Autoclaved aerated concrete
[citation needed] It is most suitable for producing a lightweight or most cost-effective alternative to traditional concrete blocks and clay bricks.
[citation needed] AAC is composed from a combination of quartz sand, gypsum, lime, portland cement, water, and aluminium powder.
[4] AAC materials are adaptable in that they can be routed, sanded, or cut to size on-site using a hand saw and standard power tools with carbon steel cutters.
[9][10] AAC was first created in the mid-1920s by the Swedish architect and inventor Dr. Johan Axel Eriksson (1888–1961),[11][12] along with Professor Henrik Kreüger at the Royal Institute of Technology.
[15] Ytong AAC was originally produced in Sweden using alum shale, which contained combustible carbon that was beneficial to the production process.
[citation needed] However, these deposits were found to contain natural uranium that decays over time to radon gas, that then accumulates in structures where the AAC was used.
This problem was addressed in 1972 by the Swedish Radiation Safety Authority, and by 1975, Ytong abandoned alum shale in favor of a formulation made from quartz sand, calcined gypsum, lime (mineral), cement, water and aluminum powder;[citation needed] These ingredients are currently in use by most major brands.
Although the European AAC market has seen a reduction in growth, Asia is experiencing a rapid expansion in the industry, driven by an escalating need for residential and commercial spaces.
The most significant AAC production and consumption occur in China, Central Asia, India, and the Middle East, reflecting the dynamic growth and demand in these regions.
[23] One of its advantages is quick and easy installation because the material can be routed, sanded, or cut to size on-site using a hand saw and standard power tools with carbon steel cutters.
[24] Due to its lower density, high-rise buildings constructed using AAC require less steel and concrete for structural members.
In some countries, like India and China, fly ash generated from coal-fired power plants, and having 50–65% silica content, is used as an aggregate.
[26] At the end of the foaming process, the hydrogen escapes into the atmosphere and is replaced by air, leaving a product as light as 20% of the weight of conventional concrete.
In Europe, it gained popularity in the mid-1950s as a cheaper and more lightweight alternative to conventional reinforced concrete, with documented widespread use in a number of European countries as well as Japan and former territories of the British Empire.
Detailed risk analyses are required on a structure-by-structure basis to identify areas in need of maintenance and lower the chance of catastrophic failure.
[28] On June 21, 2024, the Ontario Science Centre, a major museum in Toronto, Canada, permanently closed its original site due to severely deteriorated roof panels from its 1969 opening.
[51][52] As AAC has been produced for more than 70 years and a number of advantages have been reported over other cement construction materials, one of the most important being its fire resistance, which helps to save lives.
