Construction Procedures of Steel-Encasing Reinforcement

1. Base surface treatment

- Grind the base surface to remove the weathered, carbonized, rusty, and cracked parts for a solid layer.

- Flatten the base surface and remove dirt.

2. Bolt planting

- Check the existing bar arrangement in advance.

- According to the construction design, drill holes on the base surface using a percussion drill and make sure to avoid existing bars and not perforate them.

- The distance between the edges of steel plates and the drilled holes shall be 5-10mm. And the interval between two holes shall not exceed 300mm.

- Install full-thread screws.

3. Steel plate installation

- Cut the steel plates according to the actual size of the construction site.

- Steel plates should be perforated in line with the screws planted in the base layer.

- Steel plates should be de-rusted and roughened with a grinder or a wire brush machine, and the grinding pattern should be perpendicular to the force direction on the steel plates.

- Wipe the steel plates with absorbent cotton soaked with acetone.

- Fix the steel plates on the bolts and leave a gap of more than 3mm between the base surface and the plates, to ensure a sufficient thickness of the adhesive layer.

- Weld the steel plate joints.

4. Sealing

- Attach injection nozzles and vent pipes to the edges of steel plates.

- Cover the bolt heads with aluminum caps.

- Seal the edges of steel plates with specialized sealant.

5. Preparation of adhesive

- Stir Component A and B of ASR-200 separately at a speed not exceeding 300 rpm.

- Mix the component at the ratio of A: B=3:1 (by weight) and stir at a speed not exceeding 300 rpm until the color is completely uniform. 

- The container for the mixed adhesive should be large enough to dissipate heat. A high temperature would shorten the pot life of the adhesive.

- The adhesive should be consumed within a set amount of time to achieve satisfying bonding performances. So do not mix in a large amount at a time. Instead, prepare a small amount each time along with the construction process. The remaining materials shall be sealed well after the adhesive is taken.

6. Injection

- Inject the adhesive from the injection nozzles into the gap between the steel plate and the concrete surface with a pressure of 0.2-0.4MPa by grouting equipment.

- For inclined or vertical steel plates, the injection should start from the low nozzles.

- The injection should not be too fast to prevent the formation of air pockets.

- Tap the steel plates with a rubber mallet during the injection process, to check out if the gap is filled.

- When the adhesive has flown out from all the vent pipes, seal the vent pipes and maintain a lower pressure for about 10min.

7. Quality check and protection

- Check if the adhesive injected has filled the gap completely.

- Check if the bonding performances meet the requirements after curing.

- Remove all injection nozzles and seal.

- Remove all dirt and rust on the steel plates.

- Apply anti-corrosion treatment to the steel plates.