1、Designation: D7115 10Standard Test Method forMeasurement of Superpave Gyratory Compactor (SGC)Internal Angle of Gyration Using Simulated Loading1This standard is issued under the fixed designation D7115; the number immediately following the designation indicates the year oforiginal adoption or, in t
2、he 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 procedure for the measure-ment of the Superpave Gyratory
3、Compactor (SGC) internalangle of gyration using an instrument capable of simulatingloading conditions similar to those created by a hot mix asphaltspecimen.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.2.1 IEEE/ASTM SI 1
4、0, American National Standard forthe Use of International System of Units (SI): The ModernMetric System, offers guidance where use of decimal degreesfor plane angles (versus radians) and revolutions per minute forrate of gyration (versus radians per second) is acceptablewithin the IEEE/ASTM SI 10 sy
5、stem when used on a minimalbasis.1.3 The text of this test method references notes andfootnotes which provide explanatory material. These notes andfootnotes (excluding those in tables and figures) shall not beconsidered as requirements of the standard1.4 This standard does not purport to address all
6、 of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C670 Practice for Pre
7、paring Precision and Bias Statementsfor Test Methods for Construction MaterialsD2726 Test Method for Bulk Specific Gravity and Densityof Non-Absorptive Compacted Bituminous MixturesD3666 Specification for Minimum Requirements for Agen-cies Testing and Inspecting Road and Paving MaterialsD6752 Test M
8、ethod for Bulk Specific Gravity and Densityof Compacted Bituminous Mixtures Using AutomaticVacuum Sealing MethodD6925 Test Method for Preparation and Determination ofthe Relative Density of Hot Mix Asphalt (HMA) Speci-mens by Means of the Superpave Gyratory CompactorE691 Practice for Conducting an I
9、nterlaboratory Study toDetermine the Precision of a Test MethodIEEE/ASTM SI 10 American National Standard for the Useof International System of Units (SI): The Modern MetricSystem3. Terminology3.1 Definitions:3.1.1 external anglethe angle formed between the exter-nal mold diameter and a stationary r
10、eference axis of themachine frame.3.1.2 internal anglethe angle formed between the internalmold diameter and a mold end plate as a mold is gyrated in anSGC.3.1.3 top internal anglethe angle formed between theinternal mold diameter and the upper mold end plate as a moldis gyrated in an SGC.3.1.4 bott
11、om internal anglethe angle formed between theinternal mold diameter and the lower mold end plate as a moldis gyrated in an SGC.3.1.5 effective internal anglethe average of the top inter-nal angle and the bottom internal angle.3.1.6 tilting momenta force (F) acting at one end of anSGC mold platen in
12、a direction parallel to the axis of gyration,but acting at some distance (e) away from that axis. The tilting1This test method is under the jurisdiction of ASTM Committee D04 on Roadand Paving Materials and is the direct responsibility of Subcommittee D04.20 onMechanical Tests of Bituminous Mixtures
13、.Current edition approved June 1, 2010. Published June 2010. Originallyapproved in 2005. Last previous edition approved in 2008 as D7115 08. DOI:10.1520/D7115-10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book
14、of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.moment at one end of the mold platen is computed as theproduct of this distance (e)
15、and force (F).3.1.7 total momentthe sum total (M) of the tilting momentacting at the top of the mold and the tilting moment acting atthe bottom of the mold.3.1.8 eccentricitythe distance (e) away from the axis ofgyration at which a force (F) is acting at one end of an SGCmold. This use of the term e
16、ccentricity is consistent withprevious published reports describing the mechanics of gyra-tory compaction.33.1.9 standard SGC volumetric specimena standard sizedhot mix asphalt specimen prepared using an SGC for purposesof volumetric mix design. Such a standard specimen, preparedin accordance with T
17、est Method D6925, has a diameter of 150mm and a final compacted height of 115 6 5 mm.4. Summary of Test Method4.1 The internal angle of gyration of an SGC is measureddynamically with an instrument inserted into the SGC mold.4.2 A load (moment) is induced on the SGC while theinternal angle is simulta
18、neously measured. The simulatedloading conditions are similar to those created by compactionof a standard SGC volumetric specimen.4.3 The internal angles at each end of the mold are mea-sured and then averaged to obtain the effective internal angle ofgyration.5. Significance and Use5.1 SGCs are used
19、 to produce hot-mix asphalt (HMA)specimens in the laboratory to assess volumetric properties andpredict pavement performance. In the fabrication of an SGCspecimen in accordance with Test Method D6925, loose HMAis placed inside a metal mold, which is then placed into anSGC. A constant consolidation p
20、ressure is applied to thesample while the mold gyrates at a nominally constant angle(referred to as the angle of gyration) and rate. Consistency inthe density of the asphalt specimens produced as measured byTest Methods D2726 or D6752 is very important to the validityof the tests performed. Specimen
21、s of a consistent density areproduced when an SGC maintains a constant pressure and aknown constant angle of gyration during the compactionprocess.5.2 There are several manufacturers and models of SGC.Each model employs a unique method of setting, inducing, andmaintaining the angle of gyration. Each
22、 model also employs aunique calibration system to measure the external angle ofgyration. These existing calibration systems can not be useduniversally on all of the different SGC models commerciallyavailable. Inconsistencies in asphalt specimens produced ondifferent SGC models have been at least par
23、tially attributed tovariations in the angle of gyration.5.3 This method describes instruments and processes thatcan be used to independently measure the internal angle ofgyration of any manufacturers SGC model under simulatedloading conditions. The external shape of the instrumentchassis assures tha
24、t the points of physical contact between themold end plates and the instrument occur at a fixed and knowndistance away from the axis of gyration.As a result, the verticalload is applied at these fixed points, creating tilting moments ateach end of the mold.5.4 Unless otherwise specified, a tilting m
25、oment of 466.5N-m shall be applied to the SGC by the instrument whilemaking this measurement.NOTE 1The quality of the results produced by this test method aredependent on the competence of the personnel performing the procedureand the capability, calibration, and maintenance of the equipment used.Ag
26、encies that meet the criteria of Practice D3666 are generally consideredcapable of competent and objective testing/sampling/inspection/etc. Usersof this test method are cautioned that compliance with Practice D3666alone does not completely assure reliable results. Reliable results dependon many fact
27、ors; following the suggestions of Practice D3666 or somesimilar acceptable guideline provides a means of evaluating and control-ling some of those factors.NOTE 2A 466.5 N-m tilting moment corresponds to a 22 mmeccentric on the AFLS1 or a 21 deg cone angle on the DAVII-HMS withan applied load of 1060
28、3 N (600 kPa at a 150 mm diameter specimensetting).6. Interferences6.1 Debris on the SGC mold, base plates, ram head, reactionsurfaces, or instrument can cause errant measurement results.Extreme care should be taken to thoroughly clean the SGC,mold, instrument, and any work areas that will be utiliz
29、edduring the measurement procedure.6.2 Scarring or irregular surfaces on mold walls and endplates is also known to cause incorrect results. Do not use anyequipment that shows signs of damage. The precision requiredin the execution of this test method necessitates that extremecare must be taken to av
30、oid errors from damaged or improperlymaintained equipment.7. Apparatus7.1 An instrument capable of being gyrated inside an SGCmold which induces tilting moments at each end of the SGCmold while simultaneously measuring an internal angle ofgyration.7.1.1 Data AcquisitionThe timing of the data acquisi
31、tionsystem may be automatically triggered by the start of thegyration process. Provision for excluding a known number ofinitial gyrations from the angle measurement may be provided(initial delay period), and the angle shall be measured through-out a known number of subsequent gyrations (data acquisi
32、tionperiod). The durations of the initial delay and the dataacquisition periods may be programmable or fixed.7.1.2 Display OptionsThe angle measurement result(s)may be viewable on a display built into the instrument chassisor retrievable from the instrument by means of a communica-tions port, or bot
33、h.7.1.3 Temperature MeasurementThe instrument may op-tionally have a means for displaying, recording, or otherwiseindicating its internal temperature during the angle measure-ment process.7.1.4 Static Angle GageA National Institute of Standardsand Technology (NIST)-traceable angle gage device with o
34、ne3Guler, M., Bahia, H. U., Bosscher, P. J., and Plesha, M. E., “Device forMeasuring Shear Resistance of Hot Mix Asphalt in Gyratory Compactor,” Trans-portation Research Record 1723, TRB, NationalAcademy of Sciences, Washington,DC, 2000, pp. 116124.D7115 102or more known angles used to calibrate and
35、 to verify thecalibration of the angle measurement instrument.7.1.5 Wear Protection PlatesThin steel plates (optional)which protect the SGC mold end plates from any cosmeticdamage by the contact rings.7.2 Superpave Gyratory Compactor (SGC) and associatedequipment as described in Test Method D6925. T
36、he SGC shallbe in good repair with the compaction pressure, specimenheight measurement system, and gyration rate verified to bewithin specifications. The mechanisms used to induce andmaintain the angle of gyration shall be set and maintainedwithin the manufacturers guidelines.7.2.1 The SGC molds, mo
37、ld end plates, base platens, andram head surface smoothness shall be confirmed to be withinthe specifications of Test Method D6925. Any equipment notmeeting these requirements shall not be used.8. Preparation of Apparatus8.1 Before each use of the angle measurement instrument,verify the angle measur
38、ement system using the static anglegage according to manufacturers instructions. The static anglegage, which can apply one or more known angles to theinstrument, is used to confirm that the instrument is operatingwithin calibration. The instrument and the static angle gagemust be at the same, unifor
39、m, stable temperature for theverification to be accurate.NOTE 3These instruments typically have an operating temperaturerange of 20 to 40C. Consult the manufacturers instructions for specifictemperature limitations during calibration, verification, and use within theSGC.8.2 Be sure the probe tips an
40、d contact rings on the anglemeasurement instrument are free of debris.8.3 Prepare a clean compaction mold assembly.NOTE 4Accumulation of HMA on mold surfaces, mold end plates,base platens, or ram head surfaces, or combination thereof, directlyimpacts the instruments ability to accurately measure the
41、 angle ofgyration. Use mineral spirits or another appropriate solvent to clean thesesurfaces.8.4 Perform the angle measurement with the SGC mold atroom temperature. Optionally, the measurement may be madewith the mold at an elevated temperature. If the angle mea-surement is to be made at an elevated
42、 temperature, then placethe SGC mold in an oven at the desired temperature 6 5C fora minimum of 45 min prior to making the first angle measure-ment. Do not place the angle measurement instrument in theoven. Mold temperatures other than room temperature usedduring angle measurement shall be noted on
43、the report.NOTE 5The SGC manufacturer may recommend measurement of theangle at an elevated temperature for those SGC models where the anglechanges with mold temperature.NOTE 6These instruments typically have an operating temperaturerange of 20 to 40C. After use in a hot mold, the angle measurementin
44、strument can be cooled by using a fan to blow ambient air over theinstrument or by placing it in front of an air conditioner. Elevating theinstrument above the table surface so as to permit maximum airflow overthe entire instrument will increase the rate of cooling. Do not cool theinstrument below r
45、oom temperature. Consult the manufacturers instruc-tions for specific temperature limitations during calibration, verification,and use within the SGC.8.5 Verify the settings on the compactor. Unless notedotherwise, the SGC shall be initialized to provide specimencompaction using a consolidation pres
46、sure of 600 6 18 kPa,and the gyration rate shall be 30 6 0.5 rpm.8.6 Set the number of gyrations on the SGC in accordancewith the recommendations of the manufacturer of the anglemeasurement instrument. Typically, ten gyrations are sufficientto obtain an accurate angle measurement using simulatedload
47、ing.9. Calibration and Standardization9.1 The angle measurement instrument requires periodicstandardization. The system shall be standardized prior toinitial use and at least once every 12 months thereafter. Thisannual standardization shall follow instrument manufacturerrecommendations and include t
48、he following:9.1.1 Standardization of the static angle gage with a NISTtraceable measurement system, and9.1.2 Standardization of the angle measurement instrument.10. Procedure10.1 The average internal angle is based on six individualangle measurements as follows:10.1.1 The top internal angle is meas
49、ured in triplicate.10.1.2 The bottom internal angle is measured in triplicate.10.2 Each of the six individual angle measurements isperformed as follows:10.2.1 Arm the angle measurement instrument for collect-ing data.10.2.2 Place the angle measurement instrument inside theSGC mold. Orient the instrument probes or reference base asappropriate to measure the top or bottom angle.NOTE 7The operator may wish to use a specimen extruder to elevatethe bottom mold plate to a position where insertion of the anglemeasurement instrument into the SGC mold is easier
