1、Designation: D 7115 05Standard Test Method forMeasurement of Superpave Gyratory Compactor (SGC)Internal Angle of Gyration Using Simulated Loading1This standard is issued under the fixed designation D 7115; the number immediately following the designation indicates the year oforiginal adoption or, in
2、 the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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 Gyrato
3、ry Compactor (SGC) internalangle of gyration using an instrument capable of simulatingloading conditions similar to those created by a hot mix asphaltspecimen.1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user
4、 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:2D 2726 Test Method for Bulk Specific Gravity and Densityof Non-Absorptive Compacted Bituminous MaterialsD 6752 Te
5、st Method for Bulk Specific Gravity and Densityof Compacted Bituminous Mixtures Using AutomaticVacuum Sealing MethodD 6925 Test Method for the Preparation and Determinationof the Relative Density of Hot Mix Asphalt (HMA)Specimens by Means of the Superpave Gyratory Compac-torE 691 Practice for Conduc
6、ting an Inter-laboratory Study toDetermine the Precision of a Test Method3. Terminology3.1 Definitions:3.1.1 external anglethe angle formed between the exter-nal mold diameter and a stationary reference axis of themachine frame.3.1.2 internal anglethe angle formed between the internalmold diameter a
7、nd a mold end plate as a mold is gyrated in aSuperpave Gyratory Compactor.3.1.3 top internal anglethe angle formed between theinternal mold diameter and the upper mold end plate as a moldis gyrated in a Superpave Gyratory Compactor.3.1.4 bottom internal anglethe angle formed between theinternal mold
8、 diameter and the lower mold end plate as a moldis gyrated in a Superpave Gyratory Compactor.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 a direction parallel to the axis o
9、f gyration,but acting at some distance (e) away from that axis. The tiltingmoment at one end of the mold platen is computed as theproduct of this distance (e) 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 bott
10、om 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 eccentricity is consistent withprevious published reports describing the mechanics of gyra-tory compaction.33.1.9 standard SGC volumetric spec
11、imena standard sizedhot mix asphalt specimen prepared using an SGC for purposesof volumetric mix design. Such a standard specimen, preparedin accordance with Test Method D 6925, 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 gyra
12、tion 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 simultaneously measured. The simulatedloading conditions are similar to those created by compactionof a standard SGC volumetric specimen.4.3 The in
13、ternal angles at each end of the mold are mea-sured and then averaged to obtain the effective internal angle ofgyration.1This 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 Bitumino
14、us Mixtures.Current edition approved Feb. 1, 2005. Published February 2005.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe
15、 ASTM website.3Guler, 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. 116-124.1Copyright ASTM International, 100 Bar
16、r Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5. Significance and Use5.1 SGCs are used 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 T
17、est Method D 6925, loose HMAis placed inside a metal mold, which is then placed into anSGC. A constant consolidation pressure 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 specimen
18、s produced as measured byTest Method D 2726 or D 6752 is very important to the validityof the tests performed. Specimens 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 manufacturer
19、s and models of SGC.Each model employs a unique method of setting, inducing, andmaintaining the angle of gyration. Each 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 mo
20、dels commerciallyavailable. Inconsistencies in asphalt specimens produced ondifferent SGC models have been at least partially 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
21、 any manufacturers SGC model under simulatedloading conditions. The external shape of the instrumentchassis assures that 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 app
22、lied at these fixed points, creating tilting moments ateach end of the mold.5.4 Unless otherwise specified, tilting moments correspond-ing to an eccentricity of 22 mm shall be used to simulate theloading conditions of a standard SGC volumetric specimen.6. Interferences6.1 Debris on the SGC mold, bas
23、e plates, ram head, reactionsurfaces, or on the instrument can cause errant measurementresults. Extreme care should be taken to thoroughly clean theSGC, mold, instrument, and any work areas that will beutilized during the measurement procedure.6.2 Scarring or irregular surfaces on mold walls and end
24、plates 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 avoid errors from damaged or improperlymaintained equipment.7. Apparatus7.1 An instrument cap
25、able 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 acquisitionsystem may be automatically triggered by the start of thegyration process. Provision fo
26、r 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 acquisitionperiod). The durations of the initial delay and the dataacquisition periods may be prog
27、rammable or fixed.7.1.2 Display OptionsThe angle measurement result(s)may be viewable on a display built into the instrument chassisand/or retrievable from the instrument via a communicationsport.7.1.3 Temperature MeasurementThe instrument may op-tionally have a means for displaying, recording or ot
28、herwiseindicating its internal temperature during the angle measure-ment process.7.1.4 Static Angle GageA NIST-traceable angle gagedevice with one or more known angles used to calibrate and toverify the calibration of the angle measurement instrument.7.1.5 Wear Protection PlatesThin steel plates (op
29、tional)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 D 6925. The SGC shallbe in good repair with the compaction pressure, specimenheight measurement system, and gyration ra
30、te 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, mold end plates, base platens, andram head surface smoothness shall be confirmed to be withinthe specifications
31、of Test Method D 6925. 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 measurement system using the static anglegage according to manufacturers instructions. The static anglegage, which
32、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, uniform, stable temperature for theverification to be accurate.NOTE 1These instruments typically have an operating
33、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 and contact rings on the anglemeasurement instrument are free of debris.8.3 Prepare a clean compaction mold ass
34、embly.NOTE 2Accumulation of HMA on mold surfaces, mold end plates,base platens, and/or ram head surfaces directly impacts the instrumentsability to accurately measure the angle of gyration. Use mineral spirits oranother appropriate solvent to clean these surfaces.8.4 Perform the angle measurement wi
35、th 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 temperature, then placethe SGC mold in an oven at the desired temperature 6 5C fora minimum of 45 min prior to making the first
36、angle measure-ment. Do not place the angle measurement instrument in theD7115052oven. Mold temperatures other than room temperature usedduring angle measurement shall be noted on the report.NOTE 3The SGC manufacturer may recommend measurement of theangle at an elevated temperature for those SGC mode
37、ls where the anglechanges with mold temperature.NOTE 4These instruments typically have an operating temperaturerange of 20 to 40C. After use in a hot mold, the angle measurementinstrument can be cooled by using a fan to blow ambient air over theinstrument or by placing it in front of an air conditio
38、ner. 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 room temperature. Consult the manufacturers instruc-tions for specific temperature limitations during calibration, verific
39、ation,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 pressure 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 accordance
40、with the recommendations of the manufacturer of the anglemeasurement instrument. Typically, 10 gyrations are sufficientto obtain an accurate angle measurement using simulatedloading.9. Calibration and Standardization9.1 The angle measurement instrument requires periodicstandardization. The system sh
41、all be standardized prior toinitial use and at least once every 12 months thereafter. Thisannual standardization shall follow instrument manufacturerrecommendations and include the following:9.1.1 Standardization of the static angle gage with a NISTtraceable measurement system, and9.1.2 Standardizat
42、ion of the angle measurement instrument.10. Procedure10.1 The average internal angle is based on four individualangle measurements as follows:10.1.1 The top internal angle is measured twice. If the tworesults do not match to within 0.02, repeat until two readingsmatch within 0.02.10.1.2 The bottom i
43、nternal angle is measured twice. If thetwo results do not match to within 0.02, repeat until tworeadings match within 0.02.10.2 Each of the four 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 in
44、strument inside theSGC mold. Orient the instrument probes or reference base asappropriate to measure the top or bottom angle.NOTE 5The 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 ea
45、sier.10.2.3 Place the SGC mold inside the SGC.NOTE 6For some SGCs, it may be more convenient to first place themold in the SGC, and then place the angle measurement instrument in themold.10.2.4 Initiate the compaction process. For most SGCs, thisis an automatic process consisting of pressing a butto
46、n to startthe compaction process. The SGC automatically applies theram pressure, induces the angle, and gyrates the mold to thespecified number of gyrations.10.2.5 Remove the angle measurement instrument from theSGC mold.NOTE 7Use caution when removing the instrument, especially whenusing a power ex
47、truder. Take care that the instrument does not get caughtor damaged during the extrusion process.10.2.6 Record the angle result reported by the instrument tonearest 0.01. Record which angle (top or bottom) and whichreplicate (1 or 2) was measured.11. Calculations11.1 Calculate the average top intern
48、al angle as follows:average top internal angle 5 (1)top internal angle 1 1 top internal angle 2!211.2 Calculate the average bottom internal angle as follows:average bottom internal angle 5 (2)bottom internal angle 1 1 bottom internal angle 2!211.3 Calculate the effective internal angle as follows:ef
49、fective internal angle 5 (3)average top internal angle 1 1 average bottom internal angle 2!212. Report12.1 The report shall contain the following information:NOTE 8A sample report is provided in Appendix X1.12.1.1 SGC Information: Manufacturer, Model No., S/N,Owner, Location, Number of Gyrations, Consolidation Pres-sure, and Mold Temperature used during angle measurementprocess,12.1.2 Angle Measurement Instrument Identification:Manufacturer, S/N, Date of Calibration, Due Date for nextcalibration, and eccentricity,NOTE 9Consult the instrument manuf
