Researchers hope that a concrete new recipe that uses waste will create jobs and a renewable industry for a city in transition away from coal mining.
- The main ingredient in cement is fly ash, a by-product of coal-fired power plants
- The mixture incorporates 80 to 90 percent recycled products and reduces carbon emissions by up to 80 percent compared to standard concrete
- It is hoped the new product could create jobs in Collie, southwest Washington.
A team from Murdoch University in Western Australia developed the concrete and nicknamed it “Colliecrete” because the recycled products come from the regional town of Collie in WA.
Lab assistant Ramon Skane said the goal was to incorporate as much waste as possible.
“Colliecrete concrete can use up to 80 to 90 percent recycled material as a component of cement,” he said.
The main waste is fly ash, a byproduct of coal combustion, but the design may also contain bauxite residue from alumina mining and recycled aggregates.
“These materials are rubbish, they have no use,” said Mr. Skane.
Recycle waste and reduce emissions
Concrete is one of the most widely used construction products in the world, but it is also a major source of greenhouse gases.
A 2018 study by the global think tank Chatham House estimated that cement was responsible for around 8% of global emissions.
But this concrete can generate up to 80% less emissions.
“The reason that conventional concrete is so carbon intensive is that the cement used; all raw materials must be heated to over 1000 degrees,” said Mr. Skane.
“The cement we use can be made anywhere at room temperature.”
A bright future, with some obstacles
Colliecrete is a form of geopolymer concrete – which typically uses fly ash as the main ingredient in its cement.
Geopolymer concrete has been developed in other parts of Australia and has been used in projects ranging from pavements to airports.
Professor Greg Morrison, Curtin University Sustainability Policy Institute, said the use of environmentally friendly alternative products is emerging in the construction industry.
“There is great potential to use different types of mixes for concrete to reduce greenhouse gas emissions and, or, to use other types of construction technologies instead of concrete”, a- he declared.
Professor Morrison said that while the future is bright for the development of geopolymer concrete, obstacles remain.
“That’s always the problem when you have very large companies that produce cement and concrete at very low prices.
“So I think that’s the challenge, but I think it’s a wonderful idea.”
A new industry born from the ashes
Collie was chosen as the home for the new concrete because of its abundance of fly ash.
The city has been burning coal for almost 100 years, which has created a large stockpile of waste.
Bluewaters Power Station, a private coal-fired power plant in Collie, provided researchers with fly ash samples for their testing.
“We also provided them with the data from our ash analysis,” said Stephen Deonck of the station.
“They used it to create their particular blend or blend that works well with our fly ash.”
The power plant produces around 600 tonnes of fly ash every day which is currently trucked back to the coal mine and buried.
Mr Deonck said it was fantastic to see some use of waste.
Like many cities in Australia, Collie has started to move away from coal as the energy grid increasingly relies on renewable energy sources.
This means that the region is on the lookout for new industries that create jobs and possibly end the production of fly ash.
But Ramon Skane is not concerned.
“Once the plants are closed, we will be able to use the fly ash that has been stored for over 60 years in the pits,” he said.
Strong jobs for the future
So far, researchers have made concrete castings on a smaller scale, the largest measuring one cubic meter.
But Collie Shire president Sarah Stanley can see the potential.
“The Colliecrete project is exciting because it ticks all the boxes of sustainability in terms of new jobs, new job opportunities, environmentally friendly industries, and it’s also really great for our community,” said she declared.
Ms Stanley said a business case estimated the product could create between 30 and 80 jobs.
As the Colliecrete team slowly ramps up the pours to test larger concrete blocks, Ramon Skane is already looking to the future.
“At the end of the day, we can use it for any real-world application. Highway barriers… it could be used for buildings,” he said.
“It could be used for anything concrete can be used for right now.”