September 11, 2009

Concrete Matters #5 last in a series: Inspection

by Kevin Morris

This is the last post in a series on concrete and we have taken you from placing the the substrate to applying the coating system. This post contains information on little things that need to be done all along the way to inspect what you expect.

Starting with the first post in the series you should inspect the integrity of the moisture barrier for proper installation and imperfections prior to concrete placement. Identify that all reinforcing steel has been set at the right depth for adequate concrete cover. Check the slump of the concrete mix to ensure it is what you specified or requested. It may also be advantageous to take some cast cubes from the mix to test the physical properties. You should have someone available to observe the placement and finishing of the concrete to make sure the installation is proper.

In the second post of the series we discussed surface preparation. Surface preparation for coating, or lack thereof, is the cause of the greatest majority of coatings failures. Check the surface for cleanliness through visual inspection or a water bead/break test. Compare the surface profile to the ICRI CSP replica profile standards for what was specified. Check the surface to see that all surface imperfections were opened up properly. Visually inspect miscellaneous steel that might be part of the coating specification for proper cleanliness and surface profile.

In the third post we discussed the repair of multiple types of imperfections in the substrate. It is important to observe and document the processes that take place. You should always record the conditions during application which should include:

  • Surface Temperature
  • Ambient Temperature
  • Material Temperature (Including water temperature for mixing)
  • Relative Humidity
  • Calculate Dew Point
  • Product Batch Dates
  • Mixing and Application Procedures

Depending on the authority that you have given your inspector, he or she may see fit to stop the progress of work if the things above or other items are not within the parameters established in the specification or recommended by the product manufacturer.

In the fourth post of this series we discussed the application of the coatings materials. The inspection process for the application of coatings should include those listed above and any or all of the following:

  • Moisture Vapor Emission Test
  • Wet Film Thickness
  • Dry Film Thickness
  • Static Coeffecient of Friction
  • Holiday (Spark) Testing – High Voltage or Low Voltage
  • Cleanliness of all equipment used – Compressed Air, Spray Equipment, etc.

Our industry offers several formal courses for training coatings inspectors depending on the desired needs. NACE CIP, SSPC PCS, SSPC CCI are a few of the more recognized options. These courses add value to anyone that may be involved with inspecting, project management, or application of any of these phases of concrete construction.

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