To obtain a durable flooring, it is necessary to prepare a quality foundation, which is most often a concrete screed. To ensure the strength of the screed, you need to use reinforcement, but not everyone can afford to lay expensive metal fittings.
Thanks to the development of technologies for the production of building materials, an original and effective replacement of a metal mesh for reinforcing concrete foundations appeared - light and cheap fiber. Now, to organize a solid base for the finish coating, you can use fiber cement floor screed, the technology of which is simple and accessible to any home master.
Fiber fiber is produced in the form of thin (about 20 microns in thickness, length from 6 to 20 mm) rods of various materials: polypropylene, metal, fiberglass and basalt. Reinforcing fibers are used not only for organizing screeds, but also for strengthening plaster mixtures, for giving greater strength to concrete products, for compressing fractions in the road surface.
Subject to the technology of preparation of cement-sand mortar with fiber, a material is obtained in which the binder fibers are uniformly and multidirectionally distributed throughout the volume, which makes it possible to obtain unique strength characteristics of the finished product.
The different lengths of fiber are determined by the purpose of the concrete mix. So, for brickwork, fiber 6 mm long is added to the mortar, 12 mm for pouring screed, and fiber up to 20 mm long is used for concrete mortars intended for operation under difficult conditions.
Advantages and disadvantages
The use of fiberglass for floor screed allows to achieve significant qualitative improvement in cement-sand mortar. The following points are attributed to the positive results of the use of this supplement:
- Fiber increases the resistance of the material to the effects of shock and vibrational loads. The concrete base becomes much stronger, while it is able to withstand long-term static loads.
- Fiber-fibrous material is located inside the concrete mixture in a chaotic manner, which makes it possible to effectively unite the mixture and avoid separation. The uniform distribution of the reinforcing fibers during hydration eliminates such an unpleasant phenomenon as explosive chipping of the finished screed, which occurs when different parts of the solution are set at different times.
- Fiber reinforcement improves the characteristics of concrete for resistance to temperature changes, as a result of which the number of cycles increases significantly, and therefore this type of reinforced concrete is recommended for use in areas with adverse environmental conditions.
- When using fiber in the organization of screed in a wet way, there is no natural shrinkage, since the fibers that reinforce the solution do not allow voids to form. In addition, when using fiber, a smaller volume of water is required, namely an excess of this component is the cause of concrete shrinkage.
- With the final set of concrete strength, there is a decrease in internal stress, which makes the screed more durable and elastic.
When using certified fiber, there are simply no negative effects. Problems can arise only if there is a violation of the methods of preparing the solution with fiber or when using low-quality material. It is best to purchase fiber from well-known suppliers or, when purchasing from random sellers, require a quality certificate confirming the legality of the origin of the raw material.
Types of fiber and their characteristics
Manufacturers of building materials have launched the production of several types of fiber. They vary in material of manufacture and purpose.
Fiberglass
In the production of this type of soft reinforcement, zirconium is used. This material does not rot, perfectly resists corrosion and does not produce harmful fumes. They produce fiberglass up to 18 mm long and up to 10 mm thick.
Fiberglass is added to the plaster mortar, in a mixture for the preparation of foam concrete and aerated concrete blocks, used for casting decorative products and soundproof barriers. The main feature of fiberglass is its ability to maintain the integrity of thin (up to 3 cm) concrete layers.
Recommended consumption per m3 - 900 grams. Fiberglass is classified as a mid-priced material and is not used to organize screeds.
Steel fiber
To produce this product, a thin wire of high carbon steel is used. The thickness varies from 0.2 to 1.2 mm, and the length & mdsah; from 5 mm to 150 mm.
Steel fiber is used for the device of monolithic structures made of reinforced concrete, intended for the construction of critical industrial facilities (bridges, runways, fortifications).
It is not recommended to use steel fiber for screeds, since in thin layers metal fiber becomes the cause of local breaks. This process occurs due to different expansion coefficients of materials at the moment of temperature difference.
The use of steel fiber allows you to achieve the following advantages:
- labor costs are reduced by almost a third;
- the cost of the product is reduced to 7%;
- bending resistance of concrete is increased by 2 times.
Significant disadvantages that arise when using steel fiber, include a decrease in sound absorption of the concrete base. Up to 50 kilograms of steel fiber must be added per cubic meter of mixture.
Basalt fiber
It is made by remelting rocks at high temperatures. Basalt fibers are produced with a thickness of up to 500 microns, and a length of up to 15 cm. This material for organizing the reinforcement of concrete solutions is considered the most suitable for construction work. It allows you to achieve the following improvements:
- resistance to shock loads increases 5 times;
- bending resistance increases 3 times;
- resistance to compression and stretching improves 1.5 times;
- frost resistance increases by 2 times;
- 1.5 times water resistance improves;
- abrasion resistance improves 3 times.
Basalt fiber is consumed - up to 2.3 kg per m3.
Polypropylene fiber
Obtained by extrusion of a polypropylene mass, as a result of which individual fibers are obtained up to 20 microns thick and up to 20 mm long. The use of this material for reinforcing screeds slightly increases the strength characteristics of concrete, but the improvement of sound insulation is considered a positive point in the use of polypropylene fiber.
In construction, polypropylene fiber is used for floor screed. Consumption per m2 determined by recalculating the required volume per cubic meter of concrete, which is up to 900 grams per 1 m3.
Fiber consumption
In order to calculate the required volume of reinforcing fiber for the concrete mixture, it is necessary to determine the purpose of the room in which it is planned to fill the screed, as well as the level of constant and variable load on the base during operation.
For example, a laid semi-dry screed with fiberglass acquires the following characteristics when using different volumes of material:
- 300 grams per m3 slightly increase the strength characteristics of concrete;
- 600 grams per m3 will significantly increase the plasticity of the mortar and water resistance, while increasing the service life of the concrete base;
- 1500 grams per m3 consider the normal value to achieve maximum positive results of the further operation of the base.
The recommended consumption by fiber type is presented in the previous section of the article.
DIY floor screed
Any beginner builder can prepare a cement-sand mixture using fiber optic with his own hands.
Materials and Tools
The following materials will be required for the screed device:
- cement grade M400;
- sand with a fraction of 2-3 mm;
- fiberglass;
- water;
- plasticizer.
Need a hand tool:
- laser level (or hydraulic level);
- roulette;
- tap;
- building cord;
- rule
- guide profiles for mounting beacons;
- spatula and trowel;
- level.
Need a power tool:
- concrete mixer;
- trowel machine.
Semi-dry screed
For the installation of the base for the finish coating in modern construction, most often used semi-dry fiber cement floor screed.
- preparation of the base is carried out (cleaning from dust and dirt, cracks are fixed);
- to ensure water protection, a plastic film is laid;
- when organizing heated floors, the installation of the heating system is performed;
- using the laser level, find the maximum and minimum marks, after which the fill level is determined and the beacons are installed;
- the preparation ends with the installation of a damper tape around the perimeter of the room;
- within three minutes, cement and sand are mixed without using water in a concrete mixer with the gradual addition of fiber in small batches;
- at the next stage, pour water and bring the mixture to working condition;
- filling is carried out from the far wall along the lighthouses with subsequent alignment with the rule;
- the aligned base is sealed with a trowel;
- the prepared screed is covered with PVC film;
- after a day, the surface of the screed is moistened;
- the film is removed after 10 days;
- the laying of a laminate or other topcoat is started after two weeks of building up the foundation.
- prepare cement and sand in a ratio of 1: 3;
- with stirring, fibers are added to the solution in small volumes;
- when adding water, it is necessary to achieve the required plasticity of the solution (thick sour cream);
- filling is carried out starting from the far wall, alignment is performed by the rule for pre-installed beacons;
- within two days, the surface of the screed must be moistened;
- concrete gains full strength within 28 days, after which you can proceed with the installation of the finishing coating.
Fiber cement screed
Work on pouring fiber cement screed practically does not differ from the technology of laying semi-dry screed: