In modern construction, unlike the usual aggregate in concrete, aircrete has many stable air cells that are well distributed within the material to improve its structure when used in building. So, can it be used for foundations?
Aircrete can be used for foundations. It is light, hardens overnight, and continues to harden over time. It is easy to mold and shape using normal wood-shaping tools. Aircrete mostly consists of cement, water, and foam, although other materials like sand, lime, gypsum, and aluminum are also used.
This article explores the uses of aircrete, how it’s made, and the qualities that make it better than concrete. Read on to have a better understanding of how aircrete can be used for foundations.
Places Where Aircrete Is Used for Building Purposes
More often than not, you will find aircrete is preferred in large scale commercial, residential, and industrial construction projects. For low rise buildings of up to 4 stories high, it can be used in place of concrete columns. For taller buildings, it is used to partition and clad panels, saving time used to complete the project.
You can also use aircrete to construct greenhouses, living quarters and storage units, connecting slabs and pre-made blocks or panels, poured insulated roofs, floors, and pipes, as well as acoustic insulation and shock absorbent surfaces. It is also used for land-fills, abandoned mines, to replace unstable soil and fill up structures that are sensitive to weight.
Why Is Aircrete a Common Choice Over Traditional Concrete?
Aircrete is a common choice over traditional concrete because of the several different mix ratios you can achieve, depending on the aircrete needs of the project at hand. Some of the qualities of aircrete that supersede concrete are listed below:
The Overall Weight Is Lighter
Aircrete is very light in weight and is not toxic to humans. For this reason, you can use nails or screws on it, and it’s easy to repair as well. It can be reinforced for more sound structures, using fiberglass, paper, or very strong fabric. Creating a tensile membrane at the top ensures that the surface will not form cracks or crevices.
You Incur Low Construction Costs
Prefabricated aircrete supersedes additional construction materials like gravel, which is mixed with cement. Due to its smooth finish, it lowers the need to add finishing or plaster. Other than saving you the direct cost of these materials, it will also save you costs on heavy equipment and labor costs as well.
Aircrete has a low density, hence reducing the structural load. This means that there will be less use of concrete and steel in the foundation. The size of the blocks used can be increased, lowering the number of joints that require cement mortar.
Thermal Efficiency Ensures Favorable Temperatures
Aircrete has great heat insulation, derived from the numerous air cells present. In extreme weather conditions like snow or summer heat, it acts as a buffer hence lowering heating costs and saving fuel.
The thickness can also be adjusted depending on your climate. The fact that it can be molded into any shape comes in handy when constructing dome-shaped or entire walls. This leaves no room for cold gaps or thermal bridges in the seams and results in an airtight space that is easy to maintain in terms of temperature.
Fire Resistant and Withstand Very High Temperatures
Aircrete does not burn. With a melting point of over 1593°C (2900°F), it has been ranked to have the highest fire safety standard. The inorganic materials used to make aircrete are not combustible and do not produce toxic gases when exposed to a flame.
Aircrete Is Waterproof
When immersed in water, aircrete tends to float on the surface as it does not absorb water, neither does it warp or decompose even when exposed to water for a long period of time.
This makes it possible to have sprinklers for your roof garden without worrying about the water seeping inside. In an area where moisture is a concern, this is the perfect material for you to use.
The Design Keeps Out Pests and Rodents
Pest and rodent control is a very common concern. Often, we are forced to use fumigation or chemicals to keep them in check. Aircrete allows seamless integration, leaving no space or gaps for pests or rodents to find their way in or through. This makes it the perfect material to use when building storage units or greenhouse projects.
Eco-Friendly and Easy to Dispose
The ecological materials used to make aircrete are obtained from natural resources. Their weight and harmless nature ensure that even upon disposal, they do not harm the environment and leave a smaller carbon footprint.
How Is Aircrete Made?
Aircrete is made from cement, lime, sand, pulverized fuel ash (PFA), and water. Anyone with basic masonry skills and can master the correct mixing ratios can make aircrete.
The PFA mixed with sand is poured into the water to form a dense liquid. This mixture is heated before adding the cement, lime, and some Aluminum Sulphate powder.
The purpose of the aluminum is to react with the calcium hydroxide and water in the lime, forming hydrogen bubbles. The mixture expands, as a result, replacing the hydrogen with air. After being allowed to cool and set a little, it is cut to size and cured using pressurized steam in an autoclave.
To prepare aircrete at home, you will need a foaming agent, an air compressor, a weighing scale, cement, and water.Since the density of the foam is important, you will need a quality detergent with high foaming ability. The normal density of aircrete falls between 9.07 kg (20 lbs) and 27.21 kg (60 lbs)/cu.ft. with a compressive strength of between 50 psi and 930 psi.
The air cells need to remain stable, so ensure you test the foaming agent in advance to prevent the cells from collapsing due to gravity. The finer or less the foam is, the stronger and denser the aircrete will be. The foam will expand the volume of the cement to about 5 – 7 times.
DIY Steps for Creating an Aircrete
- Add the detergent (foaming agent) to the water, mix well, and measure the weight using a normal scale. The weight of the foam should range from 80 to 100 g (2.82 to 3.53 oz) per liter. 5 gallons of water requires 2 cups of a foaming agent. If the foam is heavier, add the air pressure. If lighter, reduce the pressure.
To know you have the right consistency, place some foam on your hand, and flip it. Should it remain on your hand, then you are good to go. If you prefer, you can purchase a foaming agent that has been specifically made for aircrete.
- Add one bag of cement 42.64 kg (94 lbs) to 6 gallons of water in that order, to prevent forming clumps. The water to cement ratio is 1:2, but it can vary depending on specific structural requirements. One bag of cement will make about 40 to 50 gallons of aircrete.
- Using the air compressor, add foam to the mixture. The pressure should be at least 2.5cfm @ 90 psi. The foam tends to float, so ensure you inject it into the bottom and mix thoroughly. You can also use an industrial foam generating machine, for example, the Little Dragon.
- Pour the mixture into any form and allow it to sit overnight.
- To prevent leakage, you can line the container using plastic paper.
Here a YouTube video explaining how to build a simple aircrete machine in a few minutes:
In summary, aircrete is great in terms of compressive strength but still needs to be reinforced to meet some construction standard requirements. It is by far the most cost-effective, affordable material that doesn’t compromise on quality.
As it requires no special skills, you can easily make it in the comfort of your home with normal everyday tools. It is easy to work with, cut, drill, or mold into any shape you would like.
In addition to these fine qualities, it’s very durable, great for acoustic functions, and is compatible with many color pigments to suit your style or design. If you are debating on whether to use aircrete for your foundation or construction in general, then consider this article a nudge in the right direction.
- Aircrete Europe: Aircrete Building System
- Domegaia: Aircrete
- Sustainable Living Center Oregon: Air-crete
- Steemit; Building With Aircrete
- DIYaircrete: How to make aircrete
- LandZero: How to make aircrete
- Greenhomebuilding: Formulas for lightweight concrete
- Youtube: How to Build A Simple Aircrete
- ScienceDirect: Pulverized Fuel Ash
- Understanding-cement: Autoclaved aerated concrete (AAC, Aircrete)