CR-6 and Concrete sand compresssion rates


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Old 11-10-08, 09:20 AM
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CR-6 and Concrete sand compresssion rates

Does anyone know about how much CR-6 (crusher run with powder) and concrete sand will compress on average?

I'm putting in a paver walk and now have 3 inches of the CR-6laid down and ready for compacting. Once the 3 inches is compacted with a vibrating plate machine, I'll throw down one more inch, compact it, and then move to laying down edging, sand and then the pavers themselves.

I pretty much followed all the instructions provided here and form the manufacturer of the bricks I am using, but am still wondering high to take the brick so that they compress down to grade.

Here are the dimensions of what I've got:

Excavation: = 7 inches
CR-6 layer: will be 4 inches non-compacted
Sand layer: will be 1 inch non-compacted
Brick: depth is 2 and 3/8 inches.
Brick over grade height: will be 1/4 inch

Basically, from the above, the CR-6 and sand layers will have to compress a total 3/8 of an inch for the bricks to be level with our lawn.

This seems a bit small to me. It seems that the CR-6 will compress a bit more than that.

Thanks in advance to anyone who can share some first hand experience.
 
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Old 11-10-08, 09:47 AM
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CR-6 and Concrete sand compresssion rates

You should lay down the base and compact it lightly. Add more as needed and compact fo the proper elevation. The top of the base should be parallel to the finished grade of the top of the pavers and not neceearily level if the paver surface is sloped for drainage.

The amount of compaction of the base will depend on the moisture content of the base and somewhat on the amount of fines. If it too dry, it will not compact to a high density easily or very well.

The 1" sand setting bed should be a uniform thickness before setting the pavers. You do not compact the sand base, but you should screed off the uncompacted sand to get a even surface at the planned elevation.

From your installation, I assume you are not using clay brick, but interlocking concrete pavers, that may be "brick" shape.

Compaction of the base and the compaction of the surface sanded pavers into the sand setting bed are the keys, assuming you have well anchore edge retaints.

Dick
 
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Old 11-10-08, 10:58 AM
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Thanks, now I know what I have to do...

I'll make a screed board that will keep the compacted layer of CR-6 at 3 5/8 inches below grade. This will then give me:

*the 1/4 inch "surcharge" over grade for the pavers as per the manufacturers instructions

*the 2 3/8 inch depth of the pavers

* the 1 inch layer of non-compacted sand

Since I've already got 3 inches of CR-6 down, I'll bring it to 4, compact the new layer, and then use the screed to bring it either up or down so that it is finished at the desired 3 5/8 inches below grade.

The resulting CR-6 layer will then have a thickness of about 3 and 3/8 inches. Which means that it compacted down approximately 5/8 inches down from the original 4 inches.

And yes the CR-6 will be moist not dry when it is compacted.
Also a "yes" that the "bricks" are in fact Holland style interlocking concrete pavers.
 
 

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