1、Standard Method of Test for Viscosity Determination of Asphalt Binder Using Rotational Viscometer AASHTO Designation: T 316-131American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-2b T 316-1 AASHTO Standard Method of Te
2、st for Viscosity Determination of Asphalt Binder Using Rotational Viscometer AASHTO Designation: T 316-1311. SCOPE 1.1. This test method outlines the procedure for measuring the viscosity of asphalt binders at elevated temperature from 60 to over 200C using a Rotational Viscometer apparatus as speci
3、fied by M 320 and R 29. 1.2. This standard may involve hazardous materials, operations, and equipment. This standard 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 practi
4、ces and determine the application of regulatory limitations prior to use. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: M 320, Performance-Graded Asphalt Binder R 29, Grading or Verifying the Performance Grade (PG) of an Asphalt Binder R 66, Sampling Asphalt Materials 2.2. ASTM Standards: C670, Sta
5、ndard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials E1, Standard Specification for ASTM Liquid-in-Glass Thermometers 3. TERMINOLOGY 3.1. Definition: 3.1.1. viscositythe ratio between the applied shear stress and the rate of shear is called the coeff
6、icient of viscosity. This coefficient is a measure of the resistance to flow of the liquid. It is commonly called the viscosity. The SI unit of viscosity is the Pascal second (Pas). 4. SUMMARY OF METHOD 4.1. This test method can be used to measure the viscosity of asphalt at application temperatures
7、. The torque required to maintain a constant rotational speed of a cylindrical spindle while submerged in an asphalt sample at a constant temperature is used to measure the relative resistance to rotation. The torque and speed are used to determine the viscosity of the binder in Pascal seconds. 2015
8、 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2b T 316-2 AASHTO 5. SIGNIFICANCE AND USE 5.1. This test method can be used to measure the apparent viscosity of asphalt at application temperatures. 5.2. T
9、he measured viscosity at elevated temperatures can be used to determine whether the asphalt binder can be handled and pumped at the refinery, terminal, or hot mix plant facility. Measured viscosity from this procedure can be used to develop temperature viscosity charts for estimating mixing and comp
10、action temperatures for use in hot mix asphalt mix design. 6. APPARATUS 6.1. OvenAn oven capable of maintaining any desired temperature setting from room temperature to 260C to within 3C. 6.2. ThermometersThermometers having a range from 60 to over 200C and readable to 0.2C. 6.3. BalanceA balance wi
11、th a capacity of 2000 g readable to 0.1 g for determining the mass of asphalt binder. 6.4. Cylindrical Spindles of various sizes for measurement of asphalt binders of different viscosities. 6.5. Rotational Viscometer capable of measuring the torque required to rotate the selected spindle at a select
12、ed constant speed while submerged in asphalt at constant desired test temperature and should display the viscosity in Pascal seconds automatically. 6.6. Temperature ControllerA proportional temperature controller capable of maintaining the specimen temperatures 1.0C for test temperatures ranging fro
13、m 60 to 165C or greater. 7. MATERIALS 7.1. Solvent (such as Mineral Spirits or Varsol) or a degreasing spray cleaner formulated for cleaning the sample holder, spindles, and accessories. 8. HAZARDS 8.1. Use standard laboratory safety procedures required for handling the hot asphalt binder and requir
14、ed safety procedures when cleaning with solvents or degreasers. 9. PREPARATION OF APPARATUS 9.1. The rotational viscometer must be leveled to function properly. A bubble-type level is normally located on top of the viscometer and is adjusted by using leveling screws located on the base. If the torqu
15、e controller and thermal chamber are separate units, both should be leveled in accordance with the device manufacturers instructions. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2b T 316-3 AASHTO
16、10. CALIBRATION AND STANDARDIZATION 10.1. The accuracy of the rotary transducer is checked using a reference fluid (Newtonian fluid) of known viscosity at various temperatures. The reference fluid shall be certified to be Newtonian in behavior over the full range of expected test temperatures and sh
17、ear rates. The viscosity measured should be within 2 percent or the rotary transducer requires recalibration. 10.2. The accuracy of the temperature reading of the temperature controller is checked by placing an asphalt sample in the testing chamber and equilibrating to a given temperature. The indic
18、ated temperature shall be verified by using a NIST-traceable measuring device as defined by ASTM E1. 11. PREPARATION OF SAMPLES AND TEST SPECIMENS 11.1. Preparing Test SamplesUnaged asphalt and modified asphalt binders are obtained according to R 66. 11.1.1. Anneal the asphalt binder from which the
19、specimen is obtained by heating until sufficiently fluid to pour. Annealing prior to testing removes reversible molecular associations (steric hardening) that may occur during normal storage at ambient temperature. Note 1Minimum pouring temperature that produces a consistency equivalent to that of S
20、AE 10W30 motor oil (readily pours but not overly fluid) at room temperature is recommended. The specific temperature will depend on the grade of binder and its prior aging history, if any. Temperatures less than 135C are desirable; however, temperatures above 135C may be required for some modified a
21、sphalt binders or heavily aged binders. 12. PROCEDURE 12.1. Read and understand the information in the rotational viscometer manufacturers operating manual before proceeding. 12.2. Turn on the rotational viscometer and proportional temperature controller unit. 12.3. Preheat the sample holder with th
22、e sample chamber and the selected cylindrical spindle according to the manufacturers recommendation. 12.4. Set the proportional temperature controller to desired test temperature. 12.5. Heat the required amount of asphalt binder as recommended by the manufacturer for testing according to Section 11.
23、1.1. 12.6. When the proportional temperature controller reads the desired test temperature, remove the sample holder, and add the required amount of asphalt into the sample chamber. 12.7. Insert the sample chamber into the proportional temperature controller unit. 12.8. Insert a preheated spindle an
24、d attach it to the viscometer using the necessary coupling. Gently lower the spindle into the asphalt so that asphalt covers the upper conical portion of the spindle. This procedure may vary based on the manufacturers recommendations. 2015 by the American Association of State Highway and Transportat
25、ion Officials.All rights reserved. Duplication is a violation of applicable law.TS-2b T 316-4 AASHTO 12.9. Bring the asphalt sample to the desired temperature within approximately 30 min. Set the viscometer speed at 20 rpm and set the display to read the viscosity in Pascal seconds (Pas). This opera
26、tion may be performed manually or by using a software program. The viscometer speed may be set higher than 20 rpm if it is expected that the observed torque will be out of range at 20 rpm. 12.10. Allow the asphalt sample to equilibrate at the desired test temperature for a minimum of 10 min. Begin t
27、he spindle rotation during the 10-min temperature equilibration period. Allow the readings to stabilize before recording any viscosity measurements. If the observed torque is out of range for the selected spindle and speed, change the spindle or speed based on the manufacturers recommendations for t
28、he anticipated viscosity. If a different spindle is used, restart the test with a new sample. 12.11. Start the test after the asphalt sample has reached the specified temperature and equilibrated and the viscosity readings have stabilized, as required in Sections 12.9 and 12.10. 12.12. Measure the v
29、iscosity at 1-min intervals for a total of 3 min. 12.13. Follow the procedure in Sections 12.1 to 12.12 for other temperatures. 13. CALCULATION OF RESULTS 13.1. The viscosity is reported as the average of three readings. If the digital output of the rotational viscometer viscosity is in units of cen
30、tipoise (cP), the following factor is used to convert to Pascal- seconds: 10 P = 1 Pas (1) 1 cP = 1 mPas (2) Multiply viscosity in centipoise by 0.001 to obtain the viscosity in Pas. 14. REPORT 14.1. Report the following information: 14.1.1. The date and time of the test; 14.1.2. The test temperatur
31、e to the nearest 1C; 14.1.3. The speed in rpm; 14.1.4. The size of the spindle used; 14.1.5. The torque in percent; and 14.1.6. The average viscosity in Pas. 15. PRECISION AND BIAS 15.1. PrecisionCriteria for judging the acceptability of viscosity results obtained by this method are given in Table 1
32、. 15.1.1. Single-Operator Precision (Repeatability)The figures in Column 2 of Table 1 are the coefficients of variation that have been found to be appropriate for the conditions of test described in Column 1. Two results obtained in the same laboratory, by the same operator using the same 2015 by th
33、e American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2b T 316-5 AASHTO equipment, in the shortest practical period of time, should not be considered suspect unless the difference in the two results, expressed as a p
34、ercent of their mean, exceeds the values given in Table 1, Column 3. 15.1.2. Multilaboratory Precision (Reproducibility)The figures in Column 2 of Table 1 are the coefficients of variation that have been found to be appropriate for the conditions of test described in Column 1. Two results submitted
35、by two different operators testing the same material in different laboratories shall not be considered suspect unless the difference in the two results, expressed as a percent of their mean, exceeds the values given in Table 1, Column 3. Table 1Precision Estimates Condition Coefficient of Variation
36、(1s%)aAcceptable Range of Two Test Results (d2s%)aSingle-operator precision: Average viscosity (Pas) 1.2 3.5 Multilaboratory precision: Average viscosity (Pas) 4.3 12.1 aThese values represent the 1s% and d2s% limits described in ASTM C670. Note 2The precision estimates given in Table 1 are based on
37、 the analysis of test results from eight pairs of AMRL proficiency samples. The data analyzed consisted of results from 142 to 202 laboratories for each of the eight pairs of samples. The analysis included five binder grades: PG 52-34, PG 64-16, PG 64-22, PG 70-22, and PG 76-22 (SBS modified). Unmod
38、ified binder average viscosity results ranged from 0.272 Pas to 0.719 Pas. The modified binder average viscosity results ranged from 1.621 Pas to 1.638 Pas. The details of this analysis are in the final report for NCHRP Project No. 9-26, Phase 3. Note 3As an example, two tests conducted on the same
39、material yield viscosity results of 0.500 Pas and 0.510 Pas, respectively. The average of these two measurements is 0.505 Pas. The acceptable range of results is then 3.5 percent of 0.505 Pas or 0.018 Pas. As the difference between 0.500 Pas and 0.510 Pas is less than 0.018 Pas, the results are with
40、in the acceptable range. 15.2. BiasNo information can be presented on the bias of the procedure because no material having an accepted reference value is available. 16. KEYWORDS 16.1. Asphalt binder; viscosity. 1Formerly AASHTO Provisional Standard TP 48. First published as a full standard in 2002. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.
