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Fwd: Re: Epoxy Coated Rebar

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We had a guest lecturer back in school by the name of Douglas F. Burke who
works as a researcher (he is a PE) for the US Navy.  He told us about a
study done by the Florida D.O.T. in 1987 that showed that bridges using
epoxy coated rebar were showing severe corrosion after only 7 years.  Burke
spent 6 years testing concrete (literally thousands of cylinders) at Naval
ports all over the world, testing calcium nitrite admixtures, zinc coating,
and epoxy coatings to see how they performed in terms of corrosion
resistance.  Epoxy coating did the best, but only when applied with
unrealistic quality control to prevent cracks or other damage in the
coating.

The end result was a new specification, called Fusion Bonded Epoxy (iron
workers in San Francisco call it Barney Bar, I'm told, because it's
purple).  The ASTM spec on this is ASTM A934 / A934M, and was approved in
March 1995.  Some of the notable features of the new spec are that the
coating is applied after the bars are bent into shape, specific handling
requirements (mostly common sense, but they are at last written down), and
special testing of the bars to assure there are no pinholes or cracks in
the coating (it was found in the original study that a cracked epoxy
coating was much worse than no coating at all).

For my own $0.02 on bar coatings, they are an awful lot of trouble unless
the structures exposure justifies that good, sound concrete won't be
enough.

Paul

----------
> From: Bob Shilling <shilling(--nospam--at)emf.net>
> To: Raghu Pendyala <pendyala(--nospam--at)aqua.civag.unimelb.edu.au>
> Cc: seaoc(--nospam--at)seaoc.org
> Subject: Re: Epoxy Coated Rebar
> Date: Tuesday, February 25, 1997 10:23 AM
> 
> On Tue, 25 Feb 1997, Raghu Pendyala wrote:
> 
> > 
> > In my opiinion epoxy coated bars are a complete waste of time and 
> > effort. 
> Raghu,
> Is this opinion based on actual field experience, or on experimental
data?
> I see a lot of this being used lately, and am really curious as to why 
> some people are saying it's no good.
> Thanks in advance,
> Bob
> 
> .    .    .   .   .  .  .  .  . . . . . ...........................
> Bob Shilling, SE             Berkeley, CA          shilling(--nospam--at)emf.net
> 
> 


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Subject: Re: Epoxy Coated Rebar
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