Sydney, Australia’s most populous city, is conducting the world’s first-ever ‘green’ concrete trial to construct roads using reprocessed industrial waste from coal-fired power stations and steel manufacturing—an initiative that can lower the pollution and greenhouse gases emitted during the production of concrete for laying roads.
REDUCED EMISSIONS: According to researchers, concrete contributes 7% of all greenhouse gas emissions, and the world produced about 4.1 billion tons of cement in 2018, contributing about 3.5 billion tons of Carbon dioxide (CO2). Environmentally-friendly “Geopolymer”, made from fly ash and blast furnace slag is a sustainable blend of concrete and recycled materials. Geopolymer produces about 1/3 of CO2 than traditional cement production, they said—just 300 kilograms of CO2 per ton of cement, compared to 900 kilograms from traditional cement production. It also saves the equivalent of the electricity used by an average household every two weeks.
Working with researchers from the University of New South Wales (UNSW)-Sydney, the Australian city council has replaced a section of roadway in Alexandria with geopolymer concrete made from fly ash and blast furnace slag to test the green concrete’s durability. Once the trials are successful, researchers from UNSW and the Cooperative Research Centre for Low Carbon Living (CRCLCL) will use the trial results to create the first set of industry guidelines for geopolymer concrete.
The council is also testing the geopolymer concrete on Wyndham Street, a major road leading to Sydney Airport, where 9 sensors have been embedded to monitor and compare how the concrete performs. As a major road leading to Sydney Airport, Wyndham Street’s high traffic volume provides the perfect conditions for the trial.
During the UN’s climate change conference: “COP24”, various policy makers and environmentalists reached a consensus that there was a need for the annual emissions from cement to fall by at least 16% by 2030.
Clover Moore, Mayor-Sydney, Australia, said that projects like geopolymer trial can result in new products that make a real difference in slang carbon emissions.
Mayor Clover said, “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. 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.”
Stating that 70% of the concrete produced today were used for pavements and footpaths, Moore said there is a great potential to further lower the emissions from the operations.
“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, and we already use sustainable green concrete for all our footway renewal works, which adds up to 25,000m2 per year,” she added.
While research on geopolymer was undertaken in the 1990s, it is only now that this concrete blend is being explored as a product that is not only better for the environment, but also commercially viable.
Stephen Foster, Head of School of Civil and Environmental Engineering -UNSW said, “The trial is a huge step forward and 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. This trial is important because we need demonstration projects to accurately assess the performance of geopolymer over time so that there can be broader uptake.”
Foster added that the the road performance will be monitored for up to 5 years. “A lot of the data collected in the first 3 to 12 months of this global first trial will be used to confirm our models and strengthen our predictions. If we can purchase more environmentally sustainable materials, we can fight climate change and provide quality infrastructure for our community. Concrete contributes 7% 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,” Foster said.
The low CO2 concrete has the potential to put the 400 million cubic tons 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.
For the Smart Cities World Infrastructure Online Magazine article titled, “Sydney Stages First Trial of Green Road”, please go to: https://www.smartcitiesworld.net/news/news/sydney-stages-first-trial-of-green-road-4283
For the Business Standard Online article titled, “Australia Begins First-Ever Trial to Create Roads Through Industrial Waste”, please go to: https://www.business-standard.com/article/pti-stories/australia-begins-first-ever-trial-to-create-roads-through-industrial-waste-119061800583_1.html
For the Traffic Technology Today online article titled “Sydney starts tests of world’s first ‘green concrete’ roadway”, please go to: https://www.traffictechnologytoday.com/news/planning/sydney-starts-tests-of-worlds-first-green-concrete-roadway.html