The construction industry is constantly looking for ways to strengthen and improve the properties of concrete. One of these solutions was fiber – small fibers that are added to the concrete mixture to improve its characteristics.
The importance of fiber in monolithic construction
Fiber, being an innovative component, has significantly transformed the approach to the construction of monolithic concrete structures. Its use allows us to achieve new levels of strength and durability, which makes it an indispensable element in modern construction. The material is widely used for:
- foundations of buildings and structures;
- floor slabs and crossbars;
- columns and racks;
- flights of stairs and landings;
- walls of basements and technical floors;
- waterproof pools and tanks;
- tunnels and subways;
- bridges and overpasses;
- elevator shafts and ventilation ducts
- fire and technological barriers
First of all, the additive increases the strength of concrete, which is especially critical for monolithic structures subject to significant loads. Fiber fibers are evenly distributed throughout the entire volume of the concrete mixture, creating micro-reinforcement in its structure. This strengthening allows the concrete to better resist bending and stretching, which prevents premature destruction of the material under the influence of dynamic and static loads.
Crack resistance – another significant advantage of the material. Cracks in concrete can occur for a variety of reasons, including temperature fluctuations, material shrinkage and mechanical stress. Fiber helps distribute stress within the concrete, thereby minimizing the risk of cracks. This not only improves the appearance of the structure, but also prevents the penetration of moisture and harmful substances that can accelerate corrosion of reinforcement and destruction of concrete.
Durability – a key aspect that makes fiber important for monolithic construction. Monolithic concrete structures reinforced with fiber have an increased service life, since the material is less susceptible to wear and destruction. This reduces the need for frequent repairs and replacements, saving resources and costs on a long-term basis.
In addition, micro-reinforcement helps improve the performance characteristics of concrete. Impact strength increases, which is especially important for structures exposed to mechanical shock, for example, in industrial buildings or transport facilities. Application practice shows an improvement in the frost resistance of concrete, which makes it more suitable for use in cold climates.
Fiber can be made from a variety of materials, such as glass, polymers, steel or basalt, each of which imparts specific properties to concrete. For example, glass fiber improves the thermal insulation properties of concrete, and polymer fibers increase its ductility and resistance to chemical influences.
Main types of fiber for monolithic concrete
The choice of fiber type for monolithic concrete depends on the specific design requirements and operating conditions. Let's take a closer look at the main types used in construction.
Steel fiber — this is one of the most common and researched types for a monolith. It consists of short pieces of wire of various sections and shapes, which are evenly distributed throughout the concrete mixture.
Advantages of steel reinforcement
The main advantage of steel fiber — a significant increase in the bending and impact strength of concrete, as well as an increase in its resistance to cracking. The addition of steel also improves the toughness of cast-in-place concrete, allowing it to better resist dynamic loads.
Areas of application
Steel fiber is widely used in industrial and civil construction, from the production of industrial floors to the creation of elements that are subject to high loads, such as tunnels, bridges and airfield pavements.
Fiberglass — It is a fibrous material made from glass threads. It has high tensile strength and is lightweight.
Advantages of fiberglass fiber
Fiberglass does not corrode, making it ideal for use in harsh environments such as marine or chemical environments. It also has good thermal insulation properties and is not affected by magnetic fields.
Areas of application
This type of fiber is often used in the production of sandwich panels, internal partitions and elements where lightweight construction and corrosion resistance are required.
Synthetic fibers, such as polypropylene or polyethylene fibers, are polymer products that are added to concrete to improve its performance.
Synthetic fiber improves the plasticity of concrete, its resistance to frost and freeze/thaw cycles. It also helps prevent the formation of microcracks during concrete shrinkage.
Areas of application of pp fibers
This type of reinforcing fiber is ideal for thin and lightweight structures such as paving slabs, decorative elements and sanitary ware and allows you to reduce the amount of traditional reinforcement in the monolith.
Basalt fiber — this is a material obtained from natural stone — basalt. It has high strength and resistance to aggressive environments.
Advantages of basalt in monolithic structures
The material stands out for its heat resistance and chemical resistance. It is not subject to corrosion and is able to withstand high temperatures, which makes basalt suitable for use in conditions of high temperature loads.
Areas of application
Used in the production of concrete products that are exposed to high temperatures, such as fireproof structures, and as reinforcement for concrete products exposed to aggressive chemicals.
Each of these types of fiber has its own unique properties and applications, allowing engineers and architects to select the most suitable material depending on the specific requirements of the project.
Advantages of using fiber in monolithic foundations and floor slabs
Adding fiber fiber to monolithic concrete significantly improves its performance characteristics:
- Improved strength characteristics - fibers are distributed throughout the entire volume of concrete, increasing its strength and resistance to loads.
- Increasing resistance to cracking, which is especially important for monolithic structures.
- Increasing the service life of structures - concrete with fiber is less susceptible to destruction, which increases its service life.
Technology for using fiber in monolithic concrete works
The use of fiber in monolithic concrete work requires strict adherence to technology, starting from the preparation of the mixture and ending with the hardening of the concrete.
Preparation and mixing
The first and most important stage — This is the preparation of a concrete mixture with the addition of fiber. The process begins with the selection of the appropriate type of material based on the required characteristics of the final product. The fibers must be evenly distributed throughout the concrete to ensure uniformity and prevent lumps.
To achieve uniform distribution of fibers, they are added to the concrete mixer before, during or after filling the dry components, but before adding water. Mixing times may be extended to ensure complete mixing with the concrete mixture. It is important to ensure that the water-cement ratio is not disturbed, which can affect the quality of monolithic concrete.
Laying and compacting concrete mixture
After preparing the mixture, it should be laid. Concrete with fiber is laid in the standard way, but it is worth considering that the presence of reinforcing fibers can change the fluidity of the mixture. If necessary, use supplements to improve mobility.
The compaction of the concrete mixture must be carried out carefully so as not to disturb the uniform distribution of the fiber fiber. The use of vibrators to compact concrete is acceptable, but excessive use should be avoided to avoid causing separation.
Features of hardening of concrete with fiber
Hardening of concrete with fiber — this is a process that may require more time compared to conventional concrete. Fiber additives can slow down the release of water from the mixture, which affects the rate of strength development.
It is important to provide the correct conditions for curing, such as temperature, humidity and protection from direct sunlight and wind. In some cases, it may be necessary to use thermal coatings or add hardening accelerators.
It is also necessary to control the shrinkage process of concrete, which can be enhanced by adding fibers. In this case, it is recommended to use special additives to prevent cracking.
Compliance with these technological nuances when using structural fibers in monolithic concrete works allows you to achieve optimal results and ensure the durability and reliability of the structure.