Maximum density obtained with different tests

[MRM]

Hi all,
I would be interested to hear your thoughts on the following: Is the maximum dry density for a given sandy soil approximately the same (in the same ballpark) when obtained using the modified Proctor test, compared with using the maximum dry density test obtained with the vibrating table set-up, both using the applicable ASTM standards?

Also, part B of the question: If anyone is familiar with the 1-point Michigan cone method for obtaining maximum dry density, would this test give a comparable value of max dry density when compared to the modified Proctor test? I think it would be a question of how much energy is put into each test. I my experience, the Michigan cone test certainly results in a higher max dry unit weight value than the standard Proctor test (5.5#, 12" drop, etc.), but I'm not sure about the mod. Proctor.

These questions can easily be answered simply by testing, which I wouldn't mind doing, but there's never enough time. If you know of any papers published comparing the methods please let me know.

Thanks

 

[Focht3]

Theoretically, the vibrating table method (VTM) should give you the highest dry density value for a soil with "no" fines. If the soil has enough binder to produce a "good" Proctor curve, then it will probably give you a lousy maximum density by the VTM.

I'm not familiar with the Michigan test - can't help you there.

 

[dirtman]

The only soils on which you should perform relative density vibrating table tests are those with less than 12 percent fines. The NRCS performed testing on C-33 filter sands several years ago and found a good correlation between 70 percent relative density and 100 percent of the D698A one point dry compaction dry density. I wrote an article that was published as a technical note in the October 1996 ASCE geotechnical journal. (Article by McCook)

 

[MRM]

Thanks for your responses. Dirtman, I'm looking forward to checking into your article. The correlation you suggested of maximum D698 density (D698 100% relative compaction) being equal to about 70% relative density seems to agree with the conclusions I've come to at this point. For example, it seems that the modified test gives maximum densities of approximately equal to 100% relative density-sometimes less, sometimes more depending on the sample gradation, type, and moisture content at the time of the modified test as Focht3 and others have mentioned. If the D698 generally gives a density approximately 93% to 95% of the D1557 for certain soils, then the 70% figure for the D698 would make sense to me.

After I submitted the original message, I came across a good paper that helped me out quite a bit and you may already be familiar with it: "Loose Sands-Their Compaction by Vibroflotation" by Elio D’Appolonia, American Society for Testing and Materials, 1969. In addition to the vibrocompaction aspect, the author also does some work in comparing the different methods for obtaining maximum (and minimum) unit weights of sands. I thought the explanation and discussion was very good. It's worth looking into for anyone interested in this subject.