Composite armature. Fiberglass (composite) reinforcement - pros and cons. Composite rebar diameter

Fiberglass reinforcement is a modern development that can significantly facilitate foundation and concrete work. The method is new, therefore, when choosing, it is important to know its characteristics, advantages and disadvantages in comparison with metal fittings.

AKC - what is it, its structure and appearance

Composite reinforcement is a round bar with knurled stiffeners. Made from fiberglass. Produced in various sections. Its diameter, depending on the required strength of the products, can vary from 4 mm to 18 mm. Workpieces can be cut into pieces up to 12 m.

For ease of transportation, the reinforcement is twisted if its cross section is up to 10 mm in diameter. Additional strength is achieved by using fiberglass for the production of continuous fiber. Foreign manufacturers call this method polymer equipment.

In our documents, the glass fiber reinforcement is abbreviated as AKS. Fiberglass reinforcement, made of 2 main parts:

the main detail is the central trunk. It is carried out in parallel arranged strands of fiberglass. A polymer resin is used to connect them. Such a device gives the product additional strength;
outer coils or sprinkling for better joining with concrete. They are applied in the form of several spirals along the entire length of the main trunk. There are two ways to make coils - this is powder coating and bidirectional winding of ribs. Composite rebar is available in various types of central bar. A pigtail made of carbon fiber is one of the types of this part.

Physical properties and materials used in the manufacture of reinforcing products

The main characteristics are obtained after a number of scientific research and implementation latest developments. Some properties make it possible to use it for reinforcement in residential and industrial construction:

low weight of products - steel reinforcement is an order of magnitude heavier (9 times);
not subject to destruction from corrosion, to influence of acids, alkalis. According to this indicator, metal reinforcement is inferior by 10 points;
low thermal conductivity. When arranging foundations and floor slabs, the possibility of thermal insulation damage due to cold bridges is reduced to 0.
light and plastic- this quality simplifies its delivery and production of works;
does not conduct electricity, does not lend itself to the action of stray currents;
due to plasticity accepts any form, it is not required to use welding and cutting machines.

Thanks to these characteristics, the reinforcement of the foundation with fiberglass reinforcement becomes justified both in production and in economic terms. Much in this matter is decided by the material used for the production of ASP. The industry produces composite non-metallic reinforcement from several types of modern plastics. They are based on the following materials:

Fiberglass.
Carbon fiber.
Basalt plastic.
Made from aramid.
Material created on the basis of glass-reinforced polyethylene terephthalate.

The price of some materials does not allow their use in mass quantities. For this reason, 2 types of materials are most popular. These are fiberglass and basalt-plastic products. The main trunk is woven from many threads of material. They are connected using thermosetting synthetic resins.

For a reliable connection of the rod, either sandy sprinkling is applied, or the barrel wraps around several turns going in a spiral. Using fiberglass reinforcement, its property of slight stretching in a concrete product should be taken into account. In this case, there will be very little contact with the concrete and separation of the coils or abrasive coating will occur.

Basalt plastic products do not have a reliable connection with concrete. The best fixation is given by coils made of carbon fiber, applied to the fiberglass main barrel. In this case, there is a uniform distribution of the load on the entire part and the normal fixation of the rod to the concrete mass.

Advantages and disadvantages of using

Reviews of builders allow us to recognize the following main advantages:

light weight of products allows not only to facilitate the work of workers, but also makes the structures quite light. Therefore, it is used for cellular concrete and other materials that reduce the weight of the structure while maintaining a high level of reliability and strength;
metal, able pass cold through cold bridges. The use of fiberglass reinforcement eliminates this possibility; this advantage is especially important in the case of monolithic construction of buildings;
consumption goes down material when it is packed in coils. Scourges are issued on 12 meters that allows to carry out cutting more economically. This point is especially important in private construction, when every ruble spent is scrupulously calculated;
enhances economic component, the possibility of linking without overlaps and the use of welding;
able to serve for a long time and not lose its properties, but metal, laid in concrete slab also does not decompose;
dielectric qualities give a guarantee of safe living in the building, but this dignity is debatable. Concrete is itself a dielectric;
high level resistance to chemicals is important in the production of foundation work at low temperatures. At this time, various additives are added to the concrete;
Does not interfere with the passage of radio waves. This quality is especially important in monolithic construction, metal fittings interfere with the normal operation of mobile communications and the passage of a radio signal. Usage composite reinforcement, can reduce the level of radio interference in the building.

These products also have disadvantages. A specialist using this material can easily call them:

Reinforcing fiberglass(asp) exceeds the cost of steel reinforcement. But this minus is easily covered by the possibility of using thinner reinforcement for a similar type of work;
subject to deformation and destruction at high temperatures, but the likelihood of such an impact inside the concrete is unrealistic;
if used fiberglass reinforcement for the foundation with many turns, there is no way to bend parts for bending, but the problem is easily solved. It is enough to take a piece of steel bar, bend it under right angle and tie with the main lash;
one of the main The disadvantages are low elasticity when the bar is broken. In this case, fiberglass reinforcement is inferior to steel, but it works better in tension. Due to its low fracture resistance, its use in capital construction somewhat limited;
using it in the foundation and pouring concrete from the mixer you need to be extremely careful. Glass fittings cannot be laid in a rigid frame and great pressure integrity may be compromised. Composite mesh is The best decision question.

How to knit fiberglass reinforcement, but easier than metal. This does not require the use of different hooks. It is connected with self-tightening plastic clamps. The operation is simple and requires a minimum of knowledge and tools.

Having considered the advantages and disadvantages, it is impossible to unequivocally answer the question which is better - light plastic or hard steel. It is subject only to civil engineers.

Scope of use and main types of reinforcing bars

These products are divided not only in appearance and method of applying stiffeners. The main classification is the scope of use of bars:

working;
distribution;
mounting;
produced to strengthen concrete products and structures.

Production set up various products, depending on the tasks set for reinforcement in construction:

separate, different in size, lashes;
reinforcing meshes;
Depending on the size, frames of various designs and dimensions are produced.

With a short period of use, composite reinforcement is used by various construction organizations. Used for making drainage wells, concrete walls, reinforcement is made strip foundation fiberglass reinforcement. Widely used in road construction.

With its help, they reinforce the canvas, embankments, bases of highways, well strengthen the brick and block masonry of the walls. This material has received wide application both in private households and for arranging various greenhouses and a greenhouse, to reinforce a small foundation. Such structures are lightweight, easy to install and disassemble.

Adds popularity to the material, its ease of transportation and work. For delivery, you do not need to order a truck, you can deliver it by car.

Analysis and comparison of the main parameters of two types of reinforcing materials

You can get a complete and reasoned answer to the question of which fittings are better by carefully comparing the main parameters of plastic and metal fittings.

Material properties	Steel reinforcement	fiberglass composite
Elasticity and plasticity	The metal has a sufficiently high level of these material properties	Fiberglass barrel has a high level of elasticity
Tensile strength	Steel reinforcement is inferior to plastic in this property. This value for this material is 390 MPa.	Fiberglass filaments have great advantage. The strength of the material is 1300 MPa.
Coefficient of thermal conductivity	In this matter, metal, significantly loses to the opponent. This coefficient is 46 W / (m * K).	This value is much less than that of steel and it is equal to 0.35 W / (m * K).
Material density	For this characteristic, steel bars are preferable. Their density is 7800 kg/m 3 .	Here, fiberglass significantly loses to steel. Its density is 1900kg/m 3 .

The resistance of plastic to corrosion and chemicals it is preferable to steel. This material is also better in terms of electrical safety and does not interfere with radio waves in the room. In general, no specialist can decide which material is preferable.

Only by completing other elements of the building and comparing it with the calculation of the structure using steel reinforcement, you can get a reasoned answer. And only after that we reinforce the details of the building and concrete products calmly and with confidence in the chosen material.

In conclusion, it should be noted.

Experience with this type of reinforcement appeared in construction several decades ago. Despite this, the method has gained a significant foothold in the concrete materials market. The scope of fiberglass reinforcement is quite wide.

These are the manufacture of greenhouses on a peasant farmstead, low-rise construction, use in the construction of highways. In each of these areas, the consumer receives reliable and lightweight construction at minimal cost forces and means.

Reinforcement made of metal rods until recently was considered not only the most reliable, but also the only acceptable option for creating a solid "skeleton" of the foundations of buildings for any purpose. The material that will be discussed did not appear yesterday (there are references to the experience of its use since the late 70s). But composite reinforcement did not gain popularity, so they forgot about it in our country for a while. But in foreign countries it was actively used. Therefore, it is possible to talk about the successful use of composite rods for reinforcing concrete structures. And to judge the strength and stability of such structures is obtained not unfounded, but on the basis of facts.

A few myths from unscrupulous manufacturers and sellers

Fiberglass reinforcement, although not a new (as it turned out) material, is unfamiliar to most consumers. The fact that advertising positions it as an innovation is nothing to worry about. It is worse when, taking advantage of the ignorance of potential customers, the manufacturer tries in every possible way to increase the selling price of the product, pointing out the supposedly unique properties of its composite reinforcement.

Composite reinforcement photo

While an ordinary private developer is collecting information about it bit by bit, getting acquainted with the properties and features of its application, and large construction companies are engaged in calculating the revenue and expenditure side of the budget when switching to composite instead of metal, rumors are growing and multiplying. And they need to give a reasonable and honest answer.

One of the most common myths can be debunked right now.

Outwardly this construction material represents light rods with various shades yellow color(if they are made of fiberglass) or pronounced black (provided that basalt was used). However, an attempt to make the product more attractive in appearance, namely the addition of a coloring pigment of various shades, made it possible to bring colored fittings to the market. And immediately a myth appeared: these additives do not simply color the bars, but are special components that improve the characteristics of the material. Serious manufacturers give an unequivocal answer: color does not affect the quality of composite reinforcement.

In addition to improving the presentation, behind such experiments with color there is also a very noble impulse: to highlight bars of various diameters.

Reading the regulatory documentation for building materials will help you not to succumb to the tricks of dishonest sellers.

The use of composite reinforcement

Composite reinforcement is gradually gaining space from a metal counterpart in the area of \u200b\u200bfoundation low-rise buildings. Glass, carbon, basalt or armide fibers are taken as the basis for its production. They are linked together by adding polymers.

Fiberglass reinforcement can also be produced in the form of smooth rods, but in the case when it is supplemented with a spiral winding of glass thread, a more reliable adhesion to the poured solution is provided. So it is better to give preference to the second option.

Experts call a number of advantages of composite reinforcement:

ease of transportation and use due to low weight. In addition, the installation does not apply welding work;
resistance to various aggressive environments;
resistance to corrosion;
breaking strength.

To create a foundation, composite reinforcement of a certain diameter is required. The section is calculated individually for each object. It depends on the number of storeys, the complexity of the project and a number of other reasons. At the same time, it is important that, not inferior in strength to metal bars of the same diameter, composite reinforcement will differ in lighter weight.

Composite reinforcement for foundation

Composite bars when laying the foundation are used similarly to steel ones. A frame is assembled from them according to the recommendations for a certain type of base with the desired pitch, and at the intersections, the reinforcement elements are fastened with ties or knitting wire.
Developers and manufacturers do not give recommendations prohibiting the use of composite reinforcement for the construction of any type of foundation. That is, if the developer wishes, any foundation for a low-rise building can be made using fiberglass reinforcement.
But it is possible to determine exactly in which foundations composite rods have proven themselves with the best side. We are talking about tape or columnar methods for buildings with a height of no more than three floors. For those who wish to build: a private house, cottage, sauna, garage, a solid building for household purposes.

The service life of elements of non-metallic origin is quite large - 80 years according to minimum calculations. Their cost, perhaps only slightly differs from the price of the usual steel bars, but it is quite possible to save on transportation. Fittings packed in a bay will easily fit into the trunk of a passenger car.
Construction conditions and technologies are different. Where reinforced concrete structures will be operated in the presence of an environment aggressive for metal, it makes sense to use non-metallic reinforcement.
Composite reinforcement, selected with equal strength to the reinforced concrete frame, will create a reliable foundation. And it will last much longer (due to resistance to the damaging effects of the environment and “complete indifference” to the corrosion process).

For massive buildings made of concrete, the following types of fiberglass reinforcement are used:

External. It is justified in those cases when concrete structures are subjected to destructive effects, being in an unfavorable environment.
- The characteristics of composite reinforcement, produced specifically for these purposes, allows you to create a protective barrier around the structure. It is impervious to neither air nor water. This method is called continuous. Sometimes, using it, they do the opposite. First, the frame is made, and then it is poured with concrete.
- The discrete method means that composite meshes or rebar strips reinforce the foundation from the outside.
Internal. It is also divided into two ways.

Discrete reinforcement assumes that composite meshes, individual rods or even three-dimensional frames created from many elements will be laid inside the structure.
Dispersed method somewhat simpler - crushed fiberglass is added to the total mass for pouring. The resulting material is called glass fiber reinforced concrete.
A joint. The combined method got its name not only because of the simultaneous use of two types of reinforcement, but also because it allows a combination of fiberglass and metal rods. It is used in the case when significant weight loads are expected on the foundation.

Composite rebar diameter

If you have not encountered such a problem so far, then the following information may be useful.

Metal fittings due to their design features has several indicators characterizing the diameter:
- external is measured along the ribs protruding along the profile;
- the inner one belongs to the rod itself;
- nominal, which is expressed as an integer, is the profile number.
They do not match, the diameter measured on the outside exceeds the nominal value. You should be extremely careful not to buy fittings of a smaller diameter than required, guided by these dimensions.
The definition of the above dimensions for fiberglass reinforcement has nuances. The outer diameter is determined for it in exactly the same way as for steel. When trying to get values inner size some difficulties arise.
The fact is that composite reinforcement does not have a perfectly round rod shape. This is due to the fact that numerous lines that produce this building material, due to certain features, cannot maintain such accuracy. So the fiberglass rods on the cut have a shape tending to an oval. And the larger the diameter of the bar, the more clearly the oval is visible. When measuring such a product for the first time, the consumer will receive one result. Turning the rod 90 °, repeating the procedure, he will see other numbers. The figures should be summed up and divided by 2. The result can be considered as an average indicator of the internal diameter of the composite reinforcement.

In order to carry out work on the calculation and when purchasing the material, it is required to know the nominal diameter. Under the conditions available to simple House master, this indicator cannot be obtained. For those to whom the solution of such a problem is vital, there is one trick.
The nominal diameter is, in fact, the average number between the dimensions of the outer and inner gauges. Further, the less often the ribs are located on the rod, the more the inner diameter approaches the nominal value in value.

That is, to catch an unscrupulous seller who is trying to give out the numbers of the outer diameter for its nominal size, you can do this:

you need to measure the outer diameter;
take measurements of the inner diameter;
compare the number given by the seller with both indicators.

If the outer diameter matches the nominal number according to the seller, the fittings should be bought elsewhere.

Weight of composite reinforcement

Methods for connecting composite reinforcement

Among the advantages of composite reinforcement listed above, one of the points indicated that its use does not involve welding. The bars are assembled into a frame by tying together.

Plastic ties are used less frequently, but builders value knitting wire more. This material is more traditional and has not yet been eradicated by new trends. It is carried out in the following ways:

using an automatic pistol;
using a crochet hook for construction (simple configuration);
using a screw (mechanized) construction crochet hook.

The popularity of the last two options is due to the availability of the tool. Few people can afford to buy an expensive gun for the sake of building one foundation. Some large companies, however, practice leasing expensive, but very simplifying inventory. And if such an opportunity falls, then it is worth taking advantage of it.

Among the arguments "for automation" of the knitting process are the following:

it is quite obvious that mechanized labor is more efficient and productive;
having such an "assistant" you can not overpay hired workers. With its use, one person will cope with the strapping on their own;
the gun performs equally even and strong knots on the entire frame;
the tool is functional at any temperature;
The powerful battery allows you to work all day without interruption.

Particularly advanced models of this tool are equipped with a device that allows you to bind rods without leaning close to them.

Foundation with composite reinforcement and construction in earthquake-prone areas

Another proof of the excellent strength characteristics of composite reinforcement can be considered its use in other areas of construction that require resistance to significant loads: walls and floors of buildings, roadbeds, coastal structures, bridges.
But rarely where you can find a mention that composite reinforcement can withstand impressive tremors. research institute building structures Named after Kucherenko about five years ago, they dealt with the issue of the behavior of this material under high dynamic loads. Reinforcement with a diameter of 8 mm was tested with an "earthquake" from 5 to 10 points. With its help reinforced prototypes panels, which were subjected to appropriate loads, were placed on vibration platforms. The material remained intact up to a seismic activity of nine!

Composite rebar video

Fiberglass reinforcement is a durable and easy-to-use material. Today, it is a worthy replacement for metal rods, and its use for pouring foundations for low-rise construction can be considered not only justified, but also an extremely desirable action on the part of the developer. That is why there are so many positive reviews about composite reinforcement among private developers.

Composite reinforcement is not a new material, but today it is actively expanding the boundaries of application, thanks to economical technologies for the production of polymeric materials. This modern alternative to steel reinforcing bars and wire differs from metal counterparts in terms of raw material base, technical properties and appearance. Produced in accordance with GOST 31938-2012 and specifications manufacturers.

The main components of polymer composite reinforcement

The composition of this product includes two or more materials - the main (matrix) and fillers, including reinforcing ones. The matrix and filler are selected in such a way that they make up overall structure, providing optimal performance for a specific purpose.

Matrix

It is a cured thermosetting resin that provides stress transfer and distribution in the reinforcing filler. The resistance of products to moisture, fire, and chemical environments depends on this structural component. Thermosetting resin - polyester, epoxy, vinyl ester, phenolic - after curing is solid material with a three-dimensional grid structure.

Reinforcing fillers They are fibers - continuous or staple, depending on the method of manufacture. Depending on the raw materials used, fibers are distinguished:

glass- are made of inorganic glass.
Basalt- made from basalt and habrodiabase.
Carbon- are formed by pyrolysis of organic fibers of precursors - polyacrylonitrile or hydrated cellulose. According to the value of the modulus of elasticity and tensile strength, carbon reinforcing fillers are divided into - general purpose, high-strength, medium-, high-, ultrahigh-modulus.
Aramid. Feedstock - linear fiber-forming polyamides.
Combined composites include reinforcing fillers from two or more raw materials. For example, ASPET rods contain glass fibers and fibers made from thermoplastic polymers.

Polymer composite reinforcement is designated in accordance with the reinforcing filler present in its composition:

ASK (ASP)- glass composite, the advantages of the material - a combination of low weight, high strength and affordable cost;
ABC (ABP)- basalt composite;
AUK (AUP)- carbon composite, has good strength, but due to the high cost of its use is limited;
AAK (AAP)- aramid composite;
ACC- combined. In this series, products made on the basis of glass and basalt fibers are widely used due to the combination of good wear resistance and reasonable cost.

Table of main characteristics various kinds composite reinforcement

Design features

It is made with a periodic profile. The product design includes:

Power rod- a solid element on which the main specifications product.
anchor layer. It is located evenly, at an angle to the longitudinal axis. It is formed by winding fibers on a power rod. Improves the adhesion of polymer reinforcement to the hardening concrete mix.

The reinforcement of a periodic profile is characterized by the following parameters:

Outside diameter. It is measured along the tops of periodic protrusions.
Nominal diameter. This value is indicated in the labeling of products and is used in structural calculations.
Periodic Profile Step. The distance between the centers of adjacent protrusions is determined parallel to the vertical axis of the rod.

Positive and negative characteristics of polymer composite reinforcement

This type of reinforcement cannot yet act as a full-fledged replacement for steel reinforcing bars. However, there are areas of application in which the use of composite reinforcement is more rational, due to a set of advantages, including:

Chemical passivity. Due to this property, polymer products can be used under conditions of exposure to sea water, alkaline and acidic environments, and road chemicals.
Cutting speed in size under construction site conditions is much higher compared to cutting steel rods.
Low thermal conductivity. Polymer reinforcement increases thermal insulation characteristics design, due to the absence of cold bridges.
Low temperature resistance.
small mass. Facilitates the transportation of products, storage, installation work.
Lack of current conductivity, magnetoinertness and radio transparency. This quality ensures the demand for polymer products in the construction of laboratories and other facilities for which the shielding factor of electromagnetic waves is important. In structures that use polymer reinforcement, there are no stray currents.

Characteristics that limit the scope of composite reinforcement:

The impossibility of bending the rods at a small angle at the installation site. If there is such a need, then the manufacture of bent products is ordered at production sites.
Low modulus of elasticity, limiting the use in vertical reinforcing structures.
The possibility of welding frames is excluded. Flat and three-dimensional structures made of polymer rods are constructed only by binding and with the help of plastic clips.
Little resistance to high temperatures . Therefore, it is not recommended to use such products in structures that are exposed to heat, or at objects with a high fire hazard.
Aging. Like all polymers, composite rebar loses its performance over time. Although manufacturers claim that its operational period is at least 80 years.

Areas of use

This building material is most effective in areas where the use of metal reinforcement is undesirable or impossible. Polymer reinforcing rods are used for:

installation of foundations for buildings operated in aggressive environments;
strengthening foundations or load-bearing walls;
strengthening of the roadway, embankments;
soil strengthening in mines;
formwork devices for large tanks;
reinforcing floor screeds;
fortifications of the coastline;
production of flexible connections between the structural elements of buildings, for example, between outer wall and finishing facade material.

Attention! The use of composite reinforcement in floor slabs, lintels and other structural elements, working in tension, is not recommended due to the high flexibility of the material.

Comparison of properties of polymer composite and steel reinforcement

Table comparing the characteristics of fiberglass and steel reinforcement

Reinforcement type Steel FiberglassMaterial 7900 1900 360 800 200 55 24 High resistance, no anti-corrosion measures required high 47 0,46

Low alloy steel 25G2S or 35GS	Inorganic glass melt fibers, thermosetting resins and other additives
Density, kg / m 3
Tensile strength, MPa
Modulus of elasticity, GPa
Relative extension, %	2,3
Resistance to chemically aggressive environments	Subject to corrosion, to improve the anti-corrosion characteristics required protective covering such as zinc
Electrical conductivity	Absent
Thermal conductivity, W/mK

As an argument in favor of replacing steel reinforcement with polymer, the possibility of using a polymer product of a smaller diameter, compared to a metal one, is given, based on the standard values of tensile strength. By order of the Ministry of Construction and Housing and Public Utilities of the Russian Federation No. 493 dated July 8, 2015, in Appendix “L”, reduction factors were established for the normative tensile strength, taking into account real operating conditions.

Table of reduction factors to the standard values of tensile strength, presented in GOST 31938-2012

This table means that if a polymer composite reinforcement, such as fiberglass (FRP), is designed to operate under long-term loads in a room, then the calculated value of tensile resistance is found by the formula:

R calc. = R normal * 0.8 * 0.3 = 800 * 0.8 * 0.3 = 192 MPa

Therefore, when choosing the diameter of polymer reinforcement, which should replace steel reinforcement, one should not use the normative values of tensile strength presented in GOST, but calculated in accordance with actual operating conditions.

In connection with the above factors, it can be concluded that composite reinforcing rods are a promising building material. However, it is effective only in certain areas of application, before using it, it is recommended to consult with qualified specialists.

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Strict competition requirements in the field modern construction forced to look for ways to reduce costs, including the use of new materials. There are new formulations of building stone, special grades of concrete, foundation compositions, facing and thermal insulation materials. At the same time, manufacturers of various composite products are actively trying to win a "place in the sun" in the market, previously traditional for metal fittings and special structures. Most often, these are non-metallic power elements and fiberglass reinforcement.

Why fiberglass reinforcement appeared on the construction market

Composite materials, including fiberglass reinforcement, are manufactured according to a relatively simple technological principle of impregnating glass or basalt fibers with epoxy or polyester resin matrices. Further, the beam is formed on the machine into a bar of composite reinforcement calibrated in diameter, and baked at a low temperature in a special drying oven. Usually the length of one piece of reinforcement does not exceed 100 m.

Fiberglass reinforcement does not require the operation of complex and expensive equipment, therefore, production costs are relatively small, most of the cost is the price of resin for the matrix and fiberglass tow. And yet, if we compare the cost of fiberglass and steel bars of the same diameter, metal fittings have a warehouse price of 10-20% less, and this is very a big difference for areas such as construction.

Nevertheless, fiberglass material quite strongly pressed rolled metal products, not least because of a number of specific properties, but slightly different reasons became the main factors:

Fiberglass reinforcement is increasingly being used in private low-rise construction. It is more accessible in work, it is easier and much cheaper to transport, store, cut. It does not need to be straightened and leveled before use, as is the case with the steel version. The material can be bought in a whole bay and cut into pieces of the most non-standard length. Whereas a standard 11-meter steel bar would have a lot of waste if your foundation, for example, has reinforcement 8 m long;
The availability of equipment for the production of reinforcing tow allowed many small enterprises - manufacturers of building materials to establish in-line production of fiberglass reinforcement in the most various options execution of the surface of the bar. A huge number of offers, a competent sales policy and hidden advertising allow diversifying the market;
The desire of contractors to save in construction work on a more favorable material for reinforcement, for which a formal, “blind” recalculation of the equivalent strength of composite materials and steel reinforcement is often used.

Reviews of experts, advantages and disadvantages of composite thread

If you wish, you can find the most complex calculations and fairly simple primitive arguments about what good or bad fiberglass reinforcement is. As a rule, serious studies and reviews of specialists in most cases do not give specific recommendations, in fact, the “hot” problem of the foundation, in many respects the possibilities of fiberglass-based reinforcement have to be evaluated at your own peril and risk.

Attention! Among the numerous reviews of specialists, there are practically no true professional experts in the field of structural mechanics of composite materials. Their opinion and feedback, as a rule, are reflected in the estimates and custom-made calculations for specific construction projects, cost a lot of money and are not submitted to the public.

An approach can be called professional if the reviews of certain experts evaluate a specific situation of using, for example, a fiberglass rod in the foundation of a house using practical results and analyzing the reasons. Otherwise, such reviews of specialists can be called advertising or anti-advertising at best.

The use of fiberglass rod in the foundation

Application reinforcing mesh based on fiberglass power elements began in the 60s of the last century. In addition, enough has been built and is in operation a large number of buildings and technological structures made of stone and concrete, in the foundation and walls of which fiberglass-based reinforcement is used. Feedback on the state of buildings with elements of steel and fiberglass reinforcement and years of experience exploitation will give more than all the theoretical calculations of the "experts" combined.

Almost everyone who shoots videos or posts their opinion about the shortcomings of fiberglass reinforcement is either sales managers of competing rolled steel, or amateurs who confuse the causes and consequences of the basic principles of strength and rigidity of structures. For the most part, such arguments about the shortcomings of fiberglass reinforcement are accompanied by formulas and data on the strength of steel and composite. But there are no clear reasons or processes for which fiberglass reinforcement cannot be used. If a person who undertook to comment on the advantages and disadvantages of fiberglass reinforcement did not demonstrate in practice a fragment of destroyed concrete or a piece of foundation with fiberglass reinforcement, all his reasoning remains fantasies on an arbitrary topic.

Fiberglass reinforcement has been used in construction, mechanical engineering, and in special projects for more than 40 years. If this question is fundamental for you, refer to the old Soviet textbooks of the 70s of the last century, magazines on construction topics, these sources reveal the physics and mechanics of the foundation destruction processes, give numerous examples of errors.

With high specific strength, fiberglass reinforcement can work perfectly in the most difficult conditions, but at the same time it has a number of disadvantages that limit its use in construction:

The fiberglass nature of composite reinforcement has almost zero plasticity of the material. Speaking in human terms, a frame for a highly loaded foundation or walls made of such a bar will not be able to plastically adapt to the redistribution of the load in a loaded concrete stone. As a result, in some places the foundation of the building will experience overload, which can cause cracks;
The fiberglass base perceives tensile axial loads very well, compressive loads are much worse, and catastrophically poorly tolerates shear forces. This means that any transverse shear force, of which there are many in “fresh” foundations due to sedimentary processes, will lead to the destruction of the integrity of the reinforcement;
Unfortunately, during the time that the concrete of the foundation is gaining strength, the fiberglass frame behaves somewhat differently, and at this stage, therefore, each specific case in the layout of the reinforcement requires a very careful and accurate analysis.

Therefore, in those units where it is permissible to replace metal with a composite material, instead of the traditional eight-millimeter rod, a six-millimeter fiberglass tow can be used. Few people know, but today building slabs from stressed concrete with fiberglass reinforcement are already being produced on the stream. But in production, such material is much more expensive, so almost 90% of the range, including for the foundation, are custom-made products.

Options for the use of glass fittings

The undeniable advantage of steel reinforcement is the very well predictable behavior of the metal under the most difficult load conditions. All existing skyscrapers and high-rise buildings are built only on steel reinforcement, moreover, most of these "wonders of the world" have an internal metal frame.

Glass fittings for high-rise buildings or highly loaded foundations will not work. The construction mechanics of foundations is, in general, a whole science, primarily due to the complex interaction of individual parts of the foundation with the ground, with the walls of the entire structure.

IN existing model foundation, the most problematic are the corner zones, where the reinforcement experiences tensile, bending and shear loads. In these places, not every steel reinforcement is able to provide a rigid bundle of corner blocks. The metal reinforcement in the foundation block succeeds only due to the combination of high ductility and elasticity. Fiberglass reinforcement in these foundation nodes cannot be used. Despite the high longitudinal strength, it will not be able to withstand twisting and shearing at the corner contact point of the foundation.

The strength and ductility of fiberglass reinforcement will be enough to build a foundation and a basement one or two-story house. But on the condition that special couplings will be used in the corner joints of the foundation for splicing the reinforcement at a right angle. Moreover, fiberglass is easy and simple to use for a simple strip foundation 70-90 cm deep.

It is considered successful to use fiberglass reinforcement paired with special grades of concrete for the foundation. Often, under the conditions of using special additives in the foundation that enhance frost resistance or water resistance, steel reinforcement begins to corrode intensively. Especially in foundations on soils with high content salts or in close proximity to transformer substations.

Within the walls of low-rise buildings, especially from aerated concrete block, wood concrete stone and any other building material with low rigidity and contact strength, the use of fiberglass reinforcement is even welcome. It is much simpler and easier to work with it than with a steel bar.

In addition, composite reinforcement is simply ideal for fixing external insulation or laying facing bricks, where either galvanization or stainless steel is required. And, all the more worth using a thin glass thread for work on the basement blocks of the foundation.

Conclusion

There is one more problem characteristic of the Russian reality, which is definitely worth mentioning. This is the low quality of the fiberglass reinforcement of the domestic manufacturer. Almost every bay with reinforcement has fracture defects.

During storage and transportation, a metal bar can be stolen or barbarously unloaded in an inconvenient place far from the foundation. But in any case, its quality will not suffer. Fiberglass thread can be easily damaged during transportation and not even noticed. It is definitely impossible to lay such reinforcement in the foundation.