Pouring concrete slab
The contractor wants a bed of 57 stone below the pour. What is the purpose of this stone?
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The gravel will help the slab to not settle into the dirt and crack later. It also helps the workers walking around before too. How big is the slab? 0 -
1st i no nothing about this so i am curious.
If you put stone down first wouldnt the stone shift worse than hard packed dirt?
Unless you compact the rock some how i do not understand how you can keep the concrete from cracking.
I know nothing about concrete.0 -
On mine, they used a plate vibrator to compact/settle the stone before the pour. 0 -
On mine they packed sand-clay as hard as concrete prior to the pour...
JIM...........0 -
The idea is to create a bed below the pour that will be less subject to expansion and contraction than soil when the earth freezes. It also promotes drainage of water away from the slab.
Freeze-thaw cycles and rain and melt water turn mountains into plains, and will do the same to a concrete slab.0 -
quote:Originally posted by JIM STARK
On mine they packed sand-clay as hard as concrete prior to the pour...
JIM...........
+1 red clay0 -
I used sand, no cracks. 0 -
FROST areas cause heaving of the sub-grade. Therefore a stone base is recommended to allow the frost to expand between the voids in the gravel and thus help preventing the frost from expanding upward and causing cracking of the slab. One layer of crushed 3" stone is recommended with minimum layer of a 4" layer of 3/4" to fines on top of that. Best to remove all black dirt and get down to clay type material before placing the stone. Black dirt consists of organic material which in time will cause settlement. 0 -
A gravel base will prevent the concrete from cracking and shifting. Because clay soil doesn't drain well, gravel keeps water from pooling under concrete slabs and eroding the soil when drains.
This is a must in the black gumbo soil in parts of Texas,0
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