Slab on grade, crushed agg. base 3

[sandman21]

I have an issue with compaction requirements for a crush aggregate base, we currently have no requirement. I have not been able to find information on whether there is even a compaction requirement for crush aggregate or aggregate under a slab on grade. I have looked in ACI 302 but it was no help. Does any have information on what should be used? Also what does everyone else use?

 

[ishvaaag]

"Crushed stone specs" search in google gives something. This is a first one

http://www.3b3d.com/html/Geotechnical engineering other topics/20080413/7756.html

I have seen heavy rollers compacting 60 to 80 cm say 7cm and lower typical crushed stone. I would love to remember that the compaction was made in layers, but it is not in my mind. A colleague ran the show, was for just 6 floors or so above, and placed under a structural mat of akin thickness.

 

[jbuening]

Our local DOT (Illinois)compaction requirements include in-situ dry density to be 95% of the dry density that is determined in laboratory testing. This is for PCC Pavement, so YMMV. You might check your states DOT Specifications book, as it likely spells out the compaction requirements for aggregate subbase.

 

[Ron]

sandman21....crushed aggregate, unless graded to achieve a graded aggregate base material, is not a material in which compaction specifications can be readily defined. We generally use a laboratory moisture-density relationship (Proctor test) to define the laboratory condition, then compact to achieve some percentage of that in the field (95%, 98%, 100%).

Using a gap-graded aggregate layer beneath a floor slab requires that you compact it, but you have little or no measure of compaction. Plate compactors don't work well for this, and "jumping jacks" are out of the question. A small roller, vibratory or static will work to achieve uniformity.

 

[sandman21]

Thank you for the help