ASTM D6927-04
(Test Method)Standard Test Method for Marshall Stability and Flow of Bituminous Mixtures
Standard Test Method for Marshall Stability and Flow of Bituminous Mixtures
SCOPE
1.1 This test method covers measurement of resistance to plastic flow of 102 mm (4 in.) cylindrical specimens of bituminous paving mixture loaded in a direction perpendicular to the cylindrical axis by means of the Marshall apparatus. This method is for use with dense graded bituminous mixtures prepared with asphalt cement (modified and unmodified), cutback asphalt, tar, and tar-rubber with maximum size aggregate up to 25 mm (1 in.) in size (passing 25 mm (1 in.) sieve).
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Designation:D6927–04
Standard Test Method for
Marshall Stability and Flow of Bituminous Mixtures
This standard is issued under the fixed designation D 6927; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope grade, and amount. Various agencies have criteria for Marshall
stability. Marshall flow is a measure of deformation (elastic
1.1 This test method covers measurement of resistance to
plus plastic) of the bituminous mix determined during the
plastic flow of 102 mm (4 in.) cylindrical specimens of
stability test. There is no ideal value but there are acceptable
bituminous paving mixture loaded in a direction perpendicular
limits. If flow at the selected optimum binder content is above
tothecylindricalaxisbymeansoftheMarshallapparatus.This
the upper limit, the mix is considered too plastic or unstable
method is for use with dense graded bituminous mixtures
and if below the lower limit, it is considered too brittle.
prepared with asphalt cement (modified and unmodified),
3.1.2 The Marshall stability and flow test results are appli-
cutback asphalt, tar, and tar-rubber with maximum size aggre-
cabletodense-gradedbituminousmixtureswithmaximumsize
gate up to 25 mm (1 in.) in size (passing 25 mm (1 in.) sieve).
aggregate up to 25 mm (1 in.) in size. For the purpose of mix
2. Referenced Documents
design,Marshallstabilityandflowtestresultsshouldconsistof
the average of a minimum of three specimens at each incre-
2.1 ASTM Standards:
ment of binder content where the binder content varies in
C 670 Practice for Preparing Precision and Bias Statements
one-halfpercentincrementsoverarangeofbindercontent.The
for Test Methods for Construction Materials
binder content range is generally selected on the basis of
D 2726 Test Method for Bulk Specific Gravity and Density
experience and historical testing data of the component mate-
of Non-Absorptive Compacted Bituminous Mixtures
rials, but may involve trial and error to include the desirable
D 3549 Test Method for Thickness or Height of Compacted
range of mix properties. Dense graded mixtures will generally
Bituminous Paving Mixture Specimens
show a peak of stability at a particular binder content. This
D 6926 Test Method for Preparation of Bituminous Speci-
peak binder content may be averaged with other binder
mens Using Marshall Apparatus
contents such as the binder content at the peak density from a
3. Significance and Use
density versus binder content curve and binder content at
desired air voids and voids filled values. The above test
3.1 Marshall stability and flow values along with density;
properties may be weighted to reflect a particular mix design
air voids in the total mix, voids in the mineral aggregate, or
philosophy. In addition, a mixture design may be required to
voids, or both, filled with asphalt are used for laboratory mix
meet minimum voids in the mineral aggregate based on
design and evaluation of bituminous mixtures. In addition,
nominal maximum aggregate size in the mixture.
Marshall stability and flow can be used to monitor the plant
3.1.3 Field laboratory Marshall stability and flow tests on
process of producing bituminous mixture. Marshall stability
specimens made with plant-produced bituminous mix may
andflowmayalsobeusedtorelativelyevaluatedifferentmixes
vary significantly from laboratory design values because of
and the effects of conditioning such as with water.
differences in plant mixing versus laboratory mixing. This
3.1.1 Marshall stability and flow are bituminous mixture
includes mixing efficiency and aging.
characteristics determined from tests of compacted specimens
3.1.4 Significant differences in Marshall stability and flow
of a specified geometry and in a prescribed manner. Marshall
from one set of tests to another or from an average value of
stability is the maximum resistance to deformation at a
several sets of data or specimens, prepared from plant-
constant rate of loading. The magnitude of Marshall stability
produced mix may indicate poor sampling, incorrect testing
varies with aggregate type and grading and bitumen type,
technique, change of grading, change of binder content, or a
malfunction in the plant process. The source of the variation
This test method is under the jurisdiction of ASTM Committee D04 on Road
should be resolved and the problem corrected.
and Paving Materials and is the direct responsibility of Subcommittee D04.20 on
3.1.5 Specimens will most often be prepared using Test
Mechanical Tests of Bituminous Mixtures.
Method D 6926 but may be prepared using other types of
Current edition approved Aug. 1, 2004. Published August 2004.
compaction procedures as long as specimens satisfy geometry
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
requirements. Other types of compaction may cause specimens
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D6927–04
to have different stress strain characteristics than specimens or loose motion on the guide rods.Acircular testing head with
prepared by Marshall impact compaction. Marshall stability an inside bevel having dimensions other than specified in Fig.
and flow may also be determined using field cores from in situ 1 has been shown to give results different from the standard
pavementforinformationorevaluation.However,theseresults testing head.
may not compare with results from laboratory-prepared speci-
4.2 Compression Loading Machine—The compression
mens and shall not be used for specification or acceptance loading machine (Fig. 2) may consist of a screw jack mounted
purposes. One source of error in testing field cores arises when in a testing frame and shall be designed to load at a uniform
the side of the core is not smooth or perpendicular to the core vertical movement of 50 6 5 mm/min. (2.00 6 0.15 in./min).
faces. Such conditions can create stress concentrations in The design in Fig. 2 shows power being supplied by an electric
loading and low Marshall stability. motor.Amechanical or hydraulic compression testing machine
may also be used provided the rate of loading can be
4. Apparatus
maintained at 50 6 5 mm/min (2.00 6 0.15 in./min).
4.1 Breaking Head—The testing head (Fig. 1) shall consist 4.3 Load Measuring Device—As a minimum, a calibrated
of upper and lower cylindrical segments of cast gray or ductile 22 240 N (5000 lbf) ring dynamometer (Fig. 2) with a dial
iron, cast steel, or annealed steel tubing. The lower segment indicator to measure ring deflection for applied loads is
shall be mounted on a base having two perpendicular guide required. The 22 240 N (5000 lbf) ring shall have a minimum
rods or posts (minimum 12.5 mm ( ⁄2 in.) in diameter) sensitivity of 44.48 N (10 lbf). The dial indicator should be
extending upwards. Guide sleeves in the upper segment shall graduated in 0.0025 mm (0.0001 in.) increments. The ring
direct the two segments together without appreciable binding dynamometer should be attached to the testing frame (see ring
mm in.
A 148.6 to 149.2 5.850 to 5.875
B 101.6 to 101.7 4.000 to 4.005
C 23.4 to 23.7 0.923 to 0.935
D 76.2 to 76.5 3.000 to 3.010
E 0.0 to 0.05 0.000 to 0.002
F 34.8 to 35.1 1.370 to 1.380
G 41.28 to 41.33 1.625 to 1.627
H 19.0 to 19.1 0.748 to 0.752
J 2.03 to 2.13 0.080 to 0.084
K 8.9 to 9.1 0.350 to 0.358
L8 101.5 to 101.7 3.995 to 4.005
L 152.3 to 152.5 5.995 to 6.005
M Stresses transmitted through one spherical and one flat surface.
N Geometry of guide system optional but must be appreciably free of both play and binding.
One test for binding is to lift or lower head by a single guide bushing.
FIG. 1 Testing Head
D6927–04
FIG. 2 Compression Machine
holding bar, Fig. 2) and an adapter (see ring dynamometer 4.6 Oven—An oven capable of maintaining the specified
adapter, Fig. 2) should be provided to transmit load to the test temperature 61°C (2°F).
breaking head. The ring dynamometer assembly may be
4.7 Air Bath—The air bath for mixtures containing cutback
replaced with a load cell connected to a load-deformation
asphalt binder shall be thermostatically controlled and shall
recorder or computer provided capacity and sensitivity meet
maintain the air temperature at 25 6 1°C (77 6 2°F).
above requirements.
4.8 Thermometers—Calibrated thermometers for water and
air baths shall cover the temperature range specified and be
NOTE 1—A higher capacity ring dynamometer may be required for
readable to 0.2°C (0.4°F).
high-stability mixes. These include mixes with harsh, crushed aggregate
and dense gradation, as well as mixes made with very stiff binders.
5. Procedure
4.4 Flowmeter—TheMarshallflowmeterconsistsofaguide
5.1 Aminimum of three specimens of a given mixture shall
sleeve and a gage (Fig. 3). The activating pin of the gage shall
be tested.The specimens should have the same aggregate type,
slide inside the guide sleeve with minimal friction and the
quality, and grading; the same mineral filler type and quantity;
guide sleeve shall slide freely over the guide post (see Fig. 3)
and the same binder source, grade and amount. In addition, the
of the breaking head. These points of frictional resistance shall
specimens should have the same preparation, that is, tempera-
be checked before tests. Graduations of the flowmeter gage
tures, cooling, and compaction.
shallbein0.25mm(0.01in.)divisions.Insteadofaflowmeter,
5.2 Specimens should be cooled to room temperature after
other devices such as an indicator dial or linear variable
compaction. During cooling they should be placed on a
differential transducer (LVDT) connected to a load-
smooth, flat surface. Bulk specific gravity of each specimen
deformationrecorderorcomputermaybeused.Thesealternate
shall be determined by Test Method D 2726. The bulk specific
devices should be capable of indicating or displaying flow
gravities of replicate specimens for each binder content shall
(deformation)totherequiredsensitivity.Thesedevicesmustbe
agree within 60.020 of the mean as noted in Test Method
designed to measure and record the same relative movement
D 6926.
between the top of the guide post and the upper breaking head.
5.2.1 Measur
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