Determining Moisture-Unit Weight Relations of Soil (Compaction Test) - Soil Properties: Testing, Measurement, and Evaluation - page 177

determined without the base plate. For very wet or dry soils, soil or
water may be lost if the base plate is removed. For these situations,
leave the base plate attached to the mold. When the base plate is
left attached, the volume of the mold must be calibrated with the
base plate attached to the mold rather than a plastic or glass plate
as noted in the “Volume of Compaction Mold” section.

(4.8) Determine and record the mass of the specimen and mold to
the nearest gram. When the base plate is left attached, determine
and record the mass of the specimen, mold, and base plate to the
nearest gram.

(4.9) Remove the material from the mold. Obtain a specimen for wa-
ter content by using either the whole specimen (preferred method)
or a representative portion. When the entire specimen is used, break
it up to facilitate drying. Otherwise, obtain a portion by slicing the
compacted specimen axially through the center and removing about
500 g of material from the cut faces. Obtain the water content in ac-
cordance with ASTM Test Method D 2216.

(5) Following compaction of the last specimen, compare the wet
unit weights to ensure that a desired pattern of obtaining data on
each side of the optimum water content will be attained for the
dry unit weight compaction curve. Plotting the wet unit weight
and water content of each compacted specimen can be an aid in
making the above evaluation. If the desired pattern is not ob-
tained, additional compacted specimens will be required. Gener-
ally, one water content value greater than the water content
defining the maximum wet unit weight is sufficient to ensure
data on the wet side of optimum water content for the maximum
dry unit weight.

Data collected in this test should include the following for each repeti-
tion of the compaction procedure:

DATA

[A] Density Data

Mass of mold, M md
Mass of compacted soil plus mold, M t

[B] Moisture Content Data

Mass of container, M c
Mass of container plus moist soil, M cws
Mass of container plus oven-dried soil, M cs

For each repetition of the compaction procedure, moisture content
and both wet and dry unit weights must be determined. The moisture

CALCULATIONS