Walls from waste gypsum, strong and cheap

Industrial waste has always been a burden, more so when the quantity is large and heavy without any means of disposal.

For long, public sector major Rashtriya Chemicals and Fertilizers could do little to get rid of the tonnes of gypsum waste it was accumulating till a solution came by from an Australian building material manufacturer Rapid Building Systems (RBS).

RBS’ suggestion to turn the gypsum waste into load-bearing walls was accepted and the PSU set up a Rs 75-crore plant with the Australian firm’s technology assistance.

The basic raw material for the prefabricated wall panels, ‘Rapidwall’, is phospho-gypsum or mineral gypsum, which is calcinated to form gypsum plaster.

The plaster is then reinforced with micro strand glass fibres.

Commercialising

Commercial production is all set to begin in a month and even before that a leading Mumbai builder Hiranandani along with Mahintura Consultants has agreed to lift the supply and market it as well. About 14 lakh sq m of panels will be made and the sales target is about Rs 75 crore.

The technology is widely used in Australia and China, where buildings of over 10 storeys have been built with it.

Mr A. N. Gandhe, Chief Marketing Manager, RCF, said the prefabricated wall panels could replace the conventional brick and mortar structures. No plastering or curing is needed and the panels can also be used for the ceiling.

However, the walls need to be fastened through concreting and reinforced by steel.

“The savings in construction cost will be about 25 per cent, and of time 50 per cent.” Mr P. G. Despande, Deputy General Manager, RCF, said.

It would cost Rs 750-800 a sq. m. More importantly, one 12.5-cm thick panel of 12×3 metres would save 10,000 litres of water, 86 cubic feet of river sand, a truck load of soil, 0.80 tonne of cement and prevent emission of 2.9 tonnes of carbon-dioxide.

While the panel weighs 1.5 tonne, an equivalent brick wall of 23 cm thickness would be about 19 tonnes, though the panel was many times stronger and earthquake resistant too.

Mr Despande said Rapidwall has been tested by the Structural Engineering Research Centre, the Council of Scientific and Industrial Research, and IIT Madras.

The Building Material Technology Promotion Council, under the Ministry of Housing and Poverty Alleviation, has approved the material for construction up to 10 storeys.

RCF has built a 1,220 sq.ft building house using rapidwall at its residential colony in Mumbai in 32 days, where the structural work took 12 days and other jobs such as flooring, electrification, water supply, fittings and paintings 20 days.

More such wall panels are to come from public sector company FACT, which is setting up a similar plant at Ambalamedu. RCF officials said FACT had over 60 lakh tonnes of phospo-gypsum on its premises.

Thanks: The Hindu Business Line

http://www.thehindubusinessline.com/2009/08/09/stories/2009080951230100.htm

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