Fiber-reinforced foam concrete: characteristics, production technology

An innovative building material called fiber-reinforced foam concrete combines the strength of fibers with the lightweight qualities of foam concrete. This combination produces a product that is strong and adaptable, perfect for a range of building tasks. To improve the mechanical qualities and overall performance of the concrete, fibers made of steel, glass, or synthetic materials are mixed into the mixture.

The superior strength-to-weight ratio of fiber-reinforced foam concrete is one of its main advantages. This makes it a desirable choice for projects where the structure’s weight reduction is essential, like in high-rise buildings or on unstable ground. Furthermore, adding fibers prolongs the material’s resistance to environmental elements like moisture and freeze-thaw cycles, preventing cracking and extending the life of structures made of it.

The preparation of the foam concrete mix is the first step in the production technology of fiber-reinforced foam concrete. To make this mix, cement, water, and a foaming agent are combined to create an aerated, lightweight structure. After that, the selected fibers are added to the mixture to guarantee uniform distribution throughout the material. The end product of this process is a homogenous mixture that gains the advantages of fiber reinforcement while retaining the advantageous properties of foam concrete.

Fiber-reinforced foam concrete is a promising alternative to the more environmentally friendly and efficient materials that the construction industry is still looking for. Its increased performance qualities and versatility make it appropriate for a variety of uses, from infrastructure projects to residential buildings. To maximize its potential in contemporary construction, one must comprehend its characteristics and the methods of production.

Characteristic	Description
Density	Lower than traditional concrete, making it lightweight
Strength	Enhanced by fibers, offering improved tensile strength
Thermal Insulation	Good insulating properties due to air pockets in the foam
Production Method	Mixing foam with cement, water, and fibers to create a uniform material
Application	Used in non-load-bearing walls, insulation, and soundproofing

Composition and characteristics of dispersion-reinforced foam concrete

Reinforcing fibers are added to the mixture during the preparation process of porous concrete in order to minimize shrinkage deformations and enhance the homogeneity of the structure. This type of filling greatly enhances the final product’s mechanical and physical qualities.

Because fiber-reinforced concrete requires less energy to manufacture than foam concrete, its constructions operate very differently from conventional foam concrete options. However, since this material is the primary ingredient in concrete with fiber, they share some drawbacks.

• low vapor barrier;
• low volumetric heat capacity (frequent temperature fluctuations indoors);
• the material is subject to weather conditions (winter-summer), which affect the curing time, and therefore the quality of structures as a whole.

Materials for the production of fiber-reinforced foam concrete

The following could be the primary ingredients used to produce the mixture:

1. Portland cement acts as a binder in production. Ground quicklime can also be used for the production of autoclaved hardening products.

1. Siliceous components are: quartz sand, blast furnace slag, fly ash (thermal power plant waste). To increase chemical activity, the components are usually ground and added to the mixture in the form of sand sludge. Siliceous components reduce the consumption of binder, shrinkage of foam concrete mixture and improve the quality of products.

1. The foam is prepared in foam generators by connecting an aqueous solution and organic or mineral foaming agents.

Fiber -fiber for reinforcement foam concrete

An incomplete list of issues faced by foam block manufacturers includes the heterogeneity of the block structure, inadequate strength of the final products, and cracking.

Fiber is a unique reinforcing additive that can be added to a mixture to solve these issues.

Fiber-fiber added to foam concrete products’ composition can greatly raise the caliber of the final goods:

• strength of fibropen -based products is 2.5 times higher than products from conventional foam concrete;
• Portland cement consumption is reduced by 15%;
• The process of stratification of the mixture is eliminated;
• 30% percent reduced loss indicators from battle during transportation of finished products;
• in comparison with steel reinforcement, fiber is not subject to corrosion;
• unlike rigid steel reinforcement, it reinforces products in all directions.

The most widely used filler in the manufacturing of structural products is composed of mineral or synthetic fibers:

• polypropylene;
• polyamide;
• basalt.

Polypropylene fiber

The most common kind of synthetic fiber is made by cutting and twisting polypropylene film. These fibers spread out and form a mesh-like spatial structure in the mixture.

The following properties of foam concrete can be obtained by utilizing polypropylene fiber:

• increased resistance to mechanical stress;
• high homogeneity of the mixture;
• increased wear resistance of the material;
• eliminates the formation of plastic deformations, cracks, chips;
• increases frost resistance;
• prevents chips during stripping;
• reduces the time of strength gain;
• increases water resistance.

The compressive strength of D400 foam concrete grade increases by up to 26% when 0.4% of the total cement volume is added as polypropylene fiber.

Polyamide fiber

Synthetic thread made from polyamide melts is called polyamide fiber. Polyamide fibers are strong, flexible materials that have a high wear and fire resistance (up to 250 °C).

With the help of polyamide fiber, a highly dispersed and hygroscopic substance, foam concrete solutions can have the following advantages:

• reduces water absorption:
• reduces the likelihood of cracking;
• increases the elasticity of the solid material;
• strength – deformation without destruction;
• improves the physical and mechanical properties of thin screeds;

Basalt fiber

Short fiber segments made from melted volcanic basalt are known as basalt fiber. utilized as reinforcement to enhance the material’s mechanical and physical properties.

The following advantageous characteristics of basalt fiber are added to foam concrete:

• high tensile-compressive strength;
• increases wear resistance of products by 60%;
• reduces cracking by 95%;
• increases frost resistance by 2 times;
• increases water resistance (W> 14);
• increased resistance to acid and alkaline environments;
• significantly increases durability of structures.

The product’s strength is increased to 28% by the 0.1% of cement weight that is composed of basalt fiber in foam concrete mortar. The primary drawback of basalt fiber is its high cost, which severely restricts its widespread application in home building.

The strength and durability of fiber reinforcement are combined with the lightweight and insulating qualities of foam concrete to create the novel building material known as fiber-reinforced foam concrete. To improve its structural integrity and resistance to cracking, foam concrete is mixed with different kinds of fibers, such as steel, glass, or synthetic materials. These fibers are mixed into the concrete mixture during the production process to ensure a uniform distribution that increases the material’s flexibility and ability to support loads. Fiber-reinforced foam concrete, which offers advantages in terms of both cost and performance, is quickly gaining traction as a lightweight yet durable solution for construction projects.

Application of fiber-reinforced foam concrete

Monolithic fiber-reinforced foam concrete and wall blocks made in factories are two forms of this material used in low-rise construction. The foam concrete is poured into either permanent or removable formwork.

Based on its intended use, the type of foam concrete under consideration is separated into three distinct groups:

1. Heat-insulating, density 400–500 kg/m3 .
2. Structural and heat-insulating, 600–1100 kg/m3 .
3. Structural, density 1100–1200 kg/m3 .

In individual construction, structural and heat-insulating materials are successfully used:

• fiber-reinforced foam concrete blocks for laying load-bearing walls (200x300x600);

• partition blocks for laying internal walls and partitions (100x300x600);

• U-shaped blocks used as permanent formwork for the construction of a reinforced belt and the manufacture of window and door lintels;

• lintels for equipping door and window openings;

• monolithic structures.

Wall blocks made of fiber-reinforced foam concrete

Concrete wall blocks reinforced with fiber exhibit superior performance and durability. They are suitable for use in all climate conditions due to their high water resistance and positive frost resistance.

Apart from the previously mentioned benefits, the material possesses the subsequent significant attributes:

1. Due to its cellular structure and high heat-transfer resistance, this material has proven itself as a high-quality thermal insulation material.
2. A house built from fiber-reinforced foam blocks has an excellent microclimate: warm in winter and cool in summer. Thanks to this, the possibility of fungus, mold and bacteria formation disappears.
3. The size of a wall block (200x300x600) is equal to 13 pieces of ordinary sand-lime brick (88x120x250). Now let"s imagine how much faster you can build a wall from fiber-reinforced foam concrete blocks, compared to a standard wall made of sand-lime brick.
4. Easily processed by ordinary hacksaw without the use of special equipment and tools.
5. High sound absorption capacity, corresponding to all building codes and regulations.
6. In comparison with traditional wall materials, it has a low bulk weight, which significantly reduces the load on foundations.
7. Good block geometry, which allows laying using a special adhesive mixture, without using cement-sand mortar.
8. Fiber-reinforced foam concrete blocks are assigned the first degree of fire resistance, as a result, they withstand from 3 to 7 hours of continuous fire exposure.

Window and door lintels

Door and window openings are covered with fiber-reinforced foam concrete lintels that are further strengthened by a reinforcement frame. By using these lintels, the building’s exterior walls are shielded from the development of "cold bridges."

Because of this, it is possible to prevent the emergence of cracks on the exterior walls caused by the uneven temperature extensions of different building materials by using such jumpers.

Lintels may be created on a building site under specific circumstances by employing U-shaped blocks as long-term formwork.

Floors made of monolithic fiber-reinforced foam concrete

Monolithic flooring is especially robust and long-lasting. Foam concrete’s structure allows for a uniform distribution of fibers, which prevents shrinkage and produces perfectly smooth floors.

Any developer can pour a monolithic floor because the technology is straightforward:

1. Determine the level of the floor base.
2. Beacons are installed on the base surface, regulating the height and horizontality of the future coating.
3. The screed is poured in strips (between the beacons). First, odd strips, then vice versa.
4. The fiber-reinforced foam concrete mixture between the beacons is pulled together using rules.
5. We take care of the screed for 3 days: gently water it with water without breaking the surface.
6. We extract the beacon strips, and rub the grooves from the slats with a liquid solution.
7. The design strength of the screed occurs in 3-4 weeks.

Monolithic construction using fiber-reinforced foam concrete

Recently, it has been observed that public three- to four-story buildings are being constructed using monolithic fiber-reinforced foam concrete technology and either permanent or demountable formwork.

Utilizing monolithic fiber-reinforced foam concrete has a significant financial impact because the cost of mixtures—after labor costs—is significantly less than that of completed blocks. The building’s thermal performance can be maintained while reducing wall thickness thanks to the use of monolithic dispersion-reinforced foam concrete.

Essentially, the entire construction process involves the use of either permanent or movable formwork to lay monolithic foam concrete reinforced with fibers. Brickwork, unique blocks with through voids, and a cement stove attached to equipped light metal structures or a wooden frame can all play the role of non-removable formwork. Consequently, an external wall that is finished and doesn’t need to be finished further is formed at the end of the pouring process.

There are three methods for pouring this kind of foam concrete into the enclosing structures of buildings when building monolithic housing:

1. The mixture reinforced with fiber is poured between two brick walls (external and internal) in stages, with the walls tied with a metal mesh or reinforcement frame every 6 rows of masonry (see. photo).

1. A mixture of foam concrete with fiber is poured between the external brick wall and the permanent formwork installed from the inside.

1. Removable or permanent formwork on both sides.

A novel building material with several advantages, fiber-reinforced foam concrete is a desirable option for construction projects. Foam concrete is made stronger, more durable, and has better thermal insulation qualities when fibers are added. Because of its strength and low weight, it can be used for both insulating layers and structural components.

Fiber-reinforced foam concrete is made by combining foam, cement, water, and reinforcing fibers. By changing the ratios of each component, this relatively simple process can be tailored to meet the needs of various projects. By strengthening the material’s tensile strength and resistance to cracking, the fibers contribute to the creation of longer-lasting structures.

The adaptability of fiber-reinforced foam concrete is one of its main benefits. It offers advantages like lighter structures, more energy efficiency, and ease of handling and installation for both residential and commercial construction. It’s also a top option for creating cozy interior spaces because of its superior sound and heat insulation qualities.

All things considered, fiber-reinforced foam concrete is a major development in building materials, providing a cost-effective and environmentally friendly answer to contemporary building requirements. Its uses and advantages will probably grow as technology and methods continue to advance, making it an essential part of construction in the future.

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