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Posted:
Mon 23rd Nov 2009
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Original Post |
User: jozza
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Nov 2009
Total Posts: 1
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corrosion on steel columns which were hot metal sprayed with zinc, epoxy zinc primed & powder coated. The columns are set in concrete and the corrosion is happening in the concrete footing and directly above this where the column comes out of the concrete |
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Posted:
Wed 25th Nov 2009
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Reply #1 |
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User: peter clark
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Nov 2009
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To attempt a reply to this topic much more information is required about the environment and the form of the corrosion. |
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Posted:
Fri 27th Nov 2009
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Reply #2 |
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User: jozza
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Nov 2009
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Here are a few more points to add to the previous post. I do have photos available. A picture is worth a thousand words as they say. The posts were put in place and where the concrete was to be poured around them the builder encased them with "able flex" then poured the concrete. The posts seem to be corroding in the concrete. Above the floor line there is no corrosion. Maybe water pooling & the able flex is acting as a sponge and it draws the water onto the coating, which might penetrate the coating over time ? I'm pretty sure there is no electricity leads or conduits passing through the posts. |
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Posted:
Fri 4th Dec 2009
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Reply #3 |
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User: cerri
Status: ordinary
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Dec 2009
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Posted:
Mon 7th Dec 2009
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Reply #4 |
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User: fyfecj
Status: professional
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Mar 2009
Total Posts: 6
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Although environments are different the phenomena is also occurring on offshore structures were TSA has been applied and then over coated with a three coat pint system.
SINTEF presented a paper at NACE CORROSON 2004 (Paper N° 04023) RAPID DEGRADATION OF PAINTED TSA. The paper explains why TSA duplex coated degrades rapidly in comparison to TSA applied "only" with a sealer.
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