Flux-bonded fly ash could reduce clay use in buildings

Last Updated: Thu, Feb 21, 2013 06:50 hrs

Thiruvananthapuram, Feb 21 (IANS) Flux-bonded fly ash technology is all set to drastically reduce the clay used in building material, thanks to the initiative of a group of scientists here.

A group of scientists at National Institute for Interdisciplinary Science and Technology (NIIST) of the Central Institute of Scientific Research here have been researching the new material and technology, and have now announced a breakthrough.

Fly ash could be used to manufacture bricks and tiles, and could help reduce the use of clay to as low as 15 percent.

Fly ash use in building materials is also eco-friendly. It would also be the first time that the material is used in construction.

"While the bricks and tiles made using this technology have better properties than clay-based building components, the colour of the products remains similar to that of conventional "fired bricks and tiles", an NIIST spokesperson told IANS.

Fly ash is silica-rich fine powder, one of the residues generated in the combustion of coal. If the fly ash is released into the atmosphere via smoke stack, it would create environmental problems.

Hence, fly ash is generally captured from the chimneys of thermal power plants and stored at the plant site or used as landfills along with other residual material.

"It is also a concern that the sources of traditional building materials like clay are diminishing very fast. Large-scale mining of top soil for clay is another issue that demands attention," pointed the spokesperson.

All the present day technologies utilise fly ash by making admixtures with high volume clay followed by firing or by its use with cement/lime/gypsum, followed by curing.

"In flux-bonded fly ash technology, fly ash with certain additives are used. The additives form a low melting point liquid like glass, which further reacts with fly ash during firing and finally forms a hard sintered product," the spokesperson said.

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