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Fwd: Re: Concrete in Salt Water Environment

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Norman Brudigam wrote:
> How much of the structure is exposed to the splash zone (most critical)?
Well, it vaires on the project.  The pump house sits right on the beach
and waves will be pounding it constantly (well, maybe not "pounding",
here in Santa Barbara all of our waves must be gentle to fit in with our
image you know :)  ). There are concrete "pools" which contain salt
water being pumped through them to create an environment for the marine
life.  No waves here, but constantly moving salt water.  There there are
portions that are completely under water (the intake line, which extend
several thousand feet offshore.)  And some of the building sits right
near the water, but will only have salt water on the structure during a

>  0.40 is achievable with superplastisizers
Yes, I was not considering the use of superplastisizers at first, but if
it will allow the W/C ratio to drop to .40, then I am definetly going to
use them.

> gradation will be important for workability if you have lots of steel
> and tight spaces
I am going to try and design thicker concrete sections to minimize the
steel, since the steel seems to be the problem here.
> cover and permeability are the most important in my book.  Are you using
> pozzolans?  Fly ash or slica fume should be used to cut down the
> permeability as well as the heat (thermal cracking).
I am considering the use of Fly ash, or possibly slica fume.  I have
seen literature put out by various companies that advertise their
admixture to decrease permeability and increase durability.  They all
sound wonderful, but I am wondering if these products really work.
> I know this works.  Several years ago I investigated some 1920s piles in
> Honolulu harbor that had decent cover (2 inch I think) with good
> concrete (4000 to 5000 psi about).  The failures I saw were related to
> areas with less cover (1 inch) like the horizontal concrete framing.
> i suggest increasing the cover a little to allow for "field variations"
> as was suggested by the Port of Oakland engineer.

> I don't have an opinion on the epoxy coated steel.  Caltrans seems to
> use a lot of it.  Putting a thin coating on steel, which is normally
> handled very roughly, seems like a bad idea.  you can't help but get
> nicks and scrathes and an inspection hassle.
I have the same concerns about the epoxy coating.  How in the world can
the typical rod busters be carefull enough to not put nicks in the
coating.  And how could any inspector be carefull enough to find the
small nicks that might occur.

Thanks for your input.  It was very helpful.


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