What are gas silicate blocks, their characteristics, pros and cons

In the construction industry, gas silicate blocks are becoming a popular option because they provide an effective and affordable way to build walls and other structures. A small quantity of aluminum powder is added to a mixture of sand, lime, cement, and water to create tiny gas bubbles, which is how these blocks, also called aerated concrete blocks, are made. This procedure yields a building material that is robust, long-lasting, and lightweight.

The superior thermal insulation qualities of gas silicate blocks are among their main advantages. The blocks are the perfect option for energy-efficient buildings because of the gas bubbles that are trapped within them, which help to reduce heat loss. Furthermore, because they are lightweight, they are simple to handle and install, which reduces labor costs and construction time.

But, gas silicate blocks have benefits and drawbacks just like any other building material. Positively, because of their manufacturing process, they are environmentally friendly, fire-resistant, and provide good sound insulation. Unfortunately, they can absorb moisture more easily and in some cases, extra waterproofing measures might be needed.

For your upcoming building project, knowing the features, benefits, and drawbacks of gas silicate blocks will help you make an informed choice. These adaptable blocks come with a number of advantages that can be tailored to your needs, regardless of whether you’re building a new home or remodeling an old one.

What are the blocks gas silicate

Products made of aerated concrete blocks are a contemporary building material composed of the following raw materials:

• Portland cement, which is a binding ingredient;
• quartz sand, introduced into the composition as a filler;
• lime, participating in the gas formation reaction;
• powdered aluminum, added for foaming the mass.

A chemical reaction takes place as the components are mixed, increasing the volume of the working mixture.

Molding containers with silicate mixture inside harden in different ways:

• naturally at ambient temperature. The hardening process lasts 15-30 days. The resulting products are characterized by reduced cost, but have insufficiently high strength;
• in autoclaves, where products are heated at elevated pressure. Steaming allows to increase the strength characteristics and specific gravity of gas silicate products.

Indicators of density and strength vary based on the manufacturing process. The area of use is determined by the materials’ specified properties.

There are several categories for blocks, including:

• products for structural purposes. They are designated by the D700 marking and are in demand for the construction of capital walls, the height of which is no more than three floors;
• thermal insulation and structural products. The D500 mark corresponds to these blocks. They are used for the construction of internal partitions and the construction of load-bearing walls of small buildings;
• thermal insulation products. They are characterized by increased porosity and a density reduced to D400. This allows the use of aerated concrete material for reliable thermal insulation of walls.

The weight of one cubic meter of aerated concrete, expressed in kilograms, is represented by the digital index in the block marking. The material’s ability to insulate against heat declines with density. Traditional bricks are gradually being replaced by products under the D700 brand, and products with a density of D400 have thermal insulation qualities that are on par with those of contemporary insulation materials.

Popular building materials, gas silicate blocks are recognized for their insulating, lightweight, and fire-resistant qualities. These blocks, which are composed of a lime, sand, and water mixture, are aerated to produce tiny air pockets that improve their thermal efficiency and make them easier to handle. They have a number of benefits, such as easy installation and superior sound absorption, but drawbacks as well, such as being easily damaged by moisture and needing to be handled carefully. All things considered, gas silicate blocks are a flexible and effective choice for contemporary building projects.

Gas silicate blocks – advantages and disadvantages of the material

Products made from gas silicate have several important benefits. The primary benefits of blocks made of gas silicate:

• reduced weight with increased volumes. The density of gas silicate material is 3 times less than that of brick and about 5 times lower when compared with concrete;
• increased safety factor, allowing it to withstand compressive loads. The strength index for a gas silicate block marked D500 is 0.04 t/cm³;
• increased thermal insulation properties. The material successfully competes with annealed brick, the thermal conductivity of which is three times higher than that of gas silicate;
• the correct shape of the blocks. Due to reduced tolerances for overall dimensions and clear geometry, the blocks are laid on a thin layer of adhesive mortar;
• increased dimensions. Using large-sized silicate blocks with a small weight for the construction of building walls allows to reduce the duration of construction;
• good workability. If necessary, it is easy to give the aerated concrete block a given shape or cut the block material into separate blanks;
• reasonable price. Using block aerated concrete for the construction of a cottage, private house or summer house, it is easy to significantly reduce the estimated cost of construction activities;
• fire safety. The blocks do not ignite when heated and exposed to open fire. They belong to low-flammability building materials included in the flammability group G1;
• high soundproofing properties. They are provided due to the porous structure. In terms of the ability to absorb external noise, the blocks are ten times superior to ceramic bricks;
• environmental friendliness. No toxic ingredients are used in the manufacture of aerated concrete mixture and no components harmful to health are released during operation;
• vapor permeability. Air exchange occurs through the air cells located inside the aerated concrete massif, creating a favorable microclimate inside the building;
• frost resistance. Gas silicate blocks retain the structure of the massif and operational characteristics, withstanding more than two hundred cycles of prolonged freezing followed by thawing;
• heat storage properties. Gas silicate blocks are an energy-saving material that can accumulate thermal energy and gradually release it to increase the room temperature.

Gas silicate blocks have drawbacks despite their many benefits. The material’s primary drawbacks are:

• increased hygroscopicity. Porous gas silicate blocks gradually absorb moisture through an unprotected surface, which destroys the structure and reduces strength;
• the need to use special fasteners for fixing hanging furniture and equipment. Standard fasteners do not provide reliable fixation due to the cellular structure of the blocks;
• insufficiently high mechanical strength. The block material crumbles under load, therefore it requires careful handling during transportation and laying;
• mold formation and development of fungal colonies inside and on the surface of the blocks. Due to increased moisture absorption, favorable conditions are created for the growth of microorganisms;
• increased shrinkage value. In real operating conditions, under the influence of loads, the blocks gradually shrink, which causes cracks to form after some time;
• reduced adhesion with sand-cement plasters. It is necessary to use special finishing compounds for plastering aerated concrete.

Aerated concrete blocks are still widely utilized in the low-rise construction industry to construct capital walls, insulated walls for multi-story buildings, and thermal insulation for a variety of structures, in spite of their current drawbacks. Aerated concrete blocks are preferred by private developers and professional builders because of their many benefits.

Aerated concrete block D500 – characteristics of the building material

The D500 brand’s structural and thermal insulation block serves a number of functions.

• construction of low-rise building frames;
• arrangement of interior partitions;
• reinforcement of door and window openings.

After deciding to buy block silicate with the D500 mark, you should thoroughly familiarize yourself with the functional characteristics of this widely used building material. Let’s focus on the primary features.

Strength properties

The compressive strength class of the material is contingent upon the block manufacturing technique employed:

• D500 aerated concrete, obtained by the autoclave method, is characterized by a strength index of B2.5-B3;
• the compressive strength class for similar blocks produced using non-autoclave technology is B1.5.

The D500 blocks’ strength is only 4 MPa, which is not a strong enough signal. A mesh or other reinforcement is used to reinforce the masonry in order to stop the aerated concrete material from cracking. Block construction materials can be used in low-rise buildings because of their relatively low safety factor. Gas silicate blocks are used in conjunction with bricks to provide thermal insulation for walls that are built in multi-story buildings.

Specific gravity

One crucial performance metric that describes the porosity of the block massif is the density of gas silicate blocks. A digital index and a marking in the shape of the Latin letter D are used to represent density. The weight of one cubic meter of gas silicate is represented by the number in the marking. Therefore, 500 kg is the weight of one cubic meter of gas silicate bearing the D500 marking. It is simple to determine the load on the foundation base if one knows the product marking by density, the size of the blocks, and their quantity.

Thermal conductivity characteristics

The capacity of gas silicate blocks to transfer thermal energy is known as thermal conductivity. The indicator’s value describes the gas silicate blocks’ thermal conductivity coefficient.

Depending on the amount of moisture in the material, the coefficient’s value varies:

• the coefficient of thermal conductivity of dry aerated concrete material grade D500 is 0.12 W/m⁰C;
• with an increase in humidity to 5%, the thermal conductivity of D500 blocks increases to 0.47 W/m⁰C.

Because aerated concrete has a lower heat conductivity than other building materials, it maintains a pleasant microclimate year-round in buildings made of it.

Frost resistance

The marking indicates how well aerated concrete blocks resist temperature variations brought on by deep freezing and thawing. For D500 products, the frost resistance index is F50. In light of other varieties of composite concrete, this is a reasonably reliable indicator. The amount of moisture in the blocks has an impact on frost resistance. The blocks’ ability to withstand frost increases as the material’s humidity falls.

Service life

Gas silicate is used for a very long time. For over fifty years, the structure of the gas silicate massif remains intact. As long as the blocks are shielded from moisture absorption, the manufacturers guarantee a service life of 60 to 80 years. You can increase the material’s service life by plastering it.

Fire safety

Gas silicate blocks have a 400 °C fire resistance, making them a fireproof building material. A plastered gas silicate wall can endure an open fire for three to four hours, according to tests. Blocks can be used to build chimneys, walls, and partitions that are resistant to fire.

Building materials that are both efficient and adaptable, like gas silicate blocks, are becoming more and more common in contemporary architecture. Their distinct qualities, which include their low weight, superior thermal insulation, and ease of handling, make them popular with both homeowners and builders. These blocks are made of a lightweight yet durable material called aluminum powder mixed with water, sand, and lime to produce gas bubbles.

The superior insulation qualities of gas silicate blocks are one of their main benefits. They can result in significant energy savings by assisting in the maintenance of a constant interior temperature and minimizing the need for additional heating and cooling. Furthermore, because of their light weight, they are simpler to handle and transport during construction, which expedites the building process and lowers labor costs.

Gas silicate blocks do have some disadvantages, though. Compared to other building materials, they may be more prone to absorbing moisture, so in damp environments, extra precautions may be needed. Furthermore, even though they are reasonably strong, in heavy-duty applications they might not be as durable as traditional concrete blocks.

All things considered, gas silicate blocks present a fair mix of advantages and drawbacks. Though their susceptibility to moisture and durability considerations should be taken into account during the planning process, their excellent thermal insulation and ease of use make them a practical choice for many building projects. Through comprehension of these attributes, builders can make well-informed choices and efficiently employ gas silicate blocks in their construction undertakings.

Video on the topic

Gas silicate house Buying gas silicate blocks Pros and cons Part 1

Comfortable climate in a BIG house! / What are multi-zone split systems?

Gas silicate walls of the house after 7 years