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RE: Concrete shrinkage (was curing)

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Bill,

Uniform gradation of coarse aggregate is covered in ASTM C33, "Standard Specification for Concrete Aggregates".  The only other thing you have to do is specify the "Nominal Maximum" size or "Size Number".

Thomas Hunt, S.E.
ABS Consulting




"Sherman, William" <ShermanWC(--nospam--at)cdm.com>

07/08/2004 04:40 PM

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RE: Concrete shrinkage (was curing)





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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