ASTM D3461-97(2007)
(Test Method)Standard Test Method for Softening Point of Asphalt and Pitch (Mettler Cup-and-Ball Method)
Standard Test Method for Softening Point of Asphalt and Pitch (Mettler Cup-and-Ball Method)
SIGNIFICANCE AND USE
Asphalt and pitch do not go through a solid-liquid phase change when heated, and therefore do not have true melting points. As the temperature is raised, they gradually soften or become less viscous. For this reason, the determination of the softening point must be made by an arbitrary, but closely defined, method if the test values are to be reproducible.
This test method is useful in determining the consistency as one element in establishing the uniformity of shipments or sources of supply.
SCOPE
1.1 This test method covers the determination of the softening point of asphalt and pitch in the range from 50 to 180C by the cup-and-ball apparatus, and gives results comparable to those obtained by Test Method D 36. Note 1 - If the softening point of asphalt by this Mettler cup-and-ball method fails to meet specified requirements, tests may be rerun using the Test Method D 36 (ring-and-ball) softening point apparatus as a referee method.
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
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D3461 − 97(Reapproved 2007)
Standard Test Method for
Softening Point of Asphalt and Pitch (Mettler Cup-and-Ball
Method)
This standard is issued under the fixed designation D3461; 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 flows downward a distance of 19 mm to interrupt a light beam,
as the sample is heated at a linear rate in air.
1.1 This test method covers the determination of the soft-
ening point of asphalt and pitch in the range from 50 to 180°C
4. Significance and Use
by the cup-and-ball apparatus, and gives results comparable to
4.1 Asphalt and pitch do not go through a solid-liquid phase
those obtained by Test Method D36.
change when heated, and therefore do not have true melting
NOTE 1—If the softening point of asphalt by this Mettler cup-and-ball
points. As the temperature is raised, they gradually soften or
method fails to meet specified requirements, tests may be rerun using the
become less viscous. For this reason, the determination of the
Test Method D36 (ring-and-ball) softening point apparatus as a referee
softening point must be made by an arbitrary, but closely
method.
defined, method if the test values are to be reproducible.
1.2 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the 4.2 This test method is useful in determining the consis-
responsibility of the user of this standard to establish appro-
tency as one element in establishing the uniformity of ship-
priate safety and health practices and determine the applica- ments or sources of supply.
bility of regulatory limitations prior to use.
5. Apparatus
2. Referenced Documents
5.1 AMettler dropping point cell can be used to determine
softening points by this test method. These commercially
2.1 ASTM Standards:
available instruments consist of a control unit with a digital
A314 Specification for Stainless Steel Billets and Bars for
temperature indicator, matched furnace, sample cartridges, and
Forging (Withdrawn 2009)
accessories. The control unit automatically regulates the heat-
D36 Test Method for Softening Point of Bitumen (Ring-and-
ing rate of the furnace. The softening point is indicated on the
Ball Apparatus) (Withdrawn 2009)
readout, and the heating program stopped, when the sample
D140 Practice for Sampling Bituminous Materials (With-
flow triggers a photocell detector. A general view of the
drawn 2009)
components of the Mettler apparatus is shown in Fig. 1.
D4296 Practice for Sampling Pitch (Withdrawn 2009)
5.1.1 Control Unit—This unit shall provide a continuous,
linear temperature increase from 25 to 250°C at a rate of
3. Summary of Test Method
2°C/min. A digital readout shall indicate the temperature to
3.1 In this test method the softening point is defined as the
0.1°C throughout.
temperature at which the specimen, suspended in a cylindrical
5.1.2 Furnace Unit—This unit shall be capable of heating a
cup with a 6.5-mm hole in the bottom and with a lead ball,
specimen cup assembly, as described in 5.1.3, at a linear rate of
8 mm in diameter, centered on top of the sample in the cup,
2 6 0.3°C/min. It shall include a sensing system capable of
detecting the softening point with a precision of 0.1°C.
5.1.3 Specimen Cup Assembly—A cup of chromium-plated
This test method is under the jurisdiction of ASTM Committee D02 on
brass, or stainless steel conforming to the requirements for
Petroleum Products and Lubricantsand is the direct responsibility of Subcommittee
Type 303 (UNS 530300) as prescribed in Specification A314,
D02.05 on Properties of Fuels, Petroleum Coke and Carbon Material.
with dimensions shown in Fig. 2. It shall be placed in the
Current edition approved May 1, 2007. Published June 2007. Originally
approved in 1976. Last previous edition approved in 2002 as D3461 – 97 (2002).
assembly so that the test specimen will flow down a distance of
DOI: 10.1520/D3461-97R07.
19 mm before interrupting a light beam and stopping the
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
heating program as the softening point is reached.
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.
3 4
The last approved version of this historical standard is referenced on Available from the Mettler Toledo, Inc., Balances and Instruments, 69
www.astm.org. Princeton-Hightstown Rd., Hightstown, NJ 08520-0071.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3461 − 97 (2007)
FIG. 1 General View of the Mettler FP-5/53
5.1.4 Lead Ball—A lead ball weighing 3.20 6 0.10 g. 7.2 Reagent—Use either analytical reagent or primary stan-
A32-caliber lead shot is suitable for this purpose. dard grade benzoic acid for this calibration.As this material is
hygroscopic, it must be stored in a tightly sealed container, and
6. Reagents replaced with fresh material from a newly opened supply if
hydration or other contamination is suspected.
6.1 Xylene, industrial grade.
7.3 Procedure:
7. Calibration of Mettler Apparatus
7.3.1 Filling the Specimen Cup—Place the cup on a clean,
7.1 This step, required only occasionally, is designed to flat surface. Add a small amount of benzoic acid crystals and
establish that the temperature indicated by the instrument is in press down with a rod (4.5 mm in diameter). Check that the
agreement with a known standard.Aspecial cup with a bottom bottom orifice is completely filled. Refill and repeat the
orifice of 2.8 mm is used instead of the one prescribed for the pressing step until the cup is filled with benzoic acid. Remove
specimen testing. any crystals from the exterior of the cup.
D3461 − 97 (2007)
8.2.2 If the sample is liquid, check for any surface foam
which may indicate the presence of water. If foam is found,
maintainthesampleatatemperatureofabout125°Cinanopen
container until the surface is free of foam. Take care not to
overheat.Removefromtheheatsourceassoonasthefoamhas
subsided. Proceed as directed in 9.1.
8.2.3 Crush air-dry lumps of pitch to a size of 6 to 12 mm.
Add the material to a container, having a height equal to or
exceeding its width, and having a volume of not less than
50 mL, until it is about half full. Place the container on a hot
plate, or in an oven or a bath. Do not use an open flame for
melting pitch. After melting is complete, stir gently but
thoroughly, avoiding incorporation of air bubbles. The maxi-
mum temperature of the molten pitch should not exceed the
expected softening point by more than 50°C. Any foam that
forms must be skimmed off.
8.3 Asphalt Sample Preparation:
8.3.1 Heat the sample, with care to prevent local overheat-
ing, constantly stirring until it has become sufficiently fluid to
pour. In no case, however, shall the temperature be raised more
FIG. 2 Specimen Cup
than 110°C (200°F) above the expected softening point for
asphalt. Avoid incorporating air bubbles in the sample.
7.3.2 Heating—Preheat the Mettler furnace to 121°C, and 8.3.2 Bring the asphalt sample to the pouring temperature in
maintain it at that temperature. Place the cartridge assembly not more than 2 h.
containing the benzoic acid in position in the furnace, taking
9. Test Specimen
care that the slits for the light beam are properly positioned.
Wait for temperature equilibration, that is, the furnace and the
9.1 Prepare the test specimen by slightly overfilling the
sampleareinequilibriumatthepresettemperature,butnotless
specimen cup, which rests on a brass plate. Keep the lip of the
than 30 s after inserting the cartridge, start the automatic
container close to the top of the cup to minimize entrainment
heating cycle at 0.2°C/min. The temperature will rise steadily
of air bubbles. Underpouring past the blade of a spatula is
at the correct rate until the drop point is reached, and then
helpful in this
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