Tuesday, November 18, 2008

Build a Concrete

Build a concrete should intense to the final quality of concrete, the final of concrete result must be strong and sometime should not leakage from seep water, especially when the concrete also used as open roof of our house.

For those purpose some preparation before conduct a concrete molding must be done, such as preparation and cleaning. When applying any coating to concrete or steel, and even when bonding new concrete to existing, adequate surface preparation of the substance is fundamental to success. For coating product that possess excellent adhesive properties and have a high tolerance level, thorough surface preparation and cleaning are absolutely essential.

The ideal surface for a coating material system should be:
  • Free of weak or brittle cement laitance
  • Free of loose or friable particle
  • Dry (moisture content below 4% except in special circumstances)
  • Clean and free of contaminants (especially oils and greases)
  • Open textured with a sandpaper like finish
  • Constructed with adequate reinforcement and joints, in accordance with current standards and good practice.
There are many methods of surface preparation an cleaning, including a number of proprietary systems. In principle, the most effective methods are mechanical, such as Blastrac vacuum blasting or Von ARX planning machines. Open blast cleaners, scabblers, grinders, power brushes and needle guns are suitable for use on many projects, or in confined areas and edges where not accessible by larger equipment.

With all methods of surface preparation it is important to carry out the mechanical or cleaning operations to the required standards, and to check that this is done. During maintenance and refurbishment work, it may be necessary to remove contaminants from the surface, or even from within the upper layer itself. It may, therefore, be necessary to use chemical cleaners, detergents, emulsifiers, steam cleaning, high pressure water jetting, or a combination of these to clean the substrate. This is normally best carried out prior to mechanical preparation. In cases of severe contamination this cleaning may need to be repeated after mechanical.

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