1、Standard Method of Test for Elastic Recovery Test of Asphalt Materials by Means of a Ductilometer AASHTO Designation: T 301-13 American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-2a T 301-1 AASHTO Standard Method of Te
2、st for Elastic Recovery Test of Asphalt Materials by Means of a Ductilometer AASHTO Designation: T 301-13 1. SCOPE 1.1. This method is used to determine the elastic recovery of asphalt material through the use of a ductilometer and briquet specimens. The specimens are pulled apart at a rate of 5 cm/
3、min (2 in./min) and held after a specified elongation. The specimens are then severed at the center and allowed to recover undisturbed for 1 h. Unless otherwise specified, the test shall be performed at a temperature of 25 0.5C (77 1.0F). 1.2. The values stated in SI units are to be regarded as the
4、standard. 1.3. This test may involve hazardous materials, operations, and equipment. This test does not purport to address all of the safety concerns associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the
5、applicability of regulatory limitations prior to use. 2. REFERENCED DOCUMENTS 2.1. ASTM Standards: E77, Standard Test Method for Inspection and Verification of Thermometers E220, Standard Test Method for Calibration of Thermocouples By Comparison Techniques E644, Standard Test Methods for Testing In
6、dustrial Resistance Thermometers 3. APPARATUS 3.1. MoldsThe mold shall be similar in design to that shown in Figure 1 and made of brass. The dimensions of the assembled mold shall be as shown in Figure 1 with the permissible variations indicated. 3.2. Base PlateThe base plate shall be made of nonabs
7、orbent material, of sufficient thickness to prevent deformation, and of a sufficient size to hold from one to three molds. The plate shall be uniformly flat to ensure that the bottom surfaces of each mold will touch it throughout. 3.3. Water BathA water bath capable of maintaining a temperature of 2
8、5 0.5C (77 1.0F) or other specified test temperature. The volume of water shall not be less than 10 L (2.6 gal). The depth of water shall not be less than 50 mm (2 in.) and such that the mold can be immersed to a depth of 25 mm (1 in.). The water in the bath shall be free from oil and slime or other
9、 organic growth. 3.4. ThermometersFor tests at 25C (77F), use an ASTM Saybolt Viscosity Thermometer No. 17C (17F) to measure the temperature of the water bath and the temperature of the water in the testing machine. For tests at other temperatures, use ASTM thermometers of an appropriate range and 2
10、015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2a T 301-2 AASHTO accuracy equal to that of the No. 17. Because the accuracy of the test results is dependent upon closely controlled conditions of tempe
11、rature, the thermometers should be standardized in accordance with ASTM E77. An equivalent thermometric device that has been standardized in accordance with ASTM E220 or E644 may be used. Notes: 1. All dimensions in mm 2. Material: 360 brass 3. Finish: None Figure 1Mold Assembly 3.5. Testing Machine
12、For pulling the briquet of asphalt material apart, any apparatus may be used that is constructed so that the specimen will be continuously immersed in water, as specified in Section 4.5, while the two clips are pulled apart at a uniform speed, without undue vibration. 3.6. HeaterAn oven or hot plate
13、, heated by electricity or gas, may be used to melt the asphalt material. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2a T 301-3 AASHTO 3.7. ContainerAny suitable container may be used to hold the
14、 asphalt material while it is being melted. 3.8. TrimmerAny convenient implement, such as a putty knife or spatula, may be used provided that the cutting edge is straight and at least 38 mm (11/2in.) wide. 3.9. Scissors. 4. PROCEDURE 4.1. Preparation of ApparatusAssemble the mold on the base plate.
15、To prevent the asphalt material from sticking, coat the surface of the plate and the interior surfaces of the sides a and a (as indicated in Figure 1) with a suitable release agent (Note 1). Note 1Mixtures of glycerin and dextrin or talc (3 g of glycerin to about 5 g of dextrin or talc), Dow-Corning
16、 Silicone Stop-Cock Grease, or castor oil and Versamid 900 100:1 mixture by mass heated to 204 to 232C (400 to 450F) and stirred until it is homogeneous have proven suitable. Other release agents may be used provided the results obtained are comparable to those obtained when using one of the above.
17、4.2. If the residue of a polymer-modified emulsion is being tested, the asphalt material obtained for the test should be the residue from oven evaporation of the emulsion sample at 162.8 2.5C (325 5F), not from distillation. 4.3. Molding Test SpecimensHeat the sample with care to prevent local overh
18、eating until it has become sufficiently fluid to pour. After thorough stirring, pour the asphalt material into the mold, taking care not to entrain any air bubbles. Pour the material in a thin stream back-and-forth from end to end until the mold is more than “level full.” In filling the mold, take c
19、are not to disarrange the parts of the mold and distort the briquet. Let the mold and contents cool to room temperature for 30 to 40 min. Then place the base plate and filled mold in the water bath. Unless otherwise specified, the water bath shall be maintained at a temperature of 25 0.5C (77 1.0F)
20、for 30 to 35 min. Remove the base plate and filled mold from the water bath and, with a hot trimmer, cut off the excess asphalt material so that the mold is just level full. Take care during the trimming operation that the specimen is not pulled away from the base plate or from the side pieces of th
21、e mold. 4.4. Keeping Specimen at Standard TemperaturePlace the base plate and filled mold in the water bath or testing machine. Maintain them at the test temperature of 25 0.5C (77 1.0F) or the temperature specified for 85 to 95 min. Remove the briquet from the plate, detach the side pieces, and imm
22、ediately test the briquet. 4.5. TestingAt the start of the test, the water in the tank of the testing machine shall cover the specimen both above and below. Also, the specimen shall be immersed to a depth of at least 25 mm (1 in.). Attach the clips to the pins of the testing machine, and pull the cl
23、ips apart at 5 cm/min (2 in./min) 5.0 percent until the briquet has been elongated to 20 cm (8 in.). After 20 cm (8 in.) has been reached, stop the ductilometer, and hold the specimen in its elongated position for 5 min. After 5 min, sever the specimen at its center with a pair of scissors, and allo
24、w the specimen to remain in the ductilometer, undisturbed, for 1 h. At the end of 1 h, release the ductilometer from the drive mechanism and retract the half sample until the ends of the severed sample just touch. If the ends of the sample are drooping downward, carefully lift them to the height of
25、the mold when bringing them together. Read the ductilometer pointer and record the value. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2a T 301-4 AASHTO 5. REPORT 5.1. Report the percent elongation
26、 recovery to the nearest whole number. The percent elongation recovery is given by the following equation: 20% elongation recovery 10020X= (1) where: X = final reading from the testing machine in centimeters after bringing the two severed ends of the specimen back together. 6. PRECISION AND BIAS 6.1. Information is not available to develop a precision and bias statement. 7. KEYWORDS 7.1. Asphalt; elastic recovery; percent elongation. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.
