Concrete anchors (bolts): types and kinds, as well as methods of their fastening and installation in foam concrete and aerated concrete

Bolts, also referred to as concrete anchors, are essential for fastening items to concrete surfaces. They offer strength and stability precisely where it is most needed, making them indispensable for both residential and commercial construction projects. Your construction project’s safety and success can be greatly impacted by your understanding of the various types and their unique applications.

The selection of anchors assumes even greater significance when working with foam concrete and aerated concrete. Because of their special qualities, these materials call for particular fastening techniques to guarantee a firm grip. This piece will walk you through the different kinds of concrete anchors and bolts that are available and explain how to install and use each one safely in foam and aerated concrete.

We’ll go through the most popular options, including chemical anchors and expansion bolts, and best practices for installing them. Having the appropriate information and resources will enable you to complete your building projects with dependability and durability, regardless of whether you’re a professional builder or a do-it-yourself enthusiast.

Type of Anchor	Installation Method
Expansion Bolts	Drill a hole, insert the bolt, and tighten it to expand and secure.
Threaded Rods with Chemical Anchors	Drill a hole, fill with chemical adhesive, insert the rod, and let it cure.
Sleeve Anchors	Drill a hole, insert the anchor, and tighten the nut to expand the sleeve.
Hammer Drive Anchors	Drill a hole, insert the anchor, and hammer it into place.
Nail-in Anchors	Drill a hole, insert the anchor, and drive the nail into it.

Principle of operation and application

Concrete has a heterogeneous structure and is a porous material. Additionally, different forces such as twisting, bending, shearing, cutting, compression, and tearing appear in the locations of fastenings. They are taken on by the concrete anchor, which distributes them along with the supporting structure.

Fundamental ideas behind how concrete anchors function:

• At the time of the interaction of the material and anchor material, the friction force appears – the spacer is performed by dowels, metal tsangs.
• When the material at the anchorage depth resists breaking or crushing – due to collet bushings on the fastener, the curved shape of the rod, expansion.
• Loads at the point of contact between the base and the rod are compensated by tangential stresses during monolithing or gluing – this is how embedded smooth, adhesive anchors work.

Concrete anchors come in a variety of styles, kinds, and dimensions. According to GOST, they are constructed of special steel and have an anti-corrosion coating on them. The diameter and length of the rod range from 6 to 20 millimeters.

Any anchor consists of the following components:

• The bolt itself
• A cone with a thread layer inside
• A sleeve with special cutouts

An anchor’s purpose is to support or bear weight. When connecting floor slabs, beams, columns, balcony consoles, stairwells and flights, finishing and wall panels, engineering equipment, communications, hoods, ceiling lights, etc., the load-bearing function is put into practice. Installing joists on concrete or hollow-core floors also requires the use of anchors. They are used to hang furniture from walls and fasten electrical equipment.

If the assembly’s stability is ensured by its own weight, structural fasteners are utilized to counteract part displacement; anchors are also important for straightening in construction.

Types and types of anchors and methods of their fastening

A variety of acting forces, such as emphasis, intermolecular bonding during the gluing process, friction, bending, compression, etc., can be used in concrete anchors. Concrete anchors can be frame, ceiling, foundation, or universal, depending on their intended use. With a prefabricated or solid structure, it is both straight and curved in shape.

The anchor’s surface may be smooth or corrugated. Depending on the contact area, different fastener types are used: those for dense and porous materials. The anchor fasteners for concrete can be installed using various techniques such as connecting, gluing, hammering, screwing, etc.

It is crucial what kind of material is used to make the hardware. The strongest possible fastening will be achieved if the steel is coated with an anti-corrosion layer and has a strength class of 6.8 or higher. However, brass cannot bear significant vertical loads.

Expansion

The working force in the case of concrete expansion anchors with nuts is friction. These little studs have a cone-shaped tip, a sleeve, and a thread. The fastener wedges and securely holds itself inside the monolith when it is screwed into the base.

These anchors’ primary benefits include their excellent load-bearing capacity, ease of installation, and ability to perform through installation. Wedge anchors are primarily used for dense concrete because they are deeply buried and one-time use only.

The fastening is suitable for attachments if a hook (bracket) is installed on the end of the anchor bolt in place of a nut. Sleeve and sleeve are wedge anchors. This type of bolt resembles a sleeve with unique cutouts; it can have a wedging nut or stud with a conical expansion at the end. applied to bases with medium and high densities. Significant loads can be supported even with a minimum product diameter thanks to the small contact area.

In addition to being acid-resistant (KAN), an anchor bolt with a nut can be hot-dip galvanized (KAK), electrogalvanized (KA), or both. Stainless steel screw anchors are included in this as well (RAR).

Drive-in

Dense concrete is the ideal candidate for drive-in anchors. These are small bolts with metric threads and an internal cone. When driving a stud or bolt into concrete, the fastener wedges the base so that it does not protrude onto the surface.

When installing boxes, ceiling air ducts, and engineering equipment, it is important to use these kind of bolts to install anchors in concrete. Drill a matching hole before driving an anchor into a concrete wall. Next, insert the hardware by hammering it in place, center punching it, and screwing in a threaded rod that is the necessary length.

A dowel-nail ceiling anchor is one example of this kind of anchor. Armstrong ceilings, slats, and hangers are easily attached to them. Because the bolt is fixed in place, the fastener is often used as a vandal- or fire-proof one.

Frame

Used to secure window and door frames. The sleeve has a cut all the way around it. When the wedging nut is tightened, it presses the structure firmly against the opening, moving it into the correct position. The sleeve has stops at the top to prevent displacement and rotation around its own axis.

Self-tapping screws for concrete

Here, the thread made all the way along the bolt ensures the dependability of the connection. The product develops strong resistance to tearing or shearing during the screwing process into a concrete base. Therefore, a very high load-bearing capacity is noted when employing this kind of fastener. The screw is simple to install, incredibly dependable, and capable of supporting loads up to 100 kg.

Expanding

This kind of anchor is commonly referred to as a "butterfly" (also known as a Molly bolt). It is utilized in hollow constructions with limited load bearing capacity to install cornices, shelves, lights, paintings, and other components. When the rod is screwed into the base, the wedging skirt-shaped collet on the screw or bolt presses against the interior of the base cavity. Specialized spikes that are buried deep into the concrete on the outside of the collet prevent the bolt from moving or rotating while being installed.

Chemical anchor

Concrete anchor bolts are formed from a semi-liquid mass that solidifies rapidly. The bolt or stud is cemented into the monolith using this mass. The composition makes it feasible to guarantee a consistent load distribution along the whole length of the fastener, free from local or point stresses, while maintaining a dependable connection between the base and the bolt.

Chemical anchors for concrete greatly lower the chances of destruction and deformation because they never cause internal stress.

Sizes and characteristics of anchor bolts

Because fasteners come in a range of lengths and diameters, it is important to take into account both the variety of designs and sizes when choosing which anchor is best for concrete in completing particular tasks.

Anchors categorized according to size:

• Small – cross-section up to 8 millimeters / length up to 55
• Medium anchors – up to 12/120 millimeters
• Large – with maximum dimensions of diameter 24 and length 220 millimeters

Three indicators determine the characteristics of different sizes of concrete anchor bolts. The marking M8 10/60-115, therefore, means that the anchor thread diameter is M8, the anchor length is 115 millimeters, the approximate thickness of the element that is intended to be strengthened is 60 millimeters, and the outer diameter is 10 (this is the diameter with which the hole for the fastener is drilled, this is the drill diameter).

The table lists every technical feature of the anchors, including weight, maximum torque and allowable bending moment, minimum pull-out force, ideal loads, distance to the edge and between axes, etc. All of these factors are taken into consideration when choosing appropriate products and performing high-quality anchor fastening to concrete.

Installation instructions

You must get the instruments ready before installing the anchor bolt in the concrete. You will need the following tools to finish the job: a hammer, a concrete drill, a wrench, a construction vacuum cleaner, and a drill with a rotary hammer function.

Drilling

The base is first meticulously marked out for potential drilling locations. Because of the strong fixation, it is impossible to remove the anchor bolt from the concrete after installation, so you must complete this task as precisely as possible. Additionally, install a limiter on the drill in accordance with the marking in concrete to determine the required length of drill holes (measured by the bolt’s expansion part).

The minimum distance from the wall’s edge to the hole’s depth should be 2.5 times greater. Next, a rubber bulb, a can of compressed air, and a vacuum cleaner should be used to clean the holes. If it’s not possible to get rid of all the crumbs, you can dig the hole 1-2 centimeters deeper.

Installing an anchor with a nut

The bolt’s expansion component is placed into the base and hammered into place until it is fully submerged in the concrete, flushing the edges with the wall. After that, insert a threaded stud or bolt, tighten the nut, and twist it as much as needed to prevent further turning.

It is a good idea to research the proper usage of a particular kind of fastener beforehand. The maximum tightening force may be specified by the manufacturer; in such circumstances, a torque wrench is required. When working with certain bases (foam concrete, aerated concrete), tightening to the stop can deform and destroy the material.

Installation of a chemical anchor

In order to install chemical fasteners in concrete, a slightly different set of tools is required: threaded studs, glue or capsules, mounting gun, punch, and wrench. Where small volumes of work are anticipated, the choice of capsules (ampoules) is important when selecting a large number of fasteners.

Prior to drilling and cleaning the holes, marry the base. It is best to screw a mesh sleeve into the concrete before adding an adhesive solution. This will allow the chemical to seep inside the concrete more slowly. Next, use a mounting gun to fill in two thirds of the holes with glue, or install the capsules and gradually screw in the hairpin to ensure that the adhesive is distributed evenly. It is now necessary to wait for the glue to dry before using a key to tighten the nut.

Pros and cons of application

The maximum dependability and strength of structures are the key benefits of using anchor bolts for concrete. Large loads can be supported by anchors, which also ensure excellent concrete fastening with qualities not possible with other kinds of fasteners.

The primary benefits of concrete anchors are:

• Resistance to deformation and corrosion
• Lightness, simplicity and high installation speed
• Resistance to dynamic and static loads of various types
• A large selection of anchors by length, diameter, type of fastening, load, functions, shape, material, etc..

Choosing an anchor bolt that is appropriate for a given task is not hard. There are no overt drawbacks to this kind of fastener. Unless there are certain things you should keep in mind, like how important it is to mark accurately, how to choose the right drill for concrete and how deep to drill a hole, or that you need to use a specific set of tools.

For foam concrete

Due to its low density, good thermal insulation qualities, low flammability, and resistance to temperature changes, foam concrete is used in many different applications today. The foam block is made up of a huge number of frozen bubbles. To secure the material, self-tapping screws, dowels, and screws can be utilized. Chemical and plastic anchors offer the highest level of dependability when it comes to securely fastening the foam block.

For aerated concrete

Wedge anchors that are at least 10 to 15 centimeters long are recommended for aerated concrete. This kind of fastening, which takes into account the material’s porous structure, enables achieving maximum strength and reliability. Strong fixation is also provided by a chemical anchor.

Fixtures must be fastened to foam and aerated concrete using concrete anchors, commonly referred to as bolts. There are several varieties that are appropriate for distinct uses, such as chemical anchors, wedge anchors, and sleeve anchors. In order to ensure a secure hold, proper installation entails drilling a hole, putting the anchor in, and tightening it. In order to achieve strong and dependable connections in construction projects, it is essential to comprehend the types and installation techniques.

How to install an anchor bolt in concrete

The key to a successful process is accurate measurement and precise implementation of all steps. The process itself is fairly straightforward. However, there are a few subtleties that need to be considered.

Useful advice for putting anchors in concrete:

• The strength of the fastener is affected not only by the anchor, but also by the quality of the base material (concrete in this case), proper preparation for installation, taking into account the material of the attached structure and the design of the bolt itself.
• If the wall has a finishing layer, the hole should be deeper, since the finishing layer is usually less durable than concrete.
• It is advisable to take a drill 0.5 millimeters thinner than the diameter of the future hole.
• When working with a hammer drill, it is best to use a tip made of a special carbide material.
• Read the instructions carefully – the packaging with anchors should indicate the permissible force and maximum number of revolutions.
• When screwing an anchor into foam concrete or aerated concrete, do not screw it all the way in any case, as the material may collapse.

Eternal fastener: dowel for concrete

A dowel is a polypropylene or nylon spacer element that functions similarly to an anchor in terms of features. It is attached to the concrete using self-tapping screws or specialty nails; it is not used separately. The fixation is frequently made with antennae or spikes to strengthen it.

This kind of fastening is used to shelves, TV hooks, and lighting fixtures where there aren’t any excessively heavy loads on the concrete. A hammer is used to jam the dowels in a concrete wall, and a screwdriver or screwdriver is used to screw the screws in. You will also need a standard hammer to drive nails.

Dowel-grooves made specifically to be used with a mechanical gun are also available. Concrete fasteners are made of metal; from the outside, they resemble bullets. appropriate for spaces where hanging a lot of tiny objects is required.

Nagel on concrete: quickly, but firmly

Huggled fasteners are typically utilized to arrange fasteners in close proximity to the edges of a concrete wall. Fasteners just screw into the hole where a small amount of epoxy glue is already poured; no additional fixation is needed. Drilling holes is not required because the waddle can be screwed straight into the concrete wall. It is preferable to use a drill if the concrete hole still needs to be filled (a punch may harm the wall).

Once the dowel is screwed in with a screwdriver, it cannot be taken out again. As a result, preliminary marking needs to be done with extra care.

Any construction project requires an understanding of the various types of concrete anchors and how to install them, but this is especially true when working with foam and aerated concrete. For these materials to be fastened securely and reliably, certain anchors are needed. You can provide your structures with the stability and durability they require by selecting the appropriate anchor and installing it correctly.

There are several types of concrete anchors, such as drop-in anchors, wedge anchors, and sleeve anchors, and each is appropriate for a particular use. It is better to use lightweight, high-strength anchors when working with foam and aerated concrete. To properly install these anchors, it’s crucial to adhere to the manufacturer’s instructions and use the right tools.

Drilling the hole to the right size, thoroughly cleaning it, and precisely inserting the anchor are all necessary for a proper installation. A snug fit and strong fastening will stop any possible problems later on. By taking the time to install anchors correctly, you can guarantee the longevity of your construction and prevent future issues.

You can improve your projects’ strength and safety by being aware of the different kinds of concrete anchors and how to install them. If you’re working on a large-scale construction project or a small DIY project, using the correct anchors will give you the stability and support you need for long-lasting results.

Video on the topic

Installing a chemical anchor in foam concrete

How to choose an anchor for concrete?

Universal anchors Pros and Cons | Types of fasteners for concrete | Krep-Comp

Anchor bolt. Principle of operation. Installation

Installation of an anchor bolt with a nut