The Australian city has replaced a section of roadway in Alexandria with geopolymer concrete made from fly ash and blast furnace slag.
The city of Sydney has announced a world-first ‘green’ concrete trial where it has reprocessed industrial waste from coal-fired power stations and steel manufacturing to create a new roadway.
Working with researchers from the University of NSW, the city council has replaced a section of roadway to test the green concrete’s durability.
According to the university, geopolymer generates just 300kgs of CO2 per tonne of cement, compared to 900kgs from traditional cement production. The carbon emissions savings is equivalent to the electricity used by an average household every fortnight.
The council is testing the geopolymer concrete on Wyndham Street, a major road leading to Sydney Airport, where nine sensors have been embedded to monitor and compare how the concrete performs.
Made from fly ash and blast furnace slag, geopolymer concrete is described as a sustainable blend of concrete and recycled materials.
University of NSW researchers and the Cooperative Research Centre for Low Carbon Living will use results from the trial to create the first set of industry guidelines for geopolymer concrete.
University researchers will monitor the road performance for up to five years.
"If we can purchase more environmentally sustainable materials, we can fight climate change and provide quality infrastructure for our community”
Research has been undertaken since the 1990s, but it’s only now this concrete blend is being explored as a product that is not only better for the environment, but also commercially viable.
The low CO2 concrete has the potential to put the 400 million cubic tonnes of globally documented waste from the coal and steel industries to good use. While a small amount is currently used in construction, much of it is currently stored on site.
“I’m proud that the city of Sydney was Australia’s first carbon-neutral local government and that we’re continuing to take significant steps to reduce our carbon footprint. Projects like this geopolymer trial can result in new products that make a real difference in slashing carbon emissions, said Clover Moore, mayor of Sydney.
“Local governments are responsible for maintaining local roads, so if we can purchase more environmentally sustainable materials, we can fight climate change and provide quality infrastructure for our community.”
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