or laboratory testing variation. Subcommittee D18.08 welcomes proposals that would allow for development of a valid precision statement. 10.2 Statement of Bias—There is no accepted reference value for this test method, therefore, bias cannot be determined. 10.3 While no formal round-robin testing has been completed, it is estimated by Subcommittee D18.08 from available data that the results of two properly conducted tests performed by a skilled operator on the same material at a given time and location should not differ by more than approximately 2 lb/ft3 (3.2 kg/m3). Tests performed by unskilled operators on the same material would be expected to yield substantially greater differences.
11. Keywords 11.1 The following keywords are applicable to this test method in accordance with Practice D 3584: acceptance tests; compaction tests; degree of compaction; density tests; earthfill; embankments; field control density; field tests; inplace density; inplace dry density; in situ density; relative density; sand cone; soil compaction; soil tests; unit weight.