ASTM D4125/D4125M-10(2016)
(Test Method)Standard Test Methods for Asphalt Content of Bituminous Mixtures by the Nuclear Method
Standard Test Methods for Asphalt Content of Bituminous Mixtures by the Nuclear Method
SIGNIFICANCE AND USE
3.1 These test methods are useful as a rapid, nondestructive technique for determination of asphalt content of bituminous mixtures.
3.2 These test methods are suitable for quality control and acceptance testing for construction and for research and development applications. The test method is used for determination of asphalt content only as it does not provide extracted aggregate for gradation analysis.
3.3 The non-destructive nature of the test allows repetitive measurements to be made on a single test sample for statistical analysis of test data.
3.4 These test methods determine the asphalt content of a test sample by comparing the measured asphalt content with previously established calibration data.
3.4.1 The asphalt content of a material expressed as a percentage, is the ratio of the mass of asphalt in a given mass of material to the total mass of the sample or to the mass of the solid material particles.
SCOPE
1.1 These test methods cover the procedures for determining the asphalt content of samples of uncompacted bituminous mixtures (Test Method A), and of laboratory compacted specimens of bituminous mixtures (Test Method B) by examining a test sample with an apparatus that utilizes neutron thermalization techniques.
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.
1.3 A precision and bias statement for Method B in this standard has not been developed at this time. Therefore, Method B 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. See Section 6 and 8.4.2, 8.5.6, and Note 4, for specific hazards.
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Designation: D4125/D4125M − 10 (Reapproved 2016)
Standard Test Methods for
Asphalt Content of Bituminous Mixtures by the Nuclear
Method
This standard is issued under the fixed designation D4125/D4125M; 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 D1461 Test Method for Moisture or Volatile Distillates in
Bituminous Paving Mixtures
1.1 These test methods cover the procedures for determin-
D1559 Test Method for Resistance to Plastic Flow of Bitu-
ing the asphalt content of samples of uncompacted bituminous
minous Mixtures Using Marshall Apparatus (Withdrawn
mixtures (Test Method A), and of laboratory compacted
1998)
specimens of bituminous mixtures (Test Method B) by exam-
D1561 Practice for Preparation of Bituminous Mixture Test
ining a test sample with an apparatus that utilizes neutron
Specimens by Means of California Kneading Compactor
thermalization techniques.
D3387 Test Method for Compaction and Shear Properties of
1.2 The values stated in either SI units or inch-pound units
Bituminous Mixtures by Means of the U.S. Corps of
are to be regarded separately as standard. The values stated in
Engineers Gyratory Testing Machine (GTM)
each system may not be exact equivalents; therefore, each
D4013 Practice for Preparation of Test Specimens of Bitu-
system shall be used independently of the other. Combining
minous Mixtures by Means of Gyratory Shear Compactor
values from the two systems may result in non-conformance
(Withdrawn 2013)
with the standard.
1.3 A precision and bias statement for Method B in this 3. Significance and Use
standard has not been developed at this time. Therefore,
3.1 These test methods are useful as a rapid, nondestructive
Method B should not be used for acceptance or rejection of a
technique for determination of asphalt content of bituminous
material for purchasing purposes.
mixtures.
1.4 This standard does not purport to address all of the
3.2 These test methods are suitable for quality control and
safety concerns, if any, associated with its use. It is the
acceptance testing for construction and for research and
responsibility of the user of this standard to establish appro-
development applications. The test method is used for deter-
priate safety and health practices and determine the applica-
mination of asphalt content only as it does not provide
bility of regulatory limitations prior to use. See Section 6 and
extracted aggregate for gradation analysis.
8.4.2, 8.5.6, and Note 4, for specific hazards.
3.3 The non-destructive nature of the test allows repetitive
measurements to be made on a single test sample for statistical
2. Referenced Documents
analysis of test data.
2.1 ASTM Standards:
3.4 These test methods determine the asphalt content of a
C670 Practice for Preparing Precision and Bias Statements
test sample by comparing the measured asphalt content with
for Test Methods for Construction Materials
previously established calibration data.
D75 Practice for Sampling Aggregates
3.4.1 The asphalt content of a material expressed as a
D140 Practice for Sampling Bituminous Materials
percentage, is the ratio of the mass of asphalt in a given mass
D979 Practice for Sampling Bituminous Paving Mixtures
of material to the total mass of the sample or to the mass of the
solid material particles.
These test methods are under the jurisdiction of ASTM Committee D04 on
4. Interferences
Road and Paving Materials and is the direct responsibility of Subcommittee D04.25
on Analysis of Asphalt Mixtures.
4.1 The fundamental assumptions inherent in this test
Current edition approved Oct. 1, 2016. Published October 2016. Originally
method are that the material under test is homogeneous and
approved in 1983. Last previous edition approved in 2010 as D4125/D4125M – 10.
DOI: 10.1520/D4125_D4125M-10R16.
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
Standards volume information, refer to the standard’s Document Summary page on The last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4125/D4125M − 10 (2016)
that hydrogen present is in the form of asphalt or has been
otherwise accounted for in the calibration process.
4.2 Accurate results will be dependent upon proper calibra-
tion of the apparatus to the material being tested.
4.3 Thisapparatusmeasuresthetotalamountofhydrogenin
the sample including hydrogen present in the form of water.
Unlessthetestsampleisfreeofwater,suchpercentagemustbe
determined in accordance with the provisions of Test Method
D1461 and the percentage determined subtracted from the
asphalt percentage as measured by the apparatus.
4.3.1 Alternatively, the sample may be dried to a constant
mass in an oven at 110 6 5°C [230 6 9°F], thereby nullifying
the need for the correction.
4.4 This apparatus may be sensitive to outside influences,
therefore, any other source of neutron radiation shall be kept at
least 10 m [30 ft] from the apparatus during use. The area
around the apparatus shall be kept free of large amounts of
hydrogenousmaterial,suchaswater,plastics,orasphaltduring
use.
4.5 Movingtheapparatustoadifferentlocation,evenwithin
the same laboratory, can cause a change in background
radiation measurements. Also, if objects containing hydrog-
FIG. 1 Molded Laboratory Specimen-Containers Measurement
enous materials are moved in the area near the apparatus, the
Values in SI Units (CM)—Other Values for Reference Only
measurement counts may be affected. New background mea-
surements shall be taken prior to use whenever background
conditions have changed (see Section 10).
5.3.2 Apparatus,necessarytopreparecompactedspecimens
as specified in Test Methods D1559, D1561, D3387,or
5. Apparatus Practice D4013.
5.1 While exact details of construction for the apparatus
6. Hazards
may vary, the system shall consist of the following items:
6.1 Warning—This equipment utilizes radioactive materi-
5.1.1 Neutron Source—An encapsulated and sealed radioac-
als which may be hazardous to the health of the users unless
tive source such as americium/beryllium.
proper precautions are taken. Users of this equipment must
5.1.2 Detectors—Any type of thermal neutron detectors,
become completely familiar with possible safety hazards and
such as helium-3 or boron trifluoride.
with all applicable regulations concerning the handling and use
5.1.3 Read-Out Instrument, such as a scaler or a direct
of radioactive materials. Effective user instructions together
reading digital device calibrated in percent asphalt.
with routine safety procedures are a recommended part of the
5.2 Other Apparatus:
operation of this apparatus.
5.2.1 Stainless Steel Sample Pans, of uniform size and
7. Sampling
mass.
5.2.2 Balance, capable of weighing to 20 kg [44 lb],
7.1 Obtain random samples of aggregates in accordance
readable to 1 g [0.0002 lbm].
with Practice D75.
5.2.3 Oven, capable of heating to 177 6 3°C [350 6 5°F].
7.2 Obtain random samples of freshly produced bituminous
5.2.4 Straightedge, steel, approximately 450 mm [18 in.] in
paving mixture in accordance with Practice D979.
length.
7.3 Obtain random samples of bituminous materials in
5.2.5 Flat Plate, metal or wood, having an area slightly
accordance with Practice D140.
larger than the sample pan. The metal plate shall have a
minimum thickness of 10 mm [ ⁄8 in.]. The wooden plate shall
8. Calibration
have a minimum thickness of 20 mm [ ⁄4 in.].
8.1 The test results obtained using this test method will be
5.2.6 Assorted Spoons and Mixing Bowls.
influenced by the types of aggregate, source, and grade of
5.2.7 Thermometer with a temperature range of 10 to 250°C
asphalt, and by the mix gradation. Accordingly, a calibration
[50 to 482°F].
curve must be developed for each mix type and aggregate
5.3 Additional Apparatus for Test Method B:
blend to be tested under this test method.
5.3.1 Molded Laboratory Specimen Container, (provided by 8.1.1 A new calibration curve shall be developed whenever
instrument manufacturer) to allow for proper testing of labo- there is a change in the source of asphalt or aggregate or a
ratory compacted samples (see Fig. 1). significant change in aggregate gradation.
D4125/D4125M − 10 (2016)
8.1.2 Anewcalibrationcurveshallbeestablishedfornewor 8.5.1 Heat the aggregates and asphalt cement to approxi-
repaired apparatus. mately 150°C [300°F]. Heat all bowls, sample pans, and tools
to approximately 150°C [300°F].
8.2 For Test Method A, calibrate the apparatus using the
8.5.2 To prevent samples from being biased by residual
following procedures:
asphalt retained in the mixing bowl, do not clean the bowl after
8.2.1 Sample the aggregates in accordance with 7.1 and
each mixing of the samples. Scrape it clean, leaving a coating
blend the aggregates in the proper proportions. Obtain enough
of asphalt mix residue. This allows for a more accurate mixing
aggregate for a minimum of three samples. Approximately 30
of samples. Prior to mixing the first sample, a mixture of
kg [65 lb] will be required, and
asphalt and aggregate fines may be used as a light coating on
8.2.2 Sample the bituminous materials in accordance with
the interior of the mixing bowl.
7.3. Approximately 2.5 kg [5.5 lb] will be required.
8.5.3 Using an aggregate sample of sufficient size to fill the
8.3 Use a minimum of three prepared samples to establish sample pan, add the proper amount of asphalt (within 1 g
the calibration curve. The range of asphalt contents shall vary [0.002 lb] of desired percent by mass) and mix thoroughly in
by at least two percent asphalt content from the lowest to the the mixing bowl.
highest contents in the samples.The range shall encompass the 8.5.4 Fill the sample pan in three layers.After placing each
asphalt content of the proposed mix design. The mass of the
layer in the sample pan, using a scoop or spatula, distribute the
samples shall be within 10 g [0.02 lb] of each other. layer of material evenly in the pan to reduce voids and
8.3.1 Unless the apparatus makes provision for temperature segregation. Lift the pan approximately 20 to 50 mm [1 to 2
in.] and tap it on the working surface two or three times to
corrections, all calibration samples shall be tested at a uniform
temperature, within 65°C [9°F]. Calibration samples should settle the contents. The last layer should fill the pan to a point
slightly above the top edge.
be prepared and tested as close as possible to the temperature
of test samples of completed mixes. 8.5.5 Determine the mass of the sample and add or subtract
material until the mass is within 10 g [0.02 lb] of the mass of
8.4 Prepare a blank sample (sample of hot, dry aggregate
the blank sample.
without asphalt) to determine the mass to be used for calibra-
tion and plant mix samples. Using this mass will ensure the
NOTE 2—The mass of the blank sample may not be sufficient to
completelyfillthecalibrationandplantmixtestsamplepansforallmixes.
same average density for all test samples.
The asphalt cement may act as a lubricant allowing additional consolida-
8.4.1 Thoroughly mix at least 10 kg [22 lb] of the aggregate
tion of the aggregate particles. An adjusted blank sample mass may be
after heating and drying it to a constant mass and temperature.
determined by preparing a calibration sample using these procedures and
8.4.2 Fill a sample pan with the aggregate in two or three using the mass of this sample as the blank sample mass for this and all
remaining samples.
layers, avoiding segregation. Using a scoop or spatula, distrib-
ute the aggregate to reduce voids and segregation. For each
8.5.6 Using a flat plate of wood or metal as a press,
layer raise the pan approximately 20 to 50 mm [1 to 2 in.] from
compress the sample until it is level with the top edge of the
the working surface and tap the pan against the working
pan. Waxed paper may be used under the press to prevent
surface two or three times to settle the contents. Fill the pan to
asphalt sticking to the press. (Caution—This is the only
a point slightly above the top edge. Slide a straightedge along
compactive effort the sample should receive.)
the top of the pan until the aggregate is absolutely flush with
8.5.7 Place the sample in the apparatus and take a timed
the top edge of the pan. (Caution—Do not compact the
measurement in accordance with the manufacturer’s instruc-
sample.)
tions.
8.4.3 Determine the mass of the blank sample to the nearest
8.5.8 Repeatthisprocessfortheremainderofthecalibration
gram and record data. Use this mass for all calibration and
samples.
plant mix test samples. (See Note 2.)
8.6 For Test Method B calibrate the apparatus using the
8.4.4 Place the pan containing the blank sample in the
following procedures:
apparatus and take a measurement in accordance with the
8.6.1 Sample the aggregates in accordance with 7.1 and
manufacturer’s instructions.
prepare for blending in accordance with the laboratory com-
8.4.5 Record the blank sample count.
pacted method to be used,
8.4.6 To detect changes in aggregate that may affect test
8.6.2 Sample the bituminous materials in accordance with
results, a sample of aggregate may be prepared and tested each
7.3.
day as described herein. If a significant change in the count
8.6.3 At a minimum of four (4) known asphalt contents,
[60.5 %] has occurred, then check the calibration as described
prepare at least three (3) compacted specimens using Test
in 9.3. If necessary, prepare a new calibration curve as outlined
Methods D1559, D1561, D3387, or Practice D4013. Vary the
in 8.5 (see Note 1).
range of asphalt contents by at least 2 % from the lowest to the
highest. The masses of each set of replicate specimens shall be
NOTE 1—Batch plant hot bin samples may be used to obtain the dry
aggregate count. Care must be taken to ensure that the aggregate is within 10 g [0.02 lb] of each other.
completely dried and properly mixed before testing when using hot bin
NOTE 3—Specimens prepared for other purposes such as determining
samples.
the laboratory mix design of bituminous mixtures may be used in this
8.5 Prepare a minimum of three calibration samples using
procedure, however, no other testing of the specimens should be done
the following procedures: prior to performing this procedure.
D4125/D41
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D4125/D4125M − 10 D4125/D4125M − 10 (Reapproved 2016)
Standard Test Methods for
Asphalt Content of Bituminous Mixtures by the Nuclear
Method
This standard is issued under the fixed designation D4125/D4125M; 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
1.1 These test methods cover the procedures for determining the asphalt content of samples of uncompacted bituminous
mixtures (Test Method A), and of laboratory compacted specimens of bituminous mixtures (Test Method B) by examining a test
sample with an apparatus that utilizes neutron thermalization techniques.
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the
two systems may result in non-conformance with the standard.
1.3 A precision and bias statement for Method B in this standard has not been developed at this time. Therefore, Method B
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. See Section 6 and 8.4.2, 8.5.6, and Note 4, for specific hazards.
2. Referenced Documents
2.1 ASTM Standards:
C670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
D75 Practice for Sampling Aggregates
D140 Practice for Sampling Bituminous Materials
D979 Practice for Sampling Bituminous Paving Mixtures
D1461 Test Method for Moisture or Volatile Distillates in Bituminous Paving Mixtures
D1559 Test Method for Resistance to Plastic Flow of Bituminous Mixtures Using Marshall Apparatus (Withdrawn 1998)
D1561 Practice for Preparation of Bituminous Mixture Test Specimens by Means of California Kneading Compactor
D3387 Test Method for Compaction and Shear Properties of Bituminous Mixtures by Means of the U.S. Corps of Engineers
Gyratory Testing Machine (GTM)
D4013 Practice for Preparation of Test Specimens of Bituminous Mixtures by Means of Gyratory Shear Compactor (Withdrawn
2013)
3. Significance and Use
3.1 These test methods are useful as a rapid, nondestructive technique for determination of asphalt content of bituminous
mixtures.
3.2 These test methods are suitable for quality control and acceptance testing for construction and for research and development
applications. The test method is used for determination of asphalt content only as it does not provide extracted aggregate for
gradation analysis.
These test methods are under the jurisdiction of ASTM Committee D04 on Road and Paving Materials and is the direct responsibility of Subcommittee D04.25 on
Analysis of BituminousAsphalt Mixtures.
Current edition approved Dec. 1, 2010Oct. 1, 2016. Published December 2010October 2016. Originally approved in 1983. Last previous edition approved in 20052010
as D4125 – 05.D4125/D4125M – 10. DOI: 10.1520/D4125_D4125M-10.10.1520/D4125_D4125M-10R16.
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 Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4125/D4125M − 10 (2016)
3.3 The non-destructive nature of the test allows repetitive measurements to be made on a single test sample for statistical
analysis of test data.
3.4 These test methods determine the asphalt content of a test sample by comparing the measured asphalt content with
previously established calibration data.
3.4.1 The asphalt content of a material expressed as a percentage, is the ratio of the mass of asphalt in a given mass of material
to the total mass of the sample or to the mass of the solid material particles.
4. Interferences
4.1 The fundamental assumptions inherent in this test method are that the material under test is homogeneous and that hydrogen
present is in the form of asphalt or has been otherwise accounted for in the calibration process.
4.2 Accurate results will be dependent upon proper calibration of the apparatus to the material being tested.
4.3 This apparatus measures the total amount of hydrogen in the sample including hydrogen present in the form of water. Unless
the test sample is free of water, such percentage must be determined in accordance with the provisions of Test Method D1461 and
the percentage determined subtracted from the asphalt percentage as measured by the apparatus.
4.3.1 Alternatively, the sample may be dried to a constant mass in an oven at 110 6 5°C [230 6 9°F], thereby nullifying the
need for the correction.
4.4 This apparatus may be sensitive to outside influences, therefore, any other source of neutron radiation shall be kept at least
10 m [30 ft] from the apparatus during use. The area around the apparatus shall be kept free of large amounts of hydrogenous
material, such as water, plastics, or asphalt during use.
4.5 Moving the apparatus to a different location, even within the same laboratory, can cause a change in background radiation
measurements. Also, if objects containing hydrogenous materials are moved in the area near the apparatus, the measurement counts
may be affected. New background measurements shall be taken prior to use whenever background conditions have changed (see
Section 10).
5. Apparatus
5.1 While exact details of construction for the apparatus may vary, the system shall consist of the following items:
5.1.1 Neutron Source—An encapsulated and sealed radioactive source such as americium/beryllium.
5.1.2 Detectors—Any type of thermal neutron detectors, such as helium-3 or boron trifluoride.
5.1.3 Read-Out Instrument, such as a scaler or a direct reading digital device calibrated in percent asphalt.
5.2 Other Apparatus:
5.2.1 Stainless Steel Sample Pans, of uniform size and mass.
5.2.2 Balance, capable of weighing to 20 kg [44 lb], readable to 1 g [0.0002 lbm].
5.2.3 Oven, capable of heating to 177 6 3°C [350 6 5°F].
5.2.4 Straightedge, steel, approximately 450 mm [18 in.] in length.
5.2.5 Flat Plate, metal or wood, having an area slightly larger than the sample pan. The metal plate shall have a minimum
3 3
thickness of 10 mm [ ⁄8 in.]. The wooden plate shall have a minimum thickness of 20 mm [ ⁄4 in.].
5.2.6 Assorted Spoons and Mixing Bowls.
5.2.7 Thermometer with a temperature range of 10 to 250°C [50 to 482°F].
5.3 Additional Apparatus for Test Method B:
5.3.1 Molded Laboratory Specimen Container, (provided by instrument manufacturer) to allow for proper testing of laboratory
compacted samples (see Fig. 1).
5.3.2 Apparatus, necessary to prepare compacted specimens as specified in Test Methods D1559, D1561, D3387, or Practice
D4013.
6. Hazards
6.1 Warning—This equipment utilizes radioactive materials which may be hazardous to the health of the users unless proper
precautions are taken. Users of this equipment must become completely familiar with possible safety hazards and with all
applicable regulations concerning the handling and use of radioactive materials. Effective user instructions together with routine
safety procedures are a recommended part of the operation of this apparatus.
7. Sampling
7.1 Obtain random samples of aggregates in accordance with Practice D75.
7.2 Obtain random samples of freshly produced bituminous paving mixture in accordance with Practice D979.
7.3 Obtain random samples of bituminous materials in accordance with Practice D140.
D4125/D4125M − 10 (2016)
FIG. 1 Molded Laboratory Specimen-Containers Measurement Values in SI Units (CM)—Other Values for Reference Only
8. Calibration
8.1 The test results obtained using this test method will be influenced by the types of aggregate, source, and grade of asphalt,
and by the mix gradation. Accordingly, a calibration curve must be developed for each mix type and aggregate blend to be tested
under this test method.
8.1.1 A new calibration curve shall be developed whenever there is a change in the source of asphalt or aggregate or a significant
change in aggregate gradation.
8.1.2 A new calibration curve shall be established for new or repaired apparatus.
8.2 For Test Method A, calibrate the apparatus using the following procedures:
8.2.1 Sample the aggregates in accordance with 7.1 and blend the aggregates in the proper proportions. Obtain enough aggregate
for a minimum of three samples. Approximately 30 kg [65 lb] will be required, and
8.2.2 Sample the bituminous materials in accordance with 7.3. Approximately 2.5 kg [5.5 lb] will be required.
8.3 Use a minimum of three prepared samples to establish the calibration curve. The range of asphalt contents shall vary by at
least two percent asphalt content from the lowest to the highest contents in the samples. The range shall encompass the asphalt
content of the proposed mix design. The mass of the samples shall be within 10 g [0.02 lb] of each other.
8.3.1 Unless the apparatus makes provision for temperature corrections, all calibration samples shall be tested at a uniform
temperature, within 65°C [9°F]. Calibration samples should be prepared and tested as close as possible to the temperature of test
samples of completed mixes.
8.4 Prepare a blank sample (sample of hot, dry aggregate without asphalt) to determine the mass to be used for calibration and
plant mix samples. Using this mass will ensure the same average density for all test samples.
8.4.1 Thoroughly mix at least 10 kg [22 lb] of the aggregate after heating and drying it to a constant mass and temperature.
8.4.2 Fill a sample pan with the aggregate in two or three layers, avoiding segregation. Using a scoop or spatula, distribute the
aggregate to reduce voids and segregation. For each layer raise the pan approximately 20 to 50 mm [1 to 2 in.] from the working
surface and tap the pan against the working surface two or three times to settle the contents. Fill the pan to a point slightly above
the top edge. Slide a straightedge along the top of the pan until the aggregate is absolutely flush with the top edge of the pan.
(Caution—Do not compact the sample.)
8.4.3 Determine the mass of the blank sample to the nearest gram and record data. Use this mass for all calibration and plant
mix test samples. (See Note 2.)
8.4.4 Place the pan containing the blank sample in the apparatus and take a measurement in accordance with the manufacturer’s
instructions.
8.4.5 Record the blank sample count.
D4125/D4125M − 10 (2016)
8.4.6 To detect changes in aggregate that may affect test results, a sample of aggregate may be prepared and tested each day
as described herein. If a significant change in the count [60.5 %] has occurred, then check the calibration as described in 9.3. If
necessary, prepare a new calibration curve as outlined in 8.5 (see Note 1).
NOTE 1—Batch plant hot bin samples may be used to obtain the dry aggregate count. Care must be taken to ensure that the aggregate is completely
dried and properly mixed before testing when using hot bin samples.
8.5 Prepare a minimum of three calibration samples using the following procedures:
8.5.1 Heat the aggregates and asphalt cement to approximately 150°C [300°F]. Heat all bowls, sample pans, and tools to
approximately 150°C [300°F].
8.5.2 To prevent samples from being biased by residual asphalt retained in the mixing bowl, do not clean the bowl after each
mixing of the samples. Scrape it clean, leaving a coating of asphalt mix residue. This allows for a more accurate mixing of samples.
Prior to mixing the first sample, a mixture of asphalt and aggregate fines may be used as a light coating on the interior of the mixing
bowl.
8.5.3 Using an aggregate sample of sufficient size to fill the sample pan, add the proper amount of asphalt (within 1 g [0.002
lb] of desired percent by mass) and mix thoroughly in the mixing bowl.
8.5.4 Fill the sample pan in three layers. After placing each layer in the sample pan, using a scoop or spatula, distribute the layer
of material evenly in the pan to reduce voids and segregation. Lift the pan approximately 20 to 50 mm [1 to 2 in.] and tap it on
the working surface two or three times to settle the contents. The last layer should fill the pan to a point slightly above the top edge.
8.5.5 Determine the mass of the sample and add or subtract material until the mass is within 10 g [0.02 lb] of the mass of the
blank sample.
NOTE 2—The mass of the blank sample may not be sufficient to completely fill the calibration and plant mix test sample pans for all mixes. The asphalt
cement may act as a lubricant allowing additional consolidation of the aggregate particles. An adjusted blank sample mass may be determined by
preparing a calibration sample using these procedures and using the mass of this sample as the blank sample mass for this and all remaining samples.
8.5.6 Using a flat plate of wood or metal as a press, compress the sample until it is level with the top edge of the pan. Waxed
paper may be used under the press to prevent asphalt sticking to the press. (Caution—This is the only compactive effort the sample
should receive.)
8.5.7 Place the sample in the apparatus and take a timed measurement in accordance with the manufacturer’s instructions.
8.5.8 Repeat this process for the remainder of the calibration samples.
8.6 For Test Method B calibrate the apparatus using the following procedures:
8.6.1 Sample the aggregates in accordance with 7.1 and prepare for blending in accordance with the laboratory compacted
method to be used,
8.6.2 Sample the bituminous materials in accordance with 7.3.
8.6.3 At a minimum of four (4) known asphalt contents, prepare at least three (3) compacted specimens using Test Methods
D1559, D1561, D3387, or Practice
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Questions, Comments and Discussion
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