Pea gravel mix for drilled piers?
Pea gravel mix for drilled piers?
(OP)
Hi Everyone!
I have a design which calls for 18" dia drilled piers of fc'=2500psi with a 4" slump, 1 1/2 aggragate, and a .45 wc ratio. The contractor wants to use a "7 sack" pea gravel mix design for workability. It has been a while since I've taken my mix design class (I'm 55)but I seem to remember that a 3/8" aggragate will have more surface area and thus strenght, cracking and shrinage could be a problem. Any one familiar with this application?
Thanks for your help ... and Blessings,
David
I have a design which calls for 18" dia drilled piers of fc'=2500psi with a 4" slump, 1 1/2 aggragate, and a .45 wc ratio. The contractor wants to use a "7 sack" pea gravel mix design for workability. It has been a while since I've taken my mix design class (I'm 55)but I seem to remember that a 3/8" aggragate will have more surface area and thus strenght, cracking and shrinage could be a problem. Any one familiar with this application?
Thanks for your help ... and Blessings,
David






RE: Pea gravel mix for drilled piers?
to increase the workability, decrease the shrinkage, and keep your strengths up.
RE: Pea gravel mix for drilled piers?
Are these piers placed by pumping the concrete through the auger stem? (I typically call these 'auger cast piles', and use them a lot).
If so, I think the contractor is proposing a fairly typical mix for such piles. 1 1/2" aggregate is difficult to pump down the auger stem. 3/8" aggregate mixes, in the 4,000 psi range are fairly typical mix designs.
Agree that a high range water reducer or fluidizer admixture is required for pumpability.
RE: Pea gravel mix for drilled piers?
Blessings,
David
RE: Pea gravel mix for drilled piers?
RE: Pea gravel mix for drilled piers?
RE: Pea gravel mix for drilled piers?
RE: Pea gravel mix for drilled piers?
Blessings,
David
RE: Pea gravel mix for drilled piers?
If your shafts require coring and you wish to core at first chance, your pea gravel mix could wind up helping the core bit wobble out the hole and push the gravel through the washout giving the impression that you've a void in the drilled shaft.
And on the other side of the coin, if you wait too long to core, the pea gravel mix is a much, much harder product to core.
Lot's of folks use the pea gravel and pumping since it doesn't absorb as much water as say limestone. But if you're coring look out.
good luck.
Regards,
![[pipe] pipe](https://www.tipmaster.com/images/pipe.gif)
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