Geopolymer concrete, made with industrial waste from coal-fired power stations and steel manufacturing, is being used for a green roads trial in the City of Sydney.
New concrete has been laid on a busy inner-city street, replacing a 30 metre section of roadway on Wyndham Street in Alexandria.
To test the concrete’s durability, the city has laid 15 metres of traditional concrete and 15 metres of the geopolymer concrete.
Nine sensors have been positioned to monitor and compare how the geopolymer concrete performs.
Sydney Lord Mayor Clover Moore said UNSW Sydney researchers and the CRC for Low Carbon Living will use trial results to create the first set of industry guidelines for geopolymer concrete.
“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,” Ms Moore said.
“With 70 per cent of the concrete produced today going into pavements and footpaths, there’s great potential to further lower emissions from our operations.”
Made from fly ash and blast furnace slag, geopolymer generates 300 kilograms of CO2 per tonne of cement, compared to the 900 kilograms from traditional cement production.
“We’re continually working with concrete suppliers to reduce the amount of pollution and greenhouse gases emitted during the production of concrete for our local roads,” Ms Moore said.
“We already use sustainable green concrete for all our footway renewal works – which adds up to 25,000 metres squared per year.”
According to Ms Moore, the low CO2 concrete has the potential to reuse 400 million cubic tonnes of globally documented waste from the coal and steel industries.
Australian Iron and Steel Association and Ash Development Association Executive director and industry partner Craig Heidrich said the benefits of the trial will be far-reaching.
“Our collaboration with organisations such as the City of Sydney and the publication of the research findings will further demystify and promote the use of geopolymer concrete in construction,” Mr Heidrich said.
“It’s a fundamental tenet in business that you need to be constantly innovating and investing into new technologies. This trial will provide real examples of geopolymer concrete use that we can all use.”