ASTM D3461-18

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of the standard as published by ASTM is to be considered the official document.
Designation: D3461 − 14 D3461 − 18
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*
1.1 This test method covers the determination of the softening point of asphalt and pitch in the range from 50 °C 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.3 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
A314 Specification for Stainless Steel Billets and Bars for Forging
D36 Test Method for Softening Point of Bitumen (Ring-and-Ball Apparatus)
D140 Practice for Sampling Asphalt Materials
D4296 Practice for Sampling Pitch
3. Summary of Test Method
3.1 In this test method the softening point is defined as the temperature at which the specimen, suspended in a cylindrical cup
with a 6.5 mm hole in the bottom and with a lead ball, 8 mm in diameter, centered on top of the sample in the cup, flows downward
a distance of 19 mm to interrupt a light beam, as the sample is heated at a linear rate in air.
4. 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.
5. Apparatus
5.1 A METTLER TOLEDO dropping point cell can be used to determine softening points by this test method. These
commercially available instruments consist of a control unit with a digital temperature indicator with furnace built in or attached,
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.05 on Properties of Fuels, Petroleum Coke and Carbon Material.
Current edition approved Oct. 1, 2014Dec. 1, 2018. Published November 2014January 2019. Originally approved in 1976. Last previous edition approved in 20122014
as D3461 – 97D3461 – 14. (2012). DOI: 10.1520/D3461-14.10.1520/D3461-18.
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 sole source of supply of the apparatus known to the committee at this time is available from Mettler-Toledo, LLC., 1900 Polaris Pkwy, Columbus, OH 43240,
www.mt.com. If you are aware of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive careful consideration
at a meeting of the responsible technical committee, which you may attend.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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sample cartridges, and accessories. The control unit automatically regulates the heating rate of the furnace. The softening point is
indicated on the readout, and the heating program stopped, when the sample flow triggers the softening point detection. A general
view of the components of the METTLER TOLEDO softening point instrument is shown in Fig. 1 (old instrument) and Fig. 2 (new
instrument).
5.1.1 Integrated or Separate Control Unit—The control unit shall provide a continuous, linear temperature increase from 25 °C
to 250 °C at a rate of 2 °C/min. A digital readout shall indicate the temperature to 0.1 °C throughout.
5.1.2 Integrated or Separate Furnace Unit—The furnace unit shall be capable of heating one or two sample cup assemblies, as
described in 5.1.3, at a linear rate of 2 °C 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 Sample Cup Assembly—A cup of chromium-plated brass, or of aluminum, or of stainless steel conforming to the
requirements for Type 303 (UNS S30300) stainless steel as prescribed in Specification A314, with the dimensions shown in Fig.
3. It shall be placed in the assembly so that the pitch sample softening point will be detected when it has flowed down a distance
of 19 mm.
FIG. 1 General View of the METTLER TOLEDO FP90 Control Unit with Heater FP83HT
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FIG. 2 General View of the METTLER TOLEDO DP70
FIG. 3 Specimen Cup
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5.1.4 Lead Ball—A lead ball weighing 3.20 g 6 0.10 g. between 3.00 g and 3.30 g. A 32-caliber lead shot is suitable for this
purpose.
6. Reagents
6.1 Xylene, industrial grade.
7. Calibration of METTLER TOLEDO Apparatus
7.1 This step, required only occasionally, is designed to establish that the temperature indicated by the instrument is in
agreement with a known standard. A special cup with a bottom orifice of 2.8 mm is used instead of the one prescribed for the testing
of pitch.
7.2 Reagent—Use either analytical reagent or primary standard grade benzoic acid for the calibration. As this material is
hygroscopic it must be stored in a tightly sealed container, and replaced with fresh material from a newly opened supply if
hydration or other contamination is suspected.
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7.3 Procedure—Old Instruments:
7.3.1 Filling the Sample Cup—Place the cup on a clean, flat surface. Add a small amount of benzoic acid crystals and press
down with a rod (approximately 4.5 mm in diameter). Check that the bottom orifice is completely filled. Refill and repeat the
pressing step until the cup is filled with benzoic acid. Remove any crystals from the exterior of the cup.
7.3.2 Heating—Preheat the Mettler furnace to 121 °C, and maintain it at that temperature. Place the cartridge assembly
containing the benzoic acid in position in the furnace, taking care that the slits for the light beam are properly positioned. Wait
for temperature equilibration, that is, the furnace and the sample are in equilibrium at the preset temperature, but not less than the
30 s after inserting the cartridge, start the automatic heating cycle at 0.2 °C/min. The temperature will rise steadily at the correct
rate until the drop point is reached, and then remain steady on the readout.
7.3.3 Cleaning—Immediately remove the cartridge assembly. Check to determine that the sample has passed through the light
beam and no pre-triggering has occurred. If a malfunction is suspected, the entire procedure must be repeated. Inspect the apparatus
carefully to ensure that no residue remains. Use a spatula shaped to the contour of the cup to remove most of the remaining acid
from the cup and from the bottom of the cartridge. Wash the cup and cartridge in xylene, or other suitable solvent, to remove the
last traces of the residue.
7.4 Interpretation—See 7.6.
7.5 Procedure—New Instruments:
7.5.1 Filling the Sample Cup—Place the cup on a clean, flat surface. Optionally, the sample preparation tool may be used. See
Fig. 2. Add a small amount of benzoic acid crystals and press down with a rod (approximately 4.5 mm in diameter). Check that
the bottom orifice is completely filled. Refill and repeat the pressing step until the cup is filled with benzoic acid. Remove any
crystals from the exterior of the cup. Place a glass collector below the cup and a cup cap on top, and place in the sample carrier.
Two cup assemblies may be placed in the sample carrier.
7.5.2 Heating—Preheat the furnace to 121 °C and maintain it at that temperature. Place the sample carrier containing the
benzoic acid in position in the furnace. Wait for temperature equilibration, that is, the furnace and the sample are in equilibrium
at the preset temperature, but not less than 30 s after inserting the cartridge, start the automatic heating cycle at 0.2 °C/min. The
temperature will rise steadily at the correct rate until the drop point is reached, and then remain steady on the readout. If there are
two samples, heating will continue until both have dropped.
7.5.3 Cleaning—Immediately remove the cartridge assembly. Check to determine that the sample has dropped and no
pre-triggering has occurred. The video may be viewed to make sure the drop was detected correctly. If a malfunction is suspected,
the entire procedure must be repeated. Inspect the apparatus carefully to ensure that no residue remains. Use a spatula shaped to
the contour of the cup to remove most of the remaining acid from the cup. Wash the cup and glass collector in xylene, or other
suitable solvent, to remove the last traces of the residue. Glass collectors may be treated as disposable items. Aluminum cups may
be used which may also be considered to be disposable.
7.6 Interpretation—If the result is not 123.5 °C 6 0.5 °C, repeat the test. If the second value is 0.6 °C above or below 123.5
°C, measure the dropping point of a fresh sample of benzoic acid. If the deviation exceeds 0.6 °C, the instrument requires
recalibration or repair. Consult the manufacturer’s instruction manual.
8. Sampling
8.1 Samples from shipments shall be taken in accordance with Practice D140 for asphalt and Practice D4296 for pitch and sha
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