ASTM D7369-09
(Test Method)Standard Test Method for Determining the Resilient Modulus of Bituminous Mixtures by Indirect Tension Test
Standard Test Method for Determining the Resilient Modulus of Bituminous Mixtures by Indirect Tension Test
SIGNIFICANCE AND USE
Resilient modulus can be used in the evaluation of materials quality and as input for pavement design, evaluation and analysis. With this method, the effects of temperature and load on resilient modulus can also be investigated.
Note 1—The quality of the results produced by this standard are dependent on the competence of the personnel performing the procedure and the capability, calibration, and maintenance of the equipment used. Agencies that meet the criteria of Practice D 3666 are generally considered capable of competent and objective testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with D 3666 alone does not completely assure reliable results. Reliable results depend on many factors; following the suggestions of D 3666 or some similar acceptable guideline provides a means of evaluating and controlling some of those factors.
SCOPE
1.1 This test method covers procedures for preparing and testing laboratory-fabricated or field-recovered cores of bituminous mixtures to determine resilient modulus values using a repeated-load indirect tension test.
1.2 The values stated in SI units are regarded as the standard. Values in parentheses are for informational use.
1.3 A precision and bias statement for this standard has not been developed at this time. Therefore, this standard should not be used for acceptance or rejection of a material for purchasing purposes.
1.4 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.
General Information
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:D7369–09
Standard Test Method for
Determining the Resilient Modulus of Bituminous Mixtures
by Indirect Tension Test
This standard is issued under the fixed designation D7369; 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 D6931 Test Method for Indirect Tensile (IDT) Strength of
Bituminous Mixtures
1.1 This test method covers procedures for preparing and
2.2 Other Document:
testing laboratory-fabricated or field-recovered cores of bitu-
NCHRP Project 1-28A, Research Results Digest Number
minous mixtures to determine resilient modulus values using a
285—Laboratory Determination of Resilient Modulus for
repeated-load indirect tension test.
Flexible Pavement Design, January 2004
1.2 The values stated in SI units are regarded as the
standard. Values in parentheses are for informational use.
3. Terminology
1.3 A precision and bias statement for this standard has not
3.1 Definitions:
beendevelopedatthistime.Therefore,thisstandardshouldnot
3.1.1 contact load (P ), n—the vertical load placed on
contact
be used for acceptance or rejection of a material for purchasing
the specimen to maintain a positive contact between the
purposes.
loading strip and the specimen. The contact load is 4 % of the
1.4 This standard does not purport to address all of the
maximum load (0.04 P ) and is not less than 22.2 N (5 lb),
max
safety concerns, if any, associated with its use. It is the
but not more than 89.0 N (20 lb).
responsibility of the user of this standard to establish appro-
3.1.2 core, n—an intact cylindrical specimen of pavement
priate safety and health practices and determine the applica-
material, which is removed from the pavement by drilling and
bility of regulatory limitations prior to use.
sampling at the designated location. A core may consist of, or
2. Referenced Documents include, one, two, or more than two different layers.
3.1.3 cyclic load (resilient vertical load, P ), n—load
cyclic
2.1 ASTM Standards:
applied to a specimen, which is directly used to calculate
D3387 TestMethodforCompactionandShearPropertiesof
resilient modulus.
Bituminous Mixtures by Means of the U.S. Corps of
Engineers Gyratory Testing Machine (GTM) P 5 P – P (1)
cyclic max contact
D3666 Specification for Minimum Requirements forAgen-
3.1.4 haversine-shaped load form, n—the required load
cies Testing and Inspecting Road and Paving Materials
pulse for the resilient modulus test. The load pulse is in the
D4013 Practice for Preparation of Test Specimens of Bitu-
form (1-cos u)/2 with the cyclic load varying from the contact
minous Mixtures by Means of Gyratory Shear Compactor
load (P ) to the maximum load (P ).
contact max
D6925 Test Method for Preparation and Determination of
3.1.5 instantaneous resilient modulus, n—determined from
the Relative Density of Hot Mix Asphalt (HMA) Speci-
the deformation-time plots (both horizontal and vertical) as
mens by Means of the Superpave Gyratory Compactor
described in Section 10.
D6926 Practice for Preparation of Bituminous Specimens
3.1.6 lift, n—that part of the pavement produced with
Using Marshall Apparatus
similar material and placed with similar equipment and tech-
niques. The lift thickness is the thickness of the compacted
1 bituminous mixture that is achieved with one pass of the
This test method is under the jurisdiction of ASTM Committee D04 on Road
and Paving Materials and is the direct responsibility of Subcommittee D04.26 on laydown machine and the subsequent compaction process and
Fundamental/Mechanistic Tests.
can be equal to or less than the core thickness or length.
Current edition approved Feb. 1, 2009. Published February 2009. DOI: 10.1520/
3.1.7 maximum applied load (P ), n—the maximum total
max
D7369-09.
load applied to the sample, including the contact and cyclic
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
(resilient) loads.
Standards volume information, refer to the standard’s Document Summary page on
P 5 P 1 P (2)
max contact cyclic
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D7369–09
3.1.8 test specimen, n—that part of the layer which is used frequently inspected for any grooves caused due to friction.
for, or in, the specified test. The thickness of the test specimen Alignment of the device, within the loading system, shall be
can be equal to or less than the layer thickness. achieved so that such friction is limited. The upper plate shall
3.1.9 total deformation, n—determined from the berigidenoughtopreventexcessiveorunduedeflectionduring
deformation-time plots (both horizontal and vertical) as de- loading.Apicture of the loading strip parts is presented in Fig.
scribed in Section 10. 1. The loading strips shall be perpendicular to the line
connecting the two guide columns.
4. Summary of Test Method
6.3 Temperature-Control System—The temperature-control
4.1 The repeated-load indirect tension resilient modulus test
system should be capable of maintaining a temperature of 5 to
of bituminous mixtures is conducted through repetitive appli-
45°C (41 to 113°F) 61.0°C (62°F). The system shall include
cations of compressive loads in a haversine waveform. The
a temperature-controlled cabinet large enough to house the
compressive load is applied along a vertical diametral plane of
loading device and space adequate to pre-condition at least
a cylindrical specimen of asphalt concrete. The resulting
three specimens at a time prior to testing, as described in 8.3.
horizontal and vertical deformations of the specimen are
6.4 Measurement and Recording System—The measure-
measured. Values of resilient Poisson’s ratio are calculated
ment and recording system shall include sensors for measuring
using recoverable vertical and horizontal deformations. The
and simultaneously recording horizontal and vertical deforma-
resilient modulus values are subsequently calculated using the
tions and loads. The system shall be capable of recording
calculated Poisson’s ratio. Two separate resilient modulus
horizontal and vertical deformations in the range of 0.00038
valuesareobtained.One,termed instantaneousresilientmodu-
mm (0.000015 in.) of deformation. Load cells shall be accu-
lus, is calculated using the instantaneous recoverable deforma-
rately calibrated with a resolution of 8.9 N (2 lb) or better.
tion that occurs during the unloading portion of one load-
6.4.1 Data Acquisition—The measuring or recording de-
unload cycle. The other, termed total resilient modulus, is
vices must provide real-time deformation and should be
calculated using total recoverable deformation which includes
capable of monitoring readings on tests conducted to 1 Hz.
both the instantaneous recoverable and the time-dependent
Computer monitoring systems are recommended. The data
continuing recoverable deformation during the unload or
acquisition system shall be capable of collecting 200 scans per
rest-period portion of one cycle.
second (a scan includes all deformation and load values at a
given point of time). The capability to have real-time plots
5. Significance and Use
(simultaneous to the data collection by the computer monitor-
5.1 Resilient modulus can be used in the evaluation of
ing system) shall also be provided to check the progress of the
materials quality and as input for pavement design, evaluation
test. If strip chart recorders are used without computer moni-
and analysis. With this method, the effects of temperature and
toring systems, the plotting scale shall be adjusted such that
load on resilient modulus can also be investigated.
there is a balance between the scale reduction required as a
result of the pen reaction time and the scale amplification
NOTE 1—The quality of the results produced by this standard are
dependent on the competence of the personnel performing the procedure needed for purposes of accurate measurement of values from a
and the capability, calibration, and maintenance of the equipment used.
plot.Actual load values, and not the intended load values, shall
Agencies that meet the criteria of Practice D3666 are generally considered
be used for calculation purposes and so the data acquisition
capable of competent and objective testing/sampling/inspection/etc. Users
system shall also be capable of monitoring the load values
of this standard are cautioned that compliance with D3666 alone does not
continuously during testing.
completely assure reliable results. Reliable results depend on many
factors; following the suggestions of D3666 or some similar acceptable
NOTE 2—Tests at multiple frequencies can be done. The frequencies of
guideline provides a means of evaluating and controlling some of those
factors.
6. Apparatus
6.1 Testing Machine—Testing machine shall be a top load-
ing, closed loop, electro-hydraulic or pneumatic testing ma-
chine with a function generator capable of applying a
haversine-shaped load pulse over a range of load durations,
load levels, and rest periods.
6.2 Loading Device—Loading device should be capable of
testing 101.6 or 152.4 mm (4 or 6 in.) diameter specimens of
heights up to 63.5 mm (2.5 in.). The device should be compact
enough to be used within an environmental chamber. It should
have a fixed bottom loading plate and a moving upper loading
plate. The movement of the upper plate should be guided by
two columns, one on each side of the specimen and equidistant
from the loading axis and the loading strips, to ensure it has
minimaltranslationalorrotationalmotionduringloadingofthe
specimen. The guide columns shall have a near frictionless
bearing surface. The surface of the guide columns shall be FIG. 1 Sample with Loading Strip Parts
D7369–09
0.33 and 0.5 Hz are suggested.
shall be easily removable, without disturbing the LVDT (once
the glue cures), and shall not be destructively mounted on the
6.4.2 Deformation Measurement—Both horizontal and ver-
specimen. The device shall be capable of mounting the LVDT
tical deformation shall be measured on the surface of the
at a gauge length of one-quarter and one half of the diameter of
specimen by mounting LVDTs between gauge points along the
the specimen. The LVDT shall be as close as possible to (but
horizontal and vertical diameters. The gauge length can be of
1 not touching) the surface of the specimen so as to minimize the
three sizes in relation to the diameter of the specimen: ⁄4 of the
bulging effect.To ensure uniform test results, a spacing of 5.08
diameter or 25.4 mm for a 101.6 mm-diameter of the specimen
mm (0.2 in.) is recommended. The axis of the LVDT shall not
(1 in. for a 4 in.) or 38.1 mm for a 152.4 mm-diameter of the
1 be at a distance greater than 6.35 mm (0.25 in.) from the
specimen (1.5 in. for a 6 in.), ⁄2 of the diameter or 50.8 mm for
surface of the specimen. Fig. 2 shows an example of alignment
a 101.6 mm diameter of the specimen (2 in. for a 4 in.) or 76.2
device.
mm for a 152.4 mm diameter of the specimen (3 in. for a 6 in.)
and one diameter or 101.6 for a 101.6 mm diameter of the
7. Specimens
specimen (4 in. for a 4 in.) or 152.4 mm for a 152.4 mm
7.1 Specimen Size—Resilient modulus testing shall be con-
diameter of the specimen (6 in. for a 6 in.). It is required to
ducted on 101.6 6 3.8 mm (4 in.) or 152.4 6 9 mm (6 in.)
have the two LVDTs, on each face of the specimen, one
diameter specimens that are 38.1 mm (1.5 in.) to 63.5 mm (2.5
horizontal and one vertical resulting in a total of four LVDTs
in.) in thickness. The test specimen can be obtained from field
for deformation measurement.
coring or from a Marshall-compacted specimen or from a
NOTE 3—The results obtained with gauge length of ⁄4 of the diameter
gyratory-compacted specimen. Depending on the height of the
of the specimen have the best precision.
gyratory-compacted specimen and the thickness of the test
6.4.3 Load Measurement—The repetitive loads shall be specimen, two or three specimens can be sawed from a
measured with an electronic load cell with a capacity adequate compacted specimen.
for the maximum required loading and a sensitivity of 0.5 % of 7.2 Core Specimens:
the intended peak load. During period of resilient modulus
7.2.1 Cores for test specimen preparation, which may con-
testing, the load cell shall be monitored and checked, once a tainoneormoretestablelayers,musthavesmoothanduniform
month, with a calibrated proving ring to ensure that the load
surfaces and must meet specimen diametric and thickness
cell is operating properly. Additionally, the load cell shall be requirements summarized in 7.1. Cores that are obviously
checked at any time that the QC/QA testing with in-house deformed or have any visible cracks must be rejected. Irregular
synthetic specimen (see 9.1) indicates a change in the system top and bottom surfaces shall be trued as necessary, and
response or when there is a suspicion of a load cell problem. individual layer specimens shall be obtained by cutting with a
6.5 Loading Strip—Steel loading strips, with concave diamond saw using water or air as coolant. Additional speci-
sample contact surfaces, machined to the radius of curvature of mens for each layer must be collected in the field in order to
a 101.60 6 0.10 mm diameter specimen (4.000 6 0.004 in) or perform the pretest tensile strength.
152.40 6 0.15 mm diameter specimen (6.000 6 0.006 in), are 7.2.2 If a core specimen has more than one layer, the layers
required to apply load to the test specimens. The contact areas shall be separated at the layer interface. Layers containing
1 3
of the loading strips shall be 12.7 mm ( ⁄2 in.) and 19 mm ( ⁄4 more than one lift of the same material may be tested as a
in.) wide respectively for the 4 in specimen and 6 in specimen. single specimen. Traffic direction shall be marked on each
The outer edges of the curved surface shall be filed lightly to layer after cutting, to maintain the correct orientation.
remove sharp edges that might cut the specimen during testing. 7.2.3 In order to limit non-parallelism of the two flat sides,
Thin lines should be drawn along the length of the strip at its it is recommended to place the specimen on a level surface and
center, to help alignment.Also, appropriate marking should be measuring the departure from perpendicularity. The displace-
made so as to center the specimen within the length of the ment sensor should have a precision of 0.01 mm (0.0004 in.).
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