1、Standard Method of Test for Determining the Rheological Properties of Asphalt Binder Using a Dynamic Shear Rheometer (DSR) AASHTO Designation: T 315-121American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-2b T 315-1 AAS
2、HTO Standard Method of Test for Determining the Rheological Properties of Asphalt Binder Using a Dynamic Shear Rheometer (DSR) AASHTO Designation: T 315-1211. SCOPE 1.1. This test method covers the determination of the dynamic shear modulus and phase angle of asphalt binder when tested in dynamic (o
3、scillatory) shear using parallel plate test geometry. It is applicable to asphalt binders having dynamic shear modulus values in the range from 100 Pa to 10 MPa. This range in modulus is typically obtained between 6 and 88C at an angular frequency of 10 rad/s. This test method is intended for determ
4、ining the linear viscoelastic properties of asphalt binders as required for specification testing and is not intended as a comprehensive procedure for the full characterization of the viscoelastic properties of asphalt binder. 1.2. This standard is appropriate for unaged material or material aged in
5、 accordance with T 240 and R 28. 1.3. Particulate material in the asphalt binder is limited to particles with longest dimensions less than 250 m. 1.4. This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns associ
6、ated with its use. It is the responsibility of the user of this procedure to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: M 320, Performance-Graded Asphalt Binder R 28, Acce
7、lerated Aging of Asphalt Binder Using a Pressurized Aging Vessel (PAV) R 29, Grading or Verifying the Performance Grade (PG) of an Asphalt Binder R 66, Sampling Bituminous Materials T 240, Effect of Heat and Air on a Moving Film of Asphalt Binder (Rolling Thin-Film Oven Test) T 314, Determining the
8、Fracture Properties of Asphalt Binder in Direct Tension (DT) 2.2. ASTM Standards: C670, Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials D2170/D2170M, Standard Test Method for Kinematic Viscosity of Asphalts (Bitumens) 2015 by the American Ass
9、ociation of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2b T 315-2 AASHTO D2171/D2171M, Standard Test Method for Viscosity of Asphalts by Vacuum Capillary Viscometer E1, Standard Specification for ASTM Liquid-in-Glass Thermometers E
10、77, Standard Test Method for Inspection and Verification of Thermometers E563, Standard Practice for Preparation and Use of an Ice-Point Bath as a Reference Temperature E644, Standard Test Methods for Testing Industrial Resistance Thermometers 2.3. Deutsche Industrie Norm (DIN) Standard: 43760, Indu
11、strial Platinum Resistance Thermometers and Platinum Temperature Sensors 3. TERMINOLOGY 3.1. Definitions: 3.1.1. asphalt binderan asphalt-based cement that is produced from petroleum residue either with or without the addition of nonparticulate organic modifiers. 3.2. Descriptions of Terms Specific
12、to This Standard: 3.2.1. annealingheating the binder until it is sufficiently fluid to remove the effects of steric hardening. 3.2.2. calibrationprocess of checking the accuracy and precision of a device using NIST-traceable standards and making adjustments to the device where necessary to correct i
13、ts operation or precision and accuracy. 3.2.3. complex shear modulus (G*)ratio calculated by dividing the absolute value of the peak-to-peak shear stress, , by the absolute value of the peak-to-peak shear strain, . 3.2.4. dummy test specimena specimen formed between the dynamic shear rheometer (DSR)
14、 test plates from asphalt binder or other polymer to measure the temperature of the asphalt binder held between the plates. The dummy test specimen is used solely to determine temperature corrections. 3.2.5. linear viscoelasticwithin the context of this specification refers to a region of behavior i
15、n which the dynamic shear modulus is independent of shear stress or strain. 3.2.6. loading cyclea unit cycle of time for which the test sample is loaded at a selected frequency and stress or strain level. 3.2.7. loss shear modulus (G)the complex shear modulus multiplied by the sine of the phase angl
16、e expressed in degrees. It represents the component of the complex modulus that is a measure of the energy lost (dissipated during a loading cycle). 3.2.8. molecular associationa process where associations occur between asphalt binder molecules during storage at ambient temperature. Often called ste
17、ric hardening in the asphalt literature, molecular associations can increase the dynamic shear modulus of asphalt binders. The amount of molecular association is asphalt specific and may be significant even after a few hours of storage. 2015 by the American Association of State Highway and Transport
18、ation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2b T 315-3 AASHTO 3.2.9. oscillatory shearrefers to a type of loading in which a shear stress or shear strain is applied to a test sample in an oscillatory manner such that the shear stress or strain varies in ampli
19、tude by about zero in a sinusoidal manner. 3.2.10. parallel plate geometryrefers to a testing geometry in which the test sample is sandwiched between two relatively rigid parallel plates and subjected to oscillatory shear. 3.2.11. phase angle ()the angle in radians between a sinusoidally applied str
20、ain and the resultant sinusoidal stress in a controlled-strain testing mode, or between the applied stress and the resultant strain in a controlled-stress testing mode. 3.2.12. portable thermometeran electronic device that consists of a temperature detector (probe containing a thermocouple or resist
21、ive element), required electronic circuitry, and readout system. 3.2.13. reference thermometera NISTtraceable liquid-in-glass or electronic thermometer that is used as a laboratory standard. 3.2.14. steric hardeningsee molecular association. 3.2.15. storage shear modulus (G)the complex shear modulus
22、 multiplied by the cosine of the phase angle expressed in degrees. It represents the in-phase component of the complex modulus that is a measure of the energy stored during a loading cycle. 3.2.16. temperature correctiondifference in temperature between the temperature indicated by the DSR and the t
23、est specimen as measured by the portable thermometer inserted between the test plates. 3.2.17. thermal equilibriumis reached when the temperature of the test specimen mounted between the test plates is constant with time. 3.2.18. verificationprocess of checking the accuracy of a device or its compon
24、ents against an internal laboratory standard. It is usually performed within the operating laboratory. 4. SUMMARY OF TEST METHOD 4.1. This standard contains the procedure used to measure the complex shear modulus (G*) and phase angle () of asphalt binders using a dynamic shear rheometer and parallel
25、 plate test geometry. 4.2. The standard is suitable for use when the dynamic shear modulus varies between 100 Pa and 10 MPa. This range in modulus is typically obtained between 6 and 88C at an angular frequency of 10 rad/s, dependent upon the grade, test temperature, and conditioning (aging) of the
26、asphalt binder. 4.3. Test specimens 1 mm thick by 25 mm in diameter or 2 mm thick by 8 mm in diameter are formed between parallel metal plates. During testing, one of the parallel plates is oscillated with respect to the other at preselected frequencies and rotational deformation amplitudes (strain
27、control) (or torque amplitudes stress control). The required stress or strain amplitude depends upon the value of the complex shear modulus of the asphalt binder being tested. The required amplitudes have been selected to ensure that the measurements are within the region of linear behavior. 2015 by
28、 the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2b T 315-4 AASHTO 4.4. The test specimen is maintained at the test temperature to within 0.1C by positive heating and cooling of the upper and lower plates or
29、by enclosing the upper and lower plates in a thermally controlled environment or test chamber. 4.5. Oscillatory loading frequencies using this standard can range from 1 to 100 rad/s using a sinusoidal waveform. Specification testing is performed at a test frequency of 10 rad/s. The complex modulus (
30、G*) and phase angle () are calculated automatically as part of the operation of the rheometer using proprietary computer software supplied by the equipment manufacturer. 5. SIGNIFICANCE AND USE 5.1. The test temperature for this test is related to the temperature experienced by the pavement in the g
31、eographical area for which the asphalt binder is intended to be used. 5.2. The complex shear modulus is an indicator of the stiffness or resistance of asphalt binder to deformation under load. The complex shear modulus and the phase angle define the resistance to shear deformation of the asphalt bin
32、der in the linear viscoelastic region. 5.3. The complex modulus and the phase angle are used to calculate performance-related criteria in accordance with M 320. 6. APPARATUS 6.1. Dynamic Shear Rheometer (DSR) Test SystemConsisting of parallel metal plates, an environmental chamber, a loading device,
33、 and a control and data acquisition system. 6.1.1. Test PlatesStainless steel or aluminum plates with smooth ground surfaces. One 8.00 0.02 mm in diameter and one 25.00 0.05 mm in diameter (Figure 1). The base plate in some rheometers is a flat plate. A raised portion, a minimum of 1.50 mm high, wit
34、h the same radius as the upper plate is required. The raised portion makes it easier to trim the specimen and may improve test repeatability. Note 1To obtain correct data, the upper and lower plates should be concentric with each other. At present there is no suitable procedure for the user to check
35、 the concentricity except to visually observe whether or not the upper and lower plates are centered with respect to each other. The moveable plate should rotate without any observable horizontal or vertical wobble. This operation may be checked visually or with a dial gauge held in contact with the
36、 edge of the moveable plate while it is being rotated. There are two values that determine the operating behavior of a measuring system: centricity (horizontal wobble) and runout (vertical wobble). Typically, wobble can be detected if it is greater than 0.02 mm. For a new system, a wobble of 0.01 mm
37、 is typical. If the wobble grows to more than 0.02 mm with use, it is recommended that the instrument be serviced by the manufacturer. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2b T 315-5 AASHTO
38、 Dimension 8-mm Nominal 25-mm Nominal A 8 0.02 mm 25 0.05 mm B 1.50 mm 1.50 mm Figure 1Plate Dimensions 6.1.2. Environmental ChamberFor controlling the test temperature, by heating or cooling (in steps or ramps), to maintain a constant specimen environment. The medium for heating and cooling the spe
39、cimen in the environmental chamber shall not affect asphalt binder properties. The temperature in the chamber may be controlled by the circulation of fluid such as water, conditioned gas such as nitrogen, or by a suitable arrangement of solid-state Peltier elements surrounding the sample. When force
40、d air is used, a suitable drier must be included to prevent condensation of moisture on the plates and fixtures and, if operating below freezing temperatures, the formation of ice. The environmental chamber and the temperature controller shall control the temperature of the specimen, including therm
41、al gradients within the sample, to an accuracy of 0.1C. The chamber shall completely enclose the top and the bottom plates to minimize thermal gradients. Note 2A circulating bath unit, separate from the DSR, that pumps the bath fluid through the test chamber may be required if a fluid medium is used
42、. The flow rate of the bath media should not be modified once the temperature settings have been adjusted to the desired value. Media lines should be periodically inspected and cleaned or replaced if necessary to remove obstructions 6.1.2.1. Temperature ControllerCapable of maintaining specimen temp
43、eratures within 0.1C for test temperatures ranging from 3 to 88C. 6.1.2.2. Internal Temperature Detector for the DSRA platinum resistance thermometer (PRT) mounted within the environmental chamber as an integral part of the DSR and in close proximity to the fixed plate, with a range of 3 to 88C, and
44、 with a resolution of 0.1C (see Note 3). This thermometer shall be used to control the temperature of the test specimen between the plates and shall provide a continuous readout of temperature during the mounting, conditioning, and testing of the specimen. The PRT shall be calibrated as an integral
45、unit with its respective meter or electronic circuitry. Note 3PTRs meeting DIN Standard 43760 (Class A) or equal are recommended for this purpose. 6.1.3. Loading DeviceCapable of applying a sinusoidal oscillatory load to the specimen at a frequency of 10.0 0.1 rad/s. If frequencies other than 10 rad
46、/s are used, the frequency shall be accurate to 1 percent. The loading device shall be capable of providing either a stress-controlled or strain-controlled load. If the load is strain controlled, the loading device shall apply a cyclic torque 2015 by the American Association of State Highway and Tra
47、nsportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2b T 315-6 AASHTO sufficient to cause an angular rotational strain accurate to within 100 rad of the strain specified. If the load is stress controlled, the loading device shall apply a cyclic torque accurate
48、to within 10 mNm of the torque specified. Total system compliance at 100 Nm of torque shall be less than 2 mrad/Nm. The manufacturer of the device shall certify that the frequency, stress, and strain are controlled and measured with an accuracy of one percent or less in the range of this measurement
49、. 6.1.4. Control and Data Acquisition SystemCapable of providing a record of temperature, frequency, deflection angle, and torque. Devices used to measure these quantities shall meet the accuracy requirements specified in Table 1. In addition, the system shall calculate and record the shear stress, shear strain, complex shear modulus (G*), and phase angle (). The system shall measure and record G*, in the range of 100 Pa to 10 MPa, to an accuracy of 1.0 percent or less, and the phase
