Recently, chemical anchors have been increasingly used to fasten building elements, structures and equipment to concrete. Their popularity is due to a number of advantages over mechanical counterparts. They have a higher bearing capacity, do not create stresses in the base material and make it possible to securely fix themselves in materials with pores and voids.
How does a chimanker work?
The chemical anchor-fastener consists of a steel rod element and a binding adhesive composition, with the help of which it is held in the hole and forms a single whole with the base material. "Liquid Anchor" penetrates deep into the pores, resulting in a strong bond with the base. Structures are then attached to the protruding end of the rod. It is no longer possible to dismantle the steel element, except to tear it out along with a piece of the building base.
To achieve the required fastening strength, the chemical composition must completely fill the cavity between the metal element and the walls of the hole. In accordance with the technical regulations, the hole is filled with injection mass to 2/3 of its volume. With the correct dosage of the composition, after the introduction of the rod, excess glue should come out to the surface.
The consumption of an injection anchor per fastening depends on the size of the hole (diameter and depth), the diameter of the rod and the type of base (with or without voids). For the convenience of calculating the volume of the adhesive mixture, Krepkom recommends using the chemical anchor calculator https://krepcom.ru/calc/kalkulyator-raskhoda-ankerov/.
To find out the consumption of injection mass for creating chemical anchors, you must first select the type of base (solid, hollow), and then fill in just two fields of the online calculator:
- the diameter of the used hardware
- number of attachment points
The geometrical parameters of the hole are already entered into the program. They are taken from the technical documentation for metal products. So, for example, for an M12 stud, a hole diameter of 14 mm is recommended (d stud + 2 mm), and a depth of 120 mm (d stud x 10).
The injection mass calculator will allow you to instantly calculate the number of cartridges required for installation, and of all standard volumes (300, 345, 400, 410 ml), and will also let you know how many holes one cartridge is enough for. The result obtained is applicable to all chemical anchors based on synthetic resins and a hardener.
About the composition
Chemical anchors used in the installation of any structures have a composition, which we will discuss below.
So, composition:
- Special glue.
- Metal mounting insert. It is a sleeve, which has a thread, a stud and a reinforcing bar inside. Make an insert from galvanized or stainless steel.
The adhesive itself must be very strong. After all, chemical anchors are used when working with concrete elements, for example. Naturally, the fixing force of the anchors must be significant.
As a rule, the adhesive composition is prepared using the following components:
- Artificial resins based on polyurethane, polyester or acrylic.
- Quartz sand and binder mixtures such as cement. They are used as fillers and additionally provide adhesive strength characteristics.
- Hardener. It is necessary for the glue to dry quickly and retain its properties for a long time.
Now that everything is clear with the composition of chemical anchors, it is worth understanding what types of anchors are.
About species
All adhesives for anchors are produced as two-component adhesives. They need to be prepared immediately before the installation process of the anchors themselves begins.
In most cases, the adhesive composition goes on sale in two forms:
- In ampoules that are used for a certain hole size.
- In cartridges and tubes, which come in different sizes. They consist of two compartments. In one compartment there is glue, and in the other a special hardener.
If the anchors are mounted using ampoules, then first you need to insert it into the hole. After that, you can insert the rod. He crushes the ampoule containing the adhesive composition. Due to this, the adhesive polymerizes, providing a strong connection between the anchor and the structure.
When the anchor is mounted using a cartridge or tube, it happens as follows. First, glue and hardener are squeezed into the pre-chamber in equal proportions. There they are mixed, and then squeezed into the prepared hole. After that, an anchor is inserted into it.
Cartridges and tubes are convenient to use when anchors are attached to a porous or hollow surface. It can be foam concrete, hollow brick, ceramic block with increased porosity, and so on. Only in this case, perforated sleeves must first be inserted into the surface. They will not allow glue to flow out through the voids. In general, the fastening of hollow structures using chemical anchors is strong and reliable. Analogues to this method have not yet been invented.
It should be noted that the adhesive composition of chemical anchors does not have the action of a bursting and wedging type. Therefore, they are recommended for use with materials that have a small cross section.
On the advantages and disadvantages
Like any other material or fastener used in construction, chemical anchors have their advantages and disadvantages.
The advantages include the fact that chemical anchors do not cause tensile stress in the concrete surface during the installation of the fastener. When the anchor is installed, the hole under it will be hermetically sealed with glue.
In general, the installation process is simple. Even a novice builder can cope with the task. Moreover, no special equipment is required to install the fastener. The whole process is done manually.
The scope of chemical anchors is quite large, since this fastener is characterized by increased strength and the ability to withstand high tensile stress. In other words, chemical anchors have a significant bearing capacity. At the same time, their adhesive composition has such properties as:
- chemical resistance;
- corrosion resistance;
- weather resistance.
Separately, it should be said that there are anchors that are designed for mounting on a surface with a high level of humidity. Moreover, there are even mounts that can be used underwater. In general, chemical anchors have a service life of up to fifty years or more.
As for the disadvantages, they include the high cost of chemical anchors. In addition, the shelf life of an open package with an adhesive composition is very short. Even in closed packaging, glue can be stored for no longer than twelve months.
As for the time it takes to harden, it all depends on the ambient temperature. At a temperature of twenty degrees, the glue will harden for up to forty minutes. If the temperature drops to five degrees below zero, then the glue will harden up to six hours. If the temperature is lower, then the hardening process will not occur at all.
Video. How to choose a chemical anchor | TsKI
Liquid anchor is an alternative solution for fastening mounting structures. It replaced the traditional mechanical method. The fastening is fixed due to the hardening of the chemical composition in the basis of the material. The use of this method does not involve spacers, which indicates the absence of deformation stress.
Scope of use
Such a mount is used for mounting in materials with weak solidity or density, among them:
- foam block;
- shell rock;
- clinker brick;
- aerated concrete.
Key Features
Liquid anchor 20 years ago was considered an expensive novelty, and was used only as an experiment. Since then, the composition and technique of such anchors have stepped forward, which has made this type of fastener advantageous and cheaper when working with complex materials. Quite often, this technology is called a gluing dowel.
Chemical anchor is a synthetic two-component resin for connecting and fixing metal products with the base material. This solution appeared on the market relatively recently, but due to its outstanding characteristics, it has won the recognition of consumers. Chemical anchors are most often used when conventional plastic or metal dowels fail to hold the structure.
Liquid anchor has found its distribution when working with:
- dense concrete;
- porous materials;
hollow building products.
As for porous materials, expanded clay concrete, sandstone and limestone should be additionally distinguished among them. If we are talking about building products, then in this case it is necessary to mention porous ceramics and bricks.
Varieties of liquid anchors
Liquid anchor is offered for sale in two varieties, among which are ampoule and injection. The first are one- and two-component composition. As for injection, they are sold in tubes and cartridges, and their second name is capsule.
Ampoule liquid anchors are represented by glass cylinders, inside of which the resin is located, when exposed to air, it hardens. Before using this solution, holes are drilled in the material, where the ampoule is placed. At the next stage, an anchor in the form of a metal stud is screwed in. The ampoule breaks, and glue is released from there, which seizes. Pieces of glass at the same time act as reinforcement.
Liquid chemical anchor can be mixed with styrene, the setting will depend on the air temperature and material grade. Injection anchors are applied as follows. At the first stage, a hole is made in the concrete, the internal cavity of which is well cleaned. Glue is squeezed out there and a fastener is inserted. In the process of hardening, the composition fills all the pores and irregularities. This technique is more suitable for empty building materials.
Features of the liquid anchor HIT-RE 100 from the manufacturer Hilti
Liquid anchor "Hilti" is very popular today among consumers. Among other varieties on sale you can find HIT-RE 100. This epoxy adhesive is designed to install rebar and anchors in concrete. The base is epoxy. This mixture can be transported and stored at temperatures ranging from +5 to +25 °C. The anchor can be operated at a fairly wide temperature range from -40 to +70 °C.
One of the main advantages of the anchor is the absence of the risk of cracking. The curing time of the mixture is extended, which allows you to adjust the elements during installation. Hilti Liquid Anchor, the method of application of which will be mentioned below, is suitable for indoor and outdoor use, together with the material in different conditions, namely:
- wet;
- dry;
- filled with water.
The areas of use of the anchor are:
- replacement of fittings;
- fastening of steel structures;
- fixing steel elements;
- connection and fastening of concrete reinforcement.
Cost and main features of the liquid anchor Hit Re 500 from the manufacturer Hilti
The aforementioned liquid anchor, the price of which is 2200 rubles. per package, great for holes that have an impressive diameter and depth, and were made using The material is reliable and of high quality. It is able to withstand impressive loads and allows you to install studs whose diameter exceeds M24.
There are no stresses in the concrete, which reduces the center distances and the step to the edge. The anchor is flexible and can be used even in wet holes without losing adhesion. The packaging has an economical dispenser, so you don’t have to make much effort when injecting. The volume of construction waste is reduced thanks to the unique packaging. The composition does not have a strong odor, so you can work with it even indoors. Installed rebar and studs can be controlled thanks to the red color of the mixture.
Consumption of Hilti Liquid Anchor
Chemical anchor consumption will vary depending on the hole diameter, hole depth and anchor diameter. If the last parameter is equal to M8, and the standard hole depth is 80 mm, then the filling volume of one cavity will be 4.14 ml. In this case, the diameter of the hole is equivalent to 10 mm. Using a 300 ml cartridge, you will be able to fill 72.4 holes.
With an anchor diameter of M10 and a standard hole depth of 90 mm, you will use 6.71 ml of compound with a cavity diameter of 12 mm. Using the 300 ml cartridge, you will be able to fill 44.7 holes. If the diameter of the anchor reaches M30, and the standard hole depth is 280 mm, then the volume of the composition for one hole will be equivalent to 177.71 ml. These data are relevant for a hole with a diameter of 35 mm. By purchasing a cartridge with a volume of 385 ml, you can fill 2.2 holes with the above characteristics.
Instructions for use
Drill holes before filling in one of two ways:
- use of a diamond machine;
- use of a perforator.
The first technology is the most preferable, because the holes are perfectly round and even. As for the technology with a perforator, it should include the use of calibrated drills. Sludge should be removed with a hand pump or compressor.
The installation of the anchor must be carried out using special equipment. If you decide to use a liquid anchor, you must definitely study the instructions for its use. At the next stage, the reinforcement should be installed by immersion, acting on it with little effort. In the process, a small amount of the mixture will come to the surface, which should be removed before the moment of solidification.
The master should use construction gloves and goggles. After installing the rebar, wedging should be performed until the anchor is completely hardened so that the element is not pulled out under its own weight.
Conclusion
After the composition has hardened, it is important to make sure that the anchor has been installed correctly. In this case, the mechanical element must not rotate in the base. The anchorage will not be damaged from the outside. If you are installing at low temperatures, then the base material must be heated with a propane torch or a building hair dryer. Before installation, the stud is cleaned of rust.
In terms of performance, chemical anchors are superior to mechanical ones. Connections with chemical anchors are more durable. They are more resistant to vibrations, static and dynamic loads, more evenly distribute the load on the base. Chemical anchors are indispensable for fastening to complex bases - hollow, stretched, compressed, fractured, porous, low-strength. Fasteners fit well in clean or wet holes, even underwater. The only deterrent to using chemical anchors is the high price. To optimize the cost of such fasteners, it is very important to correctly calculate the amount of injection mass required. Our “Anchor Cost Calculator” is designed to meet this challenge. Depending on the number and type of anchors, he will calculate the required number of cartridges (tubes).
How to correctly calculate the amount of injection mass for a chemical anchor?
In accordance with the manufacturer's instructions for specific design loads, the required size of the chemical anchor is adopted. Further, according to the instruction tables, we find the initial data for the “Anchor Consumption Calculator”, namely:
- Stud (reinforcement) diameter (for example, M8, M10, M12);
- hole depth;
- Hole diameter.
The “Number of holes” indicator corresponds to the number of anchors that are required to attach a part or structure. If there is no instruction, as a standard, you can take the diameter of the hole (drill) by about 2-5 mm more than the diameter of the stud, and the depth of the hole is 10 stud diameters. Entering the initial parameters into the form of a calculator, we obtain the required number of cartridges with injection mass.
The consumption of the injection mass is highly dependent on the base material. For solid foundations, such as stone, concrete, according to the calculator's algorithm, the mass volume will be equal to ⅔ of the total volume of all holes for anchors. For porous bases or with voids, such as foam or aerated concrete, hollow bricks, the injection mass consumption increases by 30% compared to solid bases. When calculating the consumption of injection mass, you must select the appropriate tab.
Cartridges with adhesive mass from various manufacturers of different sizes. Our calculator can calculate the required number of cartridges with a capacity of 300, 345, 400 and 410 ml.
Quite often, during construction, it becomes necessary to mechanically connect various structural elements (window frames, door frames, and so on). Until recently, the simplest hardware was used for this: plastic or metal dowels. However, their use is possible only in solid foundations (concrete, brick, stone). Now, for these purposes, the so-called adhesive or chemical anchor is successfully used. One of the leading manufacturers of such products is the Hilti company (Liechtenstein). Hilti chemical anchors are produced in the form of capsule products (for installing one hairpin) and injection systems (cartridges with a capacity of 330 and 500 ml). The products of this company allow you to perform almost any fastening work: from fastening a heavy shelf to a cellular concrete wall to gluing additional load-bearing reinforcing bars in heavy concrete structures.
Hilti chemical capsule anchors
This type of chemical anchor is clearly dosed for the installation of only one fastener. It is a cylindrical polyethylene container filled with an adhesive composition. The two components of the adhesive mixture are separated by an impermeable partition. The mixing of the components of the mixture occurs at the time of installation. Products of this type are marked with the letters HVU, indicating the thread of the anchor stud and the depth of the mounting hole for it. For example, the marking “HVU M16X125” means that this capsule is designed for fixing an anchor rod with an M16 thread, a hole depth in concrete of 125 mm. The line of capsules is presented quite widely: from M8 to M39.
The technology for installing a stud using an adhesive capsule is quite simple:
- We drill a hole in the base of the required diameter and depth. The manufacturer recommends choosing a drill or drill diameter for M8÷M16 studs 2 mm larger, for M20÷M39 3÷4 mm larger. For example, for the “HVU M12X110” capsule, you will need a drill with a diameter of 14 mm, a hole depth of 110 mm.
- Thoroughly clean the hole from dust using air or a brush.
- Insert the capsule into the hole.
- Clockwise, we twist the pin into the hole: the lower end of the pin breaks the capsule and when screwing in, the components of the adhesive composition are mixed.
The time of the final hardening of the adhesive, after which maximum loads can be applied to the pin, depends on the ambient temperature: from 20 minutes at a temperature of +20˚С to 5 hours at a temperature of -5˚С.
For studs experiencing increased dynamic loads, the company has developed special capsules “HVU-TZ”. The line of these types of capsules is designed to install studs from M10 to M20.
Hilti injection anchor systems
This type of chemical anchor (marked with the letters HIT) is a plastic cartridge with two fixed sealed foil containers (one with adhesive filler, the second with a hardener). To date, the company represents 7 varieties of this type of chemical anchor. The price of such anchors depends on the capacity of the cartridge (there are two varieties: 330 and 500 ml), the components of the composition, the field of application and the load that the stud installed with its use can withstand.
For example, the universal hybrid composition “HIT-MM-Plus” is a budget class chemical anchor (the cost of one 330 ml cartridge is 650÷900 rubles). Two-component adhesive based on urethane methacrylate. Recommended for installation of threaded studs in the M6÷M16 range in basic building materials such as bricks (solid and hollow), sand-lime blocks, concrete, cellular concrete blocks, artificial and natural stone. For fastening studs in hollow blocks and bricks, the company offers specially designed perforated plastic sleeves, which increase the strength of the fastening and reduce the consumption of adhesive composition.
And the composition “HIT-RE-500-V3”, which closes the line of injection anchors, already costs 2700÷3300 rubles for a package with a capacity of 330 ml and is intended for gluing releases of working load-bearing reinforcement of floors, columns, foundations and flights of stairs. Composition based on epoxy adhesive with additives that allow the installation of studs and reinforcing bars with a diameter of 10÷55 mm even in holes completely filled with water.
The extrusion of the adhesive components is carried out using a mechanical manual dispenser. For chemical anchors with a capacity of 330 ml, the dispenser “HDM-330” is intended, for 500 ml - “HDM-500”. We insert the capsules into the plastic cassette of the dispenser (it is included in the kit), fasten the mixer onto the threaded part of the cartridge (in which the components of the adhesive composition are mixed) and through its conical tube the glue enters the drilled hole. Parallel pistons are connected to the handle of the dispenser, and when it is pressed once, one portion of the adhesive composition (about 5 ml) is supplied.
Video on using the “HIT-MM-Plus” compound and the “HDM-330” dispenser:
For professional use in the production of a large amount of anchoring work, the pneumatic dispenser “P-8000-D” and the battery dispenser “HDE-500-A22” are used.
Chemical anchor calculation
For reliable and correct installation of the stud in accordance with the technical regulations, the hole must be filled with adhesive by ⅔ (the excess should protrude beyond the edges of the hole only after the stud is installed). It is easy to calculate the consumption of a chemical anchor for the installation of one product using the following formula:
V₁ = ([(π h D²):4]:1000) 0.67, where
V₁ is the volume of adhesive required to install one anchor (ml);
π is the number "PI" (3.14);
h is the hole depth (mm);
D is the diameter of the drilled hole (mm).
For example, we use the “HIT-MM-Plus” composition and the M12 hairpin. Recommended by the manufacturer: drill diameter - 14 mm, hole depth for secure fixation of the stud - 85 mm. We substitute our values into the formula and get:
V₁ = ([(3.14 85 14²):4]:1000) 0.67 = 8.762 ml ≈ 9 ml
Since one click on the dispenser handle squeezes out about 5 ml of adhesive, for our example, two clicks are enough to install one hairpin.
Advice! Since the manufacturer recommends replacing the dispenser after using the injection system, it is advisable to pre-drill and clean the required number of holes, and then install all the studs on the chemical adhesive.
Chemical anchors from various manufacturers are represented on the modern market: Hilti, Himitex, Fisher, Sormat, MKT, Mungo. The choice of one or another type of anchor depends on the base material in which the stud is to be installed, and on the planned load on it. Before buying, you must carefully read the manufacturer's instructions, then your choice will be correct both technically and materially.
In our time, thanks to innovative technological developments, new materials are constantly appearing that can facilitate and speed up construction work, significantly increase the strength and durability of the structures being created. One of these novelties is a chemical anchor, which has recently appeared on the free market.
So, chemical anchor - what is it and how to apply it? A similar question probably arises among many home masters, those who first encountered such a “curiosity” or simply heard it. The material is relatively new, and has not yet gained wide popularity, but, probably, to a greater extent - only because of the lack of information. Therefore, in this publication we will try to at least to some extent fill this gap, consider the varieties and characteristics of chemical anchors, the main technological methods for their use.
What is a chemical anchor?
A chemical anchor is essentially a two-component adhesive mass made on the basis of synthetic resins. In the technical literature and in the colloquial slang of builders, it has many other names - “pasting anchor”, “injection mass”, “anchor gluing system”, “liquid dowel or anchor”, and “chemical anchor”.
For the first time, this type of fastener was used in the mining industry - for the installation of structures with fastening to loose rocks. Over time, it spread to the entire construction industry.
Unlike traditional anchors with expansion elements, chemical materials are able to provide high reliability of fixation on an unstable, low-strength or complex material.
Chemical anchors are not just an ordinary tube of glue, but a high-tech fastening system. Usually, in addition to the compositions, devices for drilling holes, mixing guns, mass dispensers, special scrapers and brushes for cleaning holes and other necessary tools and accessories are supplied for sale.
The compositions of chemical anchors are selected for a specific task, taking into account the conditions of use, including, of course, the specifics of the material from which the foundation is built.
The proportions of the various substances used in the manufacture of chemical anchors are trade secrets of each manufacturer. The only thing that can be said with some degree of certainty is that the composition includes components such as:
- Synthetic resins based on polyurethane, acrylic or polyester.
- Quartz fine-grained sand.
- Cement composition - is used as a filler and a binder component that provides the strength characteristics of the adhesive composition.
- Hardener.
The principle of operation of a chemical anchor is to fasten a metal rod (stud) with a synthetic adhesive in concrete (including porous concrete), brick and many other structures. The chemical mass penetrates deeply into the base material, filling its pores. The synthetic resins then cure to form a monolith that securely holds the anchor piece to the base.
The technology of fixing with the help of a chemical anchor is simple - the prepared hole is filled with an adhesive mass (using a special dispenser gun or installing a special capsule). After that, a metal element is inserted into it (most often a hairpin, but it can also be just a corrugated reinforcing bar). The chemical composition, as it were, envelops the metal, filling even the narrow gaps between the threads.
These anchor connections are significantly superior to conventional anchors or dowels in terms of their ability to withstand pull-out loads. And at very high loads - they have no analogues at all.
It should be noted that the strength of the joints made with the help of chemical anchors is so high that the material is used even for roofs of buildings, bridges, moreover, in their underwater part, etc.
The use of this material is especially important in cases where traditional anchors and dowels are not able to provide a reliable connection between the fastener and the base. For example, if metal elements need to be fixed in a "weak" base - it can be hollow brick, shell rock, limestone, sandstone, expanded clay concrete, or cellular concrete. Therefore, in recent years, the popularity of this material has been steadily growing.
Different adhesives have different setting and full curing times. It can vary from several hours to days.
Varieties of chemical anchors
As mentioned above, chemical anchors are usually two-component formulations. Their components are mixed together immediately before use. They are produced and put on sale in three types: an ampoule version, compositions packed in two cartridges, and also in one cartridge, divided inside into two compartments.
Materials packed in cartridges have one principle of action. However, for different types of such packages, a different tool is also required, designed to dose the composition into drilled holes (holes).
- Ampoule anchors - are produced for a certain diameter of the hole. One ampoule is purchased for each attachment point. This type of anchor is generally used for anchoring in the base, which can guarantee high precision and cleanliness when drilling a hole.
The capsule version is more convenient to use in the sense that there is no need to control the filling level of the hole. A slight difference in the diameter of the borehole and the capsule is well compensated by the expansion of the adhesive mass during its curing.
The ampoule consists of two capsules - with an adhesive mass and a hardener, which are connected by screwing in a threaded metal element, such as a stud. In this case, the mixing of the hardener and the base substance occurs more evenly than when using cartridges.
However, this version of the chemical anchor is not suitable for use on a cellular base of a vertically located structure, since the mass will flow down before it has had time to harden.
- Two cartridges, having different volumes and interconnected at the outlet, containing an adhesive composition and a hardener. This version of the chemical anchor requires a special gun for the simultaneous batch feeding of components into the guide mixing spout. By the way, it is clearly seen that a special spiral is installed inside this mixer, which ensures the most uniform mixing of the components even before they are fed into the drilled hole.
- One cartridge, but also consisting of two departments, which also contain the adhesive mass and hardener. They are connected to each other and hang in a similar guide spout during extrusion. But for work, you can use a regular construction syringe gun, which is convenient for home use.
The last two varieties are divided into universal and intended for gluing metal parts into concrete bases. Both the first and second options are called injection anchors.
Universal anchor options are especially popular. This can be explained by the fact that there is no need to pre-calculate the number of capsules. In addition, such anchors are convenient for use when filling cone-shaped holes that expand into the depth of the base.
Anchors designed for gluing studs or reinforcing bars into a concrete base usually have a thick consistency. They include corrosion inhibitors and deoxidizers, which is especially important when installing reinforcing parts in concrete.
Some anchors designed for concrete require special chemicals to treat the rebar and drilled holes, as well as tools to press the studs or rods into the holes.
Chemical anchors packaged in cartridges have a common drawback - this is a considerable difficulty in controlling the filling of the hole. Often the mass begins to drain under the influence of gravity, if the base is hollow or porous.
It is quite possible to reduce material consumption and achieve its uniform distribution in all directions of the hole by using mesh bushings. These elements can have different sizes, and are selected in each case individually.
It is difficult to talk about the cost of chemical anchors - the price of various products can differ literally dozens of times. This largely depends on the configuration of the system and, of course, on the manufacturer.
Each of the mentioned varieties of material is on sale in a very considerable number of items, since chemical anchors are produced by many companies. Therefore, it must be taken into account that the technologies of application can differ significantly from each other.
What to look for when choosing a chemical anchor?
An important task is to achieve guaranteed compliance of the chemical anchor with its characteristics and conditions of its use. To choose the right material, before purchasing it, you must carefully study the instructions located on the package or attached to it.
The manufacturer indicates in his recommendations the types of structures and materials for their manufacture, the recommended location of the holes and their sizes, methods of fastening, the range of humidity and temperature, as well as the permissible loads for different bases. In addition, it is necessary to pay attention to possible restrictions on operating conditions, on the rate of solidification of the composition - this is especially important for chemical anchors of atmospheric hardening.
Advantages and disadvantages of chemical anchors.
Chemical anchors, like all building materials, have their positive and negative features. It is necessary to have information about them in order not to encounter unpleasant moments when using fasteners and during the operation of the finished structure.
To virtues This specific material includes the following:
- The tightness of the blockage of the hole after the installation of the anchor.
- No tensile stress in the concrete base.
- Wide scope.
- Ease of installation work that does not require experience and special training.
- High strength of the anchor during its curing, significantly exceeding this parameter for traditional expansion elements.
- The ability to withstand heavy loads and tensile stress, that is, high bearing capacity.
- Chemical anchor is a material that is resistant to external atmospheric influences, corrosion processes, and is inert to chemical influences.
- There are special anchoring compounds with characteristics that allow their use in conditions of high humidity and on waterlogged surfaces, as well as in general for structures created under water.
- The service life of such a connection is comparable to the durability of the foundation itself and is usually at least fifty years.
- Manufacturers produce adhesives that do not contain toxic substances. These options are selected for interior work. Therefore, when choosing a material, special attention must be paid to this factor.
- The coefficient of thermal expansion of the anchors is in the same range as the base materials. Due to this quality, during the operation of structures, unnecessary internal stresses do not arise during temperature changes.
Particular attention needs to be paid shortcomings chemical anchors, as they cause a lot of trouble:
- Unlike traditional anchor elements, chemical compositions require a fairly long time until the installed fastener is fully ready to accept the load. Fastening readiness period depends on the ambient temperature:
At a temperature of +20 degrees, the curing time will be 25 ÷ 40 minutes;
At 5 degrees - 5.5 ÷ 6 hours;
If the temperature is lower, then hardening (polymerization) of the compositions practically does not occur.
- Short shelf life of unopened packaging. As a rule, it is no more than one year.
- A short life of the composition after opening the cartridge. Therefore, if the package is opened, it should be used immediately.
- The high cost of the material, which scares off many potential consumers.
Manufacturers of chemical anchors
A considerable number of both domestic and foreign manufacturers present their products on the Russian market. In practice, materials produced by well-known European companies have proven themselves flawlessly.
The table below shows the leading manufacturers and a brief overview of their product range. In fact, the variety of products they produce is much wider.
| Company `s logo | Anchor type | Scope and Features of Chemical Anchor |
|---|---|---|
| Manufacturer "Fischer" (Germany) | ||
 | RM | "Reaktionsanker" - an ampoule with an adhesive mass, inside of which there is a compartment with a hardener. The manufacturer produces ampoules of different sizes - M8 (10×80), M10 (12×90), M12 (14×110), M16 (18×125), M20 (24×170), M30 (30×280). |
| FHP | "Hammerpatrone" - an ampoule with glue and hardener for installing metal elements in a concrete base. Produced in the following sizes - 10 (13×90), 12 (15×110), 16 (18×125), 20 (24×180). | |
| FIS V 360S | "Injections-Mortel" Dual cartridge, requires a special gun to work. 360 ml main cartridge and two mixers. | |
| FIS V S 150 C | "Injections-Mortel" One standard size cartridge. To work, you will need a regular construction gun for standard cartridges. The kit includes a 150 ml cartridge, two mixers and an adapter. | |
| Manufacturer «Hilti» (Liechtenstein) | ||
 | HVU | Adhisive Capsule Anchor. Ampoule with metaacrylic polyurethane resin, quartz sand and hardener. Capsules have the following volume: M8 (10×80), M10 (12×90), M12 (14×110), M16 (18×125), M20 (24×170), M30 (30×280), M33 (37 ×300), M36 (40×330), M39 (42×360). |
| HIT-HY150 | Fast Curinq Injection System. These are two double cartridges with acrylic resin and hardener. It requires a special gun to work. Cartridge volume 330 ml and two hardeners, HIT-HY20 has one hardener. | |
| HIT-HY50 | ||
| HIT-HY20 | ||
| Producer "Mungo" (Switzerland) | ||
 | MSP | Schlagpatrone. Ampoules with resin and hardener. Capsule volume: M8 (10×80), M10 (12×90), M12 (14×110), M16 (18×125), M20 (24×170). |
| MYA | Verbunanker. Ampoules with two components. Volume: M8 (10×80), M10 (12×90), M12 (14×110), M16 (18×125), M20 (24×170), M30 (30×280). | |
| MIT-P | One cartridge. For work, a standard construction gun is used. The volume of the cartridge is 150 ml, two mixers. | |
| MIT-P | Double cartridge. Set: 235 ml and two mixers. | |
| MIT-SF | Double cartridge. Volume 380 ml and two mixers. | |
| MIT-EA | Double cartridge. Volume 825 ml and two mixers. | |
| Producer "Sormat" (Finland) | ||
 | KEM | "Kemiallinen ankkuri" - ampoules with polyester resin and hardener, volume M8 (10 × 80), M10 (12 × 90), M12 (14 × 110), M16 (18 × 125), M20 (24 × 170), M30 ( 30×280). |
| KEMLA | "Kemiallinen lyontiampulli" - ampoules with polyester resin and hardener, volume M8 (10 × 80), M10 (12 × 90), M12 (14 × 110), M16 (18 × 125), M20 (24 × 170). | |
| ITH | "Injektointitekniika". Cartridge with injection mass based on polyester resin, 380 and 150 ml | |
| Producer "TOX" (Germany) | ||
 | TVA | Verbund Anker. Ampoules with resin and hardener, having a volume of M8 (10x80), M10 (12x90), M12 (14x110), M16 (18x125), M20 (24x170), M30 (30x280). |
| THP | Hammerpatrone. Ampoules with resin and hardener, volume M8 (10×80), M10 (12×90), M12 (14×110), M16 (18×125), M20 (24×170). | |
| TVM-K | Verbundmortel. Cartridge with injection mass, 380 and 150 ml. | |
The labeling of capsule products indicates their dimensional parameters. For example, M10 (12 × 90): the letter “M” is the metric thread of the stud, “12” is the cross-sectional diameter of the stud, “12 and 90” is the diameter of the hole and the depth of the metal fastener in the base.
Hilti chemical capsule anchors can be especially distinguished - this is a modified material adapted to the temperature range during installation from -18 to +40 degrees. The manufacturer supplies products for holes from 8 to 30 mm in diameter, so they can be used to install powerful reinforcing bars into the base.
Can I make my own chemical anchor?
Ready-made chemical anchors have a rather high cost, as well as a short shelf life after opening the cartridge. Therefore, many novice construction masters have a question about the independent manufacture of such a composition.
Indeed, it is quite possible to make an analogue of a chemical anchor. The mixture is made on the basis of epoxy resin. The physical and technical characteristics of this component are quite capable of providing excellent adhesion of materials. Epoxy resin has increased adhesive abilities with base materials such as concrete, brick, shell rock, etc., therefore it may well serve as the basis for creating a composition of its own production.
Making a homemade chemical anchor will require:
- Epoxy resin - ED-20.
- The hardener for it is UP-583.
- Cement or gypsum, you can add a little fine sand as a filler.
- Plasticizer DBP or DEG-1.
When preparing such a mixture, the following instructions should be followed:
- It is necessary to add a plasticizer to the epoxy resin, 5÷10% of the total volume of the resin, and then mix thoroughly.
- Further, the filler is poured into the mass and mixed well - gypsum, cement. Its amount is also small, and should be 5÷10%.
- The hardener is launched into the mixture last, it is taken in a ratio of 1:10 or 1:8 of the total volume.
After thorough mixing, you will get a ready-to-use composition that must be used immediately. Its curing time is one to two hours, depending on the ambient temperature. Therefore, a homemade anchor must be prepared in portions in order to have time to work it out. The epoxy anchor dries for a long time - 12 ÷ 24 hours, but the reaction of the resin and hardener begins immediately after mixing the components. Increases the life of the composition of the plasticizer. If gypsum is added to the mass as a filler, then the setting and hardening time is reduced.
Homemade epoxy have their advantages and disadvantages
To benefits its following qualities can be attributed:
- High strength characteristics of the hardened composition.
- Minimal shrinkage during curing.
- Good adhesive ability.
- Can be used at temperatures from -10 to +35 degrees.
disadvantages these compositions can be considered:
- Fairly long curing time.
- The possibility of using the mass only for dry and well-cleaned holes.
- During the operation of the structure, a small amount of phenol can be released from the epoxy anchor.
Hole preparation and application of chemical anchors
In order for the chemical anchor to "work" properly, one should not only use these compounds correctly, but also carefully prepare the holes for the mounted fasteners.
Drilling and hole preparation rules
Three methods are used to equip holes for the installation of metal parts using chemical anchors. Two of them are used for fastening load-bearing elements and complex structural units. The difference between the base drilling methods lies in the more accurate drilling of holes for critical fasteners. The accuracy of the arrangement guarantees a reduction in the consumption of the chemical anchor and its uniform distribution along the walls of the hole. It is clear that the diameter of the hole must exceed the diameter of the stud or reinforcement. And when studying the instructions from the manufacturer, you need to pay attention to his recommendations, since they may differ for different compositions.
Responsible fasteners include connecting parts of load-bearing structures, for example, fixing frame walls to a concrete base. Or the installation of cantilever frames of hinged systems, on which a significant static or dynamic load is expected.
The third drilling method is intended for non-responsible fasteners in the bearing walls of a building, derived from materials with a strength grade of M100 or less. The bearing capacity of such materials does not make it possible to equip critical fasteners in them. Therefore, a chemical anchor under the created conditions can only withstand the static load of a hinged system of a certain weight.
Hole drilling is carried out, on which a drill of the required size is installed. In any case, regardless of the type of material, the finished hole requires high-quality dusting. The cleaning process is best carried out with pressurized air. It is necessary to carefully release the pores of the material inside the hole, so that when the anchor composition spreads, it penetrates into them.
For purge, special pumps or cylinders with carbon dioxide are used. If these devices are not at hand, then cleaning at home can be done using a rubber pear. It is not limited to only one purge. It is recommended cleaning operations, in shifts - with a brush-brush and compressed air, to be carried out at least three to four times.
- Straight jig - this device eliminates the beating of the drill and ensures that the hole is perfectly perpendicular to the wall surface.
- The oscillating jig allows you to expand the internal space of the hole to a conical shape, while maintaining the diameter of the hole at the inlet.
When arranging such a borehole, part of the load from the anchor holding the metal element is transferred to the base (wall) material. That is, the fastening is more reliable, which is especially important for walls made of materials with low strength.
- Hollow drills are convenient for drilling - they contribute to easier cleaning of holes from construction dust.
Thorough cleaning of the borehole is a prerequisite when using a chemical anchor, as adhesion between materials depends on it. The dust remaining in the pores will be a serious obstacle to the quality contact of the adhesive mass with the base material.
In order for dust to be removed qualitatively using blowing, it is first necessary to treat the hole with a special metal brush, which can free the pores of the material. After that, it will be easy to remove it by blowing through the hole.
If holes are drilled in closed cell materials, they are washed. For this purpose, special solutions of surfactants (surfactants) on a water basis are used. When washing the holes with them, a large amount of foam is formed, which is then removed from the holes with compressed air.
It should be immediately noted that for almost all types of chemical anchors, prepared holes are suitable for fastening only immediately after cleaning.
The sequence of work when gluing the anchor
As mentioned above, it is easiest to work with a chemical anchor made in a capsule version. After installing the ampoule in the prepared hole of the required diameter, the pin is screwed. During this procedure, the resin is evenly mixed with the hardener.
When introducing the same mass with a gun, it is necessary to take into account some subtleties:
- If the installation of metal elements is planned to be carried out on a base erected from a porous or hollow material, then a mesh sleeve must be used for the holes. This element is installed in the hole before the introduction of glue and contributes to a uniform distribution of the composition over all surfaces.
- When using a two-component chemical anchor, the use of a mixer is required. The compositions are fed along this guide spout in the proportion established by the manufacturer, while simultaneously mixing with each other. For each of the chemical compositions, a special mixer is used, which comes with the cartridge.
- In order for the hole to be filled with high quality, a special dosing gun should be used. This element allows you to extrude the mass under pressure, due to this, air is well displaced from the hole, while the adhesive mass takes its place.
- If the insertion into the hole of reinforcement or studs with a length of more than 500 mm will be done manually, then it is recommended to use a special jig for this purpose, capable of mechanically supplying a metal element under a certain pressure and maintaining a perpendicular position.
- If ampoule anchors are chosen, then after they are installed in the hole, the rebar or stud is often clamped into an electric drill chuck and inserted into the hole, turning on medium speed.
- When the metal fastener is installed in the hole, it must remain stationary until the chemical composition has completely cured. The hardening time for different compositions is different, but at a temperature not lower than 15 ÷ 20 degrees, it averages 35 ÷ 40 minutes. At negative temperatures, the process can take place within 8÷12 hours. Therefore, installation work is recommended to be carried out at a temperature not lower than -5 degrees. If work must take place at lower temperatures, then special formulations should be chosen, which can also be found on sale.
- Let's note one more nuance. Chemical anchors do not always provide proper tightening fixation of a depressed rod or stud. Due to the absence of the initial tension of the metal element, deformation of the fastening may occur. Therefore, when hanging or fixing on an external structure or any device (heavy piece of furniture, etc.), it must be placed close to the supporting structure. Thus, there will be no stretchable "neck" of the bracket that is outside the zone of action of the chemical anchor, that is, protruding from the wall. In any case, the pin must be recessed into the base by at least half of its length.
In order not to overload the reader with verbal information, we invite him to watch a video that tells about the Hilti HFX cartridge-type chemical anchor and shows the process of its application.
Video: The purpose of the Hilti HFX chemical anchor and how to work with it
Appendix: How to calculate the consumption of a chemical anchor?
It has already been said that the material is very expensive, and requires prudent spending. But how to at least approximately calculate how much composition is required to fasten one stud (rod)? And how much will it take for the entire upcoming scope of work?
To do this, we suggest using the possibilities of the online calculators below.
There are two calculators.
- The first of them calculates the flow rate of the composition with a straight cylindrical hole, which is usually used on structures with a high bearing capacity of the material.
- The second one is for a conical hole, expanding deep into the shape, drilled with the help of a rocking jig. This approach is typical for walls made of materials with low strength (less than M100).
You can compare how much higher the consumption of the adhesive composition becomes in the second case, with all other parameters being equal (the depth of the hole, the diameter of the hole at the entrance to the wall, the diameter of the stud).
