Lismore City Council recently reconstructed a 500m section of road using sand produced at its glass processing plant.
According to the council, although approximately 3600 tonnes of glass is salvaged in Lismore each year, up to 30 per cent cannot be used for conventional recycling – that is, to manufacture new glass products – due to breakage or contamination, with the “lost” product ending up in landfill instead.
It was said that this form of recycling was also costly and required special technology to separate the different coloured glass.
Lismore’s glass processing plant was opened in May 2014 to address these issues. By crushing old glass and crockery back into its original state as sand, the council has claimed that hundreds of tonnes of glass could be kept out of landfill.
“As well as ensuring more glass can be recycled, transforming glass back into sand reduces the need to mine virgin material for road base and asphalt, decreasing road resealing costs and limiting truck movements on the road,” a council media statement explained.
It was noted that using glass sand as an aggregate could also add strength to road base and asphalt mixes.
Ensuring product safety
{{image2-A:R-w:220}}Jon Rigley, the quality assurance supervisor at the council-owned Blakebrook Quarry where road base and asphalt is produced, said realising the glass-to-sand concept had entailed a “mammoth effort” to ensure the aggregate’s silica content did not pose any work health and safety risks.
He explained that the product’s development had involved close collaboration across several council departments, including the quarry staff (especially its laboratory personnel), the recycling team and the roads crew.
“We needed to make sure the product was 100 per cent safe to use and that our staff were well-equipped and educated to feel safe and secure using this new product,” he stated. “Most people think we [the quarry staff] drive around out here in big trucks but a lot of our time is spent in the lab, meticulously testing our product to ensure safety for staff and for residents.”
Peter Brewer-Charles, the council’s rural works supervisor, described the resulting sand as “a consistent product with good compaction results” and said the council would be using the aggregate in all road base going forward.
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