Moisture-density curve for clean sand
Moisture-density curve for clean sand
(OP)
Standard Proctor test for clean medium to coarse grained sand always creates a problem with bleeding and dry density going up, even after crossing ZAV line. Is there any method to determine optimum moisture content and maximum dry density using curve that goes only up?





RE: Moisture-density curve for clean sand
The sand curve will often have its maximum dry density on the ZAV.
If it's too clean, you may be better specifying relative density rather than relative compaction.
Hope this helps.
f-d
¡papá gordo ain't no madre flaca!
RE: Moisture-density curve for clean sand
RE: Moisture-density curve for clean sand
RE: Moisture-density curve for clean sand
In Lars Forssblad's Vibratory Soil and Rock Fill Compaction, he discusses an assumed maximum dry density of a free-draining sand as the same dry-density you would get from compacting an oven-dried sand. After some testing of my own, I have found this to be characteristic of many sands with less than 2% fines, but shaky above that.
Hope this can be a useful reference...
RE: Moisture-density curve for clean sand
But that is not always enough. Another way of dealing with "bleeding" is to go back 3%( why not 1% or 2%? ) from the point
of crossing with ZAV and consider this point on the curve as maximum dry density at optimum moisture content.
This "bleeding" happens, more or less, in every lab when some clean sand or sand and gravel tested, especially when using modified effort.
The problem is not new, and there is no suggestion from the authors of D698 and D1557.
Any suggestion would be highly appreciated.
RE: Moisture-density curve for clean sand
Like fattdad and iandig said, it may be time to go to vibratory testing and the relative density (although you can control compaction in the field using just the percentage of the vibrated lab max density, rather than relative, once you figure out what it needs to be to give RD>70% or whatever).
RE: Moisture-density curve for clean sand
To deal with the bleeding between the bottom of the mold and the base plate, I use a little vacuum grease around the base of the mold (which I already have on hand for use on the triaxial chamber), then I tighten the wingnuts with pliers (carefully because the "wings" will snap off).
RE: Moisture-density curve for clean sand
f-d
¡papá gordo ain't no madre flaca!
RE: Moisture-density curve for clean sand