Residential slab on grade compaction testing

[slabongrade]

Above some certain depth of fill, is it recommended to use a modified proctor
instead of standard proctor?
What depth would that be?
This is for a house without drilled piers...

 

[oldestguy]

Normally most use of Modified Proctor is for high concentrated loads, such as heavy duty pavement at airports . For light pressures as from a house slab on grade foundation I'd not waste the money for the extra effort. Might not even do any testing. For thick compacted fill normally the effect of the loads takes care of any need for heavier compaction of fill. The beauty of thick fill is its ability to spread out the effects of varying settlement in the supporting soil. In my practice I never required any special work for high fills as compared to thin ones. No problems.

 

[GC_Hopi]

The most memorable place I have seen a modified proctor specified is at a zoo under the slab of the elephant shelter.

 

[slabongrade]

Thanks a lot guys, you confirmed what I was thinking.