In construction, fiber is now actively used in shotcrete. The results obtained in practice indicate the effectiveness of the additive, and ongoing research is aimed at optimizing the characteristics of the material itself and methods for its integration into the concrete matrix. The strength of the fibers, their volumetric content, diameter, length and surface quality play an important role in the effectiveness of the reinforcement.
What is shotcrete?
Guning — is a method of applying concrete or mortar mixture to a surface under high pressure using a concrete pump and hose system. The technology is common in construction for strengthening structures, repairs and restoration. The process can be either dry or wet, depending on when water is added - at the mixing stage or in advance.
Most often shotcrete is used for:
- strengthening tunnels and mines;
- restoration of historical buildings;
- hydraulic structures;
- bridge construction;
- protection against corrosion and erosion;
- repair and strengthening of road surfaces;
- construction of underground parking lots and garages;
- reconstruction of industrial facilities;
- strengthening slopes and slopes;
- construction of soundproof barriers.
Composition of shotcrete
Shotcrete consists of cement paste, aggregates (sand, gravel), water and reinforcing fiber. Fibers can be glass, steel or polymers and are added to improve the mechanical properties of concrete. It provides additional strength, reduces cracking and improves wear resistance.
Typical recipe for a gunite mixture with fiber
|Material||Quantity per m3|
|Water||190 kg (W/C=190kg/440kg=0.43)|
|Fine aggregate (dry weight, excluding natural moisture)||from 1250 to 1520 kg|
|Coarse aggregate||from 200 to 500 kg|
|Fiber||from 2 to 5 kg|
Fibre fiber for dry and wet shotcrete
Polypropylene fiber is most commonly used in shotcrete due to its cost-effectiveness. In the dry method, fiber is added directly to the dry mixture before serving, and in the wet method — into the finished mixture before loading into the equipment. Polypropylene fiber improves the adhesion of the mixture to the surface, reduces rebound and increases compressive and bending strength.
Advantages of shotcrete with fiber
The use of fiber in shotcrete significantly improves its mechanical properties, including plastic deformation, crack resistance, and strength under various types of loads. This also increases its resistance to dynamic and fire influences. Using a polymer additive instead of traditional rod reinforcement reduces labor costs and speeds up the construction process.
Fiber for shotcrete not only improves its functional performance, but also provides a number of specific advantages that make it an ideal choice for a variety of construction applications. Here are some of them:
- Improved strength and durability.
- Reduced cracking.
- Improved adhesion to the substrate.
- Possibility of use in complex geometric conditions.
- Saving on materials and labor by reducing layer thickness.
Each of these points is of great importance in the context of modern construction projects.
Features of using fiber in shotcrete
The use of fiber in shotcrete requires special attention to detail at every stage of production and placement. It's not just adding another component; it is a change in the entire process in order to optimize the original characteristics of the material. Here are the key aspects to consider:
- The amount of fiber must be precisely calculated in accordance with the requirements of the project.
- The fibers must be evenly distributed throughout the entire volume of the mixture.
- An experienced nozzle operator should consider the presence of fiber when adjusting application equipment settings.
- Preliminary strength and adhesion tests are necessary to confirm the effectiveness of the formulation.
These features highlight the importance of an integrated approach to the use of fibers in shotcrete, from the planning stage to quality control of the finished product.
Fibermix offers a wide range of polymer fibers for shotcrete, including Armotec, Polymesh and Fibermix fibers. These products are designed with the latest technological innovations and meet high quality standards. For wholesale purchases, the company provides a unique offer: a free project with concrete slab calculations. This not only saves the customer time and resources, but also ensures that Fibermix products are used optimally to achieve the best results.