The unit weight of anything is a material property. It can't be adjusted. If you dump aggregate into a one cubic foot box, it has a given weight. The weight of the aggregate in that one cubic foot box also includes the voids between the aggregates. It is not as if you have a giant, one cubic foot piece of that aggregate in determining the unit weight.
Are you trying to get at that in the lab, an open graded aggregate is clean, but in the field it mixes with other stockpiles, has migration of fines, and potentially gets crushed to smaller pieces with large vibratory rollers?
