ASTM D3461-97(2012)
(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
4.1 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.
4.2 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 180°C by the cup-and-ball apparatus, and gives results comparable to those obtained by Test Method D36. 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 D36 (ring-and-ball) softening point apparatus as a referee method.
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: D3461 − 97(Reapproved 2012)
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 4. Significance and Use
4.1 Asphalt and pitch do not go through a solid-liquid phase
1.1 This test method covers the determination of the soft-
change when heated, and therefore do not have true melting
ening point of asphalt and pitch in the range from 50 to 180°C
points. As the temperature is raised, they gradually soften or
by the cup-and-ball apparatus, and gives results comparable to
D36. become less viscous. For this reason, the determination of the
those obtained by Test Method
softening point must be made by an arbitrary, but closely
NOTE 1—If the softening point of asphalt by this Mettler cup-and-ball
defined, method if the test values are to be reproducible.
method fails to meet specified requirements, tests may be rerun using the
Test Method D36 (ring-and-ball) softening point apparatus as a referee
4.2 This test method is useful in determining the consis-
method.
tency as one element in establishing the uniformity of ship-
1.2 This standard does not purport to address all of the
ments or sources of supply.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
5. Apparatus
priate safety and health practices and determine the applica- 3
5.1 AMettler dropping point cell can be used to determine
bility of regulatory limitations prior to use.
softening points by this test method. These commercially
available instruments consist of a control unit with a digital
2. Referenced Documents
temperature indicator, matched furnace, sample cartridges, and
accessories. The control unit automatically regulates the heat-
2.1 ASTM Standards:
A314 Specification for Stainless Steel Billets and Bars for ing rate of the furnace. The softening point is indicated on the
readout, and the heating program stopped, when the sample
Forging
flow triggers a photocell detector. A general view of the
D36 Test Method for Softening Point of Bitumen (Ring-and-
components of the Mettler apparatus is shown in Fig. 1.
Ball Apparatus)
5.1.1 Control Unit—This unit shall provide a continuous,
D140 Practice for Sampling Bituminous Materials
D4296 Practice for Sampling Pitch linear temperature increase from 25 to 250°C at a rate of
2°C/min. A digital readout shall indicate the temperature to
0.1°C throughout.
3. Summary of Test Method
5.1.2 Furnace Unit—This unit shall be capable of heating a
3.1 In this test method the softening point is defined as the
specimen cup assembly, as described in 5.1.3, at a linear rate of
temperature at which the specimen, suspended in a cylindrical
2 6 0.3°C/min. It shall include a sensing system capable of
cup with a 6.5-mm hole in the bottom and with a lead ball,
detecting the softening point with a precision of 0.1°C.
8 mm in diameter, centered on top of the sample in the cup,
5.1.3 Specimen Cup Assembly—A cup of chromium-plated
flows downward a distance of 19 mm to interrupt a light beam,
brass, or stainless steel conforming to the requirements for
as the sample is heated at a linear rate in air.
Type 303 (UNS 530300) as prescribed in Specification A314,
with dimensions shown in Fig. 2. It shall be placed in the
assembly so that the test specimen will flow down a distance of
This test method is under the jurisdiction of ASTM Committee D02 on
19 mm before interrupting a light beam and stopping the
Petroleum Products and Lubricantsand is the direct responsibility of Subcommittee
heating program as the softening point is reached.
D02.05 on Properties of Fuels, Petroleum Coke and Carbon Material.
5.1.4 Lead Ball—A lead ball weighing 3.20 6 0.10 g.
Current edition approved Nov. 1, 2012. Published November 2012. Originally
approved in 1976. Last previous edition approved in 2007 as D3461 – 97 (2007). A32-caliber lead shot is suitable for this purpose.
DOI: 10.1520/D3461-97R12.
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 Available from the Mettler Toledo, Inc., Balances and Instruments, 69
the ASTM website. 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 (2012)
FIG. 1 General View of the Mettler FP-5/53
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.
7.2 Reagent—Use either analytical reagent or primary stan- 7.3.2 Heating—Preheat the Mettler furnace to 121°C, and
maintain it at that temperature. Place the cartridge assembly
dard grade benzoic acid for this calibration.As this material is
hygroscopic, it must be stored in a tightly sealed container, and containing the benzoic acid in position in the furnace, taking
D3461 − 97 (2012)
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
overheating, constantly stirring until it has become sufficiently
fluid to pour. In no case, however, shall the temperature be
raised more than 110°C (200°F) above the expected softening
point for asphalt. Avoid incorporating air bubbles in the
sample.
FIG. 2 Specimen Cup
8.3.2 Bring the asphalt sample to the pouring temperature in
not more than 2 h.
care that the slits for the light beam are properly positioned.
9. Test Specimen
Wait for temperature equilibration, that is, the furnace and the
sampleareinequilibriumatthepresettemperature,butnotless
9.1 Prepare the test specimen by slightly overfilling the
than 30 s after inserting the cartridge, start the automatic
specimen cup, which rests on a brass plate. Keep the lip of the
heating cycle at 0.2°C/min. The temperature will rise steadily
container close to the top of the cup to minimize entrainment
at the correct rate until the drop point is reached, and then
of air bubbles. Underpouring past the blade of a spatula is
remain steady on the readout.
helpful in this respect. Cool the specimen in the cup until firm,
7.3.3 Cleaning—Immediately remove the cartridge assem-
under cold water if necessary.Trim the specimen flush with the
bly. Check to determine that the specimen has passed t
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