Aerated concrete and gas silicate are two materials that are frequently mentioned when making construction decisions. Although both materials are well-liked for their ability to insulate and for being lightweight, they have key distinctions that may limit their applicability in certain situations.
The excellent thermal insulation and lightweight properties of aerated concrete are well-known. It is made by foaming the cement with an agent to produce a material that is full of tiny air bubbles. This structure is a popular choice for residential buildings because it is easy to handle and offers good heat insulation.
Conversely, gas silicate is a kind of aerated concrete that has undergone autoclaving. It is made by combining silica sand, lime, and a tiny bit of cement. It is then heated to a high pressure in an autoclave. Compared to ordinary aerated concrete, gas silicate blocks have a denser structure thanks to this process, which can increase their durability and capacity to support loads.
Depending on your unique requirements, you can choose between gas silicate and aerated concrete. Which material is best for your construction project will depend on factors like cost, thermal insulation, and load-bearing capacity. Having a better understanding of these variations will enable you to choose your building requirements more wisely.
Production technology
The primary ingredient used to make aerated concrete is an aqueous cement solution (Portland cement) supplemented with sand and lime.
The composition of gas silicate concrete, which has a cellular silicate structure, is a 0.62: 0.24 ratio of lime to sand.
Because of their porous structure, which is created when working mixtures with specific foaming agents (typically aluminum powder or paste) swell, gas blocks have excellent thermal insulation qualities. Vapors in the final product are bubbles that make up 70–90% of the material’s volume and have a diameter of 1-3 mm. They are filled with air, which serves as a heat-insulating layer because of its low thermal conductivity. The pores in premium blocks are spaced as evenly as possible.
In terms of hardening techniques, the primary factor that sets cellular aerated concrete apart from aerated concrete is the requirement for a steam heat treatment in an autoclave at a temperature between 180 and 200˚C and a pressure between 8 and 14 atmospheres. You can air-cure or autoclave aerated concrete.
The material sets much more quickly in an autoclave, gains strength, maintains its geometric shape, and experiences very little shrinkage while in use.
Aerated concrete and autoclaved aerated concrete have almost white exteriors, while non-autoclaved aerated concrete typically has a gray color.
Comparative characteristics of the parameters of aerated concrete and gas silicate
The following factors affect how porous building materials are compared:
- moisture absorption (hydrophilicity);
- frost resistance (expressed by the number of freezing-thawing cycles);
- density;
- thermal conductivity;
- compressive strength (mechanical strength);
- vapor permeability;
- masonry thickness.
The table below displays the average values for each parameter:
To select the best option for your project, it’s critical to comprehend the distinctions between gas silicate and aerated concrete. Both materials have special benefits in terms of strength and insulation, but they also have different qualities that can have an impact on cost and performance. In order to assist you in making the best decision regarding the material for your construction needs, this article will examine these distinctions.
Advantages and disadvantages of aerated concrete and gas silicate blocks
Benefits that are consistent with all the materials are:
- high rates of heat and sound insulation;
- environmental friendliness;
- quick installation due to large block sizes;
- non-flammability;
- the ability to adjust the dimensions using a regular saw;
- absence of “cold bridges” due to the minimum thickness of the seams (from 1 to 4 mm);
- good vapor permeability;
- affordable price;
- possibility of finishing with various decorative plaster.
Note: Various versions of a special adhesive solution are available from block manufacturers for use in the installation of gas silicate and aerated concrete. Essentially, this adhesive consists of a cement-sand mixture that has additional ingredients to strengthen the cement’s binding capabilities and promote quick work surface setting. The speed at which blocks lay explains the necessity for such binding additives. At this rate of application, a traditional solution will flow out of the seams because it won’t have time to solidify in the lower rows of newly laid masonry.
The drawbacks of gas silicate materials and aerated concrete typically show up early in the operating phase. The most frequent drawbacks are the brittleness of load-bearing walls and the development of cracks on facades as a result of increased moisture capacity.
Many developers’ experiences have demonstrated that, even though gas block construction materials have good thermal insulation qualities, installing underfloor heating and extra insulation is still advised in areas with long, icy winters.
Gas silicate or aerated concrete?
It is important to consider the relativity of a comparison when evaluating the benefits of one material over another. For instance, gas silicate blocks processed in an autoclave are guaranteed to be of high quality, but the cost is increased dramatically. Lower density gas block grades are more brittle but have better thermal insulation properties, and vice versa.
In contrast to gas silicate, non-autoclaved aerated concrete is not the highest quality and is the least durable. A notable distinction between gas silicate and aerated concrete, though, is the unique way non-autoclaved material can be produced independently, even on the construction site, which increases demand for the material (especially in situations where funds are scarce). Simultaneously, dishonest manufacturers make extensive use of this feature, breaking technological rules and altering material composition in an attempt to cut costs.
With the exception of moisture capacity, gas silicate blocks are superior to aerated concrete blocks in every way. This characteristic sets a maximum allowable humidity level of 60% for the use of gas silicate building materials.
Some features of working with gas blocks
The following guidelines must be followed when handling both aerated concrete and non-aerated concrete:
- Moisture penetration into the pores reduces the thermal insulation properties of the material. Therefore, facades must be protected from precipitation using external finishing materials intended for aerated concrete or aerated concrete – plaster, facade paints, suspended siding, cladding, thin-layer putty. When finishing facades with facing bricks, a ventilation gap of 30 – 40 cm should be provided. Additional protection will be provided by an increased roof overhang.
Be aware that any finishing materials need to have adequate ventilation or vapor permeability. Paint, plaster, and insulation should have vapor permeabilities that are higher than those of the wall material. It is preferable to add more mineral wool insulation.
Crucial! It’s crucial to follow this guideline when applying multiple layers of finishing and insulation: each layer’s vapor permeability should be greater than the one before it. If not, then condensation will build up and mold will eventually grow.
- Fastening of hanging furniture made of aerated concrete or gas silicate is carried out using fasteners with dowels. There are special anchor bolts for gas blocks.
- Despite the relatively low weight of gas block building materials, you should not save on the dimensions of the foundation.
- A layer of waterproofing is necessarily laid under aerated concrete and gas silicate structures.
- To protect the walls from cracking during shrinkage, reinforcement of the masonry and expansion joints are mandatory. Reinforce the first row and every fourth, as well as window openings.
| Aspect | Aerated Concrete | Gas Silicate |
| Composition | Made with a mix of cement, lime, sand, and aluminum powder. | Made from cement, lime, and silica sand, with a different foaming agent. |
| Density | Generally lighter and less dense. | Also light but may have slightly different density depending on the mix. |
| Thermal Insulation | Good thermal insulation, helps in energy efficiency. | Excellent thermal insulation, often better than aerated concrete. |
| Sound Insulation | Effective at soundproofing. | Usually provides better sound insulation compared to aerated concrete. |
| Strength | Suitable for most construction needs but not as strong as traditional concrete. | Comparable to aerated concrete in strength; used for similar applications. |
| Cost | Typically less expensive. | Can be slightly more expensive, depending on the brand and specific type. |
| Application | Commonly used in walls and partition structures. | Used in walls and blocks for various types of construction. |
Aerated concrete and gas silicate are comparable in that each material has certain advantages and uses. Because of its exceptional thermal insulation qualities and lightweight design, aerated concrete is a great choice for energy-efficient building. It can also make the building process simpler because it is simpler to handle and shape.
Conversely, gas silicate provides comparable thermal insulation but is often more resilient and has higher load-bearing capacity. Because of its stability and strength, it is frequently chosen for structural elements. However, in comparison to aerated concrete, it might be heavier and more difficult to work with.
Your unique needs and the specifications of the project will play a major role in your decision between these two materials. When making your choice, take into account aspects like structural requirements, insulation requirements, and handling ease. With their own benefits, aerated concrete and gas silicate can both be great options.
