MOISTURE-DENSITY
RELATION
Bearing
Ratio at Optimum Water Content-Using the 11-kg (25-lb.) portion prepared as
described in section 5.1,
determine the optimum moisture content and maximum dry density in accordance
with the compaction method specified, either T99 or T180. A previously
performed compaction test on the same material may be substituted for the
compaction test just described, provided that if the sample contains material
retained on the 19.0-mm (3/4 in) sieve,
soil prepared as described in section 5.1
is used (Note 3).
Note
3 –Maximum dry unit mass obtained from a compaction test performed in a
101.6-mm (4 in.) diameter mold may be slightly greater than the maximum dry
unit weight obtained from compaction in the 154.2-mm (6-in.) compaction mold or
CBR mold.
Bearing
Ration for a Range of Water Content- Using the 6.8-kg (15-lb) specimens
prepared as described in section 5.1, determine the optimum moisture
content and maximum dry density in accordance with the compaction method
specified, either T99 (Method D) or T 180 (Method D), except that the CBR molds
shall be used and each specimen shall be penetrated for CBR determination. In
addition, the complete moisture-density relationship for 25-bolows ad 10-bolows
per layer compaction shall be developed and each test specimen compacted shall
be penetrated. Perform all compaction in CBR molds. In cases where the
specified unit mass is at or near 100-percent maximum dry unit mass, it will be
necessary to include a comp active effort greater than 56 blows per layer (Note 4).
Note-4 A semilog plot of dry unit mass
versus compactive effort usually gives a straight-line relation when compactive
effort in J/m3 (ft-lb/ft3) is plotted on the log scale. This type of plot is
useful in establishing the compactive effort and number of blows per layer
needed to bracket the specified dry unit mass and water content range.
If the soaked CBR is to be determined,
take a representative sample of the material, fir the determination of
moisture, at the beginning of compaction of each specimen and another sample of
the remaining material after compaction of each specimen. Use T 265 to
determine the moisture content. If the unsoaked CBR is to be determined, take a
moisture content sample in accordance with T 99 or T 180 if the average
moisture content is desired.
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