Fiberglass reinforcement has many advantages - it is lightweight, durable, does not corrode, which is why it is actively used in construction. Nevertheless, this material also has certain drawbacks, which are usually not critical, but it is still necessary to take them into account. They somewhat limit the scope of this material. Let's take a closer look at the disadvantages of fiberglass reinforcement.
1. Insufficient heat resistance
Despite the fact that the fiberglass underlying the reinforcement is very heat-resistant, the binder plastic component does not withstand high temperatures. This does not make this material flammable - in terms of flammability, this reinforcement corresponds to group G1 - self-extinguishing materials, but at temperatures exceeding 200 ° C, it begins to lose its strength properties. Therefore, if fire resistance requirements are imposed on concrete structures for any reason, fiberglass reinforcement cannot be used for them. So you can use fiberglass fittings only in those construction areas where high-temperature heating is completely excluded. It should be noted that this is quite applicable to any housing construction and to most of the industrial construction.
It is also worth noting the low resistance to fires: if the temperature reaches 600 ° C, the concrete frame is practically left without reinforcement. Consequently, such fittings cannot be used in fire-hazardous places.
2. Low modulus of elasticity
Due to the low modulus of elasticity, fiberglass reinforcement bends easily. If this in no way interferes with the manufacture of road slabs and foundations, then special calculations will be required when constructing floors. But at the same time, the elasticity turns out to be sufficient so that curved elements cannot be bent from the reinforcement, therefore such parts are bent in production conditions.
3. Other disadvantages
Over time, the strength of fiberglass reinforcement decreases, and under the influence of substances with an alkaline reaction, it collapses. However, a technology has appeared, during which rare earth metals are leached from fiberglass, and it becomes insensitive to alkali.
Many attribute to the disadvantages of fiberglass reinforcement the impossibility of welding, although they now prefer to knit metal reinforcement.
Conclusions:
Thus, the disadvantages somewhat reduce the scope of its application, but for mass use for construction purposes they are not at all an obstacle.
2. Low modulus of elasticity
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, the developers were presented with fiberglass reinforcement, which began to compete with the time-tested steel rods.
Pros and cons of fiberglass reinforcement
Fiberglass has advantages over steel that are worth considering in detail.
pros
- Less specific gravity. The mass of the building is reduced significantly, and this is important in certain conditions of construction.
- Corrosion resistance - does not rust or rot.
- Its tensile and compressive strengths are much better, which is important for the construction of multi-storey structures.
- Resistant to aggressive, chemical environment.
- The range of application at various temperatures is from -60 to +100 degrees.
- Applicable in any geographic latitude.
- Simplicity and ease of transportation. Fiberglass fittings are sold in small coils, they are compact, so that if necessary, they can be transported by passenger 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, you need to use protective equipment for both the respiratory tract and the hands.
- Absolute radio transparency of this type of reinforcement.
- Profitable 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, you can use fiberglass reinforcement 8 mm in diameter.
- It does not conduct electric current, which makes it preferable for the construction of buildings and structures in the energy sector.
Minuses
Despite the positive aspects, there were some drawbacks.
- Low flexural elasticity. If supporting structures are being designed, then this must be taken into account.
It will not work to equip welded seams on this reinforcement, but this is often impractical if it is 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 disadvantages, they must be taken into account during construction.
Pros and cons of steel reinforcement
Steel products also have advantages and disadvantages.
pros
- Time-tested. Material release standards have long been developed. There are regulatory documents that specify steel reinforcement.
- A varied number of bar sections. Available in the range from 3 to 80 mm.
- Long and predictable service life. Such fittings serve for more than 50 years, provided they are not in contact with water and a chemical environment.
- Has good flexural readings. This material has an elasticity 4 times better than fiberglass reinforcement. Its flexural strength is much higher.
- Availability. Sold in many construction markets.
- Several mounting methods. Can be tied with wire, fastened with clamps or welded.
- 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 simply bend it into an angle of 90 degrees. With this in mind, it is easy to manufacture anchoring elements directly on the construction site.
- Excellent adhesion to concrete. The coefficient of linear expansion of the mortar and reinforcement is practically the same, which makes it possible to obtain a durable tandem.
- Frost resistance. If the reinforcement is installed in places with high negative temperatures, then its structure remains unchanged.
Minuses
- Restriction on the length of the bars. The maximum length of steel reinforcement elements is 11.7 meters; rods of 12 meters are rarely found.
- High specific gravity. To deliver this material to the site, special cargo equipment will be required.
- Corrosive tendency. 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 cannot be stored for a long time in an open area and on the ground, the material is covered with rust in a few months.
As you can see, the disadvantages are not comparable in number 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 fittings is greater and similar to concrete, which cannot be said about SPA.
- Fiberglass is non-conductive, and metal is electrically conductive.
- The range of cross-sections for steel structures is much larger, therefore, their use on complex construction projects cannot be replaced by fiberglass reinforcement.
- Fiberglass is sold in bays - 50, 100 and 150 m.
- The cost of composite reinforcement 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. When constructing a heavy building, rods are taken of a larger section than that of steel material. In fact, the difference in price, on the scale of construction, remains open to question.
Finally
From a comparative analysis, it is clear that fiberglass reinforcement is well suited for 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.
In construction, as in other industries, they increasingly resort to using the latest technologies and innovative approaches in the production of goods and services. Fiberglass reinforcement is an example of such an alternative solution. She quickly replaced traditional metal parts, overtaking them in economic and technical parameters. From this article you will learn what fiberglass reinforcement is. The characteristics of this material will be presented in comparison with others.
Fiberglass reinforcement - what is it?
Reinforcing means, or non-metallic fiberglass reinforcement, is a kind of rod with a ribbed surface made of glass fibers. Its profile is helical, and its diameter varies from 4 to 18 mm. The length of the armature can be up to 12 meters. Sometimes it is found in the form of twisted coils, the diameter of such a building material is 10 mm.
Abroad, fiberglass reinforcement, the use of which is as widespread as ours, is called polymer equipment. It is reinforced with continuous fiber. In Russia, you can often find the abbreviation AKC.
What is fiberglass reinforcement made of?
The physical body of the AKC consists of several parts:
1. The main trunk. It is made of parallel fibers that are bonded with a polymer resin. The main barrel provides strength to the reinforcement.
2. Outer layer - is a fibrous body. It is wound in a spiral around the AKC barrel. It is found in the form of sand spraying or bi-directional winding.
There are various variations of fiberglass, it all depends on the imagination of the manufacturer and the appropriateness of the know-how. On sale you can find fittings, the main trunk of which is made in the form of a carbon fiber pigtail.
Basic properties
A lot of research and testing has been done to determine the properties of fiberglass. The results obtained characterize AKC as a high-strength and durable construction equipment, which has a number of advantages over other materials:
- light weight (fiberglass is 9 times lighter than metal reinforcement);
- resistance to corrosion in acidic and aggressive chloride environments (10 times higher than the properties of steel reinforcement);
- low thermal conductivity;
- economy (it is more profitable to transport it, and replacement is carried out less often);
- magnetic inertia;
- radio transparency;
- the armature is a dielectric.
Fiberglass reinforcement: disadvantages
In addition to the indisputable advantages of AKC, thanks to which it has gained great popularity among construction companies and ordinary people, it has its drawbacks. Of course, it is very difficult to call them critical. However, it is worth keeping in mind the negative characteristics of the material, which can affect the construction process.
So the disadvantages:
- low;
- insufficient indicator of heat resistance;
- others.
Due to its low elasticity, AKC is easy to bend. For the manufacture of the foundation and tracks, this is not a serious disadvantage. But in the case of the production of floors, additional calculations need to be made, taking into account this feature of the reinforcement.
Insufficient heat resistance is a more serious drawback of AKC. The fact that fiberglass itself is heat-resistant does not mean anything. The plastic binder does not withstand high temperatures, but the reinforcement belongs to the group of self-extinguishing materials. This property is valid up to a temperature of 2000 degrees Celsius, after which the AKC loses its strength. Therefore, the use of fiberglass with concrete is prohibited. Such fittings can be used only in those areas of construction where temperature drops are completely excluded. However, these requirements are almost always met in ordinary residential and some industrial buildings.
Fiberglass reinforcement, the disadvantages of which were listed above, has a number of negative aspects. Over time, its strength is destroyed, and under the influence of alkaline compounds, the reaction rate increases several times. But modern technologies make it possible to cope with this disadvantage. Rare earth metals are added to the AKC, which make fiberglass less sensitive.
Some experts note the fact that such fittings do not tolerate welding. Therefore, many people prefer to "knit" fiberglass whips.
Fiberglass production
We very often use fiberglass reinforcement at home, for example, in the pouring of foundations, etc. AKS production does not have to be in-line. Many auto repair shops that tune cars produce this material in various configurations. - a common thing for services: they can make a new bumper and other parts out of it. But in this case we are talking about small-scale production. Only large industrial enterprises put AKC on stream.
There are several basic manufacturing methods:
- broaching;
- winding;
- manual way.
The first method is used to make various profiles. Glass fibers are unwound on a continuous flow line. Most often, parallel beams of material are unrolled from the bobbins, which do not twist together. Experts call this element of production roving. Before the bobbins go into action, the fiberglass is lubricated with a resin containing substances that polymerize it at high temperatures. Gradually, the material will harden, and this effect is achieved due to the chemical reaction that has occurred. Then the fiberglass passes through filters that free the material from excess resin, and the AKS takes on its usual cylindrical shape. Until the reinforcement has hardened, a special bundle is wound around it in a spiral. It is he who provides strength in contact with concrete. Due to this property, fiberglass reinforcement is increasingly used for the foundation. The reviews that builders leave are often positive.
After all the manipulations, the AKC passes through the oven, where it hardens at a high temperature. Next, the finished reinforcement is cut into pieces of the required length (they are called whips). Sometimes AKC is wound on bobbins, but this is possible only if it has a small diameter. Thick lashes are simply impossible to twist. Such fiberglass reinforcement, the use of which is very common, is produced in large quantities when it comes to large-scale production.
The winding method is most often produced. They are made according to the same principle as the whips. Fiberglass impregnated with resin is wound onto a special machine. The winding device, due to its rotation, makes it possible to obtain a cylindrical surface. The fiberglass is then passed through a high-temperature oven and cut into tubes of specified dimensions.
The manual method is most often used in small batch production. Fiberglass reinforcement, the disadvantages of which do not so much affect the final result, allows you to get a durable car body, bumper, etc. Craftsmen create a special matrix with a preliminary applied decorative and protective layer. This is usually done using a spray bottle to achieve a uniform effect. After that, glass material is laid on the matrix, which is cut out in advance according to the required dimensions. Glass cloth or glass mat is impregnated with a mixture of polymer resin. It is best to use a brush. With the help of a roller, the remaining air is squeezed out of the material so that there are no voids inside the fiberglass. When the fabric has hardened, it is cut, given the desired shape, holes drilled in it, etc. After that, the matrix can be reused.
Specifications
Fiberglass reinforcement is characterized by the following parameters:
- winding step;
- inner and outer diameter.
Each profile number has its own value of indicators. The only parameter that remains unchanged is the winding step. It is 15 mm.
According to TU, fiberglass reinforcement, the characteristics of which differ depending on the profile, are produced under the following numbers: 4, 5, 5.5, 6, 7, 8, 10, 12, 14, 16 and 18. These values \u200b\u200bcorrespond to the indicator of the outer diameter. The weight of the profiles varies from 0.02 to 0.42 kg / 1 l. M.
Kinds
Construction fittings come in many varieties. There are classifications that subdivide it into:
- piece;
- mesh;
- frames;
- constructions.
The fittings are also divided into groups:
- working;
- distribution;
- assembly room;
- reinforcement used in reinforced concrete structures.
In addition, rods are divided into longitudinal and transverse, smooth and round, fiberglass and composite, etc.
Scope of application of composite reinforcement
The scope of application of the material we are considering is quite wide. Very often composite reinforcement (fiberglass) is used for the foundation, namely for reinforcing elastic foundations. In this case, we are talking about the production of road slabs and slabs. Reinforcement with fiberglass reinforcement is used for the production of conventional concrete structures, drainage pipes, dowels, etc. With its help, they improve the characteristics of walls, make flexible connections between brickwork. AKS is used to reinforce car cloths, embankments for a weak base, monolithic concrete, etc.
Transportation
Fiberglass reinforcement comes in the form of coils that can be rolled up. This became possible after the manufacturers removed the self-tightening ties. The AKS coils can be easily deployed, after which the fiberglass is straightened and becomes suitable for work.
The material is packed and transported horizontally. The main thing during transportation is to follow the basic rules for the transportation of goods.
Comparison of fiberglass reinforcement with steel
AKC's main competitor is steel reinforcement. Their characteristics are in many ways similar, but in some respects, fiberglass is clearly superior to the usual type of metal equipment.
Let's compare fiberglass with steel according to some parameters:
1. Deformability. - elastic-plastic, AKS - ideal-elastic.
2. Ultimate strength: steel - 390 MPa, fiberglass - 1300 MPa.
3. Coefficient of thermal conductivity. In the first case, it is equal to 46 W / mOS, in the second - 0.35.
4. Density. Steel reinforcement has a value of 7850 kg / m 3, AKS - 1900 kg / m 3.
5. Thermal conductivity. Fiberglass is not thermally conductive, unlike steel.
6. Corrosion resistance. AKS is a stainless metal, steel corrodes relatively quickly.
7. Ability to conduct electricity. Dielectric is fiberglass reinforcement. The disadvantages of steel rods are that they are 100% current conductors.
Composite rebar is a fairly young material that has become available on the construction market not so long ago. However, due to its many advantages, it has gained wide popularity. Many manufacturers claim that such products are capable of completely replacing steel reinforcement. However, its application is not always justified. It is worth taking a closer look at both the advantages and disadvantages of a composite. This will allow you to choose a material that will last for many decades.
Composite reinforcement is a rod made of fiberglass. A carbon fiber thread is wrapped around it. Due to its use, not only the strength of the product is provided, but also reliable adhesion to concrete. Such products have both a number of advantages and certain disadvantages. For this reason, it is not always possible to use it.
Fastening of carbon fiber rods is carried out with special clamps. There is no need to use welding for bonding. This is its significant advantage.
For each situation, it is worth considering the features of using such products. Application of this approach will ensure the reliability and efficiency of fastening various structures.
With insufficient consideration of the characteristics of the product and without comparing them with metal reinforcement, it is possible to significantly harm the building structure if composite materials are used. For this reason, even before using composite products, it is worthwhile to find out in which cases their use will be appropriate.
Important! It is also worth paying attention to the physical and mechanical properties of composite products.
Main advantages
Composite reinforcement has a number of positive qualities. Among its main advantages are:
Also, the material has many disadvantages that should be considered in more detail.
Main disadvantages
Before purchasing fiberglass reinforcement, you should learn about all of its characteristics, as well as about the main disadvantages. The disadvantages of the material include:
- She does not tolerate high temperatures. However, it is quite difficult to imagine a case in which it can heat up to 200 degrees inside a concrete structure.
- High price. However, this disadvantage is overcome by the possibility of using carbon fiber products of a smaller diameter than metal products.
- Composite reinforcement has poor bendability. This property imposes certain restrictions when using it to strengthen a concrete structure. However, bent sections can also be reinforced with steel rods.
- Such products do not cope well with fracture loads. This circumstance is critical for most concrete structures.
- Compared to metal reinforcement, fiberglass products are less rigid. This disadvantage does not allow to transfer large vibration loads that appear when pouring concrete using a car mixer. When this technique is used, the concrete structure is subjected to great stress. In this regard, design defects are possible.
If we consider the disadvantages of carbon fiber reinforcement, we cannot say about the absolute advantage of one material over another. In any case, when choosing composite products, you should be careful, take into account its pros and cons, as well as the conditions of use in a particular situation.
Important! Since the composite material does not have sufficient flexural strength, it is not suitable for knitting when laying steel rods. For this, it is better to use plastic clamps.
Applications
The armature, which is made of various composites, has found application in both private and capital construction. The rules for its installation can be studied independently according to the manufacturer's instructions. Since there is no point in using composite products in capital construction, it is worth focusing on the construction of concrete foundations for private houses.
The main areas of use of fiberglass products:
To summarize the above, it is worth noting that fiberglass reinforcement can be effectively used in most cases. However, it is worth considering the shortcomings of the material and the associated operating restrictions. They are often specified by the manufacturer.
Important! Composite reinforcement is knitted using plastic clamps.
Can fiberglass reinforcement replace metal
Fiberglass products appeared on the construction market relatively recently. However, a lot of videos and text materials have been created on the topic of its use. Considering the above recommendations, it can be argued that fiberglass products can be used when strengthening walls or for connecting load-bearing structures with partitions.
The main advantage of fiberglass reinforcement is that it does not rust. In addition, when using it, cold bridges do not appear, which cannot be said about metal rods. The use of such material is justified in cases where the building being constructed will not be too heavy. It is also necessary to use it only when building a house on stable ground.
Long-term practice has not yet confirmed the success of this material. There are not enough reviews about him yet to draw a correct conclusion. For this reason, every developer takes a risk in a certain sense using composite rebar. If you plan to erect a structure to which high requirements for strength and stability are imposed, you should choose metal reinforcement.
conclusions
When choosing composite reinforcement for reinforcing concrete structures, it is worth considering its main pros and cons. So, the material is lightweight, easy to transport and has fairly good strength indicators. However, it cannot withstand high fracture loads. For this reason, traditional metal bars should be chosen for buildings with high demands in terms of strength and stability.
Such a composite consists of a fiberglass cord wrapped with a carbon fiber thread. Due to the use of the latter, adhesion to concrete is increased. If you plan to build a lightweight structure, you can use a composite. Typically, composite reinforcement is used in the construction of low-rise buildings. Fiberglass reinforcement is used for both tape and slab bases.
When using fiberglass, it is better to consult with experienced builders. It is especially important to enlist their help when drawing up a construction project.
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Scientific progress does not stand still. This also applies to the construction sector. Every day, more and more alternatives to obsolete products appear on the building materials market. This is the case with steel reinforcement. In recent years, a product such as composite rebar has been gaining popularity. These fittings are of three types: fiberglass, basalt plasticand 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. Externally, it is plastic rods with special technological ribs (like steel reinforcement) or a sand coating.
Ribs and sand are applied to the surface in order to improve the adhesion of the reinforcement to the 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 the manufacturers praise it? This question can be answered only by considering all the pros and cons of composite reinforcement. 
Pros of composite rebar
Resistance to aggressive media... The most important advantage of all types of composite rebar is biological and chemical resistance. These fittings are 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 durability in these parameters.
These areas can be: coastal fortifications, bridge construction, road construction (where there is an effect of anti-ice reagents), concrete work in winter, when various plasticizing, frost-resistant and accelerating additives are added to the concrete mixture.
Relatively light weight. Compared to steel rebar, composite rebar weighs four to eight times less, which helps to save on transportation costs and unloading and loading. In addition, due to the low weight, concrete structures are also lightened, which is important for large scales and volumes of work.
Dielectricity and radio transparency... Since plastic fittings are 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 media, the service life of composite reinforcement is very high. To date, a record of forty years has been recorded. Manufacturers claim that it can last 150 years and more, but since composite reinforcement is used in construction relatively recently, it is impossible to verify this yet.
Ease of installation work... Due to its elasticity, the composite reinforcement is twisted into small coils (with a diameter of just over one meter, depending on the cross-section of the reinforcement), which, together with its low weight, allows it to be transported by a car. In addition, one person can successfully carry out installation work, 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 diameter of rods, 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 and more meters. While the maximum size of steel reinforcement is usually limited to 12 meters.
Cons of composite rebar
- Poor bending performance. Composite reinforcement has a modulus of flexibility three to four times less than that of steel, 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 range of sizes. Due to the limited application, composite reinforcement is produced with a smaller variety of diameters than steel reinforcement. 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 reinforcement can also be welded.
- Low thermal stability. At temperatures above 100-120 degrees, the composite reinforcement begins to melt and loses all its properties. Therefore, in the event 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 little or absent.
- Increased fragility at low temperatures. Even at low negative temperatures, composite reinforcement becomes more fragile.
conclusions
Composite rebar has a number of advantages and can be successfully used in many areas of construction. But a number of significant shortcomings do not allow it to completely replace steel reinforcement.