1、Standard Practice for Preparation of Cylindrical Performance Test Specimens Using the Superpave Gyratory Compactor (SGC) AASHTO Designation: R 83-171Technical Section: 2d, Proportioning of AsphaltAggregate Mixtures Release: Group 3 (August 2017) American Association of State Highway and Transportati
2、on Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-2d R 83-1 AASHTO Standard Practice for Preparation of Cylindrical Performance Test Specimens Using the Superpave Gyratory Compactor (SGC) AASHTO Designation: R 83-171Technical Section: 2d, Proportioning of AsphaltAggrega
3、te Mixtures Release: Group 3 (August 2017) 1. SCOPE 1.1. This practice covers the use of a Superpave gyratory compactor (SGC) to prepare 100-mm-diameter by 150-mm-tall cylindrical test specimens for use in a variety of axial compression and tension performance tests. This practice is intended for de
4、nse-, gap-, and open-graded asphalt mixtures with nominal maximum aggregate sizes up to 37.5 mm. 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 th
5、e user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: R 30, Mixture Conditioning of Hot Mix Asphalt (HMA) T 166, Bulk Specific Gravity (Gmb) of Compacted Hot
6、Mix Asphalt (HMA) Using Saturated Surface-Dry Specimens T 209, Theoretical Maximum Specific Gravity (Gmm) and Density of Hot Mix Asphalt (HMA) T 269, Percent Air Voids in Compacted Dense and Open Asphalt Mixtures T 312, Preparing and Determining the Density of Asphalt Mixture Specimens by Means of t
7、he Superpave Gyratory Compactor T 342, Determining Dynamic Modulus of Hot Mix Asphalt (HMA) T 378, Determining the Dynamic Modulus and Flow Number for Asphalt Mixtures Using the Asphalt Mixture Performance Tester (AMPT) 2.2. ASTM Standard: D3549/D3549M-11, Standard Test Method for Thickness or Heigh
8、t of Compacted Bituminous Paving Mixture Specimens 2017 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-2d R 83-2 AASHTO 3. TERMINOLOGY 3.1. Definitions: 3.1.1. end perpendicularitythe degree to which an
9、end surface departs from being perpendicular to the axis of the cylindrical test specimen. This configuration is measured using a precision square with the beam touching the cylinder parallel to its axis and the blade touching the highest point on the end of the cylinder. The distance between the bl
10、ade of the square and the lowest point on the end of the cylinder is checked with 1.0-mm-diameter wire or feeler gauges. 3.1.2. end planenessmaximum departure of the specimen end from a plane. This dimension is checked using a straightedge and 0.5-mm-diameter wire or feeler gauges. 3.1.3. SGC specim
11、ena 150-mm-diameter by 160-mm-tall (minimum) cylindrical specimen for compressive tests or a 150-mm-diameter by 180-mm-tall (minimum) cylindrical specimen for tensile or tension tests prepared in an SGC meeting the requirements of T 312. (See Notes 5 and 6.) 3.1.4. test specimena 100-mm-diameter by
12、150-mm-tall cylindrical specimen that is sawed and cored from the SGC specimen. 4. SUMMARY OF PRACTICE 4.1. This practice presents methods for preparing 100-mm-diameter by 150-mm-tall cylindrical test specimens for use in a variety of axial compression and tension performance tests. 5. SIGNIFICANCE
13、AND USE 5.1. This practice should be used to prepare specimens for T 342 and T 378. 5.2. This practice may also be used to prepare specimens for other tests requiring 100-mm-diameter by 150-mm-tall cylindrical test specimens. 6. APPARATUS 6.1. Superpave Gyratory CompactorMeeting the requirements of
14、T 312 and capable of preparing 150-mm-diameter specimens that are a height of at least 160 mm. 6.2. Mixture Preparation EquipmentBalances, ovens, thermometers, mixer, pans, and other miscellaneous equipment needed to prepare SGC specimens in accordance with T 312, perform bulk specific gravity (Gmb)
15、 measurements in accordance with T 166, and perform maximum specific gravity (Gmm) measurements in accordance with T 209. 6.3. Core DrillAn air- or water-cooled, diamond-bit core drill capable of cutting cores to a nominal diameter of 100 mm and meeting the dimensional requirements of Section 9.6.3.
16、 The core drill shall be equipped with a fixture for holding 150-mm-diameter SGC specimens. Note 1Core drills with fixed and adjustable rotational speed have been used successfully to prepare specimens meeting the dimensional tolerances given in Section 9.6.3. Rotational speeds from 450 to 750 rpm h
17、ave been used. Note 2Core drills with automatic and manual feed-rate control have been used successfully to prepare specimens meeting the dimensional tolerances given in Section 9.6.3. 2017 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is
18、 a violation of applicable law.TS-2d R 83-3 AASHTO 6.4. Masonry SawAn air- or water-cooled, diamond-bladed masonry saw capable of cutting specimens to a nominal length of 150 mm and meeting the tolerances for end perpendicularity and end flatness given in Section 9.6.3. Note 3Single- and double-blad
19、ed saws have been used successfully to prepare specimens meeting the dimensional tolerances given in Section 9.6.3. Both types of saws require a fixture to securely hold the specimen during sawing and to control the feed rate. 6.5. SquarePrecision square with 8-in. beam and 12-in. blade. McMaster Ca
20、rr Pro-Value Square, Catalog Number 2278A21 (http:/ or equivalent. 6.6. 1.0-mm Diameter Carbon Steel Wire0.039-in. (1-mm) diameter carbon steel wire, McMaster Carr Catalog Number 8907K42 (http:/ or equivalent. 6.7. 0.5-mm Diameter Carbon Steel Wire0.020-in. (0.5-mm) diameter carbon steel wire, McMas
21、ter Carr Catalog Number 8907K21 (http:/ or equivalent. 6.8. Feeler GaugesTapered-leaf feeler gauges in 0.05-mm increments. 6.9. Metal RulerCapable of measuring 150-mm-long (nominal) specimens to the nearest 1 mm. 6.10. CalipersCapable of measuring 100-mm-diameter (nominal) specimens to the nearest 0
22、.1 mm. 7. HAZARDS 7.1. This practice and associated standards involve handling of hot asphalt binder, aggregates, and asphalt mixtures, and the use of sawing and coring machinery. Use standard safety precautions, equipment, and clothing when handling hot materials and operating machinery. 8. STANDAR
23、DIZATION 8.1. Items associated with this practice that require calibration or verification are included in the AASHTO standards referenced in Section 2. Refer to the pertinent section of the referenced standards for information concerning calibration or verification. 9. PROCEDURE 9.1. Select SGC Spe
24、cimen Target Height: 9.1.1. SGC specimens shall be prepared to a height of 160 mm (minimum) for compressive tests and to a height of 180 mm (minimum) for tensile or tension tests. 9.1.2. SGC specimen height shall be chosen based on the air void gradient produced by the specific SGC and effect of the
25、 sawing equipment. Note 4Test specimens with acceptable properties have been prepared from SGC specimens ranging in height from 160 mm to greater than 180 mm. Coarse-graded mixtures may require a taller height in order to ensure smooth, uniform ends with minimal or no surface irregularities after th
26、e sawing process. For tension performance testing, a taller height is required for all mixtures. Note 5Each laboratory should determine a target SGC specimen height based on the procedure for evaluating test specimen uniformity given in Appendix X2, and an evaluation of the ability of the sawing equ
27、ipment to maintain the dimensional tolerances given in Table 1. 2017 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-2d R 83-4 AASHTO 9.2. Asphalt Mixture Preparation: 9.2.1. Prepare asphalt mixture for e
28、ach test specimen in accordance with T 312 and prepare a companion test specimen for maximum specific gravity (Gmm) in accordance with T 209. 9.2.2. The mass of asphalt mixture needed for each specimen will depend on the SGC specimen height, the Gmmof the aggregate, nominal maximum aggregate size, g
29、radation (coarse or fine), and target air void content for the test specimens. Note 6Appendix X1 describes a trial-and-error procedure developed in NCHRP 9-19 for determining the mass of asphalt mixture required to reach a specified test specimen target air void content for SGC specimens prepared to
30、 a height of 170 mm. 9.2.3. Perform conditioning on the asphalt mixture for the test specimens and companion Gmmsample test in accordance with R 30. 9.3. SGC Specimen Compaction: 9.3.1. Compact the SGC specimens to the target specimen height determined in Section 9.1 in accordance with T 312. 9.4. L
31、ong-Term Conditioning (Optional): 9.4.1. If it is desired to simulate long-term aging, condition the SGC specimen in accordance with R 30. 9.4.2. To obtain accurate volumetric measurements on the long-term-conditioned specimens, also condition a companion sample of short-term-conditioned loose aspha
32、lt mixture meeting the sample size requirements of T 209 in accordance with R 30. 9.5. SGC Specimen Density and Air Voids (Optional): 9.5.1. Determine the Gmmof the asphalt mixture in accordance with T 209. If long-term conditioning has been used, determine the Gmmon the long-term-conditioned loose
33、asphalt mixture. Record the Gmmof the mixture. 9.5.2. For dense- and gap-graded mixtures, determine the Gmbof the SGC specimen in accordance with T 166. Record the Gmbof the SGC specimen. 9.5.3. For open-graded mixtures, determine the Gmbof the SGC specimen in accordance with T 269. Record the Gmbof
34、 the SGC specimen. 9.5.4. Compute the air void content of the SGC specimen in accordance with T 269. Record the air void content of the SGC specimen. Note 7Section 9.5 is optional because acceptance of the test specimen for mechanical property testing is based on the air void content of the test spe
35、cimen, not the SGC specimen. However, monitoring SGC specimen density can identify improperly prepared specimens early in the specimen fabrication process. Information on SGC specimen air voids and test specimen air voids will also assist the laboratory in establishing potentially more precise metho
36、ds than Appendix X1 for preparing test specimens to a target air void content. 9.6. Test Specimen Preparation: 9.6.1. Drill a core of nominal diameter of 100 mm from the center of the SGC specimen. Both the SGC specimen and the drill shall be adequately supported to ensure that the resulting core is
37、 cylindrical with sides that are smooth, parallel, and meet the tolerances on specimen diameter given in Table 1. 2017 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-2d R 83-5 AASHTO 9.6.2. Saw the ends
38、of the core to obtain a test specimen of a nominal height of 150 mm. Both the core and the saw shall be adequately supported to ensure that the resulting test specimen meets the tolerances given in Table 1 for height, end flatness, and end perpendicularity. Note 8With most equipment, it is better to
39、 perform the coring before the sawing. However, these operations may be performed in either order as long as the dimensional tolerances in Table 1 are satisfied. 9.6.3. Test specimens shall meet the dimensional tolerances given in Table 1. Table 1Test Specimen Dimensional Tolerances Item Specificati
40、on Method Reference Average diameter 98 to 104 mm 9.6.3.1 Standard deviation of diameter 0.5 mm 9.6.3.1 Height 147.5 to 152.5 mm 9.6.3.2 End flatness 0.5 mm 9.6.3.3 End perpendicularity 1.0 mm 9.6.3.4 9.6.3.1. Using calipers, measure the diameter at the center and third points of the test specimen a
41、long axes that are 90 degrees apart. Record each of the six measurements to the nearest 0.1 mm. Calculate the average and the standard deviation of the six measurements. Reject specimens not meeting the average and standard deviation requirements listed in Table 1. The average diameter, reported to
42、the nearest 0.1 mm, shall be used in all material property calculations. 9.6.3.2. Measure the height of the test specimen in accordance with ASTM D3549/D3549M. Reject specimens with an average height outside the height tolerance listed in Table 1. Record the average height. 9.6.3.2.1. Using the blad
43、e of the precision square as a straightedge, check the flatness of each end at three locations approximately 120 degrees apart. At each location, place the blade of the precision square across the diameter of the specimen and check the maximum departure of the specimen from the blade using the 0.5-m
44、m-diameter carbon steel wire or feeler gauge. Reject specimens if the 0.5-mm-diameter carbon steel wire fits between the blade and the specimen at any location. 9.6.3.3. Check the perpendicularity of each end of the specimen using the precision square and the 1.0-mm carbon steel wire at two location
45、s approximately 90 degrees apart. Place the precision square on a table with the beam in contact with the table and the blade extending vertically. Place the long axis of the specimen on the beam such that the blade is in contact with the end of the specimen. Check the maximum departure of the speci
46、men from the blade using the 1.0-mm-diameter carbon steel wire or feeler gauge. Reject specimens if the 1.0-mm-diameter carbon steel wire fits between the blade and the specimen at any location. 9.7. Test Specimen Density and Air Voids: 9.7.1. Determine the Gmmof the asphalt mixture in accordance wi
47、th T 209. If long-term conditioning has been used, determine the Gmmon the long-term-conditioned loose asphalt mixture. Record the Gmmof the asphalt mixture. 9.7.2. For dense- and gap-graded mixtures, determine the Gmbof the test specimen in accordance with T 166. Record the Gmbof the test specimen.
48、 Note 9When wet-coring and sawing methods are used, measure the immer sed mass, followed by the surface-dry mass followed by the dry mass, to minimize drying time and expedite the specimen fabrication process. 2017 by the American Association of State Highway and Transportation Officials. All rights
49、 reserved. Duplication is a violation of applicable law.TS-2d R 83-6 AASHTO 9.7.3. For open-graded mixtures, determine the Gmbof the test specimen in accordance with T 269. Record the Gmbof the test specimen. 9.7.4. Compute the air void content of the test specimen in accordance with T 269. Record the air void content of the test specimen. Reject test specimens exceeding the air void tolerances specified in the applicable test. 9.8. Tes
