Chemical Anchors: How Are They Used?

What Are Chemical Anchors For and How Are They Installed?

The chemical anchor, also known as a chemical fixing, is a specific type of element used in situations where the support could be damaged due to the pressure exerted. Indeed, unlike the classic mechanical anchor used for friction or interlocking, the chemical anchor is fixed to the masonry through special rigid glues.

Through the application of the resin for anchors, the wall into which the metal bar is inserted does not crumble or disintegrate. The chemical anchoring technique involves injecting the resin into the hole before inserting the bar so that, after the resin hardens, all irregularities are covered and the hold of the hole is stronger.

The hardening speed can vary from 3 minutes to a maximum of 5/6 hours based on:

• Ambient temperature;
• Humidity or presence of water in the hole. Beyond the method of application, chemical anchors differ from mechanical ones also by the unlimited depth of insertion.

In general, the choice to use a chemical anchor over a mechanical one depends on:

• The type of material to work on
• Environmental conditions
• The intensity of the load to be supported.

Different Anchors for Different Uses

The main types of chemical anchor are injection or contained in capsules. Among injection chemical anchors, the most widespread and used are the bi-component resins, available in 3 types:

• Chemical anchors for porous materials and polyester resins, generally applied on damp concrete to avoid the occurrence of alkaline hydrolysis, which could compromise their resistance over time. They are mainly used for: installing frames, thermohydraulic works, light carpentry, and applications on hollow bricks.
  
  
• Chemical anchors and vinyl ester resins, characterized by greater mechanical resistance and resistance to alkaline hydrolysis, are the ideal article for high-resistance fixings in the building, construction, heavy carpentry, and road works sectors.
  
  
• Chemical anchors and epoxy resins, this last category of products has greater resistance than the previous two, but requires up to 10 times longer for hardening and fixing. They are used for anchoring reinforcing bars and for fixing in deep holes.

Injection chemical anchors are packaged in rigid or soft cartridges that contain the base resin and the hardener. At the time of installation, resin and hardener are mixed in already fixed proportions.

Chemical anchors in capsules are available on the market in glass or soft material envelopes. The capsule contains the resin, a container for the hardener, and any inert fillers.

How Much Weight Can a Chemical Anchor Hold?

Asking about the capacity of an anchor means considering the right choice to make. The weight to be supported, along with the surface it will be applied to, is one of the factors on which the choice depends.

In general, the larger the diameter of the anchor, the greater the weight it can support (for example, a 6mm anchor can support up to 14 kg while a 10mm anchor up to 30kg). The evaluation of the right element is also linked to the material in which to insert it. From wood, concrete to steel and iron structures, the market is able to offer different types and sizes of anchors for every need.

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