New research from the University of South Australia and RMIT University could see rubber recycled from used tyres repurposed into concrete for residential constructions.
The ‘crumb rubber’ alternative to conventional concrete is both economically viable and sustainable, giving end-of-life tyres a new market.
Led by the UniSA’s Professor Julie Mills, the research is the first to practically demonstrate and construct the new crumb rubber concrete mix in the field, taking it from university research labs and straight to a concrete slab.
1.5 billion vehicle tyres are discarded each year around the globe. Less than one percent of these are reused, with the rest either unaccounted for or dumped in landfills. 51 million tyres in Australia end up in landfills, stockpiles or dumped on mine sites. The crumb rubber concrete provides a solution to the tyre landfill issue.
Co-researcher Osama Youssf says that accumulation of end-of-life tyres is a global and growing problem for the global environment.
“Rubber tyres are not biodegradable and lead to unstable landfills, breeding grounds for mosquitoes from trapped water, polluted surfaces and toxic groundwater. They pose a significant risk for toxic fires,” he says.
“In Australia, two thirds of tyres end up in landfill. Such continuous waste production and disposal is entirely unsustainable, which is why we have been investigating alternative recycling options.
“This research investigated the design and processing of various crumb rubber concrete mixes for use in residential constructions, assessing its constructability, bond strength, durability, and flexural strength.
“We found that reinforced crumb rubber concrete (with up to 20 percent sand replacement by volume) is superior to conventional concrete in some ways, with higher impact resistance, toughness and ductility, a higher damping ratio, better thermal and acoustic insulation, and a lighter weight.
“With respect to pumping, screeding, or finishing the concrete surface using a power trowel, contractors also reported no difference between using the crumb rubber concrete and conventional concrete, saying that the crumb rubber mix actually required less physical effort across all aspects.
“Additionally, the ready-mix cement companies reported no concerns relating to concrete batching, delivery or mixing, and said that the wash out of the concrete truck mixer was far easier.”
Co-researcher UniSA’s Professor Yan Zhuge says the research demonstrates the suitability of crumb rubber concrete for the slabs of residential dwellings.
“This is an exciting development for both the recycling and construction industry,” Zhuge says.
“The results clearly show that crumb rubber cement is a viable and promising alternative to conventional concrete in the residential concrete market.”
“We strongly recommend that the concrete industry considers crumb rubber concrete as a sustainable alternative to conventional concrete in reinforced residential constructions in Australia.”
