” explained Austroads project manager John Esnouf.
“The project findings to date have shown us the progression of the ageing of the binders. We haven’t got to the end life of these binders yet, so we’re getting an understanding of how these binders age.”
The aim of the project is to gain a better understanding of the performance of different bitumen seals under real-life climatic and traffic loading conditions over the duration of the pavement surface’s life.
Austroads’ transport infrastructure program manager said, “We are very keen to look at long-term monitoring sites in addition to the laboratory testing. We know that in a laboratory you get good results, but they don’t necessarily reflect performance onsite. Laboratory testing can’t replace the cooling and heating cycles, the wet and dry cycles, the effects of the sun and oxidisation and over time these things have an impact.”
Core samples from the trial sections have been collected for over a decade, from which binder is extracted and characterised using testing devices at ARRB’s testing laboratory.
“The outputs of this trial are a series of technical reports that report on the performance of the seals at different stages of their life, and at the end of the day, we’ll take that information and we’ll use it to develop models and build that into the specification requirements,” Guppy added.