Determining Moisture-Unit Weight Relations of Soil (Compaction Test) - Soil Properties: Testing, Measurement, and Evaluation - page 175

soil to dry in air at ambient temperature or in a drying apparatus
such that the temperature of the sample does not exceed 140°F
(60°C). Mix the soil frequently during drying to maintain an even
water content distribution. Thoroughly mix each specimen to ensure
even distribution of water throughout and then place in a separate
covered container and allow to stand in accordance with Table 12-2
prior to compaction. For the purpose of selecting a standing time, the
soil may be classified using ASTM Test Method D 2487, Practice
D 2488, or data on other samples from the same material source. For
referee testing, classification shall be by ASTM Test Method D 2487.

Table 12-2 Required Standing Times of Moisturized Specimens

Classification Minimum Standing Time, h

GW, GP, SW, SP No Requirement

GM, SM 3

All other soils 16

(3) Dry Preparation Method —If the sample is too damp to be fri-
able, reduce the water content by air drying until the material is
friable. Drying may be in air or by the use of drying apparatus such
that the temperature of the sample does not exceed 140°F (60°C).
Thoroughly break up the aggregations in such a manner as to avoid
breaking individual particles. Pass the material through the ap-
propriate sieve: No. 4 (4.75-mm), 3 ⁄ 8 -in. (9.5-mm), or 3 ⁄ 4 -in. (19.0-mm).
When preparing the material by passing over the 3 ⁄ 4 -in. sieve for
compaction in the 6-in. mold, break up aggregations sufficiently to
at least pass the 3 ⁄ 8 -in. sieve in order to facilitate the distribution of
water throughout the soil in later mixing.

(3.1) Prepare at least four (preferably five) specimens in accor-
dance with (2.1).

(3.2) Use approximately 5 lbm (2.3 kg) of the sieved soil for each
specimen to be compacted using Method A or B, or 13 lbm (5.9 kg)
using Method C. Add the required amounts of water to bring the
water contents of the specimens to the values selected in (3.1). Fol-
low the specimen preparation procedure specified in (2.2) for dry-
ing the soil or adding water into the soil and curing each test
specimen.

(4) Compaction —After curing, if required, each specimen shall be
compacted as follows:

(4.1) Determine and record the mass of the mold or mold and base
plate.

(4.2) Assemble and secure the mold and collar to the base plate.
The mold shall rest on a uniform rigid foundation, such as pro-
vided by a cylinder or cube of concrete with a mass of not less than
200 lbm (91 kg). Secure the base plate to the rigid foundation.
The method of attachment to the rigid foundation shall allow easy