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Standard Method of Test for

Moisture-Density Relations of Soils

Using a 2.5-kg (5.5-lb) Rammer and
a 305-mm (12-in.) Drop

AASHTO Designation: T 99-15

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Standard Method of Test for

Moisture-Density Relations of Soils

Using a 2.5-kg (5.5-lb) Rammer and
a 305-mm (12-in.) Drop

AASHTO Designation: T 99-15

1. SCOPE
1.1. These methods of test are intended for determining the relation between the moisture content and
density of soils compacted in a mold of a given size with a 2.5-kg (5.5-lb) rammer dropped from a
height of 305 mm (12 in.). Four alternate procedures are provided as follows:
 Method A—A 101.60-mm (4-in.) mold: Soil material passing a 4.75-mm (No. 4) sieve
Sections 4 and 5.
 Method B—A 152.40-mm (6-in.) mold: Soil material passing a 4.75-mm (No. 4) sieve
Sections 6 and 7.
 Method C—A 101.60-mm (4-in.) mold: Soil material passing a 19.0-mm (3/4-in.) sieve
Sections 8 and 9.

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 Method D—A 152.40-mm (6-in.) mold: Soil material passing a 19.0-mm (3/4-in.) sieve
Sections 10 and 11.

1.2. The method to be used should be indicated in the specifications for the material being tested. If no
method is specified, the provisions of Method A shall govern.

1.3. This test method applies to soil mixtures that have 40 percent or less retained on the 4.75 mm-
(No. 4) sieve, when Method A or B is used and 30 percent or less retained on the 19.0-mm (3/4-in.)
sieve, when Method C or D is used. Material retained on these sieves shall be defined as oversized
particles (coarse particles).

1.4. If the test specimen contains oversized particles, dry density and moisture corrections must be
made in accordance with Annex A1.

1.5. If the specified oversized particle maximum percentage is exceeded, other methods of compaction
control must be used.
Note 1—One method for the design and control of the compaction of such soils is to use a test fill

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to determine the required degree of compaction and a method to obtain that compaction. Then use
a method specification to control the compaction by specifying the type and size of compaction
equipment, the lift thickness, and the number of passes.

1.6. The following applies to all specified limits in this standard: For the purposes of determining
conformance with these specifications, an observed value or a calculated value shall be rounded
off “to the nearest unit” in the last right-hand place of figures used in expressing the limiting
value, in accordance with ASTM E29.

1.7. The values stated in SI units are to be regarded as the standard.

TS-1b T 99-1 AASHTO

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2. REFERENCED DOCUMENTS
2.1. AASHTO Standards:
 M 92, Wire-Cloth Sieves for Testing Purposes
 M 231, Weighing Devices Used in the Testing of Materials
 T 19M/T 19, Bulk Density (“Unit Weight”) and Voids in Aggregate
 T 85, Specific Gravity and Absorption of Coarse Aggregate
 T 217, Determination of Moisture in Soils by Means of Calcium Carbide Gas Pressure
Moisture Tester
 T 248, Reducing Samples of Aggregate to Testing Size
 T 255, Total Evaporable Moisture Content of Aggregate by Drying
 T 265, Laboratory Determination of Moisture Content of Soils
 T 310, In-Place Density and Moisture Content of Soil and Soil-Aggregate by Nuclear
Methods (Shallow Depth)

2.2. ASTM Standards:

 D2168, Standard Test Methods for Calibration of Laboratory Mechanical-Rammer Soil
Compactors
 E29, Standard Practice for Using Significant Digits in Test Data to Determine Conformance
with Specifications

3. APPARATUS

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3.1. Mold Assembly (Mold, Collar, and Base Plate)—Molds shall be solid-wall, metal cylinders
manufactured with dimensions and capacities shown in Sections 3.1.1, 3.1.2, and Figures 1 and 2.
They shall have a detachable collar approximately 60 mm (2.375 in.) in height, to permit
preparation of compacted specimens of soil-water mixtures of the desired height and volume. The
mold and collar shall be so constructed that it can be fastened firmly to a detachable base plate
made of the same material (Note 2). The base plate shall be plane to 0.005 in. as shown in Figures
1 and 2.
Note 2—Alternate types of mold assemblies with capacities as stipulated herein may be used,
provided the test results are correlated with those of the solid-wall mold on several soil types and
the same moisture-density results are obtained. Records of such correlation shall be maintained
and readily available for inspection, when alternate types of molds are used.

3.1.1. Molds having a volume of 0.000943 ± 0.000014 m3 (0.0333 ± 0.0005 ft3) shall have an inside
diameter of 101.60 ± 0.40 mm (4.000 ± 0.016 in.) and a height of 116.40 ± 0.50 mm (4.584 ±
0.018 in.) (Figure 1). Determine the mold volume in accordance with the “Calibration of
Measure” section of T 19M/T 19 for Unit Mass of Aggregate.

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3.1.2. Molds having a volume of 0.002124 ± 0.000025 m3 (0.07500 ± 0. 0009 ft3) shall have an inside
diameter of 152.40 ± 0.70 mm (6.000 ± 0.026 in.) and a height of 116.40 ± 0.50 mm (4.584 ±
0.018 in.) (Figure 2). Determine mold volume in accordance with the “Calibration of Measure”
section of T 19M/T 19 for Unit Mass of Aggregate.

TS-1b T 99-2 AASHTO

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Notes: 1. All dimensions shown in millimeters unless otherwise noted.

2. Hanger on the mold portion only cannot extend above the midheight line.
3. Figure 1 is to be used for all compaction molds purchased after the publication of the 21st edition (HM-21).

Figure 1—Cylindrical Mold and Base Plate (101.6-mm Mold)

TS-1b T 99-3 AASHTO

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Notes: 1. All dimensions shown in millimeters unless otherwise noted.
2. Hanger on the mold portion only cannot extend above the midheight line.
3. Figure 2 is to be used for all compaction molds purchased after the publication of the 21st edition (HM-21).

Figure 2—Cylindrical Mold and Base Plate (152.4-mm Mold)

TS-1b T 99-4 AASHTO

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Table 1—Dimensional Equivalents for Figure 1
mm in. mm in.
3.18 ± 0.64 0.125 ± 0.025 50.80 ± 0.64 2.000 ± 0.025
3.81 0.150 60.33 ± 1.27 2.375 ± 0.050
6.35 ± 1.27 0.250 ± 0.050 101.60 ± 0.41 4.000 ± 0.016
7.62 0.300 107.95 ± 1.27 4.250 ± 0.050
9.53 ± 0.64 0.375 ± 0.025 114.30 ± 2.54 4.500 ± 0.100
12.70 ± 2.54 0.500 ± 0.100 116.43 ± 0.13 4.584 ± 0.005
17.78 ± 1.27 0.700 ± 0.050 152.40 ± 2.54 6.000 ± 0.100
20.32 0.800 165.10 ± 2.54 6.500 ± 0.100
38.10 ± 2.54 1.500 ± 0.100 172.72 ± 2.54 6.800 ± 0.100
0.000943 ± 0.000009 m3 0.0333 ± 0.0005 ft3

Table 2—Dimensional Equivalents for Figure 2

mm in. mm in.
3.18 ± 0.64 0.125 ± 0.025 50.80 ± 0.64 2.000 ± 0.025
3.81 0.150 60.33 ± 1.27 2.375 ± 0.050
6.35 ± 1.27 0.250 ± 0.050 116.43 ± 0.13 4.584 ± 0.005
7.62 0.300 152.40 ± 0.66 6.000 ± 0.026
9.53 ± 0.64 0.375 ± 0.025 158.75 ± 1.27 6.250 ± 0.050
12.70 ± 2.54 0.500 ± 0.100 165.10 ± 2.54 6.500 ± 0.100
17.78 ± 1.27 0.700 ± 0.050 172.72 ± 2.54 6.800 ± 0.100
20.32 0.800 203.23 ± 2.54 8.000 ± 0.100
38.10 ± 2.54 1.500 ± 0.100 215.90 ± 2.54 8.500 ± 0.100

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0.002124 ± 0.000025 m3 0.0750 ± 0.0009 ft3

3.2. Rammer:

3.2.1. Manually Operated—Metal rammer with a mass of 2.495 ± 0.009 kg (5.5 ± 0.02 lb), and having a
flat circular face of 50.80-mm (2.000-in.) diameter with a manufacturing tolerance of ± 0.25 mm
(0.01 in.). The in-service diameter of the flat circular face shall be not less than 50.42 mm
(1.985 in.). The rammer shall be equipped with a suitable guide-sleeve to control the height of
drop to a free fall of 305 ± 2 mm (12.00 ± 0.06 in.) above the elevation of the soil. The guide-
sleeve shall have at least four vent holes, no smaller than 9.5-mm (3/8-in.) diameter spaced
approximately 90 degrees (1.57 rad) apart and approximately 19 mm (3/4 in.) from each end; and
shall provide sufficient clearance so the free fall of the rammer shaft and head is unrestricted.

3.2.2. Mechanically Operated—A metal rammer that is equipped with a device to control the height of
drop to a free fall of 305 ± 2 mm (12.00 ± 0.06 in.) above the elevation of the soil and uniformly
distributes such drops to the soil surface (Note 3). The rammer shall have a mass of 2.495 ±
0.009 kg (5.5 ± 0.02 lb), and have a flat circular face of 50.80-mm (2.000-in.) diameter with a
manufactured tolerance of ± 0.25 mm (0.01 in.). The in-service diameter of the flat circular face

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shall be not less than 50.42 mm (1.985 in.). The mechanical rammer shall be calibrated by
ASTM D2168.
Note 3—It may be impractical to adjust the mechanical apparatus so the free fall is 305 mm
(12 in.) each time the rammer is dropped, as with the manually operated rammer. To make the
adjustment of free fall, the portion of loose soil to receive the initial blow should be slightly
compressed with the rammer to establish the point of impact from which the 305-mm drop is
determined. Subsequent blows on the layer of soil being compacted may all be applied by
dropping the rammer from a height of 305 mm above the initial-setting elevation; or, when the
mechanical apparatus is designed with a height adjustment for each blow, all subsequent blows
should have a rammer free fall of 305 mm measured from the elevation of the soil as compacted
by the previous blow. A more detailed calibration procedure for laboratory mechanical-rammer
soil compactors can be found in ASTM D2168.

TS-1b T 99-5 AASHTO

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3.2.3. Rammer Face—The circular face rammer shall be used, but a sector face may be used as an
alternative, provided the report shall indicate type of face used other than the 50.8-mm (2-in.)
circular face, and it shall have an area equal to that of the circular face rammer.

3.3. Sample Extruder (for Solid-Walled Molds Only)—A jack, lever, frame, or other device adopted for
the purpose of extruding compacted specimens from the mold.

3.4. Balances and Scales—A balance or scale conforming to the requirements of M 231, Class G 5.
Also, a balance conforming to the requirements of M 231, Class G 2.
Note 4—The capacity of the metric balance or scale should be approximately 11.5 kg when used
to weigh the 152.40-mm (6-in.) mold and compacted, moist soil; however, when the 101.60-mm
(4-in.) mold is used, a balance or scale of lesser capacity than the 11.5 kg may be used, if the
sensitivity and readability is 1 g.

3.5. Drying Oven—A thermostatically controlled drying oven capable of maintaining a temperature of
110 ± 5ºC (230 ± 9ºF) for drying moisture samples.

3.6. Straightedge—A hardened-steel straightedge at least 250 mm (10 in.) in length. It shall have one
beveled edge, and at least one longitudinal surface (used for final trimming) shall be plane within
0.250 mm per 250 mm (0.01 in. per 10 in.) (0.1 percent) of length within the portion used for
trimming the soil (Note 5).
Note 5—The beveled edge may be used for final trimming if the edge is true within a tolerance of
0.250 mm per 250 mm (0.1 percent) of length; however, with continued use, the cutting edge may
become excessively worn and not suitable for trimming the soil to the level of the mold. The
straightedge should not be so flexible that trimming the soil with the cutting edge will cause a

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concave soil surface.

3.7. Sieves—50-mm (2-in.), 19.0-mm (3/4-in.), and 4.75-mm (No. 4) sieves conforming to the
requirements of M 92.

3.8. Mixing Tools—Miscellaneous tools such as mixing pan, spoon, trowel, spatula, etc., or a suitable
mechanical device for thoroughly mixing the sample of soil with increments of water.

3.9. Containers—Suitable containers made of material resistant to corrosion and not subject to change
in mass or disintegration on repeated heating and cooling. Containers shall have close-fitting lids
to prevent loss of moisture from samples before initial mass determination and to prevent
absorption of moisture from the atmosphere following drying and before final mass determination.
One container is needed for each moisture content determination.

METHOD A

4. SAMPLE

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4.1. Obtain a representative sample. This sample must be large enough that when the oversized
(retained on the 4.75-mm [No. 4] sieve) particles are removed 3 kg (7 lb) or more of the sample
remains.

4.2. Dry the sample until it becomes friable under a trowel. Drying may be in air or by use of a drying
apparatus that is maintained at a temperature not exceeding 60ºC (140ºF). Thoroughly break up
the aggregations in such a manner as to avoid reducing the natural size of individual particles.

4.3. Sieve the soil over the 4.75-mm (No. 4) sieve. When the sample has oversized particles, particles
retained on the 4.75-mm (No. 4) sieve, refer to the Annex A1.

TS-1b T 99-6 AASHTO

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4.4. Reduce the sample, to a mass of 3 kg (7 lb) or more in accordance with T 248.

5. PROCEDURE
5.1. Determine the mass of the mold and base plate.

5.2. Thoroughly mix the selected representative sample with sufficient water to dampen it to
approximately four to eight percentage points below optimum moisture content.
Note 6—When developing a compaction curve for free-draining soils, such as uniform sands and
gravels, where seepage occurs at the bottom of the mold and base plate, taking a representative
moisture content sample from the mixing bowl may be preferred to determine the amount of
moisture available for compaction.

5.3. Form a specimen by compacting the prepared soil in the 101.60-mm (4-in.) mold assembly (in
three approximately equal layers to give a total compacted depth of about 125 mm (5 in.). Prior to
compaction, place the loose soil into the mold assembly and spread into a layer of uniform
thickness. Lightly tamp the soil prior to compaction until it is not in a loose or fluffy state, using
either the manual compaction rammer or a similar device having a face diameter of approximately
50 mm (2 in.). Following compaction of each of the first two layers, any soil adjacent to the mold
walls that has not been compacted or extends above the compacted surface shall be trimmed using
a knife or other suitable device and evenly distributed on top of the layer. Compact each layer by
25 uniformly distributed blows from the rammer dropping free from a height of 305 mm (12 in.)
above the elevation of the soil when a sleeve-type rammer is used, or from 305 mm above the
approximate elevation of compacted soil when a stationary mounted type of rammer is used.
During compaction, the mold assembly shall rest firmly on a dense, uniform, rigid, and stable

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foundation or base. This base shall remain stationary during the compaction process (Note 7).
Note 7—Each of the following has been found to be a satisfactory base on which to rest the mold
assembly during compaction of the soil: a block of concrete, with a mass not less than 90 kg (200
lb), supported by a relatively stable foundation; a sound concrete floor; and for field application,
such surfaces as are found in concrete box culverts, bridges, and pavements.

5.3.1. Following compaction, remove the collar; carefully trim the compacted soil even with the top of
the mold by means of the straightedge, and determine the mass of the mold, base plate, and moist
soil in kilograms to the nearest one gram, or determine the mass in pounds to the nearest
0.005 pounds. Calculate the wet density, W1, as described in Section 12.1.

5.4. Detach the base plate and remove the material from the mold and slice vertically through the
center. Take a representative sample of the material from one of the cut faces (Figure 3) and weigh
immediately. Determine the moisture content in accordance with T 265 and record the results.

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TS-1b T 99-7 AASHTO

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Figure 3—Representative Moisture Content Sample Selection

5.5. Thoroughly break up the remaining portion of the molded specimen until it will pass through a
4.75-mm (No. 4) sieve as judged by eye, and add to the remaining portion of the sample being
tested. Add water in sufficient amount to increase the moisture content of the soil 1 to 2
percentage points (water content increments should not exceed 2.5 percent except when heavy

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clay soils or organic soils exhibiting flat elongated curves are encountered; the water content
increments may be increased to a maximum of 4 percent) and repeat the above procedure for each
increment of water added. When the series of determinations indicate a decrease or no change in
the wet unit mass, W1, per cubic meter (cubic foot) of the compacted soil (Note 8) perform one
more determination such that there is a minimum of two determinations over optimum moisture.
Note 8—In instances where the soil material is fragile in character and will reduce significantly in
grain size due to repeated compaction, and in cases where the soil is a heavy-textured clayey
material into which it is difficult to incorporate water, a separate and new sample shall be used in
each compaction test. In these cases, separate samples shall be thoroughly mixed with amounts of
water sufficient to cause the moisture contents of the samples to vary by approximately two
percentage points. The moisture points selected shall bracket the optimum moisture content, thus
providing samples that, when compacted, will increase in mass to the maximum density and then
decrease in mass. The samples of soil-water mixtures shall be placed in covered containers and
allowed to stand for not less than 12 hours before making the moisture-density test.

5.5.1. In instances where the soil material is fragile in character and will be reduced significantly in grain
size by repeated compaction, a separate and new sample shall be used in each compaction test.

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METHOD B

6. SAMPLE
6.1. Obtain a representative sample in accordance with Section 4, except that the sample shall have a
minimum mass of 7 kg (16 lb).

TS-1b T 99-8 AASHTO

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7. PROCEDURE
7.1. Follow the same procedure as described for Method A in Section 5, except for the following:
Form a specimen by compacting the prepared soil in the 152.4-mm (6-in.) mold assembly in three
approximately equal layers to give a total compacted depth of about 125 mm (5 in.), each layer
being compacted by 56 uniformly distributed blows from the rammer. Calculate the wet density,
W1, as described in Section 12.1.

METHOD C

8. SAMPLE
8.1. Obtain a representative sample. This sample must be large enough that when the oversized
(retained on the 19.0-mm [3/4-in.] sieve) particles are removed 5 kg (11 lb) or more of the sample
remains.

8.2. Dry the sample until it becomes friable under a trowel. Drying may be in air or by use of a drying
apparatus that is maintained at a temperature not exceeding 60ºC (140ºF). Thoroughly break up
the aggregations in such a manner as to avoid reducing the natural size of individual particles.

8.3. Sieve soil over the 19.0-mm (¾-in.) sieve. When the sample has oversized particles, see Annex
A1.

8.4. Reduce the sample to a mass of 5 kg (11 lb) or more in accordance with T 248.

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9. PROCEDURE
9.1. Determine the mass of the mold and base plate.

9.2. Thoroughly mix the selected representative sample with sufficient water to dampen it to
approximately four to eight percentage points below optimum moisture content (Note 6).

9.3. Form a specimen by compacting the prepared soil in the 101.60-mm (4-in.) mold assembly in
three approximately equal layers to give a total compacted depth of about 125 mm (5 in.). Prior to
compaction, place the loose soil into the mold assembly and spread into a layer of uniform
thickness. Lightly tamp the soil prior to compaction until it is not in a loose or fluffy state, using
either the manual compaction rammer or a similar device having a face diameter of approximately
50 mm (2 in.). Following compaction of each of the first two layers, any soil adjacent to the mold
walls that has not been compacted or extends above the compacted surface shall be trimmed
using a knife or other suitable device and evenly distributed on top of the layer. Compact
each layer by 25 uniformly distributed blows from the rammer dropping free from a height of
305 mm (12 in.) above the elevation of the soil when a sleeve-type rammer is used, or from

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305 mm (12 in.) above the approximate elevation of each finely compacted layer when a
stationary mounted-type rammer is used. During compaction, the mold assembly shall rest firmly
on a dense, uniform, rigid, and stable foundation (Note 7).

9.3.1. Following compaction, remove the collar; carefully trim the compacted soil even with the top of
the mold by means of the straightedge. Holes developed in the surface by removal of coarse
material shall be patched with smaller-sized material. Determine the mass of the mold, base plate,
and moist soil in kilograms to the nearest one gram, or determine the mass in pounds to the nearest
0.005 pounds. Calculate the wet density, W1, as described in Section 12.1.

TS-1b T 99-9 AASHTO

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9.4. Detach the base plate and remove the material from the mold and slice vertically through the
center. Take a representative sample of the material from one of the cut faces and weigh
immediately. Determine the moisture content in accordance with T 265 and record the results.

9.5. Thoroughly break up the remainder of the material until it will pass through a 19.0-mm sieve and
90 percent of the soil aggregations will pass a 4.75-mm sieve as judged by eye, and add to the
remaining portion of the sample being tested. Add water in sufficient amounts to increase the
moisture content of the soil sample by one or two percentage points, and repeat the above
procedure for each increment of water added (Note 8). When the series of determinations indicate
a decrease or no change in the wet unit mass, W1, per cubic meter (cubic foot) of the compacted
soil perform one more determination such that there is a minimum of two determinations over
optimum moisture.

METHOD D

10. SAMPLE
10.1. Obtain a representative sample in accordance with Section 8 except that it shall have a mass of
approximately 11 kg (25 lb).

11. PROCEDURE
11.1. Follow the same procedure as described for Method C in Section 9, except for the following: Form
a specimen by compacting the prepared soil in the 152.4-mm (6-in.) mold assembly in three

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approximately equal layers to give a total compacted depth of about 125 mm (5 in.), each layer
being compacted by 56 uniformly distributed blows from the rammer. Calculate the wet density,
W1, as described in Section 12.1.

CALCULATIONS AND REPORT

12. CALCULATIONS
12.1. Wet density (W1) shall be determined using the mold volume. For masses recorded in kilograms,
the unit of wet density is kilograms per cubic meter of compacted soil. For masses recorded in
pounds, the unit of wet density is pounds per cubic foot of compacted soil.
W1 = ( A – B )/V (1)
where:
W1 = wet density in kg/m3 (lb/ft3) of compacted soil,
A = mass of the mold, base plate, and wet soil,
B = mass of the mold, base plate,

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12.2. V = mold volume as determined in Section 3.1.1 for Methods A and C, or Section 3.1.2 for
Methods B and D. The dry density is related to the wet density as follows:
W1
=W × 100 (2)
w + 100
where:
W = dry density, in kg/m3 (lb/ft3) of compacted soil,
W1 = wet density in kg/m3 (lb/ft3) of compacted soil,
w = moisture content (percent) of the specimen.

TS-1b T 99-10 AASHTO

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13. MOISTURE-DENSITY RELATIONSHIP
13.1. The calculations in Section 12 shall be made to determine the wet density (unit mass) and oven-
dry density (unit mass) in kilograms per cubic meter or pounds per cubic foot of the compacted
samples. The oven-dry densities of the soil shall be plotted as ordinates, and the corresponding
moisture content as abscissas.

13.2. Optimum Moisture Content—When the densities and corresponding moisture contents for the soil
have been determined and plotted as indicated in Section 13.1, it will be found that by connecting
the plotted points with a smooth line, a curve is produced. The moisture content corresponding to
the peak of the curve shall be termed the “optimum moisture content” of the soil under the
above compaction.

13.3. Maximum Dry Density—The oven-dry density in kilograms per cubic meter or pounds per cubic
foot of the soil at optimum moisture content shall be termed “maximum dry density” under the
above compaction.

14. REPORT
14.1. The report shall include the following:

14.1.1. The method used (Method A, B, C, or D).

14.1.2. The optimum moisture content to the nearest 0.1 percent.

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14.1.3. The maximum density to the nearest 1 kg/m3 (0.1 lb/ft3).

14.1.4. Type of face if other than 50.8 mm (2 in.) circular.

14.1.5. Oversized particle correction.

14.1.5.1. The adjusted maximum dry density to the nearest 1 kg/m3 (0.1 lb/ft3).

14.1.5.2. The corrected optimum moisture content to the nearest 0.1 percent.

14.1.5.3. The oversized particles to the nearest 0.1 percent of the original dry mass of the sample.

14.1.5.4. Gsb of oversized particles to the nearest 0.001.

15. PRECISION STATEMENT

15.1. Repeatability (Single Operator)—Two results obtained by the same operation on the same sample

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in the same laboratory using the same apparatus and on different days should be considered
suspect if they differ by more than 10 percent of their mean for optimum moisture content and
35 kg/m3 (2.2 lb/ft3) for maximum density.

15.2. Reproducibility (Multilaboratory)—Two results obtained by different operators in different

laboratories should be considered suspect if they differ by more than 15 percent of their mean for
optimum moisture and 72 kg/m3 (4.5 lb/ft3) for maximum density.

15.3. ANNEX 1, Oversized Particle Correction—Since the correction for coarse particles involves no
testing but instead utilizes the results of other tests and mathematically combines the results,
determination of the precision and accuracy is not applicable.

TS-1b T 99-11 AASHTO

© 2015 by the American Association of State Highway and Transportation Officials.
All rights reserved. Duplication is a violation of applicable law.
 Copyrighted material licensed to mahmoud hamawi on 2016-08-22 for licensee's use only.
16. KEYWORDS
16.1. Compaction; moisture content; sieve; soil density; soil moisture.

ANNEX
(Mandatory Information)

A1. CORRECTION OF MAXIMUM DRY DENSITY AND OPTIMUM

MOISTURE FOR OVERSIZED PARTICLES
A1.1. This section corrects the maximum dry density and moisture content of the material retained on
the 4.75-mm (No. 4) sieve, Methods A and B; or the material retained on the 19.0-mm (3/4-in.)
sieve, Methods C and D. The maximum dry density, adjusted for oversized particles and total
moisture content, are compared with the field-dry density and field moisture content.

A1.1.1. This correction can be applied to the sample on which the maximum dry density is performed.

A1.1.2. This correction can also be applied to the sample obtained from the field while performing in-
place density. Obtain the sample in accordance with T 310, Section 9.6. Sieve the sample over the
appropriate sieve. Use the alternative drying method [A1.3.2].
Note A1— Correction may not be of practical significance for materials with only a small
percentage of oversized particles. If a minimum percentage is not specified, correction shall be

No further reproduction or networking is permitted.

applied to samples with more than 5 percent by weight of oversized particles.

A1.2. Bulk specific gravity (Gsb) of the oversized particles is required to determine the corrected
maximum dry density. If the bulk specific gravity has been determined in accordance with T 85,
this value should be used in the calculations. For most construction activities, the specific gravity
can be assumed to be 2.600.

A1.3. Determine the dry mass of the oversized and fine fractions [MDC and MDF].

A1.3.1. If necessary dry the fractions, fine and oversized, in air or by use of a drying apparatus that is
maintained at a temperature not exceeding 60ºC (140ºF).

A1.3.2. Alternatively determine the moist mass of both fractions, fine (MMf) and oversized (MMc). Obtain
moisture samples from the fine and oversized material. Determine the moisture content of the fine
particles (MCf) and oversized particles (MCC) of the material. The moisture contents can be
determined by T 265, T 217, or T 255. If the moisture content of the oversized particles is
generally known, substitute that moisture content in the calculations.

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A1.3.2.1. Calculate the dry mass of the oversized and fine particles as follows:

M D M M / (1 + MC )
= (A1.1)
where:
MD = mass of dry material (fine or oversized particles);
MM = mass of moist material (fine or oversized particles); and
MC = moisture content of respective fine or oversized particles, expressed as a decimal.

TS-1b T 99-12 AASHTO

© 2015 by the American Association of State Highway and Transportation Officials.
All rights reserved. Duplication is a violation of applicable law.
 Copyrighted material licensed to mahmoud hamawi on 2016-08-22 for licensee's use only.
A1.4. Calculate the percentage of the fine particles and oversized particles by dry weight of the total
sample as follows:

=Pf 100 M DF /(M DF + M DC ) (A1.2)

and
=PC 100 M DC /(M DF + M DC ) (A1.3)
where:
Pf = percent of dry fine particles;
MDF = mass of dry fine particles;
MDC = mass of dry oversized particles; and
PC = percent of oversized particles of sieve used.

A1.5. Calculate the corrected optimum moisture content of the total sample (combined fine and
oversized particles) as follows:

MCT (MC f Pf + MCC PC ) / 100

= (A1.5)
where:
MCT = corrected optimum moisture content of the total sample expressed as a decimal,
MCf = optimum moisture content of the fine particles, expressed as a decimal,
Pf = percent of fine particles of sieve used,

No further reproduction or networking is permitted.

MCC = moisture content of the oversized particles, expressed as a decimal; and
PC = percent of oversized particles of sieve used.

A1.6. Calculate the corrected dry density of the total sample (combined fine and oversized particles) as
follows:

=Dd 100 D f k /(D f PC + kPf ) (A1.6)

where:
Dd = corrected maximum dry density of the total sample, kg/m3 (lb/ft3),
Df = maximum dry density of the fine particles, kg/m3 (lb/ft3),
k = 1000 × Bulk Specific Gravity (Gsb) (oven-dry basis) of coarse particles, kg/m3; or 62.4 ×
Bulk Specific Gravity (Gsb) (oven-dry basis) of coarse particles, lb/ft3,
PC = percent of oversized particles of sieve used, and
Pf = percent of fine particles of sieve used.

Distributed by Thomson Reuters (Scientific) LLC, www.tec

TS-1b T 99-13 AASHTO

© 2015 by the American Association of State Highway and Transportation Officials.
All rights reserved. Duplication is a violation of applicable law.