civil engineering

A concrete technology

Hollow core concrete systems coupled with energy efficient TermoDeck technology offer several advantages when compared with traditional systems.

EFFICIENT: Hollow core concrete slabs being used on a building.

In the world of concrete, hollow core systems that have been around for about 25 years in different countries, is now knocking the doors here.

The technology of factory-made concrete slabs for floors and roofs has been in use for a long time. In Kochi, the proposed shopping mall, by the promoters of Dubai's Lulu Centre, at Edappally is likely to have hollow core slabs. For this the company that would be taking up the contract would be setting up a plant here.

Energy efficient

John Durham, Technical Director of Hollow Core Systems (India) Private Limited and TermoDeck International Limited, who made a presentation at the recent national convention of the Builder's Association of India in Kochi, made quite an impression on builders assembled here with his presentation on an energy-efficient system promoted by the company.

According to him, the system promoted by his company has not just hollow core slabs but an energy efficient system too, which goes hand in hand with the hollow core slabs.

The concrete slabs in the required specifications are set in the factory and brought to the site of construction. Fixing of the slab requires just about four workers, said Mr. Durham. A 500 sq.feet. floor can be fixed in a matter of hours, he added. A bigger area may take a day, he added. The traditional process of laying a roof takes days for the arrangements and at least 10 days for the wet concrete to set in. But with hollow core slabs it can be finished in just about a day.

The system is environment-friendly as it totally removes the need of the bamboo props that are required to give support to concrete laying by the traditional method, said Mr. Durham. The high-technology method of making the hollow core slabs reduces the weight of the concrete by 60 per cent. Water content in the concrete is reduced by 70 per cent and the span of the concrete is big.

The casting bed is 1.20-1.40 metres wide, and standard thickness, between 15 cm and 50 cm. No plastering is required on the slabs because of the fine finish, said Mr. Durham. It can straight away take a coat of paint.

The slabs have tubular holes - cores - running through its length. The slabs take its name from this hollowness inside and the main purpose of the hollow core is to decrease the weight. The materials used are comparatively much less, though there is no compromise on strength. The slabs are made on steel strands running longitudinally

The concrete beams between the holes carry the steel rods that provide the compressive stress that holds the slab together under heavy loads.