New developments for fly ash

New developments for fly ash
Published: 22 May 2008

Scientists at University of New South Wales in Australia have turned the ash waste from coal-fired power stations into a global environmental solution which promises to slash emissions in construction sector by 20 per cent. Researchers have converted the fine particulate pollution generated in coal furnaces, known as fly ash, into a new range of high-strength, lightweight building materials. The new lightweight fly-ash aggregate, known as Flashag, replaces quarried rocks such as blue metal and gravel which are usually mixed in with cement to make concrete. Flashag is the world’s first fly ash aggregate to drastically reduce the volume of cement needed to achieve high strength concrete structures.

"The environmental consequences are enormous," says inventor, Dr Obada Kayali, a senior lecturer in Civil Engineering at UNSW and ADFA (the Australian Defence Force Academy). It’s taken him a decade in the lab, but Dr Kayali says he’s finally turned a global industrial waste burden into a commercially-viable, environmental asset. The big savings in greenhouse gas emissions lie firstly in reducing the volume of cement needed to make high strength concrete.

Globally, coal-fired power generation has produced billions of tonnes of fly ash waste over the past century, with annual production now at about 800 million tonnes. Uncontrolled it is a serious source of air pollution. A small percentage of the world’s fly ash is already absorbed by the construction industry as an additive to cement, and is mixed-in with clay in bricks. This new product could significantly increase such usage.