Autoclaved Aerated Concrete (AAC) is a type of calcifies concrete compose of natural raw materials. It was first developed in Sweden in the 1920s. An architect first combined the conventional concrete mixture of cement, lime, water, and sand with a small amount of aluminum powder. The aluminum powder serves as a growth agent which causes the concrete to rise, somewhat like dough. And the result is concrete that consists of almost 80 present air. AAC concrete typically makes into blocks or slabs and is used to built mortar walls in a manner similar to that used or standard concrete block construction.
Autoclaved Aerated Concrete is manufacture with the same process which uses to mix all the concrete: aggregate, Portland cement, and water mix together to form a sludge. Upon the introduction of aluminum as a growth agent, air bubbles are introduced throughout the material, generating a low-density lightweight material. The wet concrete is in shape using forms. And then cut into slabs and blocks once partly dried. The units then proceed to an autoclave for full heal under heat and pressure, which takes only 8 to 12 hours.
AAC concrete units are highly workable and can be cut and drills with normal woodworking tools and like band saws and ordinary drills. Because it is light in weight and relatively low density and the concrete must be tested for compressive strengths, moisture content, blue density, and shrinkage.
Building with AAC Concrete :
- AAC concrete will use on floors, blocks, lintels, floor, and roof panels.
- Blocks came in the lengths of 24, 32, and 48 inches, and the thickness of 4 to 16 inches, height is 8 inches.
- Panels are available in thicknesses of between 8 to 12 inches and 24 inches width and light up to 20 feet.
AAC concrete can be used for walls, floors, and roofs, and its lightweight makes it more adapts than standard concrete. The material offers excellent sound and melting insulation and is strong and fire-resistant. But, in order to be durable, AAC must cover with an applied finish, such as polymer-modified stucco and natural or engineered stone, or siding. If used for basements. The outer face of AAC walls must be coat with a thin layer of waterproof material or membrane. AAC surfaces revealed to weather or soil moisture will break down.
Benefits of Autoclaved Aerated Concrete :
- Recyclable material.
- Highly fire and termite resistance.
- Easy to cut for chases and holes for electrical and plumbing lines.
- Easy handling and installation due to lightweight.
- Excellent material for soundproofing material and acoustic insulation.
- Available in a variety of forms and sizes.
- Easy to cut for chases and holes for electrical and plumbing lines.
- Economical shipping and handling when compared to poured concrete or concrete block.
Disadvantages of Autoclaved Aerated Concrete :
- The strength of AAC is 1/6 to 1/3 that of traditional concrete blocks.
- Unfinished exterior walls require exterior cladding to protect them from the weather.
- Products often show inconsistency in quality and color.
- Cost is higher than a conventional concrete block and wood-frame construction.
- R-values are relatively low when compares to energy-efficient insulated wall construction.
- If installed in high humidity environments and interior finishes require low vapor permeability and exterior finishes require high permeability.
AAC Block Prices :
The basic AAC block in the standard size of 8 x 8 x 24 inches costs about $2.20 to $2.50 per square foot as of July 2018. A bit more than a standard concrete block, which costs around $2.00 per square foot. But, labor costs for Autoclaved Aerated Concrete can below. Because it is lighter in weight which makes it easier to install. The difference in costs will vary from region to region. They affect by the local labor rates and building code requirements.