1、Designation: D6925 09D6925 15Standard Test Method forPreparation and Determination of the Relative Density ofHot Mix Asphalt (HMA)Mix Specimens by Means of theSuperpave Gyratory Compactor1This standard is issued under the fixed designation D6925; the number immediately following the designation indi
2、cates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the compaction of
3、cylindrical specimens of hot mix asphalt (HMA) asphalt mix into cylindricalspecimens using the Superpave Gyratory Compactor (SGC). This standard also refers to the determination of the relative densityof the compacted specimens at any point in the compaction process. Compacted specimens are suitable
4、 for volumetric and physicalproperty testing.volumetric, physical property, and mechanical testing. Smaller specimens may be cut from the compactedcylindrical specimen for specific test specimen geometry requirements. The compaction procedures apply to Laboratory MixLaboratory Compacted (LMLC) and P
5、lant Mix Laboratory Compacted (PMLC) asphalt mix.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.Thevalue given in degrees for the angle of gyration is a mathematical conversion from the SI units and is provided for inform
6、ationregarding the commonly used unit of degree.1.3 The text of this test method references notes and footnotes which provide explanatory material. These notes and footnotes(excluding those in tables and figures) shall not be considered as requirements of the standard.1.4 This standard does not purp
7、ort to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D8 Te
8、rminology Relating to Materials for Roads and PavementsD979/D979M Practice for Sampling Bituminous Paving MixturesD1188 Test Method for Bulk Specific Gravity and Density of Compacted Bituminous Mixtures Using Coated SamplesD2041 Test Method for Theoretical Maximum Specific Gravity and Density of Bit
9、uminous Paving MixturesD2726 Test Method for Bulk Specific Gravity and Density of Non-Absorptive Compacted Bituminous MixturesD3666 Specification for Minimum Requirements for Agencies Testing and Inspecting Road and Paving MaterialsD4402 Test Method for Viscosity Determination of Asphalt at Elevated
10、 Temperatures Using a Rotational ViscometerD4753 Guide for Evaluating, Selecting, and Specifying Balances and Standard Masses for Use in Soil, Rock, and ConstructionMaterials TestingD6752/D6752M Test Method for Bulk Specific Gravity and Density of Compacted Bituminous Mixtures Using AutomaticVacuum
11、Sealing MethodD6857/D6857M Test Method for Maximum Specific Gravity and Density of Bituminous Paving Mixtures Using AutomaticVacuum Sealing MethodD7115 Test Method for Measurement of Superpave Gyratory Compactor (SGC) Internal Angle of Gyration Using SimulatedLoadingE2251 Specification for Liquid-in
12、-Glass ASTM Thermometers with Low-Hazard Precision Liquids1 This test method is under the jurisdiction ofASTM Committee D04 on Road and Paving Materials and is the direct responsibility of Subcommittee D04.20 on MechanicalTests of BituminousAsphalt Mixtures.Current edition approved July 1, 2009Jan.
13、1, 2015. Published July 2009January 2015. Originally approved in 2003. Last previous edition approved in 20082009 asD6925 08.D6925 09. DOI: 10.1520/D6925-09.10.1520/D6925-15.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For A
14、nnual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not
15、be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Dri
16、ve, PO Box C700, West Conshohocken, PA 19428-2959. United States12.2 AASHTO Standards:3AASHTO PP2 Practice for Short and Long Term Aging of Hot Mix Asphalt (HMA).AASHTO PP35 Provisional Practice for Evaluation of Superpave Gyratory Compactors (SGCs)PP76 Standard Practice for Troubleshooting Asphalt
17、Specimen Volumetric Differences between Superpave Gyratory Compac-tors (SGCs) Used in the Design and the Field Management of Superpave MixturesAASHTO PP48R30 Standard Practice for Evaluation of Superpave Gyratory Compactor (SGC) Internal Angle of Gyration-Mixture Conditioning of Hot Mix Asphalt (HMA
18、)R35 Standard Practice for Superpave Volumetric Design for Hot Mix Asphalt (HMA)R47 Standard Practice for Reducing Samples of Hot Mix Asphalt (HMA) to Testing SizeAASHTO T312 Standard Method of Test for Preparing and Determining the Density of Hot-MixAsphalt (HMA) Specimens bymeansMeans of the Super
19、pave Gyratory Compactor32.3 Other References:ANSIASME B46.1 American National Standards InstituteSurface Texture (Surface Roughness, Waviness, and Lay)4Asphalt Institute MS-2 Mix Design Methods for Asphalt Concrete53. Terminology3.1 This test method uses terms as defined by Terminology D8.3.2 Defini
20、tions of Terms Specific to This Standard:3.2.1 lab mix lab compacted (LMLC) asphalt mixture, nasphalt mix samples that are prepared in the laboratory by weighingand blending each constituent then compacting the blended mixture using a laboratory compaction apparatus.3.2.1.1 DiscussionLMLC typically
21、occurs during the asphalt mixture design phase. Laboratory compaction devices such as the Superpave GyratoryCompactor, Marshall Hammer or other laboratory compaction devices may be used.3.2.2 plant mix laboratory compacted (PMLC) asphalt mixture, nasphalt mixture samples that are manufactured in apr
22、oduction plant, sampled prior to compaction, then immediately compacted using a laboratory compaction apparatus.3.2.2.1 DiscussionPMLC specimens are often used for quality control testing. The asphalt mixture is not permitted to cool substantially and it maybe necessary to place the mixture in a lab
23、oratory oven to equilibrate the mixture to the compaction temperature before molding.Laboratory compaction devices such as the Superpave Gyratory Compactor, Marshall Hammer or other laboratory compactiondevices may be used.3.2.3 reheated plant mix lab compacted (RPMLC) asphalt mixture, nasphalt mixt
24、ure samples that are manufactured in aproduction plant, sampled prior to compaction, allowed to cool to room temperature, then reheated in a laboratory oven andcompacted using a laboratory compaction apparatus.3.2.3.1 DiscussionRPMLC are often used for acceptance and verification testing. The reheat
25、ing time should be as short as possible to obtain uniformtemperature to avoid artificially aging the specimens.Asphalt mixture conditioning, reheat temperature, and reheat time should bedefined in the applicable specification. Laboratory compaction devices such as the Superpave Gyratory Compactor, M
26、arshallHammer, or other laboratory compaction devices may be used.4. Significance and Use4.1 This test method is used to prepare specimens for determining the volumetric and physical properties of compactedHMAasphalt mix.4.2 This test method is useful for monitoring the density of test specimens dur
27、ing the compaction process. This test method issuited for the laboratory design and design, field control of HMA.asphalt mix, forensics, imaging, and visualization of compactedasphalt mix.3 Available from American Association of State Highway and Transportation Officials (AASHTO), 444 N. Capitol St.
28、, NW, Suite 249, Washington, DC 20001,http:/www.transportation.org.4 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, Society of Mechanical Engineers (ASME), ASME International Headquarters,Two Park Ave., New York, NY 10036, http:/www.ansi.org.10016-5990, http:
29、/www.asme.org.5 Available from Asphalt Institute, 2696 Research Park Dr., Lexington, KY 40511, http:/www.asphaltinstitute.org.D6925 152NOTE 1The quality of the results produced by this standard are dependent on the competence of the personnel performing the procedure and thecapability, calibration,
30、and maintenance of the equipment used. Agencies that meet the criteria of Standard Practice Specification D3666 are generallyconsidered capable of competent and objective testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with PracticeSpeci-fication D3666 alone doe
31、s not completely assure reliable results. Reliable results depend on many factors; following the suggestions ofPracticeSpecification D3666 or some similar acceptable guideline provides a means of evaluating and controlling some of those factors.5. Apparatus5.1 Superpave Gyratory CompactorAn electrom
32、echanical, electro-hydraulic, or electro-pneumatic compactor comprised ofthe following system components: (1) reaction frame, and drive motor,system, (2) loading system, loading ram, and pressureindicator, and (3) recording system for height measurement and number of gyrations, and gyrations.(4) mol
33、d and base plate.5.1.1 The reaction frame shall provide a non-compliant structure against which the vertical loading ram can push compactionpressure can be applied when compacting specimens. Reaction bearings shall be capable of creating, and firmly maintaining duringthe compaction process, an exter
34、nal angle of gyration of 21.8 6 0.4 mrad (1.25 6 0.02 degrees).NOTE 2Research has shown external angle (measurement between the external mold wall and the frame of the compactor) to be different from theinternal angle (measurement between internal mold wall and top and bottom plate). The difference
35、between these measurements varies for different typesof compactors. Some discrepancies in relative density have been resolved by use of the internal angle adjustment.Agencies may choose the internal angleas the basis for calibration. If internal angle is chosen for calibration the recommendation of
36、the Superpave expert task group is to use an internal angleof 20.2 6 0.4 mrad (1.16 6 0.02 degrees). (See AASHTO PP48 for the procedure to determine the internal angle).5.1.2 The compactor shall be designed to gyrate the mold at a constant angle of gyration during the compaction process. Aninternal
37、angle of gyration of 20.25 6 0.35 mrad (1.16 6 0.02) as determined by Test Method D7115 shall be utilized.NOTE 2Research has shown external angle (measurement between the external mold wall and the frame of the compactor) to be different from theinternal angle (measurement between internal mold wall
38、 and top and bottom plate). The difference between these measurements varies for different typesof compactors. Some discrepancies in relative density have been resolved by use of the internal angle. If the external angle is chosen for operation therecommendation is to use an external angle of 21.82
39、6 0.435 mrad (1.25 6 0.02).5.1.3 The rotating base and drive motorgyration drive system shall be capable of gyrating the specimen at a rate of 30.0 6 0.5revolutions per minute. The compactorsystem shall be designed to permit the specimen mold to gyrate freely on its tilted axisduring compaction.capa
40、ble of gyrating the specimen 250 gyrations.5.1.4 The loading system, ram, and pressureforce indicator shall be capable of providing and measuring a constant vertical forceto provide an applied pressure of 600 6 60 kPa during the first five gyrations, and 600 6 18 kPa during the remainder of thecompa
41、ction process. The applied pressure is defined as the applied force divided by the area of the nominal mold diameter (150mm).NOTE 3The report on the ruggedness evaluation of AASHTO TP4 (T312)6 indicated that the pressure tolerance of 618 kPa resulted in significantlydifferent values of bulk specific
42、 gravity of the compacted specimens (Gmb) in some cases. However, since the pressure is directly set at 600 kPa, thetolerance of 618 kPa should apply only to the ability of the SGC to maintain vertical pressure during compaction. To minimize potential errors causedby pressure, operators should take
43、care during verification of calibration to assure that the specified pressure has been attained.5.1.5 The axis of the loading ram shall be perpendicular to the platenplatens of the compactor.5.1.6 The height measurement and recording system shall be capable of continuously measuring and recording th
44、e height of thespecimen during the compaction process to the nearest 0.1 mm. The height shall be recorded once per gyration.5.1.7 The system shall record test information, such as specimen heights per gyration. This may be accomplished through dataacquisition or printing.5.1.8 The system shall be ca
45、pable of stopping at a specified number of gyrations or at a specified height through automaticcontrol or operator input.5.2 Specimen MoldsSpecimen molds shall have steel walls that are at least 7.5 mm thick and are hardened to Rockwell C48or better. Molds New molds shall have an inside diameter of
46、149.90 mm to 150.00 mm and be at least 250 mm high. The insidediameter of molds in service shall be 149.90 to 150.20 mm. The inside finish of the molds shall be smooth (rms of 1.60 mmmor smoother when measured in accordance with ANSIASME B46.1).5.3 Mold Plates and Ram HeadsAll mold plates and ram he
47、ads in contact with the mixture shall be fabricated from steel witha minimum Rockwell hardness of C48. The mold plates and ram heads shall be flat. Mold plates and ram heads (if head surfacesin contact with the HMA specimen) shall mixture shall be flat and shall have an outside diameter of 149.50 mm
48、 to 149.75 mm.5.4 ThermometersArmored, glass, or dial type thermometers with metal stems Calibrated liquid-in-glass thermometers ofsuitable range with subdivisions 0.2F (0.1C) or 0.5F (0.2C) conforming to the requirements of Specification E2251fordetermining the temperature of aggregates, asphalt bi
49、nders, and asphalt mixtures between 10C and 232C, with a minimumsensitivity of 3C. shall be used (ASTM Thermometer Numbers S67F-03 or S67C-03; S65F-03 or S65C- 03; S63F-03 or S63C-03;or equivalent). Alternatively, other thermometer may be used, for example resistance thermometer (RTD, PRT, IPRT) of equal orbetter accuracy. Calibrate the temperature measurement system (probe and readout) to ensure accurate measurements within63C.6 The Superpave Gyratory Compactor, McGennis, R; Kennedy, TW; Anderson, VL; Perdomo, D, Journal of the Association of Asphal
