Reinforcement of concrete monolithic structures plastic materials finds more and more wide application in construction. This is due to such performance qualities as high strength, durability and lack of corrosion. The latter circumstance is especially important during the construction of hydraulic structures, bridges and foundations.

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

• 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 with 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

Production of periodic profiles and technical specifications 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 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 fittings is modern alternative 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 cross members 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;
• easy installation and high speed assemblies 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 the unlimited length of rods for materials supplied in coils, as well as simple cutting of blanks 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 on the use of polymers for concrete reinforcement and, often, unreliable technical data from the material manufacturer. This makes calculations difficult and forces us to assemble structures 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, thanks to increased strength 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 it will be collected bottom row spatial reinforcement frame.

At the next stage, it is necessary to assemble a lattice completely similar to the first one, lay it on top and then cut the vertical posts to the designed length. The first post is tied at the corner of the flat gratings, the second - at the adjacent intersection, as a result, this gradually forms spatial design. 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, you must remember that the ends of the reinforcing bars should be located at a distance of 35-50 mm from the formwork. This will create protective layer concrete and will 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. Her main feature consists in 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.

The modern world is changing rapidly, and this also applies to construction industry- new technologies and materials. Today, the use of composite reinforcement in construction is not widespread, and main reason because of the lack of information and real, independent reviews from the builders. After all, it is much more common and reliable to use good old metal fittings, the characteristics of which are well known and confirmed by time.

But the fittings are from composite materials has been used in Western countries since the 70s, and has received quite a high rating. Although even there she was unable to squeeze out steel.

In our country, many people still ask: what is fiberglass reinforcement? And they receive a lot of information - both fantastically laudatory (usually coming from the manufacturers of plastic fittings themselves) and very negative (manufacturers of steel fittings do not need competitors either). We will try to calmly and impartially analyze the advantages and disadvantages of composite reinforcement.

How are composite reinforcement produced?

Let's start with the fact that the term “composite reinforcement” combines all types of non-metallic reinforcement produced on the basis different types fibers that are used as a reinforcing base of the rod. The fibers from which the reinforcement is produced can be the following:

• 1. basalt fiber;
• 2. glass fiber;
• 3. aramid fiber.
• 4. carbon fiber.

Thus, the types of composite reinforcement, depending on the applicable fibers, are as follows:

• 1. Basalt-plastic reinforcement, usually black (ABP);

• 2. Fiberglass reinforcement, light yellow in color, but thanks to coloring additives, a wide range of colors (ASP);

• 5. Combined reinforcement (based on fibers of different types).

Any composite reinforcement is produced on the same equipment, the technology is also no different. The only difference is the type of fiber. Currently, there are several production methods:

1. A bundle of fibers, having previously formed a rod - the main reinforcement rod, is impregnated with epoxy resin and pulled out. Then the bundle of fibers is pulled through the shafts, while at the same time a bundle made of the same fibers using resins is wound onto it. The harness in this process performs two tasks - it tightly presses the fibers of the rod, and serves as reinforcement ribs, which will improve the adhesion of reinforcement and concrete in the future. After this, the reinforcement goes through the oven drying stage, and now the reinforcement is ready. This method is the oldest; it is used by almost all Russian manufacturers of plastic fittings.

1. Fiber feeding system (fiberglass, carbon fiber, basalt fiber)

2.Polymer bath (polyester, epoxy resins)

3. Preforming device

4. Die

5.Heating/cooling zones of the die

6.Pulling machine

7.Cutting machine

2. The second method differs from the first only in that the rope is wound onto the rod with very strong force; it is literally pressed into the main rod, as a result of which the ribs are formed from the fibers of the rod itself. Such fittings are more durable than those produced by the first method, since there is no risk of ribs falling off. However, finding similar fittings Russian production almost impossible, since most people use the first method.

3. The third method is also similar to the first, however, the tightening rope here does not form ribs, but only tightens the fibers of the rod until polymerization in the oven. To adhere to concrete, a layer of abrasive - quartz sand - is applied to the reinforcement. This type of reinforcement has the poorest adhesion to concrete, and on top of that, it has the shortest service life. The point is that epoxy resin It degrades quite quickly in the alkaline environment of concrete, and polyester resins, which are not afraid of alkali, are extremely rarely used by manufacturers in Russia.

4. Finally, reinforcement made using the pultrusion method. In this case, the fibers are formed into a rod, impregnated with polymer resins, pulled through dies with different sections, arranged in descending order. This method makes it possible to form a periodic relief (ribs) with high accuracy, thanks to which they can be used as a thread (for example, as a tie screw for formwork, with a fiberglass or steel nut). The fittings produced in this way are different high quality, durability and high price. In addition, such fittings are almost never produced in Russia.

If you look, you can find absolutely nothing on sale. unusual material- composite reinforcement with an internal cavity. Despite its exotic nature, tube reinforcement deserves attention - after all, thanks to the cavity, the diameter increases, and with the same number of fibers, reinforcement with a cavity has a larger area of ​​​​contact with concrete, and therefore better adhesion.

Composite reinforcement pros and cons

Like anyone building material, composite reinforcement has its advantages and disadvantages. Advantages of composite reinforcement:

1. Weight - non-metallic fittings are almost like feathers compared to metal ones. The weight of composite reinforcement is 10-12 times less than steel reinforcement of equal strength. For example, 1 meter of 10 mm plastic reinforcement weighs 100 grams, and steel reinforcement of the same diameter weighs 617 grams. And the fact that plastic rolls into coils allows you to load several coils (the length of a coil is usually 100-200 meters) of reinforcement into the trunk passenger car.

2. Composite reinforcement has an impressive tensile strength - 2.5-3 times more than steel (of course, this means with the same diameter). Thus, composite reinforcement with a diameter of 12 mm replaces steel reinforcement with a diameter of 14-16 mm. Hence the term “equal strength replacement” is used by builders and manufacturers.

3. The cost of composite reinforcement today is lower than that of metal, although a few years ago it was the other way around. Moreover, the price for steel reinforcement grows steadily, while the composite remains almost in place.

4. Another plus - composite reinforcement is sold in coils of 100-200 meters, which can significantly reduce the number of scraps when reinforcing structures.

But not everything is so rosy; there are also disadvantages of composite reinforcement:

1. Experts call the main disadvantage of composite reinforcement the low modulus of elasticity, 4 times lower than that of steel - and this is with the same diameter. Of course, this is not a critical drawback; the main thing is to make additional calculations, and it is better if specialists do this. Or our calculator.

2. Composite reinforcement can only be bent in production, at construction site You won't be able to bend it at an angle. True, few elements in the form of rods at an angle are usually required, and they can be replaced with steel reinforcement.

3. Fiberglass reinforcement cannot withstand high temperatures - at 100 degrees it ceases to be elastic and breaks easily.

4. Welding when using composite reinforcement is unacceptable, although some experts consider this an advantage. Indeed, when reinforced with either steel or plastic reinforcement, both are mainly tied with wire or plastic ties.

There is an erroneous statement that tying composite reinforcement can only be done with plastic ties (clamps). Of course this is not true. Moreover, we recommend knitting with regular baked steel knitting wire. The process of tying composite reinforcement is no different from tying metal reinforcement. And the goal is the same - to fix the frame until the concrete gains strength, then it doesn’t matter at all what and how the fiberglass reinforcement was knitted.

By the way, it is necessary to say a few words about cutting composite reinforcement. Not everyone knows that it is possible to chop, bite or resaw fiberglass reinforcement, but it is not at all necessary. The best option cut the composite using a grinder. The fact is that biting or chopping creates microcracks, which, although not visible to the naked eye, go deep into the core. Water and alkali get into the cracks, and during freezing and defrosting, the cracks will expand, gradually destroying the reinforcement.

Important! When cutting composite reinforcement, you should take the necessary safety measures - protect your eyes and respiratory organs, since fine dust from basalt or glass fibers is extremely harmful.

Where is fiberglass reinforcement used?

The use of composite reinforcement in construction is quite widespread, although not very widespread in Russia. It is mainly used in the construction of foundations in private housing construction, in the construction of roads, and in the production of slabs. It is often used to create flexible connections between brickwork, to improve the characteristics of walls, etc.

If you have experience using composite reinforcement, please share in the comments!

The construction industry is constantly evolving. New materials that meet high requirements are appearing on the market. Residential and industrial buildings are being built in short terms. During their construction, various modern materials And innovative technologies. Recently, fiberglass reinforcement was introduced to developers, which began to compete with time-tested steel rods.

Pros and cons of fiberglass reinforcement

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

Pros

1. Less specific gravity. The weight of the structure is reduced significantly, and this is important in certain construction conditions.
2. Corrosion resistance - does not rust or rot.
3. Its tensile and compressive strength indicators are much better, which is important for the construction of multi-story structures.
4. Resistant to aggressive chemical environments.
5. The range of application at different temperatures is from -60 to +100 degrees.
6. Applicable in any geographical latitudes.
7. Simplicity and ease of transportation. Fiberglass reinforcement is sold in small coils; they are compact, so that, if necessary, they can be transported in passenger cars.
8. 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, you need to use protective equipment for both the respiratory tract and your hands.
9. Absolute radio transparency of this type of reinforcement.
10. Advantageous from an economic point of view - the low cost of such material. Moreover, 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.
11. Does not conduct electric current, which makes it preferable in the construction of buildings and structures in the energy sector.

Cons

Despite the positive aspects, there were some disadvantages.

1. Low bending elasticity. If load-bearing structures are being designed, this must be taken into account.
   Equip welds this will not work with this fitting, but this is often impractical if not provided for by the design.
2. Low strength at high temperatures. As soon as the material is heated to 600 degrees, all its strength characteristics completely disappear, since high temperature changes the structure of the material.
3. Although there are not many disadvantages, they must be taken into account during construction.

Pros and cons of steel reinforcement

Steel products also have their advantages and disadvantages.

Pros

1. Time-tested. Standards for the production of material have long been developed. Eat regulatory documents, which indicate steel reinforcement.
2. Various number of rod sections. Available in the range from 3 to 80 mm.
3. Long and predictable service life. Such fittings serve for more than 50 years, provided they do not come into contact with water or chemical environments.
4. Has good readings to bend. This material has elasticity 4 times better than fiberglass reinforcement. Its bending strength indicators are much higher.
5. Availability. Sold in many construction markets.
6. Several installation methods. You can tie it with wire, fasten it with clamps or use welding.
7. Environmental friendliness. Negative Impact on human body equals zero.
8. Easy to manufacture anchors. If the rod is heated with a simple torch, then simply bend it into a 90-degree corner. Taking this into account, it is easy to produce anchor elements directly on the construction site.
9. Excellent adhesion with concrete mortar. The coefficient of linear expansion of the mortar and reinforcement is almost the same, which makes it possible to obtain a durable tandem.
10. Frost resistance. If the fittings are installed in places with large negative temperatures, then its structure remains unchanged.

Cons

1. Limitation on rod length. Maximum length steel reinforcement elements are 11.7 meters long; rods 12 meters long are rare.
2. High specific gravity. To deliver this material to the site, special cargo equipment will be required.
3. 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.
4. Special storage requirements. It cannot be stored for a long time in an open area or on the ground; the material becomes covered with rust within a few months.

As we see, the shortcomings are not comparable in number with positive aspects.

Comparison of fiberglass and steel reinforcement

1. Fiberglass has greater tensile strength, but steel rods have 4 times higher elasticity.
2. The strength and coefficient of linear expansion of metal reinforcement is greater and similar to concrete, which cannot be said about SPA.
3. Fiberglass does not conduct current, but metal does.
4. Range of cross-sections steel structures much more, so their use on complex construction sites Fiberglass reinforcement will not replace it.
5. Fiberglass is sold in coils of 50, 100 and 150 m.
6. The cost of composite reinforcement is much less than that of metal.

If we consider the strength of these materials, it is worth considering that fiberglass reinforcement has lower bending strength. When constructing a heavy building, rods are taken larger section than steel material. In fact, the difference in price and the scale of construction remains questionable.

In conclusion

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

The main advantages of composite reinforcement are its low weight, high tensile strength, high chemical and corrosion resistance, low thermal conductivity, low coefficient of thermal expansion and the fact that it is a dielectric. High tensile strength, significantly higher than that of steel reinforcement with the same diameter, allows the use of composite reinforcement of a smaller diameter instead of steel.

You can’t even imagine how beneficial the use of fiberglass reinforcement is! The economic gain from its use consists of a number of factors, and not just the difference in cost between linear meter steel and composite reinforcement.

Take the time to look at the full description of the factors that make up your savings in money, time, man-hours, electricity, consumables etc. in the article “SAVINGS FROM USING COMPOSITE REINFORCEMENT”

But, you need to remember that composite reinforcement also has significant disadvantages. Majority Russian manufacturers These disadvantages are not advertised, although any construction engineer can notice them on their own. The main disadvantages of any composite reinforcement are the following:

• The elastic modulus of composite reinforcement is almost 4 times lower than that of steel reinforcement even with the same diameter (in other words, it bends easily). For this reason, it can be used in foundations, road slabs etc., but application in floors requires additional calculations;
• when heated to a temperature of 600 °C, the compound that binds the reinforcement fibers softens so much that the reinforcement completely loses its elasticity. To increase the resistance of a structure to fire in the event of a fire, it is necessary to take additional measures on thermal protection of structures that use composite reinforcement;
• Composite reinforcement, unlike steel, cannot be welded using electric welding. The solution is to install steel tubes at the ends of the reinforcing bars (in the factory), to which electric welding can already be applied;
• It is impossible to bend such reinforcement directly on the construction site. The solution is to manufacture reinforcing bars of the required shape in production according to the customer’s drawings;

Let's sum it up

Despite the fact that all types of composite reinforcement are a fairly new material on the Russian construction market. Its application has great prospects. Today it can be safely used in low-rise construction, in the foundations various types, in road slabs and other similar structures. However, for its use in multi-story construction, in bridge structures, etc. — it is necessary to take into account its physical and chemical characteristics even at the stage of preparation for design.

An interesting fact - the reinforcement is in coils!

The main use of reinforcement in low-rise construction is its use for reinforcing foundations. At the same time, steel reinforcement of class A3, with diameters of 8, 10, 12 mm, is most often used. The weight of 1000 linear meters of steel reinforcement is 400 kg for Ø8mm, 620 kg for Ø10mm, 890 kg for Ø12mm. Theoretically, you can purchase steel reinforcement in coils (if you find it), but later you will need a special device for re-aligning such reinforcement. Will you be able to transport 1000 meters of such reinforcement in your car to the construction site to reduce delivery costs? Now imagine that the specified reinforcement can be replaced with composite reinforcement of a smaller diameter, namely 4, 6, 8 mm instead of 8, 10, 12 mm. respectively. The weight of 1000 linear meters of composite reinforcement is 20 kg for Ø4mm, 36 kg for Ø6mm, 80 kg for Ø8mm. In addition, its volume has decreased somewhat. Such reinforcement can be purchased in coils, with the outer diameter of the coil being slightly more than 1 m. In addition, when unwinding such a coil, the composite reinforcement does not require straightening, since it has virtually no residual deformation. Could you imagine that you could transport the reinforcement required for construction country house or a dacha, in the trunk of your own car? And you don't even need help loading and unloading!

Not a single more or less large concrete structure can do without a reinforcing frame. The use of rolled metal has become commonplace round section for these purposes. But the industry does not stand still and manufacturers are actively promoting its composite analogue, namely fiberglass reinforcement.

Interstate standard 31938-2012 regulates general technical specifications on polymer reinforcing products. The material is solid rods of round cross-section, consisting of two or more components: base, filler and binder. For fiberglass it is:

• Staple glass fiber, known to every builder as an excellent insulation and reinforcing element.
• Polyamide fiber filler, which gives the finished product an increased degree of tensile and tear strength.
• Polymer thermosetting resins (epoxy, vinyl ester and others).

Composite reinforcement is produced using rods with a cross-section of 4-18 mm. The product is cut and packaged either in six-meter bundles or coils (length - up to 100 m). Buyers are offered 2 types of profile:

1. Periodic – corrugation is achieved by spirally wrapping a rod with a thin fiberglass strand. A layer of polymer resin is applied on top to protect the material.

2. Conditionally smooth - the finished product is sprinkled with fine quartz sand to improve adhesive properties with the concrete composition.

The main purpose is to reinforce standard and prestressed structures that are used in aggressive environments. But since the melting point of synthetic binders starts from approximately +120 °C, and the combustion temperature starts from +500 °C, the buildings being erected must meet the fire resistance requirements in accordance with GOST 30247.0-94, as well as the fire safety conditions specified in GOST 30403-2012.

Fiberglass is used in the following areas:

• Construction of enclosing structures in low-rise construction: foundations of pile, strip or grillage type, multilayer or monolithic walls made of concrete, brick, cellular concrete blocks, floors and partitions.
• Arrangement road surface, sidewalks, sleepers.
• Strengthening screeds, industrial floors, decking, bridge structures.
• Production of shaped products, reinforced concrete products.
• Formation of frames for greenhouses, small hangars, panel installations.

Companies engaged in the construction of houses made of wood and wood materials(OSB or chipboard, wood concrete), fiberglass reinforcement is actively used for fastening dowels, intersections, etc. This is due to the fact that hardware Over time, they rust, unsightly streaks appear, and fasteners and ligaments may weaken.

The scheme for forming a reinforcing frame from a composite is identical to the rules for working with rolled metal. The main task is to strengthen the foundation, floor or wall in the area of ​​maximum tensile or bending stress. The horizontal part is located closer to the surface of the structure with a minimum step between “layers” of up to 50 cm, and transverse and vertical supporting elements are mounted at intervals of at least 30 cm.

Advantages and Disadvantages

Let's list the advantages of fiberglass composite:

1. Light weight. A composite rod with a diameter of 8 mm weighs 0.07 kg/linear meter, and a metal rod of the same section weighs 0.395 kg/linear meter.

2. Dielectric properties. The material is inert to radio waves and magnetic fields, does not conduct electricity. It is thanks to this quality that it is used for the construction of special-purpose buildings: laboratories, medical centers, testing complexes.

3. Chemical resistance. The products are characterized by their inertness to aggressive compounds of acidic and alkaline types (concrete milk, solvents, bitumen, sea water, salt compounds). It is used in areas where the soil is highly acidic or alkaline. The foundation, piles and other similar structures will retain their basic properties even if the concrete part is superficially damaged.

4. Corrosion resistance. Not subject to oxidation, thermosetting resins do not interact with water.

5. The thermal expansion index of glass composite is similar to that of cement concrete, which eliminates the risk of delamination when sharp changes temperature.

6. Easy to transport and install. Packed in bundles of rods or rolled into coils. The weight of the package does not exceed 500 kg, so small freight vehicles or light-duty passenger vehicles can be used for transportation. For installation, knitting wire or special plastic clamps are used.

Now let's look at the other side of the coin:

1. Temperature limits use of glass composite – from -10 to +120 °C. At sub-zero temperatures, reinforcement becomes brittle and easily breaks under load.

2. The modulus elasticity index does not exceed 55,000 MPa. For comparison, the same steel coefficient is 200,000. So low rate for a composite it means that the rod does not work well in tension. As a result, defects appear on concrete structure(delaminations, cracks).

3. When pouring concrete, fiberglass products exhibit poor stability, the structure wobbles and bends.

4. Plastic clamps are used to tie crosshairs and overlaps. In terms of reliability, they are seriously inferior to knitting wire and welding.

5. Corners, curved areas, points of rod output for subsequent connection with a wall or column are processed with rolled metal. Fiberglass composite is categorically not recommended for these purposes.

6. High cost of material. If a steel rod with a diameter of 88 mm costs 8 rubles per linear meter, then the price of fiberglass reinforcement is 14 rubles. The difference is not too big, but the purchase volume starts from 200 m or more.

Cost in Moscow

ASP, section in mm	Price in rubles per linear meter
	Corrugated ASP	ASP with sand coating
4	7	11
6	9	12
8	14	17
10	20	25
12	25	37
14	35	47
16	46	53

Feedback from design specialists is clear: the use of glass composites should be limited exclusively to low-rise construction.

Comparison of fiberglass and metal

Fiberglass composite is positioned as an alternative to rolled metal. Let's make a comparison:

1. Deformation and physical and mechanical properties.

Based on the data in the table, glass composite works worse in tension and does not withstand the same loads as metal. But at the same time, the first type of reinforcement, unlike rolled steel, does not create “cold bridges”.

2. Reactivity.

Metal products are afraid of moisture in any form, as it contributes to corrosion of the product and its splitting. The material can withstand any sub-zero temperatures without losing its basic properties, and the frame is not afraid of fires - the melting point of steel starts from +1400 °C.

Fiberglass does not react with water, saline, alkaline and acidic solutions, and there is no interaction with such aggressive compounds as bitumen, solvents and the like. However, when the temperature drops below -10 or -15 °C, the product becomes brittle to break. Fiberglass composite belongs to the flammability group G2 (moderately flammable) and in the event of a fire it can create an additional source of fire.

3. Security.

Steel is a material that does not contain volatile impurities such as formaldehyde, toluene and others, so talk about emissions harmful substances unreasonable. The same cannot be said about fiberglass. Thermosetting resins are synthetic polymer compositions that contain various toxic components, including phenol, benzene, the well-known formaldehyde, etc. Therefore, fiberglass does not belong to the category of environmentally friendly products.

One more point: metal fittings have been tested by time and vast experience in its use has been gained, there is real reviews. The advantages and disadvantages have become well known, and methods have been developed to overcome the latter. The confirmed service life is on average 30-40 years, the same cannot be said about glass composite. Manufacturers claim that their material can last no less.

The conclusion from the above confirms the opinion of experts: rolled reinforcement is the leader in almost all parameters and replacing it with fiberglass is irrational.

People's opinions

"When developing a project small dacha the architect proposed for strip foundation use fiberglass. I've heard a little about this material, but on forums on the Internet there is often a negative opinion about it. Primarily due to the lack of calculation methods and clear standards for replacing metal with composite. The developer convinced me of the feasibility of such a solution. Reviews may be different, but you should rely on the recommendations provided by the official manufacturer. The document contained basic instructions: replacement not by equal strength, but by diameter in a ratio of 1 to 4. The house was rebuilt in six months, and there are no signs of damage on the foundation yet.”

Yaroslav Lemekhov, Voronezh.

“According to technology, a house made of foam blocks is reinforced every four rows. Both metal and fiberglass composite can be used. I chose the latter. According to reviews, such fittings are easy to install, there are no difficulties with welding or transportation. It’s very easy and fast to work with, and time costs are reduced significantly.”

Vladimir Katasonov, Nizhny Novgorod.

"For the foundation under frame bath with insulation I wanted to choose newfangled rods, but my neighbor-engineer criticized my positive opinion about the product to smithereens. In his deep conviction, fiberglass in concrete is full of disadvantages with a minimum of advantages. If physical properties metal are similar to the concrete component, it is very difficult to make the composite work with cement-sand mixture. Because of this problem, negative reviews appear, so I used it for anchoring multilayer walls. It also has low thermal conductivity.”

Anton Boldovsky, St. Petersburg.

“When I built the log house, I used fiberglass reinforcement instead of metal for dowels and joints. I put the remains in the barn, a year later they came in handy. I poured a small tape under the brick fence, and made a full-fledged composite frame for reinforcement. The disadvantages of the material in the form of a low tensile strength coefficient did not prevent me from building a good, durable fence, which has been in service for about three years.”

Evgeny Kovrigin, Moscow.