NB/SH/T 0740-2025 Polymer Modified Asphalt Separation Test Method

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Card type: Test method

1. Method number / full title / English name / replacement relationship

• Standard number: NB/SH/T 0740—2025
• Chinese title: Polymer Modified Asphalt Separation Test Method
• English title: Standard test method for separation of polymer modified asphalt
• Replacement relationship: replaces SH/T 0740—2003 "Polymer Modified Asphalt Separation Test Method" (first issued in 2003, this is the first revision)
• Publication/implementation: published on 2025-12-18, implemented on 2026-06-18
• Issuing body: National Energy Administration
• Custodian: Petroleum Asphalt Subcommittee of the National Technical Committee for Standardization of Petroleum Products and Lubricants (SAC/TC280/SC4)
• Drafting organizations: China University of Petroleum (East China), Sinopec Qilu Branch, Taizhou Customs of the People's Republic of China, Beijing Municipal Road and Bridge Building Materials Group Co., Ltd., CNOOC Chemical and New Materials Research Institute (Beijing) Co., Ltd., PetroChina Liaohe Petrochemical Branch, PetroChina Karamay Petrochemical Co., Ltd.
• Main drafters: Zhang Xiaoying, Chang Yuyan, Cai Hongmei, Xu Junqiang, Wang Zhichao, Cao Pengyun, Guo Ning, Lin Xixiong, Zhou Xiaoguang, Li Jun, Jiang Chenzhe, Lü Yuchao

2. Scope of application and non-applicability

• Applicable: specifies a test method for the stability of modified asphalt under hot storage conditions; the stability index is expressed as the difference in softening point between the upper and lower sections of modified asphalt in the storage aluminum tube. Applicable to polymer, waste rubber powder, and modified asphalt prepared with the above two types of modifiers as the main modifiers.
• Not applicable: not applicable to modified asphalt blended by the solvent method and emulsion method.
• Reference use: other modified asphalts that have a tendency to phase separate under the test conditions specified in this document may also be used with reference to this document.
• Default conditions (unless otherwise specified): storage temperature 163 °C±5 °C, storage time 48 h±1 h.

3. Method principle

Inject a certain amount of modified asphalt sample into an aluminum tube of specified capacity and dimensions, place the aluminum tube containing the sample vertically at the specified temperature for a period of time, take out the aluminum tube and place it vertically in a freezer for a period of time, then simultaneously determine the softening points of the specimens in the upper and lower sections of the aluminum tube in the same softening point apparatus, and calculate and report the separation softening point difference.

4. Reagents and materials (purity / preparation)

• Aluminum foil or cork wrapped in aluminum foil: used to seal the opening of the aluminum tube; the diameter of the cork matches the opening of the aluminum tube (5.9).
• Heating medium: water (when the softening point of the specimen with the higher softening point among the upper and lower softening points is not higher than 84.5 °C); glycerol (when one of the highest softening points exceeds 84.5 °C) (7.7).
• Other reagent purity and preparation: not provided in the available source.

5. Apparatus and equipment

• 5.1 Softening point apparatus: ring-and-ball softening point apparatus and its accessories, supplies, etc. meeting the requirements of GB/T 4507.
• 5.2 Aluminum tube: an aluminum tube made of thin aluminum sheet or aluminum foil with a closed lower end, diameter 25.0 mm±0.5 mm, height 140 mm±0.5 mm.
• 5.3 Oven: used for melting and/or storing samples, temperature control range not less than 250 °C, temperature control accuracy within ±5.0 °C of the set temperature. The oven continuously maintains the test temperature for at least 3 days. If used for melting samples, any heating equipment meeting the above temperature control accuracy requirements may be used.
• 5.4 Refrigerator: used for freezing the stored specimens, temperature control capability -10 °C±10 °C; equipment meeting this freezing requirement, such as a freezer, may be used.
• 5.5 Support: a metal support that can keep the aluminum tube vertical in the oven and refrigerator.
• 5.6 Knife: a small knife with a single-sided opening, sharp and hard, which can be heated for cutting low-temperature samples.
• 5.7 Electronic balance: accurate to 0.1 g, range between 100 g~1000 g.
• 5.8 Tweezers: used to determine the position of the highest liquid level and the meniscus in the aluminum tube.
• 5.9 Aluminum foil or cork wrapped in aluminum foil: used to seal the opening of the aluminum tube; the diameter of the cork matches the opening of the aluminum tube.
• 5.10 Container: 100 mL±20 mL, used for melting the frozen specimen.
• 5.11 Stripping pliers or scissors: used to cut open the aluminum tube and strip off the aluminum tube skin.

6. Recommended operating conditions

• Storage temperature: 163 °C±5 °C (unless otherwise specified).
• Storage time: 48 h±1 h (unless otherwise specified).
• Freezing conditions: -10 °C±10 °C, standing vertically for 4 h±0.5 h until the sample is completely solidified.
• Melting (sample conditioning) conditions: melt in an oven at 163 °C±5 °C until sufficiently fluid; heating time should not exceed 30 min.
• Heating medium for softening point determination: use water when the softening point of the specimen with the higher softening point among the upper and lower softening points is not higher than 84.5 °C; use glycerol when one of the highest softening points exceeds 84.5 °C.
• Other operating conditions: not provided in the available source.

7. Sampling and specimen preparation

• 6.1 Obtain a representative modified asphalt sample in accordance with the requirements of GB/T 11147.
• 6.2 Carefully heat the sample until it is sufficiently fluid and easy to pour. The heating temperature should not exceed the softening point by 90 °C; during heating, appropriate stirring is advisable to avoid local overheating, and the heating time should be as short as possible to avoid affecting the sample properties. Stir the sample uniformly to obtain a representative sample.
• 7.1 Place 2 empty aluminum tubes with closed lower ends meeting the requirements of 5.2 vertically on the support.
• 7.2 Inject 50 g±0.5 g of the sample prepared according to 6.2 into each aluminum tube, and immediately while hot seal the opening of the aluminum tube with aluminum foil or a cork wrapped in aluminum foil. When pouring, the sample should avoid being poured along the tube wall, to prevent air from being trapped in the sample in the aluminum tube and causing deep depression of the sample after freezing.

8. Analytical procedure

• 7.3 Place the just-poured aluminum tube containing the sample together with the support into an oven already stabilized at the storage temperature.
• 7.4 After removing the support and aluminum tube from the oven, immediately place them in a refrigerator at -10 °C±10 °C and let stand vertically for 4 h±0.5 h until the sample is completely solidified.
• 7.5 Take out the support and aluminum tube from the refrigerator, open the aluminum foil or remove the aluminum foil cork, and quickly strip off the surrounding aluminum tube skin with stripping pliers or scissors. Use tweezers to determine the positions of the highest liquid level and the lowest point of the meniscus of the sample in the aluminum tube. Place the aluminum tube on a sturdy flat plate, quickly use a hot knife to evenly divide the specimen into three sections from below the midpoint between the highest liquid level and the lowest point of the meniscus, and include the sample above the midpoint in the upper section. Discard the middle section and retain the upper and lower sections for subsequent testing.
• 7.6 Combine the upper sections and lower sections of the two aluminum tubes respectively and place them into two containers of 100 mL±20 mL. Let stand in an oven at 163 °C±5 °C and melt until sufficiently fluid; heating time should not exceed 30 min.
• 7.7 Stir the upper and lower section specimens uniformly. According to the method of GB/T 4507, prepare upper and lower section softening point specimens, and place the upper and lower section softening point specimens together in the same softening point apparatus for simultaneous softening point determination. When the softening point of the specimen with the higher softening point among the upper and lower softening points is not higher than 84.5 °C, use water as the heating medium; when one of the highest softening points exceeds 84.5 °C, use glycerol as the heating medium. Record the softening point values of the upper and lower section specimens, and calculate the specimen softening point difference.

9. Qualitative and quantitative determination and calculation formula

The softening point difference of the specimen is calculated according to formula (1):

ΔSP = SPupper − SPlower　(1)

Where:

• SPupper——the softening point of the upper section specimen, accurate to 0.1 °C;
• SPlower——the softening point of the lower section specimen, accurate to 0.1 °C;
• ΔSP—— the softening point difference value, accurate to 0.1 °C.

The calculated difference between the upper and lower softening points is taken as the separation test result of the sample, recorded as the separation softening point difference.

10. Precision

9.1 Repeatability precision: in the same laboratory, by the same operator using the same equipment, according to the same test method, and within a short time interval, independent tests on the same test material are carried out; the absolute value of the difference between two test results shall not exceed the repeatability precision requirement in Table 1. 9.2 Reproducibility precision: in different laboratories, by different operators using different equipment, according to the same test method, independent tests on the same test material are carried out; the absolute value of the difference between two test results shall not exceed the reproducibility precision requirement in Table 1.

Table 1 Precision requirements

Note: The precision of this document was determined by testing elastomer polymer, waste rubber powder, and modified asphalt prepared with the above two modifiers as the main modifiers.

9.3 Bias: In this test method there is no standard material used to determine standard deviation, so this document does not state a standard deviation.

11. Report

Report the softening points of the original sample and the upper and lower section specimens after the separation test, and the separation softening point difference of the sample.

12. Referenced documents

• GB/T 4507 Test method for softening point of asphalt Ring-and-ball method
• GB/T 11147 Method for sampling asphalt
• GB/T 1.1—2020 Guidelines for standardization work Part 1: Structure and drafting rules for standardization documents (drafting basis)

13. Source and verification

This page is an AI translation of the available Chinese method card. Human verification is pending. It is not an official translation of the standard. Check the source standard and product certificate before use.

14. Quick reference Q&A