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( AAC) Light weight block equipment introduction Areated concrete brick (light brick ) is the light and porous buidling material. It has light keeping temperature cant burn and other advantages. It can be made into many kinds of bricks (for example: 600x200x100, 80x80x180, 240x115x53, 600x200x125 ), they could be used industry building and common building. They are more and more popular in the world. In the future, they will replace the Clay brick completely. AAC working process Unlike most other concrete applications, AAC is produced using no aggregate larger than sand. Quartz sand, lime, and/or cement and water are used as a binding agent. Aluminum powder is used at a rate of 0.05% to 0.08% by volume (depending on the pre-specified density). When AAC is mixed and cast in forms, several chemical reactions take place that give AAC its light weight (20% of the weight of concrete) and thermal properties. Aluminum powder reacts with calcium hydroxide and water to form hydrogen. The hydrogen gas foams and doubles the volume of the raw mix (creating gas bubbles up to 1/8 inch in diameter). At the end of the foaming process, the hydrogen escapes into the atmosphere and is replaced by air. When the forms are removed from the material, it is solid but still soft. It is then cut into either blocks or panels, and placed in an autoclave chamber for 12 hours. During this steam pressure hardening process, when the temperature reaches 374° Fahrenheit (190° Celsius) and the pressure reaches 8 to 12 bars, quartz sand reacts with calcium hydroxide to form calcium silica hydrate, which accounts for AAC's high strength and other unique properties. After the autoclaving process, the material is ready for immediate use on the construction site. Depending on its density, up to 80% of the volume of an AAC block is air. AAC's low density also accounts for its low structural compression strength. It can carry loads up to 1, 200 PSI, approximately only about 10% of the compressive strength of regular concrete. Since 1980, there has been a worldwide increase in the use of AAC materials. New production plants are being built in the USA, Eastern Europe, Israel, China, Bahrain, India, and Australia. AAC is increasingly used by developers, architects, and home builders
