Characteristics of thermal conductivity of foam concrete

Because of its exceptional insulating qualities, foam concrete is a versatile building material that has become more and more well-liked in recent years. Foam concrete is a great material for energy-efficient construction because of one of its biggest benefits: it conducts heat well. Having a thorough understanding of foam concrete’s thermal conductivity properties can assist architects and builders in selecting the material for a variety of applications.

The term "thermal conductivity" describes a material’s capacity to transfer heat. Because of the particular composition of foam concrete—a mixture of cement, water, and foam—many air pockets are formed inside the substance. These air pockets offer superior thermal insulation by drastically lowering heat transmission. Thus, fewer additional heating or cooling systems are required in buildings made of foam concrete since the interior temperatures can be maintained more steadily.

The energy savings that result from foam concrete’s low heat conductivity are an additional advantage. Foam concrete can assist in reducing energy consumption and, thus, energy costs by enhancing a building’s insulation. Because of this, it’s a desirable choice for homeowners and builders who want to create more eco-friendly homes without sacrificing comfort.

The thermal characteristics of foam concrete can also lengthen a building’s overall lifespan and durability. Good insulation shields buildings from temperature changes that can cause traditional building materials to expand and contract over time, causing wear and tear. Foam concrete helps preserve the integrity of buildings by reducing these effects, guaranteeing that they will continue to be strong and dependable for many years to come.

In conclusion, foam concrete’s low heat conductivity has a number of advantages, such as improved durability, improved insulation, and energy efficiency. These qualities make it the perfect material for contemporary building, meeting the rising need for affordable and environmentally friendly building solutions. For those looking to build more wisely and sustainably, foam concrete offers a useful alternative for projects that are residential, commercial, or industrial.

Scope

While foam concrete is relatively new in our country, it has already established a strong reputation as a respectable substitute for traditional building materials in the West, where it has been actively used for several decades. Brick and concrete are still superior in multi-story construction because of their lower strength, which is the only real disadvantage.

Foam concrete is advised for construction of houses no taller than two stories.

Buildings over two stories can be constructed by combining "concrete frame + foam blocks," although this is a rare option. Foam concrete is primarily used in low-rise buildings, such as homes, garages, utility rooms, and commercial and industrial structures.

Foam concrete manufacturing technology

This construction material, which is a cellular variant of traditional concrete, is composed of the following elements:

cement;
water;
sand;
synthetic foaming agent;
additives that improve the performance properties of the material.

There are currently three methods used to create foam concrete.

The traditional technique uses a foam generator, a specialized tool, to feed foam into cement mortar. After the mixture is well combined, it is put in a particular chamber to solidify and maintain a specific temperature. Cellular concrete, the result, is regarded as the best because it is dependable, long-lasting, and of the highest quality.

It will cost a lot of money to buy the tools you need, and it will take a long time to make foam concrete at home.

When applying the dry mineralization method, foam is first added to the dry mixture, and water in the appropriate amounts is added only after the mixture has been thoroughly mixed. This process is typically applied in continuous manufacturing. Although the cellular concrete produced in this manner has better durability, it has worse thermal conductivity properties.

The foaming agent and water are combined first in the barotechnology method, and the other ingredients are added to the resulting mixture only afterward. Pressure chambers, which guarantee the mixing process under excessive pressure, are used to produce foam blocks of a quality that is acceptable. Although it doesn’t involve heating, the hardening process usually takes a lot longer, and the material may shrink or even crack.

Every single block is distinguished by a closed structure of air pores, which guarantees its superior thermal insulation qualities regardless of the manufacturing process employed.

Foam concrete is a popular choice in construction because of its excellent thermal insulation properties. Its special cellular structure filled with air bubbles causes its thermal conductivity, which measures how well it conducts heat, to be significantly lower than that of conventional concrete. Because of these air pockets, buildings stay warmer in the winter and cooler in the summer. This feature not only improves energy efficiency but also lessens the requirement for additional insulation materials, which supports sustainable building practices.

Main characteristics of cellular concrete

The following foam concrete grades are differentiated based on density:

Thermal insulating cellular concrete is represented by grades D300-D500. Low density (about 300-500 kg / cubic meter) provides standard-sized blocks with low weight (12-19 kg) and low thermal conductivity. Since the strength of such foam blocks is low, they are used exclusively to form a thermal insulation layer;

Table showing how foam concrete compares to other materials

Structural and heat-insulating foam concrete (grades D600-800), having the appropriate density and block weight within 25-35 kg, is characterized by an optimal strength-thermal conductivity ratio, therefore this grade is predominant in low-rise construction;
Structural cellular concrete is blocks of grades D900-1200, characterized by a weight of 40-47 kg and a density of 900-1200 kg/cubic meter. They are moderately strong and resistant to compression, therefore (with certain restrictions) they can be used in multi-story construction, requiring an additional layer of insulation;
Structural porous foam blocks (grades D1300-1600) are distinguished by high strength, allowing the construction of buildings of unlimited number of storeys, but they are not manufactured on an industrial scale.

Thermal conductivity

The capacity of a building material to conduct heat is its second most crucial feature. In addition, there is an inverse relationship between foam concrete’s strength indicators and its thermal conductivity.

The best natural material for thermal insulation is air. An order of magnitude less heat conductivity than that of concrete or brick was achieved by reducing the thermal conductivity of a foam concrete block to 0.08 W/m°C thanks to the block’s structure’s abundance of air-filled pores.

Thermal conductivity is a crucial consideration when selecting a material.

Since this digital indicator doesn’t tell much to the average user, we’ll compare the features of cinder blocks, ceramic brick, and foam concrete instead: For a wall to have a thermal conductivity of approximately 0.18 W/m°C, a 300 mm-thick layer of D700 foam concrete is needed. The wall thickness for cinder blocks will already be 1080 mm, and for red brick, it will be 1400 mm.

Compressive strength

The range of applications for cellular concrete is directly influenced by its strength properties. Thermal insulation blocks are robust enough to support the slabs and beams of low-rise buildings, and structural ones can be used in the construction of multi-story buildings, provided that thermal insulation grades of foam concrete—which have low compressive strength and low thermal conductivity—are only utilized as a thermal insulation layer.

A table that compares various foam concrete grades

Grades of foam blocks’ compressive strength (kg/sq. cm):

D400 – 9;
D500 – 13;
D600 – 16;
D700 – 24;
D800 – 27;
D900 – 35;
D1000 – 50;
D1100 – 64;
D1200 – 90.

The accuracy of the geometric dimensions of the blocks and the existence of internal voids are two equally significant characteristics of cellular concrete. The latter factor determines how much masonry mortar is used: if uneven blocks are used, the seam must be thickened from 3 to 10 mm, which results in the formation of "cold bridges" and a reduction in the building’s energy efficiency.

Characteristic	Description
Thermal Conductivity	Foam concrete has low thermal conductivity, making it a good insulator.
Density	The density of foam concrete affects its thermal conductivity; lower density means better insulation.
Moisture Content	Higher moisture content can increase thermal conductivity, reducing insulation properties.
Temperature Range	Foam concrete maintains its insulating properties across a wide temperature range.
Application	Commonly used in walls, roofs, and floors for its insulating properties.

Because of its exceptional thermal conductivity, foam concrete is a particularly useful building material. Because of this feature, it is very effective at insulating and creating a cozy interior while using less energy. Its capacity to sustain steady temperatures is one of the factors boosting its acceptance in energy-efficient building projects.

The density of foam concrete affects how thermallyconductive it is. Because of the increased air content trapped in the material, foam concrete with a lower density provides superior insulation. Heat transfer is slowed down by the thermal barrier that this air creates. Low-density foam concrete buildings thus require less heating and cooling, which over time results in significant energy savings.

Additionally, foam concrete is not only effective but also eco-friendly. Compared to conventional concrete, it usually requires less energy and raw materials during the production process. Because of its insulating qualities and sustainable nature, foam concrete is a great material for contemporary, environmentally conscious building projects.

In conclusion, foam concrete is a great material for building ecologically friendly and energy-efficient structures because of its advantages in thermal conductivity. Its capacity to offer efficient insulation lowers energy expenses and advances a more sustainable future. In the construction industry, foam concrete is expected to be very important as the need for green building solutions grows.