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PowerTech Analysis

 

The following is a summary analysis of the results of a durability test of Termarust Technologies Coating System that were conducted by an independent testing laboratory - PowerTech Labs, of Surrey, British Columbia, Canada. The protocol for the durability testing was developed by Alberta Transportation & Utilities in conjunction with seven other Departments of transportation (DOT's) that chose the KTA-Tator Enviro Cabinet Cyclic immersion test to duplicate actual corrosion phenomena. The pictures shown below illustrate why Alberta Transportation & Utilities chose to use the KTA-Tator Enviro Test with its immersion cycles as opposed to Prohesion Cabinet that does not use an immersion cycle. It can be seen that Poltus rust develop and continues because moisture, sand and salt collect and remains on sections of a structure that rarely dry.


Redwood bridge Winnipeg panel point. Snow, salt, sand and rain sit year-round creating a continous immersion condition. - February 1995.



McDonald street bridge Edmonton, Alberta. Salt, snow, sand and rain accomulate on plates causing poltus rust. - March 1995.

The KTA-Tator Enviro-test Cyclic Cabinet with its 3 immersion cycles duplicates the above condition. It stresses the test coatings for 3 consecutive 2-hour cycles of immersion. Each time the test-coated panels change positions, the sample runs through a salt bath. The remaining 3, 2- hour cycles include a baking cycle at 60 degres C, a UV-B ultraviolet light exposure cycle and a third humid environment like salt fog cycle. In conversations with Mr. Paul Carter, from Alberta Transportation & Utilities, he stated that they believe they have a fairly accurate picture of failure mechanisms in the field, and is as close to real world situations as they can get. Crevice corrosion and Poltus rust is the most serious failure mechanisms in bridge overcoating or recoating, any tested coating that does not do well in the immersion cycles will most likely fail on a flange edge and in the panel point areas, as shown in the photos above.

 

The results received from PowerTech can be explained as follows: When the zinc systems were immersed in the chloride solution the coating failed and the steel was exposed to the electrolyte, the zinc became active, sacrificed itself, exposing the steel which allowed it corrode. Termarust 2100 (RAVCS®) Primer/Topcoat, with its affinity for metal, does not allow the moisture to penetrate the surface or undercut at the scribe. Thus, Termarust 2100 (RAVCS®)'s excellent test results due to superior performance. The mechanisms that allow this high level of performance are explained below.

The Termarust (RAVCS®) chemistry imparts the following performance properties:

  • Hydrophobicity -resistant to the egress of moisture
  • Polarity -superb metal wetting and moisture displacement
  • Inhibition -buffering the PH at coating / metal interface
  • Physical Barrier -a proprietary process that grows uniform synthesized crystals. These crystals increase the distance moisture will have to travel to get to the metal surface.

 

The Termarust (RAVCS®) series coatings:

  • neutralize surface acidity and keep the pH at approximately 10.0
  • displaces moisture because of their high polar attraction to steel
  • maintains a hydrophobic barrier, due to its crystalline structure, which aligns at the steel surface, similar to fish scales, therefore increasing the distance moisture has to travel.
  • wets the surface and penetrates into all pitted areas
  • remains flexible to eliminate cracking from expansion, contraction & structure deflection.
  • easy to apply at excessive film builds, which ensures enough coating is applied to complex geometries, edges and areas of limited accessibility
  • non-hazardous low waste stream - no equipment flushing required
  • single component - no mixing/no wasted catalyzed material
  • single coat, wet-on-wet application reduces costs

The results shown include the March 14, 1995 report on Termarust 2100 (RAVCS®) Primer/Topcoat performance at 5 mils D.F.T. in PowerTech testing.

 

Following are some interesting correlations:

  1. Enviro-test exposure over-aged alkyd (overcoat) using Termarust 2100 (RAVCS®)
    • Primer/Topcoat
    • 1st round at 10 mils D.F.T. 1,200 hours
    • 2nd round at 5 mils D.F.T. 1,520 hours

    The March 14, 1995 PowerTech tests confirm our laboratory results that 5 mils D.F.T. of Termarust 2100 (RAVCS®) Primer/Topcoat performs better than the 10 mils D.F.T. of Termarust 2100 (RAVCS®) Primer/Topcoat when overcoating an existing alkyd system. Explanation: This phenomenon occurs because the thinner film will more efficiently permeate moisture from the surface of the existing alkyd coating system. The March 14, 1995 PowerTech results show a 25% performance increase over aged alkyd paint systems with Termarust 2100 (RAVCS®) Primer/Topcoat at 5 mils D.F.T. This film thickness makes Termarust 2100 (RAVCS®) a very cost effective solution, without paying a performance penalty. Termarust 2100 (RAVCS®) Primer/Topcoat at 5 mils D.F.T. out-performed all other systems tested when applied over an aged alkyd.

  2. Enviro-test exposure over cleaned steel
    • 1st round at 10 mils D.F.T. 4,445 hours
    • 2nd round at 5 mils D.F.T. 2,218 hours

    The March 14, 1995 PowerTech test again confirmed our own laboratory results, that over a blasted surface Termarust 2100(RAVCS®) Primer/Topcoat's performance is linear. The performance is proportionate to the thickness of the film, therefore a more accurate method of predicting life cycle cost. i.e.: we assume 10 mils will give us 50+ years performance. This estimate is based on Termarust 2100(RAVCS®)'s test results compared to the 3-coat moisture cured urethane zinc system and the M-50 lead alkyd system. Termarust 2100 (RAVCS®) Primer/Topcoat should give 25+ years performance at 5 mils D.F.T. Due to these conclusions we believe that Termarust 2100(RAVCS®) Primer/Topcoat will make the overcoating option a very cost-effective solution.

    A third observation was made on a blasted steel substrate. Comparing Termarust 2100 (RAVCS®) Primer/Topcoat at 5 mils D.F.T. to the 3-coat moisture cured urethane zinc system and the 2-coat epoxy mastic systems. The Termarust 2000(RAVCS®) Series out-performed the zinc systems as well as the epoxy mastics.

    In the original round of PowerTech testing, Termarust 2000 (RAVCS®) Series did not perform well during the ASTM D2247 water resistance (humidity) test at 10 mils D.F.T. over both aged alkyd and blasted steel. We have since run tests with a modified formula for B.C. Hydro and have exceeded the 1000 hours minimum requirement over blasted steel.

A summary of the Independent laboratory tests done by PowerTech is listed in the attached table. To view table click here.

Due to budget constraints testing stopped, however by that time, the Termarust 2100 (RAVCS®) Primer/Topcoat system met the minimum requirements, failure had not occurred, and no other systems were left in the test.

The above results show that Termarust 2100 (RAVCS®) Primer/Topcoat displays excellent resistance in the humidity chamber test. It outperforms three-coat zinc, epoxy, urethane systems and 3-coat moisture cured urethane zinc systems in all categories, and it is clearly the winner in tests run by PowerTech for blasted steel. Termarust 2100(RAVCS®) Primer/Topcoat is also a clear winner when applied over aged alkyd at only 5 mils D.F.T. When Termarust 2100 (RAVCS®) Primer/Topcoat was applied at 5 mils D.F.T., which is our overcoating dry film thickness minimum requirement, Termarust 2100 (RAVCS®) finished first in the EnviroTest. Copies of the original test results are available on request. Please call 1-888-279 5497 ext 261






 
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