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How to make autoclaved aerated concrete?

By Bagofconcrete
Page last updated: 10/22/2022 | Next review date: 10/22/2024
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The article aims to answer the question “How to make autoclaved aerated concrete?”. It will also explain the manufacturing process that is involved in the making of autoclaved aerated concrete. 

How to make autoclaved aerated concrete?

  • A slurry of cement, lime, water, finely powdered sand, and, in certain cases, fly ash is first prepared. 
  • The fluid mixture is poured into a mold and cast into a big billet with the addition of an expansion agent, such as aluminum powder. 
  • The combination expands when the slurry interacts with the expansion agent to produce air bubbles. It is then necessary to wire cut and bake the resultant “cake” once it has first been set (autoclaved). 
  • The heat aids in the curing process, allowing blocks and panels to retain their original proportions. Prior to curing, panels are reinforced using a variety of materials.

What do I need to make autoclaved aerated concrete?

Aggregate

Cement

Expanding agent 

What is autoclaved aerated concrete?

Aggregates, cement, as well as an expansion agent are the main ingredients in autoclaved aerated concrete (AAC), which rises in the autoclave like bread dough. 

In fact, the air content of this concrete is as high as 80%. The material is molded and cut into precise units at the factory where it is manufactured. Thin mortar is used to join cured concrete blocks or panels that have been autoclaved aerated. 

Components can be applied to the walls, floors, and roofs of a building. As with all cement-based materials, the lightweight material provides excellent sound and thermal insulation. 

AAC must be finished with a polymer-modified stucco, natural or manufactured stone, or siding in order to be long-lasting. Concrete masons can easily erect autoclaved aerated concrete units (blocks) because of their resemblance to traditional forms. 

Installers and carpenters work together on projects from time to time. A crane is needed to lift and place the panels because of their weight and size. Manufacturers often offer training seminars, and one or two knowledgeable installers are usually sufficient for small-scale projects. 

They can be mechanically or directly attached to the AAC surface, depending on the finish type chosen.

What are the advantages of autoclaved aerated concrete?

  • Walls, floors, and roofs may all benefit from autoclaved aerated concrete’s dual-purpose properties as an insulator and a structural support. 
  • It is simple to cut, shave, and shape, accepts nails and screws, and can be routed to form chases for electrical conduits and smaller-diameter plumbing lines because of its lightweight/cellular qualities. 
  • This enables it to be more adaptable in terms of design and construction, as well as field alterations.
  • durability and the capacity to maintain its shape. AAC is a cement-based substance that is impervious to moisture, rot, mold, mildew, and insects. As a result, each unit is a work of art with a clean, precise look.
  • AAC’s fire resistance is outstanding, having a four-hour rating at eight inches thick (actual performance exceeds that and meets test requirements for up to eight hours). It’s also noncombustible, so it won’t burn or emit harmful gases when it’s used.
  • Lightweight implies that R-values for AAC are similar with traditional frame walls, but they have more thermal mass and are airtight. 
  • When utilized as internal partition walls, the lightweight nature of the material provides a great level of seclusion, both from outside sounds and from the adjacent rooms.
  • However, there are certain limits to the content. Even if it isn’t widely accessible, it can be transported anywhere. Having a low weight makes it easier to ship. 
  • In load-bearing applications, it is generally reinforced because of its lesser strength compared to most concrete materials or systems. In order to keep the material from deteriorating, it must be coated in a protective layer.

How aerated concrete is manufactured?

  • The same method is used to mix any concrete, including autoclaved aerated concrete: In order to create a slurry, the following ingredients must be combined: Portland cement, aggregate, and water. 
  • When aluminum is used as an expansion agent, air bubbles are injected into the material, resulting in a low-density, lightweight material. Forms are used to shape the still-wet concrete, which is subsequently sawed into slabs and blocks after it has partly dried. 
  • After that, the units are taken to an autoclave for an 8–12-hour cure under high pressure and heat.
  • Using common woodworking instruments like band saws and power drills, you can easily cut and drill holes in AAC concrete modules. 
  • Testing for compressive strength, moisture content and bulk density as well as shrinkage is necessary for lightweight concrete because of the material’s low density and low weight.
  • Similar to normal concrete blocks, cured autoclaved aerated concrete blocks or panels are bonded with thin bed mortar. In order to increase the wall’s structural integrity, steel or other structural components might be inserted vertically within the blocks.
  • Because of its low density and low weight, AAC concrete is more adaptable than ordinary concrete when it comes to construction applications. Insulation properties are good, as well as fire resistance, and the material is quite durable. 
  • A finish such as polymer-modified stucco, natural or engineered stone, or siding must be put on AAC in order for it to be long-lasting. 
  • A heavy coating of waterproof material or membrane must be applied to the exterior face of AAC walls if they are to be used in basements. AAC surfaces that are exposed to the elements, like rain or soil moisture, degrade. Finished or unfinished interior surfaces include drywall, plaster, tile, and paint.

Conclusion

Naturally sourced raw materials are used to make autoclaved aerated cement (AAC). In the 1920s, an architect in Sweden first included a tiny quantity of aluminum powder into the traditional concrete combination of cement, lime, water, and sand. 

The aluminum powder acts like an expansion agent and causes the concrete to expand. As a consequence, the concrete is virtually entirely made up of air. An alternative to ordinary concrete blocks, AAC concrete is often molded into blocks or slabs and used to create mortared walls.

Frequently asked questions (FAQS): How to make autoclaved aerated concrete?

How to make autoclaved aerated concrete?

A slurry of cement, lime, water, finely powdered sand, and, in certain cases, fly ash is first prepared. 

The fluid mixture is poured into a mold and cast into a big billet with the addition of an expansion agent, such as aluminum powder. 

The combination expands when the slurry interacts with the expansion agent to produce air bubbles. It is then necessary to wire cut and bake the resultant “cake” once it has first been set (autoclaved). 

What are the advantages of autoclaved aerated concrete?

Walls, floors, and roofs may all benefit from autoclaved aerated concrete’s dual-purpose properties as an insulator and a structural support. 

It is simple to cut, shave, and shape, accepts nails and screws, and can be routed to form chases for electrical conduits and smaller-diameter plumbing lines because of its lightweight/cellular qualities. 

This enables it to be more adaptable in terms of design and construction, as well as field alterations.

What are the advantages of autoclaved aerated concrete?

Walls, floors, and roofs may all benefit from autoclaved aerated concrete’s dual-purpose properties as an insulator and a structural support. 

It is simple to cut, shave, and shape, accepts nails and screws, and can be routed to form chases for electrical conduits and smaller-diameter plumbing lines because of its lightweight/cellular qualities. 

This enables it to be more adaptable in terms of design and construction, as well as field alterations.

Durability and the capacity to maintain its shape. AAC is a cement-based substance that is impervious to moisture, rot, mold, mildew, and insects. As a result, each unit is a work of art with a clean, precise look.

AAC’s fire resistance is outstanding, having a four-hour rating at eight inches thick (actual performance exceeds that and meets test requirements for up to eight hours). It’s also noncombustible, so it won’t burn or emit harmful gases when it’s used.

Bibliography

Autoclaved Aerated concrete. PCA. retrieved from: https://www.cement.org/cement-concrete/paving/buildings-structures/concrete-homes/building-systems-for-every-need/autoclaved-aerated-concrete#:~:text=First%2C%20several%20ingredients%20are%20blended,air%20bubbles%2C%20the%20mixture%20expands.