If an empty drum is found, it means that the carbon fiber cloth and the concrete are not completely fitted, and the purpose of joint stress has not been achieved. If the effective area is less than 95% of the total construction area, it means that the reinforcement project is unqualified, and the project needs to be reworked.

So how did the empty drum come about?

1. The concrete is not smoothed before pasting

The carbon fiber cloth is too wide or the concrete is not polished before pasting, etc., which will cause the hollowing phenomenon of the carbon fiber cloth to be pasted. Therefore, the builder needs to grind the concrete foundation before pasting. The corners must be ground into an arc shape to keep it dry. If there are cracks, the cracks need to be repaired and smoothed before pasting.

2. Different thicknesses when brushing glue

When brushing carbon fiber glue, you must pay attention to evenly brushing, and you can apply more at the corners.

3. Glue coating uneven

In addition to the need to brush glue when pasting, it is also necessary to apply glue evenly after pasting to ensure that the carbon fiber cloth is infiltrated in both directions to achieve a better reinforcement effect.

4. Carbon cloth paste is not smooth

The constructor must align the carbon cloth tightly when pasting the carbon cloth, and use a scraper to completely remove the air inside to avoid the phenomenon of hollowing.

5.  Carbon fiber cloth quality problems

If the carbon fiber cloth is too hard and the weaving is not tight, it will easily lead to hollowing problems. When choosing carbon fiber cloth, the constructor must ensure that the selected carbon fiber cloth is a qualified product.

Empty drum treatment method

Small area empty drum:

If the area of a single hollow drum is not more than 10000mm², we can use the method of needle injection, but this method may cause the problem that the needle cannot be injected, or can not completely solve the hollowing phenomenon, so this method is generally rarely used.

Large area empty drum:

If the area of a single hollow drum is greater than or equal to 10000mm², the builder can directly cut off the hollow drum, then repair it with repair glue, and re-paste the hollow drum with carbon fiber cloth. When overlapping, the overlapping length of each end in the direction of force should not be less than 200mm. If the number of pasting layers exceeds 3, the lap length should not be less than 300mm. For the non-stress direction, the lap length on each side can be 100mm. When scraping the cloth, the scraper should be rolled back and forth to ensure that the air is completely discharged; the carbon glue should be evenly brushed.