Determining Moisture-Unit Weight Relations of Soil (Compaction Test) - Soil Properties: Testing, Measurement, and Evaluation - page 173

(5.1) The volume obtained by either method should be within the
volume tolerance requirements of the “Apparatus and Supplies”
section.

(5.2) The difference between the two methods should not exceed
0.5% of the nominal volume of the mold.

(5.3) Repeat the determination of volume if these criteria are
not met.

(5.4) Failure to obtain satisfactory agreement between the two
methods, even after several trials, is an indication that the mold is
badly deformed and should be replaced.

(5.5) Use the volume of the mold determined using the water-filling
method as the assigned volume value for calculating the moist and
dry density.

(1) The required sample mass for Methods A and B is approxi-
mately 35 lb (16 kg), and for Method C is approximately 65 lb (29
kg) of dry soil. Therefore, the field sample should have a moist mass
of at least 50 lb (23 kg) and 100 lb (45 kg), respectively.

TEST SAMPLE [2]

(2) Determine the percentage of material by mass retained on the
No. 4 (4.75-mm), 3 ⁄ 8 -in. (9.5-mm), or 3 ⁄ 4 -in. (19.0-mm) sieve as appro-
priate for choosing Method A, B, or C. Make this determination by
separating out a representative portion from the total sample and
determining the percentages passing the sieves of interest by ASTM
Test Methods D 422 or C 136. It is only necessary to calculate
percentages for the sieve or sieves for which information is desired.

(1) Select the proper compaction mold in accordance with the
method (A, B, or C) being used. Determine and record its mass to
the nearest gram. Assemble the mold, base, and extension collar.
Check the alignment of the inner wall of the mold and mold exten-
sion collar. Adjust if necessary.

PREPARATION OF
APPARATUS [2]

(2) Check that the rammer assembly is in good working condition
and that parts are not loose or worn. Make any necessary adjust-
ments or repairs. If adjustments or repairs are made, the rammer
must be recalibrated.

To carry out a laboratory compaction test, a soil at a selected water con-
tent is placed in three layers into a mold of given dimensions, with each
layer compacted by 25 (Methods A and B) or 56 (Method C) blows of a
5.5-lb (24.4-N) rammer dropped from a distance of 12 in. (305 mm),
subjecting the soil to a total compactive effort of about 12,400 ft-lb/ft 3
(600 kN-m/m 3 ). The resulting dry unit weight is determined. The proce-
dure is repeated for a sufficient number of water contents to establish a
relationship between the dry unit weight and the water content for the

PROCEDURE [2]