Walls from aerated concrete blocks: characteristics, structural and operational features

Aerated concrete blocks are becoming more and more common in contemporary construction because of their special combination of strength and low weight. By adding gas bubbles to the concrete mixture, these blocks are made of a material that is both easy to work with and sturdy. The adaptability and effectiveness of aerated concrete blocks are valued by contractors and home builders.

The superior thermal insulation of aerated concrete blocks is one of their most notable features. By controlling interior temperature, the air pockets in the blocks lessen the need for extra insulation and increase the energy efficiency of homes. This feature helps to maintain a comfortable living environment all year round, which is especially helpful in areas with extreme weather.

Despite their light weight, aerated concrete blocks have remarkable load-bearing capabilities structurally. Because they can be used to build both load-bearing and non-load-bearing walls, they are an adaptable option for a range of architectural styles. Their consistent size and shape also aid in quicker construction times and better craftsmanship.

Aerated concrete blocks are also well-known for their ability to withstand fire and absorb sound. Because these blocks are heat-resistant, they offer an extra degree of security in the event of a fire. Moreover, their density contributes to the creation of quieter interior spaces by minimizing noise transmission. Aerated concrete blocks are a well-rounded choice for creating sturdy and cozy homes because of these functional characteristics.

Characteristic	Description
Material	Aerated concrete blocks are lightweight, porous, and made from cement, lime, sand, and water.
Insulation	These blocks offer excellent thermal insulation, keeping homes warm in winter and cool in summer.
Strength	Aerated concrete is strong enough for most residential buildings, but may require reinforcement for larger structures.
Ease of Use	The blocks are easy to cut and shape, allowing for quick and efficient construction.
Cost	Building with aerated concrete blocks is cost-effective due to their affordability and reduced need for additional insulation.
Soundproofing	The porous nature of the blocks provides good sound insulation, making homes quieter.
Environmental Impact	Aerated concrete blocks are eco-friendly, using less raw material and energy in production compared to traditional concrete.
Durability	They are durable and resistant to fire, pests, and mold, ensuring long-lasting walls.

What are gas concrete blocks

When sodium sulfate and caustic soda react with aluminum powder or paste, pores are created in the concrete, resulting in aerated concrete. It can harden in the presence of high temperatures in an autoclave or in natural settings.

Since the conditions of handicraft production do not allow for the second option, the fact that the blocks hardened in an autoclave speaks volumes about the volume and gravity of the production.

These products have homogeneous composition, best characteristics, and more accurate dimensions. About the composition, by the way.

Aerated concrete can be filled with fly ash from thermal power plants or quartz sand, a silica component. This information comes from GOST. In the second scenario, the manufacturer must name the component (aerated ash concrete) in the mixture’s name.

Note: The external color of the blocks made from it will differ from those made from conventional concrete. The only difference is that ash gives them a gray tint. Aerated concrete walls are exactly the same as regular aerated concrete in terms of technical and other features. Additionally, the cost is essentially the same.

Porous structure – is it good or bad?

The material could not hold a prominent position in the construction industry if it lacked notable benefits. And the preceding decades have already demonstrated its positive attributes.

• Durability. In low-rise housing construction, the walls do not experience dynamic loads, as in industrial buildings, so increased strength is not required from them. The heaviest thing that could be loaded on them is reinforced concrete floor slabs, which are usually abandoned in standard projects in favor of metal or wooden beams.

Because it is against building codes to erect aerated concrete basement walls, slab floors are typically provided above the basement floors. Other loads are not heavy enough to be supported by gas block masonry.

Note: Gas blocks are exclusively utilized in multi-story buildings to fill in the spaces between the supporting reinforced concrete frame’s structures when enclosing them.

• Weight. Since there is no large aggregate in cellist concrete, products from it have a much smaller share than that of blocks from any other concrete. The weight, of course, depends on the density of the stone and its dimensions, but in the most popular version D600 600*200*300 mm it is only 28 kg.

When compared to brick, the larger format enables you to build an aerated concrete wall more quickly, and the masonry material’s small mass allows for work to be completed with just basic lifting tools.

• Thermal conductivity. With a density of 600 kg/m3, aerated concrete has a thermal conductivity coefficient of 0.17-0.18 W/(m K), which is very close to wood. This is three times less than that of a hollow brick and five times less than that of a solid brick. The same thing happens if you compare it with expanded clay concrete. So, the walls of a house made of aerated concrete 400 mm thick, with correctly calculated external insulation, will be as warm as wooden ones.
• Ease of processing. Due to the relatively low density of porous stone, it is easy to saw, drill or grind it with your own hands to give it the desired shape – for example, an arched one.

• Vapor permeability. The body of an aerated concrete stone is permeated by many pores that have an open structure. On the one hand, this increases hygroscopicity, and on the other hand, it allows air to circulate. External walls made of aerated concrete allow you to create the same comfortable microclimate in the house as in a log house, except that there is no aroma inherent in wood. By the way, the presence of pores in aerated concrete makes enclosing structures practically soundproof.

Disadvantages and ways to mitigate them

Aerated concrete’s primary drawback is one of its own benefits. Because there are open pores, there is a high coefficient of water absorption. As such, keeping moisture away from aerated concrete walls is crucial.

To accomplish this, you’ll need:

1. Under no circumstances should the material be used for the construction of basement and plinth walls. These structures should be either traditional reinforced concrete monolith or blocks, or red clay bricks.
2. To avoid capillary suction of moisture, it is necessary to provide a double layer of waterproofing between the first row of masonry and the plinth (usually roofing felt is glued to bitumen-polymer mastic).
3. External wall decoration is required, despite the aesthetic appearance of the masonry. It is important that a ventilated gap is provided under the finishing layer, which will prevent the formation of condensation, or the decorative material itself (for example, plaster) is vapor-permeable. Under the cladding, if these are panels, a layer of water-proof and windproof membrane is mounted.
4. In the case when a sealed finish is made on the outside with a dense material – tiles on glue or bricks with wells filled with polyurethane, the internal walls made of aerated concrete must have a finish that will prevent steam from penetrating into the thickness of the masonry. That is, if steam cannot escape from the walls, then it should not get into them.

Shrinkage: is it so terrible

The development of masonry cracks is one of the drawbacks of aerated concrete. This occurs most frequently during the foundation shrinkage period, which can affect any building because it is related to the material—in this case, cement stone—losing moisture.

It should be noted that the shrinkage rate of aerated concrete is only 3 mm/m2, which is four times less than that of lumber. The foundation for aerated concrete walls needs to be properly calculated and installed in order to reduce the effects.

If the house is on piles, a reinforced concrete grillage is an option, but a monolithic strip or slab is preferable. The best way to level out soil mobility during spring thawing, which is the root cause of cracks, is with a monolith.

Features of reinforcement

Is reinforcing aerated concrete walls necessary? is a question that piques the interest of many people. Yes, it is required. The best defense against the emergence of shrinkage cracks is the reinforcement in addition to properly positioned lintels above door and window openings.

Masonry reinforcement ought to be carried out:

1. in the second row;
2. in every fourth row;
3. in the window sill zone with an entry into the thickness of the masonry by 90 cm;
4. in the support zones of the lintels;
5. inside the reinforcing belt, if the floors are planned to be made monolithic or slab.

In order to provide inter-row reinforcement, periodic rod reinforcement AIII with an 8 mm diameter is placed in grooves that have been specially designed to prevent the seam from becoming thicker. The most common type of reinforcement is steel because it is more pliable.

• However, fiberglass (composite) reinforcement is also often used. It cannot be bent and is not connected by welding, and specially designed factory sleeves are used to reinforce corners.
• Composite reinforcement is not subject to corrosion, therefore it lasts longer than metal, and in addition, it does not create cold bridges, since fiberglass has a lower thermal conductivity coefficient than steel.
• In addition to rods, galvanized steel strip with a cross-section of 8 * 1.5 mm, or a 3 mm thick mesh made of wire – or the same fiberglass can be used to reinforce the masonry.
• If a house is being built in a zone of increased seismicity, along with horizontal reinforcement, vertical reinforcement can also be performed. In this case, the rods, monolithic at one end in the foundation, are passed through the entire wall.
• Vertical reinforcement is placed in corner areas and at the intersections of walls, with an indentation from their ends of at least 20 cm, and 60 cm from window openings.

Via ducts, hollow ventilation blocks composed of aerated concrete are built. They can also be used to install ventilation ducts, though many people find that ceramic bricks work better in this regard.

U-shaped blocks are available from all aerated concrete block manufacturers; they can be used to pour reinforcing belts or to install lintels.

Adhesion problems

The poor surface adhesion of aerated concrete to adhesive and plaster compositions, particularly those based on gypsum, is a drawback of the material. Therefore, the base needs to be impregnated twice with a deep penetration primer before painting, gluing plasterboard, applying wallpaper, or installing tiles on aerated concrete walls.

Installing a fiberglass mesh beneath tiles and gypsum plaster is preferable since it will shield the ornamental material from the same kinds of cracks that can occur on aerated concrete. Regardless of the type of plaster, fiberglass mesh is installed when plastering externally.

Features of fastening

Another drawback of concrete’s cellular structure is the base’s poor strength, which makes it difficult to fasten objects to it. You need a specific fastener for this; dowel-nails, which are used for heavy concrete and brickwork, won’t work in this situation.

Porous bases require special dowels to be made. This could be a spiral-shaped plastic sleeve or a spacer mechanism that, once installed in the hole, cannot be removed.

The dowel can be driven in or screwed in, depending on the design of the ribs and tip.

Options for fasteners for interior work are shown in the above photo. Special anchors that can sustain pullout loads of 100 kg or more are more frequently used for exterior work, such as installing a ventilated facade. The particulars of the task at hand determine which fasteners are best.

Parameters and methods of insulating aerated concrete walls

Cellular block masonry is only used to build structures up to three stories high due to its low strength indicators. If it is higher, it will only be so if a reinforced concrete frame supports it. A floor’s height can reach 3.6 meters, but this is typically reserved for offices; in residential buildings, the maximum is typically 3.3 meters.

The maximum length of an aerated concrete wall cannot be determined because it is a function of both the building’s length and design standards, and it cannot be stated in absolute terms. On this account, the primary SNiP requirement is that the wall be fastened every six meters to transverse structures, pillars, or columns.

Based on the area’s average winter temperature, the density of the aerated concrete, and the kind of material used for external cladding, a heat engineering calculation determines the thickness of the walls and whether or not to insulate them.

Since there can be many variations, we won’t get into calculations and will just list a few common schemes:

We also recommend watching the video in this article, which shows you how to construct walls out of aerated concrete as explained by a professional.

Because of their special qualities, aerated concrete blocks are a great option for modern construction. They are easy to handle and perfect for rapidly and effectively building walls because they are robust but lightweight. Because of the material’s excellent thermal insulation and porous structure, energy savings and a cozy interior atmosphere are achieved.

Aerated concrete block walls are very sturdy and stable structurally. Because of the identical size and shape of the blocks, air leaks are minimized and less additional insulation is required to ensure a tight fit. Better structural integrity and increased energy efficiency are the results of this.

Because aerated concrete blocks are simple to work with, construction projects can be completed more quickly. Simple tools can be used to cut and shape them, allowing for on-site customization and adjustments. These environmentally friendly and fire-resistant blocks also provide modern buildings with sustainability and safety.

In conclusion, there are many advantages to using aerated concrete blocks for wall construction, ranging from sustainability and ease of use to energy efficiency and safety. They are a great option for many different types of construction projects because of their versatility.

Aerated concrete blocks are a well-liked option for walls because of their special blend of durability, insulation, and light weight. In order to demonstrate why aerated concrete blocks are a practical and affordable choice for contemporary building, this article examines the essential features of aerated concrete blocks, their structural advantages, and their performance under varied operating conditions.

Video on the topic

6 rules for building from aerated concrete blocks. For novice builders and professionals #shorts #homebuilding

Correct laying of walls from aerated concrete

Do-it-yourself laying of internal walls from aerated concrete