Fiberglass or steel reinforcement: pros and cons. Fiberglass reinforcement: disadvantages, characteristics, application Cons of composite reinforcement for the foundation

Scientific progress does not stand still. This applies to the construction sector as well. Every day, more and more new alternatives to obsolete products appear on the building materials market. This is the case with steel reinforcement. In recent years, such a product as composite reinforcement is gaining popularity. This fitting is of three types: fiberglass, basalt plastic and carbon fiber. It is based, depending on the type, either glass, or carbon, or basalt, or aramid fibers and polymer binders in the form of resins. Outwardly, it consists of plastic rods with special technological ribs (like steel reinforcement) or a sandy coating.

Ribs and sand on the surface are applied to improve the adhesion of reinforcement to concrete. The technological process and characteristics of composite reinforcement have been known for many years. But, despite this and the bold statements of manufacturers that it is more durable than steel reinforcement, steel still remains the leader. Is it possible that it will replace steel and is it as good as manufacturers praise it? This question can be answered only by considering all the pros and cons of composite reinforcement.

Advantages of composite reinforcement

Resistance to aggressive media. The most important advantage of all types of composite reinforcement is biological and chemical resistance. This fitting is neutral to the effects of microorganisms and their metabolic products. It is also neutral to water and highly resistant to various alkalis, acids and salts. This allows it to be used in those areas of construction where steel reinforcement shows poor resistance in these parameters.

Such areas can be: coastal fortifications, bridge building, road construction (where there is an effect of anti-icing reagents), concrete work in winter, when various plasticizing, frost-resistant and accelerating hardening additives are added to the concrete mixture.

Relatively light weight. Compared to steel rebar, composite rebar weighs four to eight times less, which helps save on transportation and handling costs. In addition, due to the low weight, concrete structures are also lightened, which is important for large scale and volume of work.

Dielectricity and radio transparency. Since plastic fittings are a dielectric, this avoids emergency situations and loss of electricity due to faulty wiring. Also, composite reinforcement does not interfere with radio waves, which is important in the construction of commercial and other types of buildings.

Long service life. Due to its composition and structure, as well as resistance to aggressive environments, the service life of composite reinforcement is very high. To date, a record of forty years has been recorded. Manufacturers claim it can last 150 years or more, but since composite reinforcement has been used in construction relatively recently, this cannot be verified yet.

Ease of installation work. Due to elasticity, composite reinforcement is twisted into small bays (a little more than one meter in diameter, depending on the reinforcement section), which, together with its low weight, allows it to be transported by car. In addition, installation work can be successfully carried out by one person, since the technology for assembling structures is relatively simple.

Strength. The tensile strength of composite reinforcement is much higher than that of steel. With the same rod diameters, composite reinforcement withstands longitudinal loads 3-4 times greater than steel reinforcement.

No length restrictions. Due to its elasticity, plastic reinforcement can be twisted into coils of 50, 100 or more meters. While the maximum size of steel reinforcement is usually limited to 12 meters.

Cons of composite reinforcement

Poor bending work. Composite reinforcement has a flexibility modulus three to four times less than steel reinforcement, which can lead to deformation of concrete structures and the formation of cracks. In addition, due to its high elasticity, it is not intended for the manufacture of bent structures (for example, foundation corners).
Small size range. Due to the limited application, composite rebar is produced with a smaller variety of diameters than steel rebar. The range of produced sections is limited to sizes from 4 to 32 millimeters.
Limited types of installation work. Installation of structures is carried out only with a bunch of wire or plastic ties. While steel rebar can also be welded.
Low thermal stability. At a temperature of more than 100-120 degrees, composite reinforcement begins to melt and loses all its properties. Therefore, in case of fires in such buildings, their further operation can be dangerous.
Lack of sufficient documentation and regulatory framework. Although there are GOSTs for composite reinforcement, in most SNiPs, calculations for composite reinforcement are either poorly presented or absent altogether.
Increased brittleness at low temperatures. Even at low negative temperatures, composite reinforcement becomes more brittle.

conclusions

Composite reinforcement has a number of advantages and can be successfully used in many areas of construction. But a number of significant shortcomings does not allow it to completely replace steel reinforcement.

The construction industry is constantly evolving. New materials appear on the market that meet high requirements. Residential and industrial buildings are built in a short time. Various modern materials and innovative technologies are used in their construction. Recently, fiberglass reinforcement was presented to the developers, which began to compete with time-tested steel bars.

Pros and cons of fiberglass reinforcement

Fiberglass has advantages over steel that are worth considering in detail.

pros

Less specific weight. The mass of the structure is reduced several times, and this is important in certain construction conditions.
Corrosion resistance - will not rust or rot.
Its tensile and compressive strength indicators are much better, which is important for the construction of multi-storey buildings.
Resistant to aggressive, chemical environment.
Range of application at various temperatures - from -60 to +100 degrees.
Applicable in any geographic latitudes.
Ease and convenience of transportation. Fiberglass reinforcement is sold in small bays, they are compact, so that if necessary they can be transported by cars.
Fast and practical installation. You can cut the material with a grinder, and connect the elements together with plastic clamps. But it is worth noting that when working with this material, it is necessary to use protective equipment, both respiratory tract and hands.
Absolute radio transparency of this type of reinforcement.
Favorable from an economic point of view - the low cost of such a material. At the same time, in places where it is necessary to use metal rods with a cross section of 12 mm, fiberglass reinforcement 8 mm in diameter can be used.
It does not conduct electric current, which makes it preferable in the construction of buildings and structures in the energy sector.

Minuses

Despite the positives, there were some negatives.

Low bending elasticity. If load-bearing structures are being designed, then this must be taken into account.
It will not work to equip welds on this reinforcement, but this is often impractical, if not provided for by the project.
Low strength at high temperatures. As soon as the material is heated to 600 degrees, all its strength characteristics completely disappear, since the high temperature changes the structure of the material.
Although there are not so many minuses, they must be taken into account during construction.

Pros and cons of steel reinforcement

Steel products also have their advantages and disadvantages.

pros

Proven by time. Material release standards have long been developed. There are regulatory documents that specify steel reinforcement.
Various number of sections of bars. Is issued in the range from 3 to 80 mm.
Long and predictable life. Such fittings serve more than 50 years, provided they do not come into contact with water and chemical environment.
It has good bending characteristics. This material has 4 times better elasticity than fiberglass reinforcement. It has a much higher bending strength.
Availability. Sold in many construction markets.
Several mounting methods. You can tie with wire, fasten with clamps or apply welding.
Environmental friendliness. The negative impact on the human body is zero.
Ease of making anchors. If the rod is heated with a simple burner, then it is simply bent into an angle of 90 degrees. With this in mind, it is easy to manufacture anchor elements directly on the construction site.
Excellent adhesion to concrete mortar. The mortar and reinforcement have almost the same coefficient of linear expansion, which makes it possible to obtain a durable tandem.
Frost resistance. If the fittings are installed in places with high negative temperatures, then its structure remains unchanged.

Minuses

Bar length limitation. The maximum length of steel reinforcement elements is 11.7 meters, bars of 12 meters in length are rare.
Large specific gravity. To deliver this material to the site, special trucks will be required.
Tendency to corrosion. When steel is exposed to an aggressive environment or water, the corrosion rate is from 0.1 to 1.5 mm per year.
Special storage requirements. It is impossible to store for a long time in an open area and on the ground, the material becomes rusty in a few months.

As you can see, the disadvantages are not comparable in quantity with the positive aspects.

Comparison of fiberglass and steel reinforcement

Fiberglass has greater tensile strength, but steel bars have 4 times higher elasticity.
The strength and coefficient of linear expansion of metal reinforcement is greater and similar to concrete, which cannot be said about SPA.
Fiberglass is non-conductive, while metal is electrically conductive.
The range of sections for steel structures is much larger, so their use on complex construction sites cannot be replaced by fiberglass reinforcement.
Fiberglass is sold in coils - 50, 100 and 150 m.
The cost of reinforcement made of composite is much less than that of metal.

If we consider the strength of these materials, then it is worth considering that fiberglass reinforcement has a lower bending strength. During the construction of a heavy building, the bars take a larger cross section than steel material. In fact, the difference in price, on the scale of construction, remains in question.

Finally

From a comparative analysis, it is clear that fiberglass reinforcement is well suited for the private construction of houses from lightweight materials. For the construction of complex and heavy structures, steel should be used. It is difficult to give an unequivocal answer to the question: which is better - steel or fiberglass reinforcement.

Thanks to the reinforcement, it acquires increased strength and durability. Previously, only metal rods interconnected into a frame were used as reinforcement, but now plastic or composite reinforcement frames have appeared on sale. These products are made from basalt, carbon or glass fibers with the addition of polymer resins. Plastic fittings, the pros and cons of which will be discussed below, are produced in accordance with the requirements of the international standard, which are worth studying in more detail.

Forms of release of plastic fittings

Standard 31938-2012, which regulates the technical requirements related to polymer reinforcement products, defines elements of this type as solid round bars. The bars consist of a base, a filler and a binding component.

Composite reinforcement is produced in the form of rods with a cross section of 4 to 32 mm. Such products are sold either in sliced form, or in bundles or bays up to 100 m long.

There are two types of plastic profile:

Periodic - corrugated rods obtained by the method of spiral winding.
Conditionally smooth. In this case, fiberglass rods are sprinkled with quartz sand, so that the finished products have better adhesive properties.

Important! in terms of its parameters, it must necessarily comply with GOST 30247.0-94 for fire resistance and GOST 30403-2012 for fire safety.

To determine whether to use composite materials instead of metal, consider the pros and cons of fiberglass reinforcement.

Advantages of composite reinforcement

The advantages of fiberglass products in comparison with metal counterparts include:

Light weight. For reinforcement with plastic rods, smaller cross-section bars are used, due to which the total weight of the structure is almost halved. For example, a fiberglass rod with a diameter of 8 mm will weigh only 0.07 kg / p m, while a metal rod with the same cross section weighs 0.395 kg / p m. Due to its lower weight, plastic products can be transported even in a car, while for metal fittings, a heavy-duty machine is required.

Corrosion resistance. Fiberglass products do not oxidize and do not act with moisture.
dielectric indicators. Composite rods are radio-transparent dielectrics, which are inert to electricity and radio waves. That is why plastic reinforcement is considered the best material for the construction of medical centers, laboratories and other specialized facilities.
chemical resistance. Aggressive components such as: concrete milk, bitumen, sea water, solvent or salt compositions have a negative effect on metal profiles over time. In turn, composite materials remain inert to such a “neighborhood”.
Temperature Range. Composites can be used in the mode from -60 to +120 degrees.
High thermal conductivity. The heat conductivity index for fiberglass is 47 W / m * K, and for metal - 0.5 W / m * K.
Increased strength indicators. The tensile strength of the composite material is much higher than that of a metal product. With the same diameter, plastic reinforcement withstands 3-4 times more longitudinal loads.
Long service life. Manufacturers of composite materials claim that such reinforcement will last more than 150 years. It is not yet possible to verify this, however, the record-breaking recorded service life of a plastic armoframe was 40 years.
Mounting speed. Fiberglass rods are quickly cut with an ordinary grinder and knitted with plastic clamps.

In addition, due to the increased elasticity, plastic products are produced in almost any length.

However, let's not rush to conclusions about which fittings are better. In fairness, it is also worth considering the negative aspects of fiberglass rods for reinforcing monolithic concrete buildings.

Cons of composite reinforcement

Among the disadvantages of composite materials used when laying reinforcement, the following are distinguished:

Low bending elasticity. Due to the fact that plastic elements have a low modulus of elasticity, this can lead to deformation of the concrete structure. Well bending elements are difficult to use when. For comparison, the elastic modulus of the composite is 55,000 MPa, while for plastic this figure reaches 200,000 MPa.
Small size range. Today, when choosing steel fittings, consumers are offered a greater variety of products of different sections.
Lack of SNiPs. Although fiberglass products are standardized according to GOST, there is no other regulatory framework for building elements of this type. Based on this, the process of designing objects is complicated, since it is still quite problematic to make calculations.
Unable to use in some regions. Plastic products are not recommended for use in the construction of facilities in areas where too low temperatures are recorded in winter.
Instability. complicated by the poor stability of plastic rods. The structure begins to wobble, so you have to resort to "tricks" to fix the frame before pouring the concrete mix.
Relatively high cost of the material. Fiberglass will cost 2 times more than steel counterparts.

Speaking about plastic fittings, its pros and cons, many attribute to the disadvantages of these products such things as: the impossibility of using welding equipment and low resistance to heat. However, in reality, welding is practically not used in the assembly of the reinforcement cage. Just as absurd is the theory about the instability of the material to high temperatures. Fiberglass completely loses its properties when heated above 600 degrees, but not every concrete is able to withstand such a temperature.

Based on the foregoing, it becomes obvious that when reinforcing concrete structures, in order to determine which reinforcement is more suitable - metal or fiberglass, you need to clarify for what purposes you need a reinforced frame. On the one hand, the latest composite materials clearly win, but in terms of cost, it may be more profitable to purchase steel products.

Fiberglass reinforcement is a building material created on the basis of fibers bound by a complex composition. It is produced on the basis of basalt, glass and carbon fiber, and they can be combined. However, basalt-plastic reinforcement and fiberglass are considered the most popular.

What is it made from?

It consists of two parts. The first is the trunk, due to which the high strength of the material is achieved. The fibers are bonded together by the polyester resins of the composite. The outer layer serves for reliable adhesion to concrete: it is a fibrous body that is wound around the trunk in a spiral. It is thanks to this composition that plastic fittings received positive reviews as a reliable material for construction. There are various variations of rebar models, and some of them are quite unusual. For the production of this building reinforcement, fiberglass is used. Its peculiarity is that there are practically no analogues in the world, and its positive qualities significantly expand the scope. In addition, this material is modern and efficient, and therefore perfectly meets the requirements of the construction process.

At the heart of any fiberglass reinforcement are two components. The first is the reinforcing material itself, the second is the binder (a mixture based on the ratio of these components is 75 to 25. In composite reinforcement, all mechanical loads fall on the reinforcing component, while the binding materials are a kind of matrix that evenly distributes load on the entire length of the rod and protects it from external influences.

The most common recipe can be considered the following: glass roving or basalt fiber acts as a reinforcing link, epoxy resin is used for bonding, in addition, a hardener and an accelerator will be included in the composition of the material. However, there is no universal composition, since each manufacturer builds its own technological process.

What is the secret of popularity?

It must be said that compared to metal materials, plastic products are much more in demand today. Moreover, plastic fittings are used in any construction process. This is achieved through several qualities:

Resistance to corrosion, aggressive environment, including the alkaline environment of concrete. Unlike metal, plastic does not rust or break. These qualities contribute to the fact that plastic structures are widely used in the equipment of berths, protective structures at water bodies.
Reliability and strength, which is greater for plastic products than for steel ones. It is reliability that allows them to be used in the construction of building structures for various purposes and volumes.
High tensile strength.
The lightness of the reinforcement: for example, compared to the steel variety, the plastic one is five times smaller in weight and 11 times smaller in diameter. Such indicators indicate that it is possible to save on construction work, as well as on the transportation of material to the site.
Low thermal conductivity, due to which cold does not penetrate into the premises. It is no coincidence that plastic reinforcement for the foundation is increasingly being used: during its construction, it is possible to achieve high energy efficiency due to economical materials.
Resistance to exposure to radio waves.
Possibilities of application in various temperature conditions: from -70 to +100 degrees.
Costs: buying a linear meter of plastic fittings will be much cheaper compared to, for example, a one-meter segment of a metal bar.

Features of composite fiberglass

Composite fiberglass reinforcement appeared on the domestic market not so long ago and today is considered a new technology. Such plastic reinforcement also received good reviews, since it has a number of advantages compared to metal counterparts. Firstly, such structures are lightweight, so there will not be too much load on the foundation, which means that the building will last much longer. Secondly, due to the high tensile strength, such reinforcement can be used for the construction of objects with complex design features. Thirdly, the composite material is resistant to aggressive environments and does not conduct electricity.

On the other hand, composite plastic reinforcement has a weaker elastic modulus compared to steel products. Elasticity is especially lost when the composite is heated to 600 degrees. But on the other hand, it is this characteristic that speaks in favor of the fact that plastic fittings have also found application for the installation of the foundation, where tensile strength is very important.

Where are composites needed?

In floor slabs: as a rule, reinforcement is placed in the upper or lower concrete zone, while the concrete class should be B25.
When reinforcing structures made of concrete and reinforced concrete.
When erecting foundations that have a zero level of occurrence.
In reinforced structures that are exposed to aggressive environments.
During repair work associated with damage to concrete due to exposure to aggressive environments.
For reinforcing brickwork, especially if it is done in winter.

Where is fiberglass reinforcement used?

The scope of this building material is extensive:

Due to the tensile strength of fiberglass, it is advisable to use it for the construction of the base for objects. First, the installation will be simple. Secondly, the foundation will be strong. Plastic reinforcement for the foundation receives positive reviews due to the fact that it allows you to create a monolithic base. It is placed directly into the concrete solution during the pouring process, which makes the adhesion of materials stronger. In order not to form pores and cavities at the junction, specialists use special vibration equipment.
When equipping a high voltage power line. Since the material does not conduct current, energy will be lost to a minimum, while its operation will be safe.
Plastic reinforcement reviews builders receive positive due to its versatility. So, it can be used to strengthen the strength of the roadway, supports, bridges.
Composite materials form the basis for the production of sleepers. Due to the intense vibration that causes concrete to break down, a new material was needed, and fiberglass reinforcement was the right and effective solution.
The metal is not resistant to aggressive environments, high humidity, solvents and acids, respectively, its service life is not very long. Fiberglass, used in the construction of docks, piers, various barriers on the coastline, shows the best performance.
Plastic reinforcement is also used in the equipment of mines when fixing a special mesh that protects the walls and vaults of the mine from collapse and fixes them.
You can not do without this material and when fixing the insulation or facing material on the finished wall.

Varieties of fiberglass reinforcement

Plastic reinforcement in construction today is used more and more often, due to its unique characteristics. In addition, composite reinforcement today means a number of non-metallic structures, which significantly expand the scope of their application. So, modern manufacturers offer fiberglass and basalt-plastic reinforcement. At the same time, a variety of substances can act as polymer resins that bind the fibers, each of which has its own characteristics.

Any building material is used on the basis of certain rules and requirements. This also applies to composite reinforcement. Plastic fittings, the characteristics of which are so diverse, are used in construction on the basis of SNiP, approved back in 2003. By the way, each type of material is controlled by the manufacturer, and therefore the fittings must necessarily correspond to the parameters that were originally declared.

Reinforcement for the foundation: how to choose?

Today, in private housing construction, plastic reinforcement for the foundation is increasingly used. When choosing it, experts advise contacting official dealers and reliable manufacturers, since the strength and durability of the building as a whole will depend on the quality of the material. An important role is played by the quality of the product, as well as the density of the winding of glass roving along the entire length of the rod. The coils must also be filled with high quality. Good quality materials are the best choice when equipping any foundation - slab, strip or column. The type should be chosen depending on the bearing capacity of the soil, as well as the load on the building as a whole.

Reinforcement of the foundation is necessary in order to make the load on the foundation of the building more uniform during operation. Concrete has compressive strength, but its structural integrity can be compromised by stress. It is with the help of reinforcement that greater adhesion to concrete is achieved, respectively, the foundation becomes stronger and more reliable. The main requirements when choosing fittings should be the following:

providing rigid adhesion to concrete;
durability;
flexibility;
rust and corrosion resistance.

The fittings can be working, that is, reducing stress and external loads, as well as distributive, when the load is evenly distributed on each rod - this helps to maintain the correct location of the working rods. With the help of clamps, the rods are connected into a frame, protecting the concrete from cracking. Transverse rods protect against the occurrence of inclined cracks in the foundation, and longitudinal - from vertical ones.

slab foundation

When erecting this type of base, reinforcement with a ribbed surface with a diameter of at least 10 mm is needed. It is the diameter that affects how strong the reinforcement will be. Plastic reinforcement for the foundation, reviews of which are so good, should be selected depending on the type of soil. Suppose, on non-porous and dense, that is, with good bearing capacity and resistance to deformation, the thickness and diameter can be small. If the house is massive, but on soft ground, the reinforcement should be thicker - about 14-16 mm. With this option, the reinforcement of the slab will be upper and lower, and the total number of bars will be more than 100. Knitting can be done in several ways. For example, first reinforcement bars in the lower chord can be connected longitudinally and transversely, then vertical bars are attached to them, then again transversely and longitudinally. When knitting fiberglass reinforcement, it makes sense to use clamps and plastic ties. This is the so-called binding of reinforcement with plastic clamps.

Strip foundation

As a rule, the tape base has a height greater than the width. Accordingly, the tape, due to its small size, is prone to bending, and therefore, when building such a foundation, reinforcement with a smaller diameter can be used. The peculiarity of this base is that two reinforcement belts will be needed, regardless of what its height will be. The process of laying reinforcement will be as follows: rods are laid longitudinally in the upper and lower parts of the foundation at a distance of up to 5 cm from the concrete surface - it is on them that all the load will be in case of deformation. Reinforcement in several bars can be used for weak or moving soil, as well as for the construction of oversized houses. Fiberglass reinforcement ideal for the construction of a strip foundation - grades f6 and f7 (for houses on one floor), grades f8 and f10 - for residential buildings with an attic or two floors.

Column Foundation

Good plastic fittings (reviews confirm this) and during the construction of this structure. When reinforcing the columns, metal reinforcement with a diameter of 10 mm or fiberglass f6 is useful. As vertical bars, it is better to choose reinforcement with a ribbed surface, and horizontal ones are needed only for tying the bars into a single frame. The reinforcing cage is 2-4 bars as long as the height of the post. For example, when reinforcing a pillar 2 meters high and 20 cm in diameter, four f6 bars will be needed. They need to be placed 10 cm apart, and also tied up with smooth fittings with a diameter of f4 or f5. For any type of foundation, fittings for plastic pipes will also be required.

Features of knitting reinforcement

The foundation is an important component of any building, its quality and reliability are the guarantee that it will stand for a long time and serve reliably. The reinforcement of the base must be approached wisely. Consider how plastic reinforcement is knitted for a strip foundation, since it is it that is used most often in private housing construction. Knitting is needed in order to make the design of the reinforcing cage uniform and more durable. The rods are connected in those places where they intersect. A piece of wire is bent in the middle, then it is put on a special hook, which is applied to the reinforcement and tightened. An easier knitting method involves the use of plastic ties.

When creating a reinforcing system, plastic valves are important. Its main function is to contribute to a more durable and reliable fastening of plastic rods to each other. The most popular details in this regard are clamps, which are special and contribute to the creation of a protective layer with a certain thickness in concrete. The plastic rebar retainer is created by injection molding from polyethylene under high pressure. They are needed in order to securely fix reinforcing bars and frames in space, which will provide a protective layer in a concrete or reinforced concrete structure. Clamps can be designed for horizontal and vertical surfaces, as well as for creating formwork.

How is plastic reinforcement made?

When you decide to build your home, pay attention to a lot of little things and start by building a foundation. Many are interested in the question of where to buy plastic fittings. Experts advise contacting trusted companies, since the durability of the service of the structure itself depends on the foundation of the house, its quality and reliability. Equipment for the production of fittings is quite expensive, and the quality of materials depends on its quality.

Plastic fittings, the production of which is carried out on high-tech equipment, can be produced in different diameters - 4-24 mm. Depending on the type of line, a different number of bars will be produced, as well as different sections. As a rule, the scope of delivery includes a number of devices - from a thread heating device and an impregnation bath to a broaching device and a control cabinet. Thus, the equipment for plastic fittings should be chosen correctly in order to make the technological process efficient.

Plastic fittings: customer reviews

In their reviews, builders - experienced and not very experienced - agree on one thing: plastic fittings are just perfect for installing the foundation. For example, some have used a combination of steel and plastic rods: the foundation slabs and basement walls are made from plastic, while the floors, where stronger materials are needed, are built from steel. Many also note the convenience of knitting compared to metal reinforcement, which is supplied in one rod. In terms of tensile strength and resistance to decay, there is also no better plastic reinforcement.

But, on the other hand, it does not do without negative reviews. True, judging by them, these shortcomings are still more than offset by advantages. For example, there is an opinion that hands itch after working with fiberglass. In addition, it is almost impossible to bend it to make, for example, corners in the form of the letters L or P. At the same time, the manufacturers themselves focus on the fact that fiberglass reinforcement should be used exclusively for the installation of the foundation.

Steel or plastic: what to choose

For a beginner in construction, the choice of materials is always an important issue. For example, when making a foundation, it is important to perform competent knitting of reinforcement. Of course, in the case of building a bath, you can use simple metal rods, but what to choose for a solid home? Today there is a choice between steel and plastic structures, each of which has its own distinctive features and disadvantages. If we talk about the merits, then they can be reduced to the following points:

As you can see, the advantages of the plastic variety are still greater. The disadvantages of steel include: the occurrence of corrosion and the large weight of the structure, while plastic fittings are only difficult in terms of bending. Thus, in terms of its technical characteristics, fiberglass reinforcement is in no way inferior to steel, while it costs less. On the other hand, it is very important to remember about the features of the construction of a particular house. For example, if you need to connect the facing material and the wall, then you can use plastic-based fittings. But when equipping concrete floors with reinforcement, it is better to use metal structures, because, due to their large weight, they will not float when pouring concrete. Thus, when choosing structures for reinforcement, several factors should be taken into account at once, which means that it is better to use the professional help of specialists.

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

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

glass-composite or fiberglass - ASK;
carbon composite - AUK;
basalt composite - ABA;
aramidocomposite - AAK;
combined - ACC.

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

General description and manufacturing technology

Due to their 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 manufacture use:

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

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

Specifications

The production of a periodic profile and the 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;
length of straight rods from 0.5 to 12 meters;
the possibility of supplying materials in coils with a diameter of up to 8 mm inclusive;
marking and symbols;
quality control methods;
rules for storage and transportation.

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.

The data on the 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, if necessary, to reduce the cross sections of reinforcing materials.

Scope and method of application

Plastic fittings are a modern alternative to rolled metal. The same shape of the rods allows its use according to the technology similar to steel. Reinforcing cage made of composite plastic reinforcement is formed in the form of a flat grid or a 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 at a distance of 0.5-0.8 m. The connection of individual rods at the intersections is carried out using polymer screeds or knitting wire. Docking of individual rods on one horizontal line is carried out with an overlap.

Benefits of plastic fittings

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

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

In addition, it should be noted that the materials supplied in coils have an unlimited length of rods, as well as a 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 much cheaper. Therefore, such material is in high demand in construction.

Flaws

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

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

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

Technology of reinforcement of foundations with composite materials

The light weight of plastic reinforcement for the foundation simplifies the process of assembling a reinforcing cage 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 counterparts.

The technological process of mounting concrete monolithic structures using polymer rods consists of the following steps:

installation of formwork and marking the level of pouring concrete;
assembly and installation of the reinforcing frame;
pouring concrete into the formwork;
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 comply with the size and shape of the foundation. As a formwork material, you can use standard factory-made panels, boards, moisture-resistant plywood or chipboard. For fixed formwork, polystyrene foam sheet is most often used.

After assembling and fixing the formwork panels, on their inner side, using a water level, marks are made for the upper limit of pouring the concrete mix. This will reduce the time to complete the job and help spread the concrete more evenly.

Spatial reinforcing frame for strip foundation

The foundation reinforcement scheme, laying and the diameter of the rods are always indicated in the project. The use of composite reinforcement, especially based on carbon fiber, allows you to reduce the diameter of the rods by one size. The laying of the material must exactly correspond to the calculated data. The assembly of the frame is carried out on a flat area.

Work begins with cutting blanks. To do this, sections of the required length are unwound from the bay and installed on stands at a height of 35-50 mm above the support pad or ground. After that, transverse jumpers are laid, according to the drawing, and at the intersections they are connected with wire or ties. Thus, the bottom row of the spatial reinforcement cage will be assembled.

At the next stage, it is necessary to assemble a lattice that is completely similar to the first one, lay it on top and then cut the vertical posts of the 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 in this way. If there are more horizontal rows, then the second lattice is fixed at the desired height, and then the next one is fixed. The vertical stand in this case is one whole segment.

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

Plastic fasteners.

At the bottom of the trench, it is necessary to pour a sand-gravel cushion and compact it well. After that, 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 adjoining sections. Usually these are two grids located one above the other from long straight rods and vertical racks.

All work is done on site. First, according to the design drawing, the lower mesh is knitted, and the upper mesh is laid on top of it. After that, vertical racks are installed, as described for tape structures. The lower grid must be installed on stands.

Pouring concrete on a plastic reinforcement cage

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