Does concrete have to have rocks in it to fill in cinderblock holes?


  #1  
Old 07-15-05, 07:56 AM
M
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Does concrete have to have rocks in it to fill in cinderblock holes?

Hi, I finished the base of my 12' x 12' shed which has 4 rows of blocks.
I am pouring concrete into the holes to strengthen it and put J-bolts in it in preparation for the wood framing.
It's taking me 1 (60 lb) bag of concrete mix per hole and there's 68 holes total.
Since I have a huge pile of leftover sand, I was wondering if I could just buy portland cement, mix it with the sand and save some trips, not to mention lifting.
Would a cement/sand mix be strong enough to fill cinderblock holes or does it have to have the gravel in it?

tks,

-MC
 
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Old 07-15-05, 10:47 AM
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Does concrete have to have rocks in it to fill in cinderblock holes?

In normal construction where grout (concrete mix) in the cores is used to bond the reinforcing steel to the block it is not necessary to use coarse aggregate(gravel). It is also desirebale for the grout to be weaker than the block.

In your case you seem to be using ing the grout for stability. You can use a mixture of cement and sand. A coarse sand would be better as long as the grout fills the block completely. You can add rock if it does not interfere with the flow of the flow. Some vetical steel in a few core could help hold things together.

Dick
 
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Old 07-15-05, 11:12 AM
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thank you

this will save me a few trips and allow me to use some of this sand in my yard,

tks,

-MC
 
  #4  
Old 07-15-05, 12:35 PM
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Make sure you have clean sand (very little dust).

Dick
 
 

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