‘Green’ concrete made using industrial waste from coal-fired power stations and steel manufacturing is being trialed as road material in Sydney.
UNSW Sydney researchers and the CRC for Low Carbon Living (CRCLCL) will use results from the trial to create the first set of industry guidelines for geopolymer concrete.
The City of Sydney is putting the geopolymer product to the test on a busy inner-city street in Alexandria.
To test durability, it has laid 15m traditional concrete on the roadway and 15m of geopolymer concrete, a blend of concrete and recycled materials.
Nine sensors have been positioned under the concrete to monitor and compare how the geopolymer concrete performs.
Sydney Lord Mayor Clover Moore said projects like the geopolymer trial could result in new products that made a real difference in slashing carbon emissions.
“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,” she said.
Made from fly ash and blast furnace slag, geopolymer generates 300kg of CO2 per tonne of cement, compared to the 900kg from traditional cement production.
Trial to drive ‘step change’ in industry says researcher
UNSW School of Civil and Environmental Engineering head Professor Stephen Foster is the CRCLCL project lead and describes the trial as “a huge step forward”.
“This trial will help drive step change in the industry. Many concrete companies are already doing a lot to change, but this trial really gives it another push,” Professor Foster said.
“Research into geopolymer has been undertaken since the 90s, but it’s only now that it’s starting to be commercialised.
“While we’ll monitor the road performance for up to five years, a lot of the data collected in the first three to 12 months of this world-first trial will be used to confirm our models and strengthen our predictions.
“Concrete contributes seven per cent of all greenhouse gas emissions and in 2018 the world produced about 4.1 billion tonnes of cement, which contributed about 3.5 billion tonnes of CO2.
“Alternative, low CO2 concrete materials offer potential benefits in reducing the greenhouse gas emissions associated with conventional concrete.”
The Sydney road trial was important as such projects were needed to accurately assess the performance of geopolymer over time to allow broader uptake, he said.