Cellular Lightweight Concrete / Foam Concrete
Updated: Nov 26, 2022
Foam concrete by definition; can be dated as a light material produced by homogeneously placing the stable foam obtained with the appropriate foam generator into the mortar consisting of a mixture of cement, water, and aggregate, by creating air spaces and placing it in the concrete homogeneously. In other words, there is no material other than natural aggregate and cement in its composition, and since the foaming agent, which is the main ingredient in the foam added to the mortar, is a completely natural material, it does not pose a danger to human health.
Foam concrete is a very fluid, lightweight cellular concrete fill material, produced by blending a cement paste (the slurry or mortar), with a separately manufactured, preformed foam. The density of foam concrete is determined by the ratio of foam to slurry and densities range typically between 300 and 1600 kg/m3. Sand, pulverized fuel ash (PFA), quarry dust, or limestone dust may be used to further enhance the properties of foam concrete. Foam concrete is created by a uniform distribution of air bubbles throughout the mass of concrete. The foam cells must have walls, which remain stable during mixing, transportation, pumping, and placing of fresh concrete. The cells or bubbles are discrete and range in size between 0.1 and 1 mm. Foam concrete is free-flowing and can be placed without compaction.
Recently, sound and heat insulation has become important in order to prevent noise, which is environmental pollution, to provide soundproofing of interior walls and industrial structures, and to reduce our country's dependence on foreign energy needs. Therefore, it is important to develop and produce thermal insulation materials with higher energy efficiency with fewer resources in the production and usage stages. Therefore, the importance of cellular lightweight concrete material has increased in today's conditions.
Foam concrete can be easily cut into desired dimensions without scattering with a sharp saw.
Foam Concrete technical specifications
Foam concrete can be produced by adjusting foaming agents of different densities (400-1600 kg/ m³) at appropriate dosages. It has closed air spaces, which are independent of each other, at the rate of 75%-80% of its volume. It has features such as high fluidity, low unit weight, minimal use of aggregates, and low strength. The most important feature is that the air-gapped structure, which provides heat and sound insulation, is composed of closed cells, thus providing water insulation. Thanks to its heat and sound insulation, it can be used as an alternative material instead of the building elements used in the interior and exterior walls and floors of all buildings. In addition, it is possible to use it with room partitions, infill, and load-bearing walls. It can also be used where higher strength is required, i.e. road subfloors, floor, and roof coverings. Since the unit volume weight of foam concrete, which is a cellular lightweight concrete type, is lower than normal concrete, the dimensions of the bearing elements will also decrease with the decrease of the dead load in the structures, and a decrease in the overall weight of the structure will occur. With the decrease in the overall weight of the structure, the cost will be reduced, but the most important in terms of engineering is the effect of the dynamic forces that will occur during the earthquake event will decrease. Buildings will be more resistant to earthquakes by reducing the stresses caused by these dynamic effects. Foam concretes have good heat and sound insulation properties. At the same time, the share of use in the construction sector is increasing due to its features such as being fire resistant, easy to manufacture, and less labor needed.
Limitation of Foam Concrete
Foam concrete is difficult in finishing Project.
The process of mixing the concrete is difficult and costs more in terms of labor than that of normal concrete.
The parts for foam concrete are harder to find when compared with ordinary cement or concrete, hence the higher cost.
It is difficult to mix and finish the Project when it is not supported by proper tools or equipment for mixing and finishing purposes. Also, the pressure is low while mixing foam concrete and hence need special equipment to mix it to achieve an acceptable density during the process.
It is difficult to ace the strength of finished structure during the completion phase.
Since foam concrete is a mixture of different materials, it varies depending on each product (such as sand, cement, water and additives etc.).
It may have a problem when applied on uneven surfaces such as brick. Due to the fact that it doe not have a uniform density during the process and hence may splay out the sometimes causes problems in finishing or installation phases of these structures.
Foam concrete has very low compressive strength and hence may not be as strong as normal concrete.
Foam concrete is not as resistant as to destructive agents like acid, oils and grease. In order to protect it fa from these issues, ypu have to apply protective coat on the surface of foam concrete before the usage or installation phase.
Foam concrete has a relatively high paste content and no coarse aggregate, it will shrink more than normal concrete.
The durability of foam concrete is mainly influenced by the ratio of the connected pore to total pore.
Since it has higher cement content than normal concrete. So it becomes costly.
