Aerated concrete blocks

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Expo

The Autoclaved Aerated Concrete (AAC) material was developed in 1924 in Sweden. It has become one of the most used building materials in Europe and is rapidly growing in many other countries around the world.

AAC is produced from the common materials lime, sand, cement and water, and a small amount of rising agent. After mixing and molding, it is then autoclaved under heat and pressure to create its unique properties. AAC has excellent thermal insulation and acoustic absorption properties. AAC is fire and pest resistant, and is economically and environmentally superior to the more traditional structural building materials such as concrete, wood, brick and stone.

Advantages

AAC has been produced for more than 70 years, and it offers several significant advantages over other cement construction materials, one of the most important being its lower environmental impact.

  • Improved thermal efficiency reduces the heating and cooling load in buildings.
  • Porous structure allows for superior fire resistance.
  • Workability allows accurate cutting, which minimizes the generation of solid waste during use.
  • Resource efficiency gives it lower environmental impact in all phases of its life cycle, from processing of raw materials to the disposal of waste.
  • Light weight saves cost & energy in transportation, labor expenses, and increases chances of survival during seismic activity.[6]
  • Larger size blocks leads to faster masonry work.
  • Reduces the cost of the project.
  • Environmentally friendly: When used, it helps to reduce at least 30% of environmental waste as opposed to going with traditional concrete. There is a decrease of 50% of greenhouse gas emissions. When possible, using autoclaved aerated concrete is a better choice for the environment.
  • Energy savings: It is an excellent property that makes it an excellent insulator and that means the interior environment is easier to maintain. When it is used, there is usually not a need for any supplementary insulation.
  • Fire resistant: Just like with regular concrete, ACC is fire resistant. This material is completely inorganic and not combustible.
  • Great ventilation: This material is very airy and allows for the diffusion of water. This will reduce the humidity within the building. ACC will absorb moisture and release humidity; this helps to prevent condensation and other problems that are related to mildew.
  • Non-toxic: There are no toxic gases or other toxic substances in autoclaved aerated concrete. It does not attract rodents or other pests nor can it be damaged by such.
  • Lightweight: Concrete blocks that are made out of ACC weigh about one-fifth of typical concrete. They are also produced in sizes that are easy to handle for quick construction.
  • Accuracy: The panels and blocks made of autoclaved aerated concrete are produced to the exact sizes needed before they even leave the factory. There is less need for on-site trimming. Since the blocks and panels fit so well together, there is a reduced use of finishing materials such as mortar.
  • Long lasting: The life of this material is extended because it is not affected by harsh climates or extreme changes in weather conditions. It will not degrade under normal climate changes either.
  • Quick assembly: Since it is a lightweight material and easy to work with, the assembly is much quicker and smoother.

Disadvantages

AAC has been produced for more than 70 years, however some disadvantages were found when it was introduced in the UK (where cavity wall with clay brick two-skin construction has been the norm).

  • Installation during rainy weather: aircrete is known to crack after installation, which can be avoided by reducing the strength of the mortar and ensuring the blocks are dry during and after installation.
  • Brittle nature: they need to be handled more carefully than clay bricks to avoid breakages.
  • Fixings: the brittle nature of the blocks requires longer thinner screws when fitting cabinets and wall hangings and wood-suitable drill bits or hammering in. Special, large diameter wall plugs (aircrete anchor) are available, though at a higher cost than common wall plugs.[7]
  • Insulation requirements in newer building codes of northern European countries would require very thick walls when using AAC alone. Thus many builders choose to return to traditional building methods installing an extra layer of insulation around the building as a whole.

Examples

Notes

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Links

Wikipedia

A concrete masonry unit (CMU) is a standard size rectangular block used in building construction.

Those that use cinders (fly ash or bottom ash) are called cinder blocks in the United States, breeze blocks (breeze is a synonym of ash) in the United Kingdom, and hollow blocks in the Philippines. In New Zealand and Canada they are known as concrete blocks or more commonly as just blocks. In New Zealand, they are also known as construction blocks. In Australia they are also known as Besser blocks or Besser bricks, because the American-based Besser Company was a major supplier of concrete-block-making machinery. Clinker blocks use clinker as aggregate. In non-technical usage, the terms cinder block and breeze block are often generalized to cover all of these varieties.