Aircrete and foamcrete and are both types of lightweight concrete. By definition, lightweight concrete is a type of concrete that has incorporated an expanding agent, increasing the volume of the mixture, giving it more desirable qualities like a low physical weight, but which is better?
Note that aircrete and foamcrete are used for specific structural purposes. Where aircrete is ideal, foamcrete may be lacking in some aspects and vice versa.
With many similar physical characteristics, the major difference between aircrete and foamcrete is in how the air bubbles in the cement mixture are generated. In this article, we have shed some light on how each is made, what it’s used for, advantages and disadvantages as well. Let’s have a look.
The Fundamental Difference Between Foamcrete and AirCrete
Foamcrete is ideal for backfilling voids that are no longer in use, particularly in inaccessible places, such as pipes and sewage systems, culverts, and road trenches. It is also used to fill voids under floors, sub-screeds, and flat concrete roofs.
Foamcrete is a construction material that is made using a cement-based mortar with at least 20% volume of air within. It is made by introducing gases or foam into a mixture of cement slurry and fine sand. Therefore, it has no coarse aggregates.
Aircrete is popular for its use in constructing housing systems from foundations, soundproof wall and floor slabs, shock-absorbent surfaces, ceilings, and even roofs. It is also effective in replacing unstable soil and covering underground structures that are sensitive to weight.
For industrial purposes, pulverized fuel ash is used instead of sand and lime instead of cement.
How Foamcrete Is Made
Foamcrete is made in two major ways. Air or gas can be injected during the mixing process via chemical reaction, or a stable, pre-formed foam can be introduced into the cement slurry.To generate the foam, a surfactant is diluted in water at a ratio of 1:30 and passed through a foam generating machine to produce stable foam, then mixed into the cement slurry.
The foaming agent used should be very stable. A quick test is just to pour it into a glass. The foam should hold without shrinking or forming liquid at the bottom of the glass. Small bubbles are ideal, as they are stronger than the bigger ones.
Foaming agents can be synthetic or protein-based. Protein-based foaming agents produce more stable bubbles, making it possible to use more air, while synthetic foaming agents tend to expand more, resulting in a lower density.
In terms of volume, the foam is about 40-80%. Foamcrete is cured in the same way as normal concrete since it has a higher cement content. The air bubbles in foamcrete are smaller in size than those found in aircrete, making them more durable.
The density of foamcrete depends on the amount of foam introduced into the mixture, while the strength depends on the sand quantity used. More foam means less weight and, consequently, less strength. However, with less weight comes better thermal insulation.
A more detailed explanation of how it’s made is available here.
Applications of Foamcrete
Advantages of Foamcrete
Disadvantages of Foamcrete
How Aircrete Is Made
Aircrete is made by mixing cement, lime, pulverized fuel ash, aluminum powder, and water. The chemical reaction catalyzed by the aluminum forms multiple air bubbles then dissolves, resulting in a very lightweight block.
In aerated concrete, the foam is generated from a chemical reaction between aluminum powder and calcium hydroxide, an alkaline element formed when the cement is mixed with water. This reaction forms hydrogen bubbles that remain in the cement slurry. After setting, the aerated concrete is cut into blocks and autoclaved for extra strength. It has the strength and durability of traditional concrete, without the physical weight. For a more compressive procedure on how it’s made, you can have a quick look here.
Applications of Aircrete
Advantages of Aircrete
Disadvantages of Aircrete
From these advantages and disadvantages, here is a quick comparison of some aspects of both aircrete and foamcrete:
| Aspects | Foamcrete | Aircrete |
| Cost | Reduction in the use, and consequently cost of concrete and steel in high rise buildings | Reduction in the use, and consequently cost of concrete and steel in high rise buildings |
| Quality | Final quality varies depending on the foaming agent used. | The quality of the final product is consistent, as it is available ready for use. |
| Acoustic properties | Sound absorption or insulation is great. | Sound absorption or insulation is great. |
| Thermal conductivity | Low thermal conductivity of about 0.24 Kw-M/C | Low thermal conductivity of about 0.32 Kw-M/C |
Aircrete is better than Foamcrete in some applications, while foamcrete is better in others. The similarities in both include low density, reduced dead weight in construction, and easy to nail, saw, or cut.
Both are self-compacting and free-flowing; therefore, they can fill cavities and voids even when pumped over a distance. When it comes to cost-effectiveness, they both save on materials used, and time is taken to complete the project and manual labor as well. They pose a minimal threat to the environment and are fire-resistant.
There are common disadvantages such as sensitivity due to the use of water during production, and they have a smooth, porous exterior, which makes applying finish difficult.The key is to remember that each has different applications specific to its properties. Before settling on either, be sure to check if it applies to the project you have in mind.
