Substrate Preparation and Quality Testing

Preparation Method

There are many factors that can affect the adhesion and bonding capabilities of a polymer system to the substrate. In order to achieve optimum adhesion, the sustrate must be clean and prepared properly. Therefore, it is ultimately necessary and absolutely important to check the conditions of the substrate in order to correctly identify the proper and correct method of preparation.

The preferred method of concrete surface preparation is by use of an abrasive shot-blasting machine, on all horizontal surfaces. Chemical preparation, although acceptable and commonly used, is a less desirable method of surface preparation due to potential for insufficient recovery of the cleaning solutions and the surface being left un-abraded. Shot-blasting of a concrete substrate is by far the most effective surface preparation technique available; both from a costt and environmental standpoint.

A highly effective method of surface preparation used prior to the application of coatings, sealers or overlays to a substrate. Shot-blasting not only cleans a surface by removing surface contaminants, it provides a surface profile which will allow for the best adhesion of the coating or overlay. Shot-blasting is the preferred method of surface preparation for several reasons:

  • Shot-blasting is a one-step method that will strip, clean and profile a surface.
  • Shot-blasting is a dust-free operation, using self-contained dust collectors thus making it ideal for sensitive environments.
  • Shot-blasting does not use chemicals, therefore there is no post-cleanup and no hazardous material use.
  • Shot-blasting is faster than other methods. Substrate is ready for coating immediately after blasting.
  • Shot-blasting does not impregnate perticulate into the surface.

Special Considerations

Condition of Concrete — Newly placed portland cement concrete (PCC) is designed to develop its full strength typically in 28 days, at which time a polymer system can be applied. A light steel troweled finish is most desirable. Existing concrete should be structurally sound an devoid of any detrimental materials and any surface contaminates.

Surface Contaminates — These include a variety of foreign compounds including; curing compounds, release agents, hardeners, grease, oils, food by-products, chemicals, fatty acids, old coatings, dust and dirt.

Moisture — To achieve proper adhesion of the polymer system, repairs and or additional coatings may be necessary to eliminate the movement of water and vapors through the substrate.

Evaluation Factors

Repairs of surface irregularities (including cracks, delamination, deteriorated joints, pitching for drainage, etc. ) can be accomplished after the surface preparation is complete, and must be done prior to application of the polymer system. Dura-Guard offers several products for patching and crack repair. These repairs should be appropriate and consistent with the system and method of application that will be used.