Disadvantages of composite reinforcement for foundations. Plastic (composite) reinforcement for the foundation. Where is fiberglass reinforcement used?

After the invention of composite reinforcement, the pros and cons of the new material remained the subject of heated debate for some time. But practice has shown that the technical and operational characteristics of the material allow it to successfully compete with classical steel reinforcement. For the production of composite reinforcement, fibers impregnated with a special substance - a hardener - are used.

Like steel, composite construction has ribs to improve adhesion to concrete. In some cases, the ribs are replaced with sand spraying.

Types of composite reinforcement

The production of reinforcing rods of this type is carried out from different fibers. This feature determines the type of composite reinforcement:

Carbon fiber and Kevlar reinforcement differs from other types in its increased elastic modulus characteristics. These materials are very expensive and are mainly used in the construction of military facilities. Civil Engineering prefers to use fiberglass reinforcement. It is the optimal combination of technical characteristics and affordable price.

Advantages of composite reinforcement

All consumers note the relatively light weight of the material. On average per one linear meter accounts for only 0.07 kg. Fiberglass reinforcement 5 times lighter than metal. This feature simplifies the transportation of the material and its installation. During installation, it is enough to use binding wire or plastic clamps to obtain a durable structure.

In the construction of medical centers, laboratories, and testing facilities, composite reinforcement is increasingly used due to its dielectric properties. It is inert to:

• electricity;
• magnetic field;
• radio waves.

The chemical stability of the material allows it to be successfully used in areas with high alkalinity and acidity of soils. In this case, the foundation retains its properties even after partial damage to the concrete. Fiberglass reinforcement is resistant to acids and alkalis, which include sea water, solvents, bitumen, and concrete laitance. At the same time, high corrosion resistance is observed. Thermosetting resins do not react with water, so composite reinforcement is not subject to oxidation.

The possibility of concrete delamination due to sudden temperature changes when using composite reinforcement is minimized. This is explained by the similar value of the thermal expansion index for glass composite and concrete.

Disadvantages of composite material

Fiberglass reinforcement has a small number of disadvantages, but each of them imposes certain restrictions on working with it. For example, it can only be worked at temperatures above -10°C. This is due to the fact that at lower temperatures the material becomes brittle, unable to withstand even minimal loads.

At mechanically When pouring concrete, the structure made of composite material is characterized by poor stability. At manual way filling this problem is easier to deal with.

U glass plastic fittings modulus elasticity characteristics are significantly lower than those of steel. In the case of fiberglass, the elastic modulus differs by 4 times. With the slightest defect in the placement of reinforcement, this indicator can cause cracking or delamination due to the weak tensile strength of the material. Craftsmen and engineers need to carry out additional calculations when working to ensure high strength of the structure.

Fiberglass composite cannot cope with increased loads, for example, curved areas, exit points for connection to walls. Such areas require working with metal.

According to the experts, the disadvantages of the material include other features of working with it:

At the same time, manufacturers are often ready to offer ready-made curved parts different sizes. Research to find a way to increase the strength of the composite material is still underway. Already presented on the market various options, significantly different in their properties.

Comparison of metal and composite reinforcement

The pros and cons of fiberglass reinforcement are easier to identify when comparing the main characteristics with metal. The main problem of reinforced concrete structures is the corrosion of metal elements. During the work process, they often resort to additional costs for primer mixtures, but even they are not able to protect the metal from rust. Rust causes concrete to deteriorate.

The advantage of composite materials is their tensile strength. Metal is 3 times inferior. Light weight saves on shipping and labor when loading or unloading. If composite rods are cut by specialists directly at the construction site, then the customer gets the opportunity to save on material scraps. In warm weather, composite fibers of any thickness can be easily cut with wire cutters or bolt cutters.

The material is resistant to temperature changes. At the same time, fiberglass, due to its thermal expansion index, does not cause concrete defects. This is another plus in favor of composite structures. The low modulus of elasticity of fiberglass reinforcement is successfully compensated by reducing heat loss. Unlike metal, composite fibers do not provoke the appearance of cold bridges in concrete.

Many craftsmen, in their reviews of the properties of composite structures, include an indication of the possibility of completely replacing metal with fiberglass. It is already confidently used for:

According to consumer reviews, fiberglass reinforcement is much more economical than metal. At the same time, the price per linear meter of composite fiber is slightly higher than for steel. The benefit is achieved by the absence of scraps, ease of storage, transportation, and the absence of the need for welding work and additional treatment of the structure with special protective compounds.

There are enough advantages of fiberglass reinforcement, but for me it has one significant drawback. When sawing, it raises dust from small particles glass It is not always possible to work in thick glasses and a respirator, so after filing you feel as if there are a million glass splinters in your throat and nose.

Ivan. Concrete worker. 4 years of experience

My husband and I were planning to install a bathhouse. When purchasing fittings, they diligently tried to convince us to choose fiberglass, claiming that, according to experts, it is better in many respects. Before my eyes, the child broke off a piece of the rod with his hands. But the seller insisted that this was normal, because the reinforcement must withstand longitudinal loads. In general, I was categorically against it, and my husband was tempted by the low cost. It turned out that it was more convenient to install than metal. We poured the foundation and it has been successfully standing under the bathhouse for 3 years. Didn't burst, didn't bend over.

For a long time, customers have been suspicious of composite reinforcement. But over the last 5 years it has started to become popular. Accordingly, many factories began to produce it. To attract the attention of the buyer, various dyes are added and the number of winding ribs is increased. In practice, it turned out that some color pigments impair the strength of the fiber, and the number of ribs affects only the cost. Otherwise, I’m happy with the composite reinforcement: it’s comfortable to work with.

Oleg. Concrete worker. 8 years of experience

For what purposes is plastic fittings used? Why is foundation reinforcement performed? These questions are relevant for beginners in the construction business; let’s try to find out the pros and cons of using reinforcement in modern construction. Plastic reinforcement for foundations has been used in the construction industry for quite a long time. With its help, you can increase the strength of concrete structures. Basically, the fittings are made of durable steel with excellent technical parameters. Plastic reinforcement is 7-8 times stronger than concrete itself. By placing reinforcement bars in concrete, it is possible to obtain a monolithic system, the operational life of which is several decades.

Types of material for strengthening the foundation

Plastic rods for foundations appeared in the construction industry relatively recently. Basically, reinforcing bars are made of steel. Depending on the degree of ribbing, profiled and smooth shapes are distinguished.

Advice! In cases where it is necessary to evenly distribute the load, use a ribbed shape.

To give a certain structure the desired shape, smooth reinforcement is used.

Characteristics

Today, plastic reinforcement for foundations is actively promoted in the modern construction market. Not all professionals recommend this material for strengthening the foundation. Plastic fittings: pros and cons, we should talk about them in detail in order to analyze the effectiveness of use of this material in construction.

Plastic does not conduct electricity, therefore plastic fittings are suitable for grounding. Its weight is 4-5 times less than that of its steel counterparts. This material is offered to consumers in special bays.

The steel rods are shaped directly on the construction site. Such actions cannot be carried out with polymer materials. If you need plastic rods to arrange the foundation irregular shape, you must order them from the factory in advance.

Attention! It is impossible to change the shape of polymer reinforcement on your own.

Plastic fittings, reviews of which can be found on construction sites, are made from a high-molecular compound of organic origin, which provides this material with chemical resistance to aggressive substances. Plastic does not break down if it gets into concrete excess moisture. If you comply with all the technological requirements for this material, the resulting structure will retain its original characteristics for decades. Let us also note the disadvantages of this material.

Plastic melts at a temperature of 200-300 degrees, and the melting point of steel is 600 degrees. A foundation made of concrete with the addition of plastic reinforcement will sag after a short period of time. The reason for this phenomenon lies in the elongation coefficient, which is 10-11 times higher than its value for steel. Sagging is also observed when arranging a strip foundation.

Advice! If you plan to build a monolithic two-story house, it is better to use classic steel reinforcement.

About the material parameters for creating a foundation

When choosing material for the foundation, it is necessary to take into account the condition of the soil, the material of the walls and roof. When determining the diameter, the flowability of the soil, the degree of its freezing in winter time, the mass of the structure being built. Fiberglass rods involve the use of rods made of durable glass fibers.

The main advantages of this material, highlighted by consumers, are its low weight and high strength. Fiberglass reinforcement is used as an alternative metal structures. The advantage of plastic rods is their resistance to corrosion. There are two types of such polymer material: basalt and polymer reinforcement. The polymer base has insignificant weight; it is mainly used in individual construction. Fiberglass material is a composite rod characterized by its low weight. Its main purpose is to strengthen and bind concrete structures.

When using reinforcement of this type, structures are strengthened solid foundation, and also reinforce unstressed concrete foundations. Fiberglass rods are suitable for aerated concrete and asphalt concrete. Reviews indicate that this material has virtually no disadvantages, so they may well become an alternative for heavy steel structures. Such reinforcement can be used when constructing unforeseen structures. Owners of suburban dacha plots purchase such rods to create supports for plants.

About the characteristics

Fiberglass rods have the following characteristics:

• spiral pitch parameters;
• Weight Limit;
• internal and external diameter.

When manufacturing fittings of this type, the following numbering is used: 4, 5, 5; 6, 7, 8, 10, 16, 14, 18. These numbers coincide with the outer diameter parameters. When changing the profile number, the weight of the structure changes, as well as the outer diameter parameters.

Attention! The profile pitch value is unchanged, it is 1.5 cm.

The mass of the rod is calculated taking into account the profile number. This parameter is in the range of 0.02 - 0.42 kg per linear meter. A composite rod contains several elements. The first part is presented in the form of the main trunk. It is made of parallel fibers, combined into one structure using a polymer resin. The video presents interesting information about polymer reinforcement

This part of the structure is responsible for strength. The second element of fiberglass reinforcement is fibrous raw material. It is presented in the form of sand spraying or winding in two directions. The advantage of this material is that it is offered to customers in the form of huge bays. They are deployed as needed, making the rod suitable for certain construction tasks. Fiberglass reinforcement is transported horizontally.

In modern industrial and private construction, steel reinforcement is increasingly being replaced with polymer rods. Fiberglass has such a quality as elasticity, so a fiberglass rod significantly reduces the weight of the foundation, without losing the operational characteristics of the foundation. Fiberglass reinforcement has low thermal conductivity, so it is suitable for tying multilayer wall masonry and inter-row reinforcement of masonry. Corrosion resistance allows the use of fiberglass material for strip-type concrete foundations.

Conclusion

The main reviews of fiberglass reinforcement are positive, so this material has a wide range of applications. Currently, this material is used to reinforce many porous materials, for example, aerated concrete. The cost of polymer rods is significantly lower than their steel counterparts, which attracts an increasing number of consumers. Currently there are:

• lightweight structures (greenhouses, fences);
• medium-heavy structures (major two-story buildings, stone fences);
• heavy structures (buildings with 3-4 floors).

Any modern construction associated with the use of reinforcement. This building element must connect with each other individual elements structures, strengthen the monolith of the base material, fix the facing material to the wall.

In connection with the development of nanotechnology traditional materials are giving way to new composite materials created from polymer chemicals. Plastic reinforcement is placed in the concrete mixture during direct pouring in order to strengthen the monolithic concrete structure. To increase adhesion and eliminate the risk of cavities and pores, vibration equipment is used at the point of direct contact. In addition, mine-type polymer reinforcement is used to fix the mesh, which prevents rock collapse and strengthens mine vaults and walls. Fiberglass materials perfectly withstand aggressive environments, which is why it has gained popularity in the construction industry.

Composite reinforcement(made of plastic) in last years often competes with conventional steel. This is explained by a number of its advantages. But this material also has its drawbacks and features of its application. Often advertising interferes with an objective assessment of both, and today the article will present the characteristics of this material, talk about its types and areas of application.

Materials for manufacturing

Today, the composite reinforcement market is represented by three types:

• fiberglass;
• basalt-plastic th;
• carbon fiber.

Fiberglass reinforcement

The first type of reinforcement is made of fiberglass. This technology appeared in the USSR about 50 years ago. Then printed wiring in radio electronics began to gain momentum, and textolite began to be used as a material for boards, when the base was fabric and the fastening composition was artificial resin. Later, fiberglass was used instead of ordinary fabric, and this expanded the use of fiberglass.

It has found its place in aircraft manufacturing, furniture and household goods, and sometimes even in the military industry. Gradually it began to be used in construction, and fiberglass reinforcement became excellent option for foundation frames operating in aggressive conditions - for example, in water.

The materials for fiberglass are glass and epoxy resin.

This material does not contain fiberglass, but basalt. Its manufacturing technology is simpler than glass, because glass production requires several types of raw materials, and basalt plastic- only basalt.

Compared to the previous composite, basalt plastic has a higher elastic modulus and tensile strength, has lower thermal conductivity, but is slightly heavier.

Carbon fiber reinforced plastic

It is made from carbon fiber and the same resins, but this material is expensive. This is due to the production technology of carbon fiber - the basis of such materials. Technological process requires strict adherence to temperature and processing time parameters, since organic fibers serve as the raw material.

Carbon fiber plastics are actively used in the automotive industry, the production of sporting goods, aircraft and shipbuilding, and science.

Carbon fiber reinforcement is stronger than fiberglass and has a higher modulus of elasticity, but it is not without its drawbacks. Thus, the fragility of this material is great, which does not allow its use in long, stressed structures such as floor slabs.

Production technology of composite reinforcement

There are three ways to make composite reinforcing bars. They have English names, which reflect the essence of technology.

Needletrusion- this is the twisting of individual fibers into one with simultaneous impregnation and braiding. Allows you to reduce the cost of the process due to the high speed of such production lines. Giving the relief characteristic of reinforcement is achieved by winding with threads of a periodic profile. The thicker the reinforcement, the larger number threads are used. Thus, rods with a cross-section of up to 10 mm are wrapped with one thread, from 10 to 18 - with two, and above - with four. Products made using this method have good adhesion to concrete due to their relief - and this despite the fact that composite materials have a low adhesion coefficient.

Method plaintrusions consists of pre-forming the main rod and then winding it spirally in two directions.

Most old way production of composite reinforcement - pultrusion. It involves drawing molded, impregnated and already hardened fiber through a system of dies, which, at the polymerization temperature of the plastic, finally gives the reinforcement the required form and pull it out. This method is characterized by a lower production speed and higher cost.

Comparison of quality characteristics

To compare different kinds composite, and also compare them with steel, you can use the following table.

In addition, composite reinforcement has the following properties: fragility, which distinguishes it from steel for the worse. Because of this, and also because of its instability to high temperatures, it is not used in structures experiencing strong bending loads and in places where are at risk of fires.

Advantages of the material

Composite reinforcement has a number of advantages over standard steel. These include:

• Increased tensile strength. It can be several times higher than that of steel.
• Corrosion resistance. Plastic fittings do not rust.
• Low heat transfer coefficient. Unlike metal, plastic does not create cold bridges.
• Plastic fittings do not work as an antenna - after all, they are dielectric and diamagnetic. Therefore, the probability of radio interference in structures with such reinforcement is zero.
• Small specific gravity . Steel reinforcement is several times heavier.
• Temperature coefficient of expansion is the same as concrete, therefore, the formation of cracks for this reason is excluded.

Disadvantages of composite materials

The advantages of composite materials often cannot be fully realized due to the disadvantages that reveal themselves in a number of application cases. This is first of all:

• Low modulus of elasticity. Plastic reinforcement is not rigid, its elastic deformation is in low limits (that is, the ability to return to its original shape after the load is removed is lower).
• Fragility. When bending forces are applied, such reinforcement does not bend, but breaks. In this regard, it is impossible to bend it without heating.
• Low temperature resistance. Fiberglass when it reaches 150 degrees loses its positive properties, and at 300 it simply collapses, releasing toxic substances. Carbon fiber reinforced plastics have higher operating and limiting temperatures, since the roads and polymers used in their manufacture are more expensive, but their fragility is also higher than that of other types. Steel can work up to 600-750 degrees before it begins to soften and melt.

Application of composite reinforcement

Composite products have proven themselves very well where static loads are combined with an aggressive environment - for example, in hydraulic structures. Sometimes such reinforcement is used on its own, sometimes together with steel, which helps to use the advantages of both types and compensate for each other’s disadvantages.

Plastic products in the form of meshes are actively replacing steel ones in brickwork with cladding, where an air gap is provided. Steel mesh gradually corrodes, and sometimes this leads to disastrous consequences (a piece of cladding may fall off). The composite has no such drawback.

Equivalent replacement

If we look at the table in the previous chapter and specifications specific products, then the issue of equivalence is decided depending on the conditions under which the reinforced concrete structure will be used.

Yes, indeed, in terms of tensile strength, steel reinforcement in a cross section of 12 mm can be replaced with fiberglass 8 mm, and steel reinforcement 18 with fiberglass 14. But all this is relevant when this reinforcement is needed solely to keep the structure from creeping under load. Simply put, this is how you can make strip and slab foundations.

But in situations where deflection occurs, this rule does not work. Thus, to manufacture a lintel or floor slab, it is necessary to increase the number of rods by 4 times - after all, the elastic modulus of the composite is the same amount less. When the load increases in the middle of a composite-reinforced slab, it will not actually burst, but it will bend more, and the result may be pieces of concrete falling on your head.

The low elastic limit prevents the use of composites when reinforcing concrete pillars. The compressive strength of concrete is quite high, but with increased loads on a small unit area, especially if they are uneven, the modulus of elasticity can have a real impact on resistance to failure.

At the moment, the use of polymer reinforcement is regulated by SNIP 5201–2003, and changes have been made to it in the form of correction factors for calculating such reinforcement in different conditions operation (Appendix L of 2012).

Main product details

In recent years, the number of companies producing composite reinforcement (especially fiberglass) has grown many times, but the quality of their products leaves much to be desired. Here are some ways to recognize a marriage:

• Pay attention to the color of the products. High-quality fittings in one batch are always the same color. If this is not the case, it means that the temperature regime during production was violated.
• There should be no cracks or delaminations. They are easy to see in the cut.
• Fiber breaks reduce the declared characteristics. They are also visible to the naked eye.
• Uneven profile (winding). Most likely, the production used old equipment where continuity was broken.

Now the requirements for composite materials will become more stringent. Rolled steel is becoming more expensive, and plastic fittings have every chance of displacing steel ones from a fairly large segment of the market. Undoubtedly, less than conscientious manufacturers take advantage of this, so you should be on your guard.

Modern construction technologies involve the use of new materials with improved characteristics. One of the latest developments in scientific and construction organizations is plastic reinforcement. Thanks to the complex operational properties, it successfully competes with metal rods, which are gradually destroyed as a result of corrosion processes. Glass reinforcement is used to provide an increased safety margin for concrete structures in contact with fresh and salt water, as well as aggressive environments.

Composite reinforcement – ​​fiberglass material for strengthening concrete

Composite fiberglass reinforcement is a new building material made from various fibers:

• basalt;
• glass;
• polyamide;
• carbon.

Fiberglass reinforcement is a building material created on the basis of bonded complex composition fibers

The name of the polymer reinforcement is determined by the type of fiber used:

• basalt-plastic rods are made from basalt thread;
• fiberglass reinforcement is made on the basis of glass fiber.

Novice developers are interested in whether it is possible to use fiberglass reinforcement for the foundation, and also how fiberglass reinforcement behaves in aerated concrete walls. Modern technology manufacturing, which involves impregnation of a bundle of fibers with a thermoplastic mixture based on polymer components, ensures the required strength of the finished product.

Polymerizing at elevated temperatures, the threads collected in a bundle harden and acquire the required shape. Combining fiber threads can improve performance properties.

Improved adhesion of glass reinforcement to concrete is ensured by applying the following materials to the outer surface of polymer rods:

• fine sand;
• marble particles;
• crushed granite.

Transverse or spiral corrugations increase the strength of the reinforcement and improve adhesion to the concrete mass.

The fibers are connected to each other polyester resins composite

Plastic fittings - features of building materials

Plastic reinforcement, designed to increase the strength of concrete structures, has its own characteristics.

The main difference of this material is its light weight, as well as its two-layer construction:

• the inner layer is the core of the rod, consisting of longitudinal threads filled with a composite mixture. The core increases the resistance of the material to tensile and compressive loads;
• the outer layer is formed by a group of threads twisted in a spiral. The characteristic arrangement of the outer fibers increases the resistance of the rods to torsion, and also improves the contact of the polymer reinforcement with concrete.

Polymer threads improve the performance properties of composite rods, which successfully compete with standard metal reinforcement. Distinctive features glass fittings:

• weight reduced by 4-5 times compared to steel rods. The main advantage of the material makes it easier to work and reduce costs associated with transportation;
• The polymer material is twice as durable as steel in terms of tensile strength. This makes it possible to provide the required safety margin with reduced parameters of the outer diameter;
• resistance to corrosive destruction and neutrality to aggressive liquids. Polymer rods retain their properties in a humid environment;
• reduced thermal conductivity coefficient compared to steel. Polymer material allows for the construction and repair of houses, preventing the formation of cold bridges;
• possibility of assembly power frames without electric welding. This simplifies the process of fixing the bars and also reduces costs.

Fiberglass is used to produce this construction reinforcement

Design features and operational characteristics allow the use of glass reinforcement instead of steel rods to solve a wide range of problems.

Glass reinforcement - types of rods

Plastic fittings are made from different types threads The following types of composite rods are used:

• fiberglass, abbreviated as ASP. The core is made of glass fibers that are highly resistant to moisture. Products are used to increase strength fundamentals roads and pavements;
• basalt plastic, marked ABP. Easily distinguished by the black color of basalt fibers. Basalt plastic rods are superior to fiberglass rods in their ability to withstand tensile loads, as well as the magnitude of elastic deformation;
• Carbon fiber rods marked UGP are made on the basis of carbon, used in the production of concrete composites. The increased level of costs for purchasing carbon fiber reinforcement is compensated by the working properties of the material, as well as the ease of working with it;
• combined. Reinforcement with the ACC index is made of basalt and glass fibers and is characterized by increased strength properties. ACC polymer rods on a glass-basalt base are used for special purposes.

The choice of composite rods is carried out depending on the complexity of the tasks.

There are different variations of fitting models, some of which are quite unusual

How plastic fittings are made

The production process of polymer reinforcement is carried out on automated lines and includes the following stages:

1. Filling the feed module hopper with a polymer composition.
2. Feeding composite fibers and ensuring uniform tension.
3. Heat treatment of the material to remove water and oil inclusions.
4. Loading polymer fibers into a tank with heated binding ingredients.
5. Pulling the impregnated threads through a nozzle that winds them.
6. Polymerization of the starting material in an oven at high temperature.
7. Cooling the resulting rods and cutting them into pieces of the required sizes.

The characteristics of the equipment guarantee the quality of the resulting products.

Scope of glass reinforcement

Polymer reinforcement is used to solve various problems:

• production of composite concrete used for the construction of monolithic structures;
• construction of building foundations and pouring monolithic slabs;
• increasing the strength of walls built of brick;

The scope of application of this building material is extensive.

• construction of port facilities and special structures to strengthen the coastline;
• covering structures highways and strengthening of concrete slopes;
• construction of protective structures for railways and transport highways;
• production of concrete products requiring prestressing;
• construction of transport interchanges, bridges, overpasses and overpasses;
• construction of concrete structures in seismic zones.

Plastic rods do not require waterproofing, regardless of the choice of structural reinforcement scheme. The use of fiberglass reinforcement for concrete reinforcement and the use of polymer rods is carried out on the basis of previously performed calculations. Employees of specialized organizations are proficient in the technique of calculating reinforced concrete for construction.

Advantages of glass fittings

Developers are interested in what the pros and cons of plastic fittings are. Like all building materials, fiberglass reinforcement has disadvantages and advantages. The main advantages of glass fittings:

• increased safety margin;
• acceptable price level;
• light weight of rods;
• corrosion resistance;
• resistance to aggressive environments;
• reduced thermal conductivity;

Plastic reinforcement is used more and more often in construction today, due to its unique characteristics.

• environmental cleanliness;
• long period of operation;
• ease of machining;
• convenient delivery option;
• possibility of assembling frames without welding;
• preservation of properties at low temperatures;
• dielectric characteristics.

Thanks to a set of advantages, composite rods are popular.

Weaknesses of fiberglass rods

Along with the advantages, glass fittings also have disadvantages.

Main disadvantages:

• decrease in strength properties when heated above 200 °C;
• increased likelihood of fire when heated;
• insufficiently high elastic modulus;
• decrease in strength properties during operation and contact with alkalis;
• impossibility of bending rods without the use of special technological methods.

These disadvantages limit the scope of use.

Reinforcement of concrete monolithic structures plastic materials is increasingly used in construction. This is due to such performance qualities as high strength, durability and lack of corrosion. The last circumstance is especially important when constructing hydraulic structures, bridges and foundations.

Manufacturers building materials They produce 5 types of composite plastic reinforcement:

• glass composite or fiberglass - ASC;
• carbon composite – AUK;
• basalt composite – ABK;
• aramidocomposite - AAC;
• combined – ACC.

From the name you can understand which material is the basic basis for the manufacture of plastic fittings.

General description and manufacturing technology

Due to its low cost and good performance, fiberglass reinforcement is most widely used. Its strength is slightly lower than other composites, but the cost savings justify its use. For its production use:

• staple fiberglass;
• epoxy thermosetting resins as a binder;
• special polymer additives to increase strength and improve other characteristics.

Composite fiberglass reinforcement for foundations can have a smooth or corrugated surface. According to the manufacturing technology, bundles of the required diameter are initially formed from fiberglass and impregnated epoxy resin. Afterwards, to obtain a corrugated variable cross-section, the surface of the smooth rod is wrapped in a spiral with a cord, which is also woven from fiberglass. Then the resulting blanks are polymerized in an oven at high temperature and, after cooling, cut into straight sections or wound into coils.

Specifications

The production of periodic profiles and technical characteristics of fiberglass reinforcement are regulated by GOST 31938-2012. The standard defines:

• types of plastic fittings depending on the materials used;
• nominal diameters ranging from 4 to 32 mm;
• the length of straight rods is from 0.5 to 12 meters;
• possibility of supplying materials in coils with a diameter of up to 8 mm inclusive;
• markings and symbols;
• quality control methods;
• storage and transportation rules.

Characteristics of types of composite reinforcement.

The weight of the material depends on the size of the cross section and can range from 0.02 to 0.42 kg/m.

Weight of plastic fittings.

Data on ultimate strength and elasticity given in GOST show that these parameters exceed the characteristics of rolled steel with the same diameters. This allows the use of polymer reinforcement in particularly critical structures or when it is necessary to reduce the cross-sections of reinforcing materials.

Area and method of application

Plastic reinforcement is a modern alternative to rolled metal. The identical shape of the rods allows its use using technology similar to steel. A reinforcement frame made of composite plastic reinforcement is formed in the form of a flat mesh or spatial structure designed to strengthen and increase the strength of reinforced concrete monoliths.

Polymer reinforcing materials are used in the construction of roads, bridges, hydraulic structures, columns, walls, ceilings, foundations and other monolithic structures.

The main load falls on the longitudinal rods of the structure. They have a larger cross-section and are located at a distance of no more than 300 mm from each other. Vertical and transverse elements can be located at a distance of 0.5-0.8 m. The connection of individual rods at intersections is carried out using polymer ties or knitting wire. The joining of individual rods on one horizontal line is carried out with an overlap.

Advantages of plastic fittings

When comparing composite rods with metal rods (we have already carried out a comparison in this article), a number of pros and cons of plastic reinforcement are clearly identified. These include:

• reducing the weight of the reinforcement frame by 5-7 times;
• higher strength, allowing the diameter of the rods to be reduced;
• corrosion resistance and chemicals in the composition of concrete;
• simple installation and high speed of assembly of reinforcing frames;
• simplified technology for creating round and oval structures;
• excellent dielectric and thermal insulation properties;
• ease of transportation.

In addition, it should be noted that the length of rods for materials supplied in coils is unlimited, as well as simple cutting of blanks of the required length.

Reinforcement made on the basis of fiberglass is 20-30% inferior in strength to other composites, but is significantly cheaper. Therefore, such material is in higher demand in construction.

Flaws

Among the main disadvantages of composite reinforcing materials, experts call:

• low maximum temperature of use, not exceeding 60-70°C;
• poor mechanical stability under lateral loads;
• the impossibility of bending with a small angle of curvature and the need to use special elements.

It should be noted that there is no regulatory framework for the use of polymers for concrete reinforcement and, often, unreliable technical data from the manufacturer of the material. This makes calculations difficult and forces structures to be assembled with a safety margin.

Technology of foundation reinforcement with composite materials

The low weight of plastic reinforcement for the foundation simplifies the process of assembling a reinforcement frame of any design. At the same time, due to the increased strength of the material, the cross-sectional diameter is taken one number less than for metal analogues.

The technological process of installing concrete monolithic structures using polymer rods consists of the following stages:

1. installation of formwork and marking the pouring level concrete mixture;
2. assembly and installation of the reinforcing frame;
3. pouring concrete into formwork;
4. removal of formwork panels.

Work on the installation of reinforced monolithic structures must be carried out in accordance with the adopted design decisions. The deck configuration must fully correspond to the size and shape of the foundation. As formwork material, you can use standard factory-made panels, boards, moisture-resistant plywood or chipboard. For permanent formwork Expanded polystyrene sheets are most often used.

After assembling and securing the formwork panels, they inside, using a water level, make marks for the upper limit of pouring the concrete mixture. This will reduce the time it takes to complete the job and help distribute the concrete more evenly.

Spatial reinforcing frame for strip foundation

The foundation reinforcement scheme, laying and rod diameter are always indicated in the project. The use of composite reinforcement, especially those based on carbon fiber, makes it possible to reduce the diameter of the rods by one size. The laying of the material must exactly correspond to the calculated data. The frame is assembled on a level area.

The work begins with cutting the workpieces. To do this, pieces of the required length are unwound from the coil and placed on stands at a height of 35-50 mm above the support pad or ground. After this, the transverse jumpers are laid according to the drawing, and at the intersections they are tied with wire or ties. In this way, the bottom row of the spatial reinforcement frame will be assembled.

At the next stage, you need to assemble a lattice completely similar to the first one, lay it on top and then cut it vertical racks design length. The first post is tied at the corner of the flat gratings, the second at the adjacent intersection, as a result, a spatial structure is gradually formed. If there are more horizontal rows, then the second grid is fixed at the required height, and then the next one is fixed. The vertical post in this case is one whole segment.

When assembling the frame, it is necessary to remember that the ends of the reinforcing bars should be located at a distance of 35-50 mm from the formwork. This will create a protective layer of concrete and increase the service life of the structure. For this purpose, it is very convenient to use special plastic clamps.

Plastic fasteners.

It is necessary to pour a sand-crushed stone cushion at the bottom of the trench and compact it well. After this, it is recommended to cover the sand layer with geotextile or waterproofing material. This will prevent moisture from entering the concrete and the germination of weeds.

Horizontal reinforcement of slab foundations

When pouring slab-type foundations, horizontal reinforcement technology is used. Its main feature is the absence of turning and adjacent sections. Usually these are two grids located one above the other from long straight rods and vertical posts.

All work is carried out on site. First, according to the design drawing, the lower mesh is knitted, and the upper mesh is laid on top of it. After this, vertical posts are installed, as described for strip structures. The lower mesh must be installed on stands.

Pouring concrete onto a plastic reinforcement frame

Technologically, pouring a concrete mixture is no different from work using steel reinforcement. However, given the lower strength of the material under lateral radial impact, compaction with a vibrator should be done carefully so as not to damage the integrity of the plastic rods.