Canberra, May 10 : Australian scientists have developed a process that can pave the way for lighter, stronger concrete, with a smaller greenhouse footprint, by utilising the waste "fly-ash" from coal-fired power stations.
Developed by researchers at the University of NSW (New South Wales), the new process has the potential to capture all of the 14 million tonnes of ash particles churned out each year by Australian energy plants and turn them into a form of aggregate, which bonds with cement.
According to Dr Obada Kayali, a civil engineering lecturer at the Australian Defence Force Academy and the University of NSW, "The environmental benefits are enormous, really huge, because you are looking at a much smaller volume of cement per cubic metre."
"I would be absolutely surprised if it's not less expensive than producing other lightweight aggregates that are on the market," he added.
Cement and concrete manufacture is estimated to generate about ten per cent of the world's total greenhouse gas emissions, but the inventors of the new process have said that it has the potential to slash emissions in the construction sector by 20 per cent.
The new process involves baking the tiny fragments of ash caught in the filters of a power station, turning them into bricquettes, and crushing those to form a strong, light, carbon-rich dust.
Coal-burning power plants already capture almost all the fly-ash they generate, but much of it is not deemed commercially useful and is dumped in old coal mines or used for landfill.
The reconstituted ash has been shown to be stronger than other fly-ash products being used in concrete overseas, meaning less energy-intensive cement is needed to bind the mixture.
As well as making concrete, the ash can be used in bricks and paving stones.
The invention has sparked interest among some NSW generators, including at Bayswater Power Station, near Muswellbrook in NSW, but researchers are seeking government support to get local production off the ground.