Corrosion of reinforced concrete on bridges.

Reinforced Corrosion concrete bridges are designed to maintain their service and function in the long term. During this service period, concrete is subjected to many strong influences, including variable loads and vibrations, extreme weather conditions, and the presence of reinforced chloride in concrete in marine environments.
Figure : Cracked concrete
Original cause:
Steel reinforcement corrosion
Freeze – thaw action. Impact
Figure: Unstructured cracks
Original cause:
Shrinking
Temperature
Alkaline fusion (AAR)
Figure: Corrosion to reinforcement
Original cause:
Chloride solution
Stray current
Figure : Absorb
Original cause:
Wet
Figure: Structural cracks
Original cause:
 
Overload
Textured movement / Vibration
Earthquake impact
Figure: Corrosive steel structure
Original cause:
 
Incomplete steel coating
Chloride solution
Wet

Protecting and waterproofing concrete by applying polyurea is a very common job. Thanks to the advantages of the seamless polymer elastomer, polyurea is effectively used for roofing, waterproofing the foundation, protecting tanks, floors, covering swimming pools and protecting any Corrosion concrete structure.

Before applying polyurea to concrete, it is necessary to carry out some preparation activities. First of all, all dirt, defective and weak concrete surface should be removed from the surface. The cleaned concrete floor must be dry (no visible moisture, moisture not exceeding 8%). If there are large cavities, potholes and debris in the concrete, its surface should be filled.

Ứng dụng polyurea
Applying polyurea waterproofing the foundation

If the condition of the vertical surface is not satisfactory, a high-strength repair grout may be required prior to application of polyurea.

Its main purpose is to close relatively large voids present on the concrete surface. For high demands on decorative properties (eg, surface finishing of swimming pools), care should be taken to smooth out the plastering. The standard thickness of the polyurea coating is 1.5-3 mm. The application of polyureas can only conceal minor defects made during the preparation. After construction, the leveling and filling layers must be cured to a full ripeness and moisture content as indicated for use.

Ứng dụng polyurea
Pictures of waterproofing Polyurea on the roof

After the preparation work is completed, the plastering wall and the concrete surface of the floor must be primed one or more layers to increase the adhesion strength better and to overlap the voids. The primers, which penetrate the surface porosity, not only insulate the pores but also form a durable composite component that protects the applied polymer coating from the moisture of the substrate. One and two component inoculants based on epoxy and polyurethane resin, compatible with polyurea, can be used as a primer. The applied primer must be cured until fully cured according to the instructions. When applying polyurea without pre-priming or with incorrectly selected priming ingredients, potentially breaking the polymer’s adhesion and hardness. Air and moisture, voids of concrete or other porous substrates (plaster, cement, foam concrete, brick, wood) are displaced during the use of polyurea. This process leads to the formation of defects in the form of craters and even holes.

The application of polyurea is carried out on a concrete surface prepared according to the procedure described above, in one or several layers, depending on the required thickness. The specifications and service life of the protective coating depend directly on the correct compliance with the polyurea application technology and surface preparation.

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