What is Cellular Concrete
Cellular concrete is a special engineering concrete made by mixing portland cement, sand, fly ash, water, and preformed foam in various proportions to form a cured material with a drying oven density of 50 pounds per cubic foot (PCF) or less.
It is lightweight concrete that is made by introducing large cavities into the concrete or mortar. Its density varies from 3 kN / m3 to 8 kN / m3, while the raw concrete density is 24 kN / m3. It is also known as aerated concrete, foam, or gas concrete.
The important property of cellular concrete is its self-compacting property, in which no compaction is required, the concrete flows out of the pump to fill the mold. With this property, it can be pumped over long distances and at heights.
In a broader sense, any cementitious mortar or cementitious material that uses an externally generated foam to increase the air content above 10% can be considered cellular concrete. Cellular concrete can have other names, including foam cement, aerated concrete, or light liquid backfill.
Although there are a number of lightweight cementitious materials, the main differentiator between aerated concrete and other lightweight cementitious materials is the use of externally generated foam to reduce density. The material closest to aerated concrete is probably aerated autoclaved concrete (AAC).
The main differences are the methods of generating air in the material and the equipment required. AAC uses a chemical reaction within the suspension itself to create air pockets to reduce density. However, making aerated concrete with externally generated foam provides a more versatile material at a fraction of the capital cost of equipment.
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Material Used in Making Cellular Concrete
1. Cement
2. Fly Ash
3. Foam
What is the process for making cellular concrete?
There are two methods for producing cellular concrete.
The first is the batch production process, in which externally generated foam is injected into the drum of a mixer for a calculated time.
The second is the continuous production process in which the foam is injected inline from the pressure side of a pump.
What is the set time for cellular concrete?
The setting time of Cellular concrete is usually a little longer compared to “normal” concrete due to the surfactants used in foam production. However, as with anything made with Portland cement, production and placement time is limited. In general, the recommended working time is limited to about four hours after mixing the Portland cement with water or about three hours after adding the foam. After this time, the material should be left alone to continue the setting process. Further pumping or moving the material can cause the material to collapse and fail. However, the set-up time can vary depending on the application, construction site conditions, and the use of retarders or accelerators.
Properties of cellular concrete
It has the following properties:
1. It is light in weight.
2. It has good fire resistance.
3. It has good thermal insulation properties.
4. The thermal expansion is negligible.
5. Problems with freezing and thawing are absent.
6. Sound absorption is good.
7. It is less prone to flaking.
Uses of Cellular Concrete
- It is used for building partition walls.
2. It is used for partition walls for thermal insulation.
3. It is used for the construction of filled hollow floors
4. Maintain the acoustic balance of the concrete.
5. Manufacture of cement and plaster-based light panels.
6. Manufacture of special heat-resistant ceramic tiles.
7. For draining water from the ground.
8. Use in the deck to prevent freezing.
9. Used for filling tunnels and manholes and for making lightweight concrete.
10. Production of perlite plaster and perlite lightweight concrete.
References
- https://theconstructor.org/concrete/cellular-concrete-types/28732/
- https://qgreentech.com/cellular-concrete/
- https://www.concrete.org/topicsinconcrete/topicdetail/cellular%20concrete?search=cellular%20concrete
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