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From: jgd@Dixie.Com (John G. DeArmond)
Newsgroups: sci.military
Subject: Re: Pouring concrete (as regards Iraqi shelters)
Keywords: concrete
Message-ID: <1991Feb13.030550.24632@cbnews.att.com>
Date: 13 Feb 91 03:05:50 GMT
References: <1991Feb11.043911.28147@cbnews.att.com>
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From: jgd@Dixie.Com (John G. DeArmond)

jln@elaine39.stanford.edu (Jared Nedzel) writes:

>As for times, well, a 36m slab of concrete would certainly have to be placed
>in lifts, with time between lifts (just how much time, I'm not sure).

>It will take somewhere between several hours and a day or two for the
>concrete to set, but it will take significantly longer for it to gain
>strength. You get a lot of strength after a week, but you won't reach
>design strength for a month or so. I can't say how long it would take
>to pour 36m of concrete, except to say that it would be a good long 
>while (months).

My first "real" job was as a heavy equipment operator at the construction
site of the Sequoyah Nuclear Plant in Chattanooga, TN.  More specifically,
I ran the ammonia-cooled ice plant that was part of a field-erected 
concrete batch plant.  I started my job a couple of weeks before the
pour of the reactor building foundation.  This was a slab about 200 ft
in diameter and 35 ft thick.

This slab was laid as a continuous pour.  It took about 3 weeks of around
the clock pouring to lay it.  To put this in perspective, the batch plant
was about 6 stories high, received its raw materials by river barge and 
mixed a truckful in a single batch.  The ice plant alone had 200 hp 
motors running the ammonia compressors.  In other words, we could make a 
LOT of concrete.  It'd be hard for me to imagine a batch-plant this 
large being transported out in the desert away from grid power.  I suppose
it could be done.  I think that the 3 week period for a pour this size
is probably the minimum one could expect.

John

-- 
John De Armond, WD4OQC        | "Purveyors of speed to the Trade"  (tm)
Rapid Deployment System, Inc. |  Home of the Nidgets (tm)
Marietta, Ga                  | 
{emory,uunet}!rsiatl!jgd      |"Politically InCorrect.. And damn proud of it