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RE: Concrete shrinkage (was curing)

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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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