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Express Course

Chemical anchor in concrete

Find out how to fix metal anchor in concrete substrate with Ceresit CF 850 or Ceresit CF 920.

Crucial to know

clean the hole before adhesive application

make a trial squeeze of the adhesive

 

Tools needed

a hammer drill

a hand pump

Step 1

A hole for a metal anchor

Drilling a hole

Drill with hammer drill a hole into the base material to the size and embedment depth required be the selected anchor. In case of aborted drill hole shall be filled with mortar. Standing water in the bore hole must be removed before cleaning.

  • Starting from the bottom or back of the hole, blow the hole with compressed air or hand pump a minimum of four times. If the bore hole ground is not reached, an extension shall be used.
  • The hand-pump can be used for anchor sizes up to bore hole diameter 20 mm. For bore holes larger than 20 mm or deeper than 240 mm, compressed air (min. 6 bar) must be used. 
  • Check brush diameter as required and attach the brush to a drilling machine or a battery screwdriver. Brush the hole with the right sized wire brush larger than minimal hole clearance diameter a minimum four times. If the bore hole ground is not reached with the brush, a brush extension shall be used.
  • Finally blow the hole clean again with the compressed air (min. 6 bar) or hand pump a minimum of four times. If the bore hole ground is not reached an extension shall be used. For bore holes larger than 20 mm or deeper 240 mm, compressed air (min. 6 bar) must be used.

The bore hole has to be protected against re-contamination until dispensing the mortar in the bore hole. If necessary, the cleaning repeated has to be directly before dispensing the mortar.

Step 2

Mortar application

Attach a supplied static-mixing nozzle to the cartidge and load the cartidge into the correct dispensing tool. Cut off the foil tube clip before use. For every working interruption longer than the recommended working time as well as for new cartridges, a new static-mixer shall be used.

  • Prior to inserting the anchor rod into the filled bore hole, the position of the embedment depth shall be marked on the anchor rods. 
  • Prior to dispensing into the drill hole, squeeze out separately a minimum of three full strokes and discard non-uniformly mixed adhesive components until the mortar shows a consistent grey colour.
  • Starting from the bottom or back of the cleaned anchor hole fill the hole up to approximately two-thirds with adhesive. Slowly withdraw the static mixing nozzle as the hole fills to avoid creating air pockets. If the bottom or back of the anchor hole is not reached, an appropriate extension nozzle must be used.

Observe the gel-/working time.

Step 3

fixing of a sleeve

Metal anchor installation

Push the threaded rod into the anchor hole while turning slightly to ensure positive distribution of the adhesive until the embedment depth is reached. The anchor should be free of dirt, grease, oil or other material.

  • Be sure that the anchor is fully seated at the bottom of the hole and that excess mortar is visible at the top of the hole. If these requirements are not maintained, the application has to be renewed. For overhead application the anchor rod should be fixed (e.g. wedges).
  • Allow the adhesive to cure to the specified time prior to applying and load torque. Do not move or load the anchor until it is fully cured.

After full curing, the add-on part can be installed with the max. torque by using a calibrated torque wrench.

Tips & Tricks

For professionals

What types of chemical anchors are available on the market? 

Chemical Anchoring is based on two different types of chemical systems:

Reaction resin mortar for use in solid natural stones, concrete substrates and in hollow bricks, with fast curing time (Ceresit offer).

Epoxy system for concrete use only and with slower curing time.

products used

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    CERESIT CF 850
    Polyester chemical anchor is a two-component, quick-setting adhesive based on reactive resins. 
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    CERESIT CF 920
    Two-component, fast-setting injection mortar for anchoring based on reactive resins, styrene free. It is characterized by high load carrying capacity. 

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