UFC 3-260-03
15 Apr 01
are provided in Appendix B. The ECP is typically used for tests requiring greater penetration depths. The
DCP is adequate for most pavement structures and is considerably easier to deploy and implement.
(4) Density Determinations. Three density determinations should be made at each elevation
tested if samples of about 0.0014-cubic-meter (0.05-cubic-foot) volume are taken; if somewhat larger
samples are taken, the number of density determinations may be decreased to two. If a reasonable
agreement is not found between the test results, two additional tests should be performed. A reasonable
agreement is considered to provide for a tolerance of about 80 kilograms/cubic meter (5 pounds per cubic
foot) wet density. For example, test results of 1730, 1,777, and 1,810 kilograms/cubic meter (108, 111,
and 113 pounds per cubic foot) wet density are in reasonable agreement, and their average is
1,777 kilograms/cubic meter (111 pounds per cubic foot). A nuclear density device is used for density
determinations in the small aperture test method.
5. SAMPLES. Samples of the pavement, base course, subbase course, and subgrade materials are
required for laboratory testing; the size of the samples depends on the type of laboratory tests to be made.
a. Rigid Pavement. All concrete cores obtained during the preliminary testing and all test speci-
mens cut from the test pits should be retained for laboratory tests. The specimens should be slightly more
than three times as long and three times as wide as the pavement thickness, except when 152- by
152-millimeter (6- by 6-inch) beams are cut from the top and bottom of the specimens for three-point load
beam tests.
b. Base and Subbase Courses Under Rigid Pavements. Bag samples of base and subbase
courses underlying rigid pavements will be required for classification and compaction tests. The size of
the sample will depend on the amount of large aggregate in the base course. In general, a 91-kilogram
(200-pound) sample is sufficient. However, if laboratory CBR tests are necessary, which may be the case
in the evaluation of a nonrigid overlay on rigid pavements, the size of the base-course sample should be
about 272 kilograms (600 pounds).
c. Flexible Pavement. Samples of typical pavement, base, subbase, and subgrade materials
should be obtained for laboratory tests. The base and subgrade samples should be taken in a manner
that will assure representative materials. Sampling methods are discussed in TM 825-01/ AFM 32-
1124(I)/NAVFAC DM 21.10. The samples to be obtained from the various materials are summarized in
the following tabulation:
Material
Samples Per Pit
Remarks
Pavement
8 cores, 91 kilograms
Chunks should be 203-254 millimeters (8-10 inches) in
(200 pounds) of chunks
minimum dimension to permit separation of courses
Base and subbase 272 kilograms (600 pounds) Disturbed sample
courses
3 samples
Undisturbed cylinders to be taken of material with
plastic fines where applicable
Subgrade
204 kilograms (450 pounds) Disturbed sample. Increase to 272 kilograms
(600 pounds) if much coarse material is present
3 samples
Undisturbed cylinders
3-8
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