GB/T 4508-1999 Asphalt ductility determination method

This standard specifies the method for determining the ductility of asphalt. The asphalt specimen is stretched to the length at the time of fracture at a certain temperature and a certain speed. The specimen should be of the dimensions specified in Section 5. GB/T 4508-1999 Method for determining the ductility of asphalt GB/T4508-1999 Standard download decompression password: www.bzxz.net

GB/T4508—1999
This standard is equivalent to the American Society for Testing and Materials standard ASTMD113—1986 (1992) "Asphalt Ductility Determination Method". The main differences between this standard and GB/T4508—1984 are as follows: Scope of application: GB/T4508—1984 is applicable to the determination of the ductility of petroleum asphalt, while this standard is applicable not only to the ductility of petroleum asphalt, but also to the ductility of coal tar asphalt. The name of the method is also changed from "Petroleum Asphalt Ductility Determination Method" to "Asphalt Ductility Determination Method". The difference between this standard and ASTMD113 is the error requirements, namely: 1. This standard adds restrictions on the three measured values. If the three measured values ​​are within 5% of their average value, the average value of the three parallel measured results is taken as the measurement result. If the three measured values ​​are not within 5% of their average value, but the two higher values ​​are within 5% of the average value, the lowest measured value is discarded and the average value of the two higher values ​​is taken as the measurement result, otherwise the measurement is repeated. 2. The repeatability and reproducibility in ASTM D113-1986 (1992) are presented in the form of graphs, which is inconvenient for actual operators to use; this standard converts the graphs into specific numbers, which are clear to users at a glance. This standard replaces GB/T4508-1984 from the date of implementation. This standard is proposed by China Petrochemical Corporation. This standard is technically managed by the Heavy Oil Research Institute of Petroleum University (East China). The drafting unit of this standard: Heavy Oil Research Institute of Petroleum University (East China). The main drafters of this standard: Wang Cuihong and Zhang Yuzhen. 1 Scope
National Standard of the People's Republic of China
Standard test method for ductility of bitumenHYTKA AONTKAca-
GB/T4508-1999
Replaces GB/T4508-1984wwW.bzxz.Net
1.1 This standard specifies the test method for ductility of bitumenHYTKA AONTKAca-
GB/T4508-1999
Replaces GB/T4508-1984
1.1 This standard specifies the test method for ductility of bitumen The asphalt specimen is stretched to the length at the time of fracture at a certain temperature and a certain speed. The specimen shall be of the size specified in Section 5. Unless otherwise specified, the test temperature is 25°C ± 0.5°C and the stretching speed is 5cm/min ± 0.25cm/min.
1.2 This standard is applicable to the determination of the ductility of petroleum asphalt and also to the determination of the ductility of coal tar asphalt. 1.3 This standard does not specify any safety issues. If necessary, the user is responsible for formulating appropriate personal safety protection measures before use.
2 Referenced Standards
The provisions included in the following standards constitute a part of this standard by reference. Unless otherwise specified in the standard, the following referenced standards shall be the current valid standards.
GB/T4509 Asphalt needle penetration test method
GB/T5304 Petroleum asphalt thin film oven test method 3 Method overview
Pour the molten sample into a special mold, cool it at room temperature first, and then cool it in a water bath maintained at the test temperature. Use a hot knife to cut off the sample that protrudes above the mold, put the mold back into the water bath, and after a certain period of time, move it to the ductility meter. 4 Significance and use
4.1 This test method is suitable for determining the ductility required by the technical specifications of asphalt products, and can determine the tensile properties of asphalt materials. 5 Instruments and materials
5.1 Mold: The mold should be designed according to the style given in Figure 1. The specimen mold is made of brass and consists of two arc-shaped end molds and two side molds. The size variation range of the assembled mold is shown in Figure 1. 5.2 Water bath: The water bath can keep the test temperature change no more than 0.1℃, the capacity is at least 10L, the depth of the test piece immersed in water shall not be less than 10cm, a shelf with holes is set in the water bath to support the test piece, and the shelf shall not be less than 5cm from the bottom of the bath. Approved by the State Administration of Quality and Technical Supervision on August 10, 1999, implemented on June 1, 2000
GB/T4508—1999
A—Distance between the center points of the two end die rings 111.5~113.5mm; B—Total length of the test piece 74.575.5mm; C—Distance between the end dies 29.7~30.3; D—Shoulder length 6.8~7.2mmE—Radius 15.7516.25mm; F—Minimum cross-sectional width 9.9~10.1mmG—end die width 19.8~20.2mm;H—distance between two semicircle centers 42.943.1mm;I-end die hole diameter 6.5~6.7mmJ thickness 9.9~10.1mmFigure 1 Ductility tester mold
5.3 Ductility tester: For measuring the ductility of asphalt, any instrument that can meet the requirements of 7.1 to continuously immerse the specimen in water and stretch the specimen at a certain speed can be used. The instrument should have no obvious vibration when starting. 5.4 Thermometer: 0~50℃, with a graduation of 0.1℃ and 0.5℃. Note: If the ductility specimen is placed in a standard penetration bath at 25℃, the above thermometer can be used instead of the thermometer specified in GB/T4509. 5.5 Metal mesh with a mesh size of 0.3~0.5mm. 5.6 Isolation agent: It is prepared by weight from two parts of glycerin and one part of talcum powder. 5.7 Support plate: Metal plate or glass plate, one side must be polished to a surface roughness of R0.63. 6 Preparation
6.1 Assemble the mold on the support plate, and apply the release agent to the surface of the support plate and the inner surface of the side mold in Figure 1 to prevent asphalt from sticking to the mold. The mold on the plate should be placed horizontally so that the bottom of the mold can fully contact the plate. 6.2 Heat the sample carefully to prevent local overheating until it becomes completely liquid and can be poured. The time for heating the petroleum asphalt sample to the pouring temperature shall not exceed 2h, and the heating temperature shall not exceed 110℃, the expected softening point of the asphalt; the time for heating the coal tar asphalt sample to the pouring temperature shall not exceed 30min, and the heating temperature shall not exceed 55C, the expected softening point of the coal tar asphalt. Sieve the melted sample, and after sufficient stirring, pour the sample into the mold. Be careful not to mess up the accessories when assembling the mold. When pouring, make the sample dry and thin, pour from one end of the mold to the other end, make the sample slightly higher than the mold, cool the sample in the air for 30 to 40 minutes, then put it in a water bath at a specified temperature for 30 minutes, take it out, and use a hot straight knife or shovel to scrape out the asphalt that is higher than the mold, so that the sample is flush with the mold. 6.3 Constant temperature: Put the support plate, mold and specimen into the water bath together, and keep them at the test temperature for 85 to 95 minutes, then remove the specimen from the plate, remove the side mold, and immediately conduct a tensile test. 7 Test steps
7.1 Put the holes at both ends of the mold on the columns of the experimental instrument respectively, and then stretch at a certain speed until the specimen is stretched and broken. Stretching speed 2
GB/T4508—1999
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The allowable error is ±5%. Measure the distance the specimen travels from stretching to breaking, expressed in centimeters. During the test, the distance between the test piece and the water surface and the bottom of the water shall not be less than 2.5 cm, and the temperature shall be kept within the range of ±0.5°C of the specified temperature. 7.2 If the asphalt floats on the water surface or sinks to the bottom of the tank, the test is abnormal. Ethanol or sodium chloride should be used to adjust the density of water so that the asphalt material neither floats on the water surface nor sinks to the bottom of the tank. 7.3 In a normal test, the specimen should be pulled into a cone until the actual cross-sectional area is close to zero at the time of fracture. If normal results are not obtained in three tests, it is reported that the ductility cannot be measured under this condition. 8 Precision
The reliability of the test results shall be judged according to the following provisions (confidence level 95%). 8.1 Repeatability
The results of repeated measurements of the same sample by the same operator shall not exceed 10% of the average value. 8.2 Reproducibility
The results of the same sample measured in different laboratories shall not exceed 20% of the average value. 9 Report
9.1 If the measured values ​​of the three specimens are within 5% of their average value, the average value of the three parallel measured results shall be taken as the measurement result. If the measured values ​​of the three specimens are not within 5% of their average value, but the two higher values ​​are within 5% of the average value, the lowest measured value shall be discarded and the average value of the two higher values ​​shall be taken as the measurement result, otherwise the measurement shall be repeated.
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