ASTM D3387-83(2003)
(Test Method)Standard Test Method for Compaction and Shear Properties of Bituminous Mixtures by Means of the U.S. Corps of Engineers Gyratory Testing Machine (GTM)
Standard Test Method for Compaction and Shear Properties of Bituminous Mixtures by Means of the U.S. Corps of Engineers Gyratory Testing Machine (GTM)
SCOPE
1.1 This test method covers two separate modes of operation of the Gyratory Testing Machine (GTM), namely: (1) GTM fixed roller mode; and (2) GTM oil-filled roller mode. The fixed roller mode of operation is employed in testing for compaction and strain indices only, while the oil-filled roller mode of operation is employed in testing for strength properties as well as compaction and strain indices. This test method is for use with mixtures containing asphalt cement, asphalt cut-back, asphalt emulsion, or tar and aggregate up to 1 in. (25.4 mm) maximum size in the 4-in. (101.6-mm) diameter specimen and 1.5 in. (38.1 mm) maximum size in the 6-in. (152.4-mm) diameter specimen.
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation:D3387– 83(Reapproved 2003)
Standard Test Method for
Compaction and Shear Properties of Bituminous Mixtures
by Means of the U.S. Corps of Engineers Gyratory Testing
Machine (GTM)
This standard is issued under the fixed designation D3387; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.2 gyratory angle—a measure of the magnitude of the
gyratory strain. Three pertinent angles are defined as follows:
1.1 This test method covers two separate modes of opera-
3.1.2.1 Initial gyratory angle or shear strain (machine set-
tion of the Gyratory Testing Machine (GTM), namely: (1)
ting) u (see Fig. 1),
GTM fixed roller mode; and (2) GTM oil-filled roller mode. o
3.1.2.2 Minimum gyratory angle or shear strain (minimum
The fixed roller mode of operation is employed in testing for
gyrograph band width) u (see Fig. 1), and
compaction and strain indices only, while the oil-filled roller i
3.1.2.3 Maximum gyratory angle or shear strain (maximum
mode of operation is employed in testing for strength proper-
gyrograph band width) u (see Fig. 1).
ties as well as compaction and strain indices. This test method max
3.1.3 gyratory stability index (GSI)—the ratio of the maxi-
is for use with mixtures containing asphalt cement, asphalt
mum gyratory angle to the minimum gyratory angle (see Fig.
cut-back, asphalt emulsion, or tar and aggregate up to 1 in.
1).
(25.4 mm) maximum size in the 4-in. (101.6-mm) diameter
3.1.4 gyratory compactibility index (GCI)—the ratio of the
specimen and 1.5 in. (38.1 mm) maximum size in the 6-in.
unit mass (total mix) at 30 revolutions of the GTM to the unit
(152.4-mm) diameter specimen.
mass (total mix) at 60 revolutions of the GTM.
1.2 This standard does not purport to address all of the
3.1.5 gyratory shear strength (S )—the shear resistance of
G
safety concerns, if any, associated with its use. It is the
the specimen which is, among other things, a function of the
responsibility of the user of this standard to establish appro-
imposed vertical pressure and degree of strain (seeAnnexA1).
priate safety and health practices and determine the applica-
3.1.6 gyratory shear factor (GSF)—the ratio of the mea-
bility of regulatory limitations prior to use.
sured gyratory shear strength to the approximate theoretical
2. Referenced Documents
maximum induced shear stress, that is, a factor of safety type
index with regard to failure in simple shear for the defined
2.1 ASTM Standards:
loading conditions.
C136 Test Method for Sieve Analysis of Fine and Coarse
Aggregates
4. Significance and Use
C670 Practice for Preparing Precision and Bias Statements
4.1 Either mode of operation (fixed roller or oil-filled roller)
for Test Methods for Construction Materials
is intended to be used for guidance in selection of the optimum
3. Terminology
bitumen content and establishing unit mass requirements;
additionally the oil-filled roller mode of operation is intended
3.1 Definitions:
for use in arriving at a shear strength factor (referred to as
3.1.1 gyrograph—a recording of shear strain experienced
gyratory strength factor, GSF) with regard to shear under the
by the bituminous mixture during the compaction test (see Fig.
load and strain conditions selected for the test. The procedure
1).
described here is for one selected degree of shear strain (in this
case an initial gyratory angle of 1°) and some selected vertical
This test method is under the jurisdiction of ASTM Committee D04 on Road
pressure (in this case the anticipated tire contact pressure).
and Paving Materials and is the direct responsibility of Subcommittee D04.26 on
Attention is called to the fact that the gyratory angle selected
Fundamental/Mechanistic Tests.
should relate to the anticipated pavement deflection. The 1°
Current edition approved July 10, 2003. Published September 2003. Originally
approved in 1974. Last previous edition approved in 1998 as D3387 – 83 (1996).
angleselectedhereshouldhavewideapplicationbutshouldthe
DOI: 10.1520/D3387-83R03.
pavement engineer select a different shear angle (such as a
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
degree of shear strain), it should be so indicated in the report.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on It is essential that the vertical pressure correspond to the
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D3387– 83 (2003)
FIG. 1 GTM Compaction and Shear Test
D3387– 83 (2003)
FIG. 2 Gyratory Testing Machine
maximum anticipated tire contact pressure, since the theoreti- bitumen content as does the widening of the gyrograph which
cal stress for compaction and maximum induced shear used in gives a stability index in excess of unity.
determining the compaction requirements and the gyratory 4.4 The gyratory compactibility index (GCI) is an indicator
strength factor (GSF) is based on the concept of employing of the compactibility of the mix. The closer this index
realistic loads for the test. approaches unity, the easier the mix is to compact.
4.2 The gyratory strength factor (GSF) must be interpreted
5. Apparatus
with due recognition of the use of the somewhat arbitrarily
selecteddegreeofstrainandtheassumptionofplanemaximum
5.1 Gyratory Testing Machine (GTM) and Appurtenances—
shear (the unit contact pressure divided by p) for a strip load
The primary equipment for this test is the Gyratory Testing
on a homogeneous elastically isotropic mass.
Machine (GTM) and appurtenances. Fig. 2 is an assembly
4.3 The use of this method for guidance in the selection of
drawing of the machine (and appurtenant equipment) indicat-
the optimum bitumen content is limited to mixtures that are
ing essential features, including the wall friction apparatus and
susceptible to the development of excess pore pressure when
a schematic of the gyrating mechanism. The fixed upper roller
the voids become overfilled with bitumen. (This restriction
and the oil-filled upper roller are interchangeable; the roller
does not apply to the gyratory strength factor, GSF.)Agyratory
being selected to fit the mode of operation of the GTM.
stability index (GSI), in excess of unity, indicates a progressive
5.2 Ovens—Ventilated ovens shall be provided for heating
increase in plasticity during densification. An increase in this
aggregates, bituminous material, and specimen molds and for
index indicates an excessive bitumen content for the compac-
curing cut-back mixes and emulsion mixes. It is recommended
tion pressure employed and foretells instability of the bitumi-
nousmixturefortheloadingemployed.Areductioninoil-filled
roller pressure during the compaction process likewise indi-
A novel mechanization of the original Texas gyratory principle. This machine
cates loss of stability because of overfilled voids; this phenom-
is manufactured by Engineering Developments Co., Inc. of Vicksburg, MI 39180,
enon also serves as an indicator of maximum allowable under letters Patent Nos. 2972249 and 3478572.
D3387– 83 (2003)
FIG. 3 GTM Shear Test
that the heating units be thermostatically controlled so as to extremely critical mixes, lower the incremental change of
maintain the required temperature within 5°F (2.8°C).
bitumen content to 0.3 % and for highly absorptive aggregates,
5.3 Balances, one having a capacity of 5 kg or more,
increase the incremental change of bitumen content to 1.0 %.
sensitive to 1.0 g; and one having a capacity of 2 kg, sensitive
Tests on additional bitumen contents should be conducted as
to 0.1 g.
necessary when check tests are needed.
5.4 Thermometers—Armored glass or dial-type thermom-
6.2 Preparation of Aggregates—In accordance with Test
eters with metal stems are recommended. A range from 50 to
Method C136, obtain a sieve analysis on the fine and coarse
400°F (9.9 to 20.4°C) with sensitivity of 5°F (2.8°C) is
aggregate (aggregate shall be separated by means of a No. 4
required.
(4.75-mm) sieve). Separate the aggregate into the various size
5.5 Spacer Blocks, two metal spacer blocks for use in
fractions necessary for accurately recombining into test mix-
zeroing the specimen height measuring equipment. These shall
tures conforming to specified grading requirements.
all be of 2-in. (50.8-mm) diameter with one each of the
6.3 Preparation of Mixtures—Combine the moisture-free
following lengths: 2.50 6 0.005 in. (63.50 6 0.013 mm) and
aggregates into batches sufficiently large to make specimens
3.75 6 0.005 in. (95.25 6 0.013 mm).
approximately 2.50 in. (63.5 mm) long in the 4-in. (101.6-mm)
5.6 Miscellaneous Apparatus—Trowels, spatulas, scoops,
diameter mold and 3.75 in. (95.3 mm) long in the 6-in.
gloves, rubber gloves, metal pans, 4-in. (101.6-mm) diameter
(152.4-mm) diameter mold. For normal aggregates, this will
paper disks, and 6-in. (152.4-mm) diameter paper disks.
require approximately 1200 g for the 4-in. (101.6-mm) diam-
6. Test Specimens
eter specimens and approximately 4050 g for the 6-in. (152.4-
mm) diameter specimens. Heat the aggregate to the proper
6.1 Selection of Bitumen Content for Specimens—Conduct
mixing temperature; then weigh the required amount of bitu-
laboratory tests for one specimen each at a minimum of three
men at the proper temperature into the aggregate mixture.
bitumen contents, one above, one below, and one at the
estimated optimum content (see Note 1). The incremental Mixing of the aggregate and bitumen shall be as thorough and
change of bitumen content should generally be 0.5 %. For rapid as possible; mechanical mixing is recommended.
D3387– 83 (2003)
FIG. 4 Compaction and Shear Properties vs. Bitumen Content
NOTE 1—A first approximation of the optimum amount of bitumen for
should be dried to constant weight at 221 to 230°F (105 to
the aggregate may be determined by any method commonly employed by
110°C). The liquid asphalt should be combined with the
the laboratory.Amethod that has been found suitable in some laboratories
aggregate at room temperature. Following mixing, cure the
is the centerfuge kerosene equivalent method.
loose mixture in a ventilated oven maintained at 221 to 230°F
6.3.1 For mixes employing penetration/viscosity grades of
(105 to 110°C) for at least 12 h prior to compaction at this
asphalt, the temperature of the aggregate and asphalt at the
temperature. The mix may be stirred occasionally during
time of mixing should correspond to the temperatures antici-
curing to accelerate loss of volatiles.
pated to be used at the plant during manufacture of the paving
6.4 Size of Specimens—The 4-in. (101.6-mm) diameter
mix. These temperatures will generally be somewhere in the
specimensshallbeapproximately2.50in.(63.5mm)long.The
range of 250 to 325°F (121 to 149°C). Once the mixing
6-in. (152.4-mm) diameter specimens shall be approximately
temperature is selected, it should be so controlled that the
3.75 in. (95.3 mm) long.
viscosity of the bitumen will not vary more than 650 cSt
7. Calibration
during the mixing process.
7.1 See Annex A2.
6.3.2 For tar mixtures, the temperature of the aggregate and
tar at the time of mixing should correspond to the temperatures
8. Procedure
to be used at the plant during manufacture of the paving mix.
8.1 General—The GTM-fixed roller is employed when the
This temperature will generally not exceed 225°F (107°C).
compaction test only is required. The GTM oil-filled roller is
Once the mixing temperature is specified, it should be so
employed when both the compaction test and the shear test are
controlled that the viscosity of the tar will not vary more than
required. The oil-filled roller procedure is accomplished in
65 Engler specific viscosity during the mixing process.
sequential steps including the compaction test, shear test, and
6.3.3 For mixtures employing liquid asphalts (cut backs or
wall friction test as outlined in this section. (The procedure for
emulsions), the asphalt need not be heated but the aggregate
determining the machine correction for S is presented in
G
Annex A2.) When using the fixed roller, inapplicable portions
California Highways and Public Works, Vol 20, No. 7, July 1942, pp. 14-17. of the following instructions are ignored.
D3387– 83 (2003)
8.2 Compaction or Compaction and Shear Test—Fig. 1 and assembly drawing, Fig. 2. With the vertical load acting on the
Fig.3illustratedatasheetswhicharesuitableforrecordingand specimen, the force required to overcome wall friction and
move the mold with respect to the specimen shall be deter-
calculating compaction or compaction and shear test results
and for displaying the gyrograph (shear strain) recording. The mined by observing the pressure gage of the jack while
actuating the jack. The pressure reading will be found to
gyratory strain angles u , u, and u are indicated on the
o i max
increase with each thrust of the jack until there is sufficient
gyrograph displayed in Fig. 1. For this test, set the initial
force to move the mold with respect to the specimen. The
gyratory angle, u , at 1°. Roller positions 2 and 4 (Fig. 1) are
o
pressure reading will then stabilize to about the same value
usedinsettingtheinitialgyratoryangle, u .Atrialbatchofmix
o
after each thrust of the jack. The reading of the wall friction
is used in making the initial gyratory angle adjustment. Make
gage shall be recorded in the space provided as illustrated in
certain that the specimen molds are thoroughly clean and free
Fig. 3. Immediately after completion of the wall friction test,
of defects. Excessive wear or grooving in the molds in the area
the test specimen should be removed from the GTM and the
of contact with the upper and lower plates will have an adverse
lower roller brought back to the 1° setting so that the machine
effect upon the compaction as well as the gyrograph (shear
is ready for the next test specimen.
strain) recording. Instructions for the compaction temperatures
for the laboratory specimens are presented in 6.3.1 through
9. Calculations
6.3.3. Set the GTM heater at 140°F (60°C) at least 15 min
9.1 Calculations for Compaction—Calculate the following
before starting the compaction test. Preheat the mold and base
compaction properties for each specimen, as illustrated
...
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