AUSTRALIAN university researchers have developed a strong, lightweight building material that they believe could generate a thriving new “green” industry for countries such as China and India. Coal-burning power plants spend millions of dollars disposing of waste fly ash, a fine powder that contains toxic chemicals. An estimated 200 million tonnes of the by-product is generated in China each year, much of it sent to waste disposal sites on increasingly scarce land and it is also responsible for serious air and water pollution. In India about 100 million tonnes of fly ash is generated each year. The Indian Government passed a law in October 2005 stating that a minimum of 25 percent of fly ash must be used in the manufacture of clay bricks for use in construction activities within a 50 km radius of coal burning thermal power plants.
Obada Kayali and Karl Shaw of the Australian Defence Force Academy have developed bricks and building aggregate that can be manufactured entirely from waste fly ash. Their unique manufacturing method traps any harmful chemicals, creating an eco-friendly construction material that saves on construction costs and reduces generation of greenhouse gases. Flash Bricks are 28 per cent lighter and 24 per cent stronger than comparable clay bricks while the aggregate, Flashag, can be used to make concrete that is 22 per cent lighter and 20 per cent stronger than standard products. This results in lighter structures, shallower foundations, cheaper transportation, and less usage of cement and steel reinforcement. This also results in more slender building components and hence, larger rentable space. Neil Simpson of New South Innovations, the university’s commercialisation arm, says the products had won widespread praise from structural engineers. “Because Flashag results in lightweight yet sturdy concrete, it can be used effectively in high-rises where smaller structural columns are needed to maximise floor space and in concrete bridges requiring longer spans.” The Fly Ash technology has two patents and licenses have been issued for the UK and US markets. NSi is seeking interest from companies wanting to develop the technology for China, Japan, Southeast Asia, Europe and India.
Source: Construction Contractor