Autoclaved Aerated Concrete (AAC) – A New Green Building System

Autoclaved Aerated Concrete (AAC) | Efficient Building Systems | Green Material

Autoclaved Aerated Concrete (AAC) was developed in Sweden in the late 1920s and has been used successfully in a variety of applications in commercial, industrial and residential construction. AAC is a lightweight, high strength building material and is produced in a variety of forms from blocks, to structural floors and wall panels.

AAC is credited by LEED (Leadership in Energy and Environmental Design) and USGBC (US Green Building Council) as an “green” alternative to traditional construction materials. Indian Green Building Council (IGBC) recommends its use in India.

AAC consists of 80% of air. It is manufactured by combining silica in the form of sand or recycled flyash, cement, lime, water and an expansion agent – aluminium powder and paving it into a mold.

Autoclaved Aerated Concrete (AAC) – A New Green Building Material
Autoclaved Aerated Concrete (AAC) – A New Green Building Material

Structurally reinforced AAC products like lintels or roof panels, steel rebar or mesh are also placed in the mould.

When added to concrete, the aluminium powder reacts with the silica, resulting in the formation of millions of microscopic hydrogen bubbles. The hydrogen bubbles cause the concrete to expand to roughly five times its original volume.

The hydrogen evaporates and leaving a highly closed cell aerated concrete. It is then cut into blocks or panels which are then steam and pressure cured in an autoclaved. Using AAC is very advantageous because it is environmentally friendly qualifies as a ‘green’ building material from manufacturing to recycling.

All the waste material like trimmings, rejected units are all recycled and hence there is zero wastage. All the waste on the sites is crushed and safely used as a fill or buried shallow underground. Spread AAC dust on the lawn serves as a great lime supplement.

AAC is so lightweight, it weighs 1/5th of the weight of the standard concrete, which results in lower transportation costs, faster work-flow lower material handling costs etc. AAC is in ‘ready to build’ material, requiring no onsite curing time. It has unparalleled workability because it can be sown, drilled, nailed, screwed and milled with common hand tools. AAC openings are easily and alternately cut.

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Leading the Green Building Movement | TKM College of Engineering (Chennai)

“A green building is one which uses less water, optimizes energy efficiency, conserves natural resources, generates less waste and provides healthier spaces for occupants, as compared to a conventional building.”

As the world reels under the stress of economic recession and Peak oil, efforts are being made to minimize the use of energy, to maximize return on invested resources by recycling and optimum use of natural resources. Such efforts have culminated into the new Green building movement across the planet.

Brief Introduction of the Project

A contemporary convention centre having state of art facilities, using modern building techniques and energy efficiency as the prime design parameters.

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Case Study | LBHS College, Mumbai | Green Building Architecture

LBHS is an architecture college situated in the suburbs of Mumbai, in India. It is a prime example of Green Building  Architecture. The city of Bombay is a bit crowded, and as such, land is at a premium. So, the location provides enough space for expansion and providing sufficient infrastructure to students.

LBHS Mumbai - site plan
LBHS Mumbai - Site plan

This project is special because it has implemented many energy-saving devices and techniques to make it one of the first green building designs in India. From light sensors for auto-switching of lights, to water recycling, use of solar arrays and use of earth air tunnels, this project has done everything. It is a very interesting case study. The designers have aimed at developing an semi-autonomous building, almost self-sufficient building complex.

It is inferred that such buildings reduce environmental impacts, increase security, and lower costs of ownership.

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