Cellular concrete wall blocks: technical characteristics of the material, types and manufacturing features

A growing number of builders are selecting cellular concrete wall blocks for their lightweight and adaptability. These blocks, sometimes referred to as aerated concrete blocks, have a number of benefits that make them a worthwhile choice for a range of construction projects.

The composition and manufacturing process of cellular concrete give it its distinct qualities. These blocks, which are composed of cement, lime, water, and a foaming agent, are highly regarded for their superior soundproofing and thermal insulation qualities. Compared to conventional concrete blocks, they are simpler to handle and transport due to their lightweight design.

Cellular concrete blocks come in a variety of forms, each ideal for a particular use case. In order to ensure maximum performance and durability for your project, it can be helpful to understand the technical features and production processes of these blocks.

For contemporary building, cellular concrete wall blocks provide a flexible and effective option. These blocks are well-known for being lightweight and having superior thermal insulation qualities, which make them perfect for a variety of construction uses. Comprehending the technical attributes of cellular concrete, encompassing its diverse varieties and the production procedure, facilitates the appropriate selection of material for particular construction requirements and guarantees peak efficiency in your undertakings.

General description of the material, features of the composition and production technology

Cellular concrete is a collection of materials, as was previously mentioned. Foam and aerated concrete, as well as foam aerated concrete, which combines both manufacturing technologies and, consequently, properties, are its representatives.

A brief word on the composition now. GOST 21520-89 Small cellular concrete wall blocks governs it.

• Such blocks are obtained from a mixture of cement, lime, sand, foaming agent, plasticizer and other additives that improve the quality of the future material.

• In essence, this is a mixture of a siliceous component, liquid, binder and additives that cause swelling of the solution and, as a result, the formation of cells.
• Not only sand, but also highly basic ash and other industrial waste can act as a silica component.
• The main binder, in addition to cement, can be: slag, mixed binder, ash, lime.
• As a rule, cement should be used of grade no lower than 400-500.
• Sand is mainly added quartz.
• Plasticizers are used to increase the plasticity of the solution. In this case, the blocks are of better quality. They are protected from cracking at the production stage.
• If we talk about foam blocks, then the formation of cells in the solution occurs due to the addition of a foaming agent. In the case of aerated concrete, everything is somewhat different. Pores are formed as a result of the reaction of aluminum powder and quicklime.

• As a result, the pore structure of the materials is different: foam blocks are closed, and aerated concrete blocks are open. This also affected some of the property values.

Kindly take note! The mixture’s preparation ratio has a direct impact on the outcome. For instance, foam blocks with less cement or more porous gas will weigh less. They will also have low density and strength indicators, as well as a low thermal conductivity coefficient.

There are several methods for building strength. Here are a few of them:

• Use of specialized additives;
• Use of sand as a silica component, not ash.
• Adding a larger amount of binder in percentage terms;
• Autoclave treatment makes the material more durable and resistant to mechanical stress.

Regarding the manufacturing procedure, the release of both kinds of blocks is comparable.

1. First, the solution is mixed, which is then sent to the molds.
2. They are filled approximately one third, since swelling of the mixture can lead to overflow.
3. After the pore formation process is complete, the product should harden a little.
4. Then the formwork is removed.
5. The last stage depends on which hardening method will be used. This can be autoclave treatment or drying in natural conditions.

Aerated concrete and foam that hardens with hydration can be made by hand. The cost of construction will be greatly decreased by doing this. The usage of the instructions above is highly appropriate.

A brief note regarding the tools utilized. A stationary line of equipment or a series of conveyor-type machines are the two options available for producing foam and gas blocks in a factory.

In the first scenario, production will be automated and as economical as feasible, with a daily production volume of up to 200 or 300 cubic meters.

In the second scenario, there will be a much smaller volume and a greater need for outside labor, but the cost will be lower.

A full set of molds and a mixer will suffice if the wall block is made at home. Additionally, a mobile unit that can produce up to 20 m3 per day can be purchased.

Characteristics of foam and gas blocks

Now that we have a basic understanding of the raw material composition and technological process, it is time to focus on the primary characteristics of the material and their numerical values.

All manufacturers of the material are required to abide by a number of requirements set forth by GOST. Due to intense competition, all of them are attempting to set themselves apart from the competition by upgrading their manufacturing processes and altering the ratios of raw materials to enhance their core offerings. Let’s look at the lowest that the standard permits and the highest that manufacturers provide.

Technical and operational properties

Let’s examine the primary characteristics of two members of the group of materials under consideration using the table.

Table 1 lists the technical specs of the cellular concrete small wall blocks.

Property name	Its value for foam and gas concrete blocks, comments
Frost resistance	The indicator is set by GOST. Minimum threshold – 25 cycles. Products intended for the construction of external walls must comply with this value in relation to the frost resistance grade.

The frost resistance of the thermal insulation type of material is also not standardized, and this value is not set for partition blocks.

In actuality, producers guarantee prospective buyers that the foam blocks can endure up to 100 cycles and the material up to 150 cycles.

Types of blocks and their application

Let’s take a quick look at the classifications.

As we discussed earlier, there are a few different ways to harden the block, including letting it harden naturally or by processing it in an autoclave. In the first scenario, high temperatures and pressures greater than atmospheric pressure are used to exert the impact.

The second scenario allows for the application of mild heat and moisture treatment, which enhances the qualities and speeds up the drying process.

The autoclave has several advantages over its rival, including:

• Frost resistance grade and durability;
• The ratio of strength, average density and heat retention capacity;
• The autoclave curing block has better geometry and a pure white color;
• It is less fragile.

However, it is important to note that hydration curing products have a marginally lower price—roughly 10% less.

There is another classification based on density.

• Blocks characterized by a density value of 300 or 400 kg/m2 are called heat-insulating. They are used, of course, in the process of thermal insulation.

Note: Monolithic material is also used for this, in addition to slabs and blocks. It is actively used in floor screeds, enclosing structures, and sound and heat insulation of roofs.

• If the products have a density value of 500, 600, 700, 800 or 900 (kg / m3), then they are structural and heat-insulating. With their help, you can build a wall of a building or a partition. They are great as the main material for low-rise construction.
• But if you decide to build a 3- or 4-story building, it is better to buy a gas-foam block with an increased strength and density index, that is, structural. They are able to withstand a more significant load, and with their help you can build a building several stories high.

Be aware that the foam concrete line also includes structurally porous products. They have a particularly high density. They are made to order, not in large quantities. Their existence is not mentioned in GOST.

Regarding the goal:

• Walls are erected using wall blocks;
• Partitions – using partition blocks;
• Stationary formwork can be constructed from U-shaped. They are also used in the installation of door and window openings.

Various accuracy categories for blocks can be assigned based on the size of allowed deviations. The image below displays the standard’s requirements.

Kindly take note! The category has a major impact on the future wall’s thermal conductivity. This is explained in very basic terms. Products from the first category, for instance, are placed on glue with as little seam thickness as possible. There aren’t many cold bridges as a result.

If third-category products are laid, an adhesive composition cannot be used; instead, a solution must be used, the thickness of which depends on the deviations from linear size. It has a 2 cm and 3 reach. There are consequently a lot more openings for cold penetration.

For this reason, it is advised to use the third category when constructing non-residential structures.

Wall blocks come in two surface options: smooth and ridged. In the latter scenario, building a nearly perfect surface will be possible and wall laying will be considerably simpler for the novice.

There are foam block products with a textured front surface as well. Acquiring one of these will free the developer from having to complete the building from the exterior.

Positive and negative sides of the material

Table 2: Benefits of aerated concrete and foam

• This fact indicates the possibility of saving on delivery by finding the nearest dealer in your region.
• The range of sizes will allow almost any developer to select the desired dimensions.
• The gallery below the table presents some of the most popular and largest manufacturers of products from this group of concretes.

Table 2: Drawbacks:

Useful tips for self-masonry work

Now that we are aware of every feature of the material, let’s work out how to use it properly to maintain these qualities.

Preparation of tools and material for masonry

The first step in masonry is to prepare the materials and tools. It is sufficient to purchase adhesive composition from a store if that is the chosen method of application. It’s a fairly broad range.

The following indicators, as listed by the manufacturer, should be observed:

• Viability of the mixture;
• Plasticity;
• Thermal conductivity;
• Resistance to temperature changes;
• Strength;
• Consumption.

For every m3, an average of 1.3–1.5 bags of mixture are consumed. Stock up on cement, water, and sand if you still choose to use a solution. For mixing, a concrete mixer is also required.

The following equipment is required:

Stages of building construction

Now, let’s talk about the phases of masonry work.

Table 4: Work stages for Masonry Technology

Given that the solution’s shelf life is limited, experts advise doing this as frequently as possible.

The video in this article, "Wall blocks made of cellular concrete d600," will walk you through the steps involved in installing common goods.

Calculation of the composition of the solution for masonry work

Aspect	Description
Density	Lightweight with densities ranging from 300 to 800 kg/m³.
Thermal Insulation	Excellent thermal insulation, helps in energy conservation.
Sound Insulation	Good sound insulation properties, reduces noise transmission.
Compressive Strength	Moderate compressive strength, generally between 2.5 to 7 MPa.
Types	Includes autoclaved aerated concrete (AAC) and non-autoclaved cellular concrete.
Manufacturing	Made from a mix of cement, lime, water, and an expanding agent, then cured in an autoclave or air-dried.

Because of their many advantages, cellular concrete wall blocks are a common option in construction. Their excellent thermal and acoustic insulation qualities, along with their lightweight design, make them effective in a variety of building applications.

Cellular concrete blocks come in a variety of varieties to meet a range of requirements. Standard blocks are ideal for everyday use, while special variants are made for better insulation or load-bearing applications. It is essential to comprehend the manufacturing process because it affects the performance and quality of the blocks. These blocks are guaranteed to hold their intended qualities over time thanks to the meticulous material blending and precise curing techniques.

Making the switch to cellular concrete blocks can result in lower energy costs and a cozier home. Their significance in contemporary building practices is highlighted by their versatility and efficacy in various construction scenarios.

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