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Re: Repair of reinforced concrete members.

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With proper equipment, training, and experience and experience and
experience ultrasound testing is a good way to go.  But for the normal
routine concrete repair I'd prefer a hammer, chain, and can of paint.  I
have had applications where I have specified ultrasound, but my
specifications for the testing agency are very tight.  As a matter of
fact I believe that I listed only 2 testing firms that would be able to
provide these services.

I have heard of the horror stories of ultrasound misapplication, and I
won't get into them here.  I am fortunate that phone calls to some
colleagues prevented a recurrence on any of my projects.

Regards,
Harold Sprague
 ----------
From: Arvel L. Williams, P.E.
To: seaoc(--nospam--at)seaoc.org
Subject: Re: Repair of reinforced concrete members.
Date: Tuesday, October 07, 1997 12:32AM

Lew Midlam wrote:

> Sprague, Harold O. wrote:
> >
> >... <snip>...
>
> > the patch tended to delaminate from the parent concrete as a
> > unit.  Sounding with a hammer easily revealed the lack of a proper
> > bond between the patch and the parent concrete.
>
> This is often the result of not excavating deep enough.  If the bar
> isn't *fully* excavated then an anode/cathode system develops between
> the upper and lower surfaces of the bar.  Corrosion is very rapid, and
>
> delamination occurs at the bond between the new and old concrete.
>
> > I would strongly advocate
> > periodic inspections to repaired structures to monitor performance.
> >
>
> 100% agreement here.  The fisrt repair is just that - the *first* of
> what is usually many during the remaining life of the structure.
>
> Lew Midlam, P.E.
> http://www.lcm.com

Gentlemen:

Any opinions on using Ultrasound transmission for qualitative evaluation
of repairs.

Arvel L. Williams, P.E