See ASTM D4718 "Standard Practice for Correction of Unit Weight and Water Content for Soils Containing Oversize Particles"

Let's say you have some fine to coarse sandy gravel with silt. You process out the plus 3/4 and run a proctor. You have 30 percent oversize material. From the minus 3/4 you get 125 pcf at 12 percent moisture. (I'm just pulling this example out of my head.) Well the rock that you removed (if it was present) would add 165 pcf if it was floating about the minus 3/4 material. So for any given cubic foot of material compacted to 100 percent relative compaction, you'd have 70 percent at 125 pcf dry density and 30 percent at 165 pcf dry density. That'd give you a maximum dry density of 137 pcf. That just isn't much water inside a plus 3/4. So, your optimum moisture content would go to 8 or 9 percent. I'd have to look at the equations in the ASTM for that, as there may be some assumptions for SSD moisture. On first principals, though it all makes sense to me. . .

f-d

¡papá gordo ain’t no madre flaca!

Perhaps my question was not clear. I simply want to know how to figure the oversize moisture content to use in the equation. ASTM D4718 says to do just what you said fattdad, a weighted average. I.e. (percent passing 3/4"*moisture of passing 3/4")+(percent oversize*oversize moisture). But what is the oversize moisture?