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RE: Shrinkage in Concrete

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Mike,

An additional note.  

The mix will vary with the pumping equipment.  A slick line will not pump as
stony of a mix as an overhead.  Get as big a pump and large of a diameter
pipe and hose that you can.  

They will not be able to prime the pump with a stony mix.  That's OK let
them prime with a grout, and dump the grout.  

The pumper will also want to push your fines to the upper end of the 8-18%
gradation, and they will want to use ash.  The ash should not be a problem
if you watch the C3A of the combined ash and cement.  Some cement suppliers
are grinding cement after they blend in ash.  It gives you a finer ash.  The
ash will drop your 7 day breaks slightly, that is OK if the 28 day breaks
are good.


Regards,
Harold Sprague


> -----Original Message-----
> From:	Sprague, Harold O. [SMTP:SpragueHO(--nospam--at)bv.com]
> Sent:	Friday, May 05, 2000 7:38 AM
> To:	seaint(--nospam--at)seaint.org
> Subject:	RE: Shrinkage in Concrete
> 
> Mike,
> 
> Sorry for the previous post.  I was cleaning my send button and it went
> off
> by accident.
> 
> The first thing that you need to do is determine what level of shrinkage
> is
> acceptable.
> 
> Re: "Shrinkage and Curling of Slabs on Grade", by Ytterberg, Concrete
> Intentional, April May June of 1987.  If you send a request to Kalman
> Floor
> Company (800) 525-7840, they will send you a reprint.  The article lists
> all
> the contributors for shrinkage, and puts together recommendations for mix
> design and testing.
> If you opt for shrinkage compensating concrete, approach with caution.  It
> may expand slightly, the details become very important.  
> Use as big of an aggregate as possible, and uniformly grade the aggregates
> all the way through the fines.  Check out various articles by Jim
> Shilstone.
> Use a stony mix.  An 8-18% is what is generally recommended on each sieve.
> I like to reduce the water as much as possible (super plasticizers) more
> to
> reduce the volume of cement than for anything else.  Reduce the cement as
> much as possible also (use no more than you need for strength).  I really
> like the polycarbonate super plasticizers.  Reducing the water for a given
> volume of cement does not help reduce shrinkage.  The goal is to reduce
> cement.  The super plasticizers help handling the stony mixes that
> finishers
> are not accustomed to.  Use a cement with a C3A in the range of 8 to 10
> percent.
> Do field testing for shrinkage.  The Kalman people have a modified field
> test.  Call them to see if they will share the information.
> 
> Regards,
> Harold Sprague
> 
> 
> > -----Original Message-----
> > From:	Michael Zaitz [SMTP:zmanpe(--nospam--at)bellsouth.net]
> > Sent:	Thursday, May 04, 2000 7:11 PM
> > To:	seaint(--nospam--at)seaint.org
> > Subject:	Shrinkage in Concrete
> > 
> > Hello,
> > 
> > I have a project for a foundation that will need to be pumped due to
> lack
> > of
> > access.  A big concern of the equipment supplier is shrinkage of the
> > concrete and achieving tight tolerances for the placement of the
> concrete.
> > What all can I do to eliminate shrinkage in a pumped concrete?  Type 5
> > cement? shrinkage reducing admixtures?  Super plasticizer?  Any other
> > ideas?
> > 
> > Thanks
> > 
> > Mike
> > 
>