CHEMICAL ANCHORING 

 Chemicle Anchoring

Chemical anchoring is a technique of fastening reinforcement bars or threaded rods to previously casted concrete using chemical adhesives. These chemical adhesives take place between concrete and reinforcement bars to transfer the applied load from the anchor to the concrete.

 

Reasons for chemical anchroring

 

•      Errors of the provided reinforcements. (Location changes of the provided reinforcement, insufficient covering to the reinforcement etc.)

•      When the lap length of provided rebar is insufficient

•      Design changes of a building after concreting.(ex: adding new staircase/molding)

•      When the contractor was not able to provide required reinforcement before concreting the structural element.









 

 Chemiicle anchoring diagram


8.1 P Cone Holes

 Treatment for P Cone Holes

P cone holes are producing in all of the structural concrete as per the brazing methodology.

(Figure 8.1)

Figure 8.1. Brazing methodology                            Figure 8.2. P Cone hole

After removal of the p cone, 9 mm tread bar projection was broken by hand tool (Figure 8.2). Then, QD Zinc Phosphate Primer (red) was applied to exposed surface of the tread bar to prevent corrosion. Outer surface of the p cone hole was chipped to receive proper bonding of the new application. After chipping process, holes were cleaned and Barra emulsion was applied to p cone hole surface. Then, non-shrinkage grout (MasterFlow 810) which was mixed in a trowellable stage was applied by hand trowel and proper sealing was done by masonry trowel.

8.2 MasterFlow 810

MasterFlow 810, formerly known as construction grout is a ready to use non-shrink natural aggregate cementatious grout. (Figure 8.3) It is a flowable and self levelling grout able to fill intricate voids. It can be used over a wide range of water additions. There is two stages in this grout, flowable and trowellable. The quantity of water required for a 25 kg bag is approximately,

Ø  Flowable – 4.5 liters

Ø  Trowellable – 3.2 – 3.4 liters Estimate setting time: 

Ø  Initial: 5.30 hours

Ø  Final: 6.30 hours  

 

 Figure 8.3 MasterFlow 810

 

                Table 8.1: Compressive strength of MasterFlow810 (N/mm2)

Days

Flowable

Trowellable

1

25

45

7

55

65

28

65

80

 

 

 

 

 

Curing agent (MASTERKURE 128) was applied just after application of the trowellable grout before pass 3 hours from application time.


























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