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RE: Concrete shrinkage (was curing)

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Bill,

I reference the sieves from ASTM C33. I specify the maximum nominal C33 aggregate, and then I require all of the smaller sieves to retain a minimum of 8% and a maximum of 18% on ALL of the sieves. It is a derivation of the Shilstone method of grading aggregates. It provides for less shrinkage and a more workable mix by avoiding gradation gaps.

Regards,
Harold Sprague



From: "Sherman, William" <ShermanWC(--nospam--at)cdm.com>
Reply-To: <seaint(--nospam--at)seaint.org>
To: seaint(--nospam--at)seaint.org
Subject: RE: Concrete shrinkage (was curing)
Date: Thu, 8 Jul 2004 19:40:10 -0400

Let me re-phrase my question - what specification language do you use to
ensure that you get "a uniform gradation on the coarse aggregates"?

William C. Sherman, PE
(Bill Sherman)
CDM, Denver, CO
Phone: 303-298-1311
Fax: 303-293-8236
email: shermanwc(--nospam--at)cdm.com


> -----Original Message-----
> From: Harold Sprague [mailto:spraguehope(--nospam--at)hotmail.com]
> Sent: Tuesday, July 06, 2004 9:46 AM
> To: seaint(--nospam--at)seaint.org
> Subject: RE: Concrete shrinkage (was curing)
>
> Bill,
> After it is in the mix, the only proof would be in the form
> of a petrographic analysis.  As in any aspect of concrete mix
> verification, the best verification approach is independent
> inspection at the batch plant.
> Independent verification, special inspection or whatever you
> want to call it was more common in the past.
>
> We (engineers in general) have drifted away from batch plant
> inspection in more recent years.  But I have found that the
> practice helps avoid problems that can cost hundreds of
> thousands of dollars.  A few years ago, I had a batch plant
> in Colorado's Front Range switch fly ash and cement portions.
> We noticed the problem when the removal of the anchor bolt
> templates removed the anchor bolts after 24 hours from
> placing.  The batch plant paid for the cost of fixing the
> problem, but the schdule impact really hurt the project.
> The project would have been better served with an on-site,
> independent, concrete mix inspector.
>
> Specifically to gradation, the inspection is just a sieve
> analysis on the stock pile that any of the labs that do
> concrete work should be able to do.
> The quarries that produce crushed rock mostly use
> computerized sieves now, and they should not have a problem
> with mixes that are not the standard C33 gradations.
>
> Regards,
> Harold Sprague
>
> >From: "Sherman, William" <ShermanWC(--nospam--at)cdm.com>
> >Reply-To: <seaint(--nospam--at)seaint.org>
> >To: seaint(--nospam--at)seaint.org
> >Subject: RE: Concrete shrinkage (was curing)
> >Date: Fri, 2 Jul 2004 19:48:57 -0400
> >
> >I agree. But I am curious - what method do you use to get
> the concrete
> >supplier to provide "a uniform gradation on the coarse aggregates"?
> >
> >William C. Sherman, PE
> >(Bill Sherman)
> >CDM, Denver, CO
> >Phone: 303-298-1311
> >Fax: 303-293-8236
> >email: shermanwc(--nospam--at)cdm.com
> >
> >Harold Sprague wrote:
> >
> > > Related to this is my tendency to use polycarbonate
> > > superplasticizers and a uniform gradation on the coarse
> aggregates.
> > > This is to minimize cement and minimize water.

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