California Bearing Ratio Test - Soil Properties: Testing, Measurement, and Evaluation - page 396

Figure 24-2 Loading Machine
(Courtesy of Soiltest, Inc.)
be substituted for the compaction test just described, provided that
if the sample contains material retained on the 3 ⁄ 4 -in. (19-mm) sieve,
soil prepared as described above is used (Note 1).
Note 1 —Maximum dry unit weight obtained from a com-
paction test performed in a 4-in. (101.6-mm) diameter mold
may be slightly greater than the maximum dry unit weight
obtained from compaction in the 6-in. (152.4-mm) compaction
mold or CBR mold.
(1.1) For cases where the CBR is desired at 100% maximum dry
unit weight and optimum water content, compact a specimen us-
ing the specified compaction procedure, either ASTM Test Methods
D 698 or D 1557, from soil prepared to within ±0.5 percentage
point of optimum water content in accordance with ASTM Test
Method D 2216 (Chapter 4).
Note 2 —Where the maximum dry unit weight was determined
from compaction in the 4-in. (101.6-mm) mold, it may be nec-
essary to compact specimens, using 75 blows per layer or some
other value sufficient to produce a specimen having a density
equal to or greater than that required.