1、Designation: D8079 16Standard Practice forPreparation of Compacted Slab Asphalt Mix Samples Usinga Segmented Rolling Compactor1This standard is issued under the fixed designation D8079; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisio
2、n, 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 practice covers the fabrication of slabs of asphaltmix using an automated laboratory rolling compa
3、ctor (RC).Compacted specimens are suitable for volumetric and physicalproperty testing. This practice should not be used for accep-tance or rejection of a material or for purchasing purposes.1.2 UnitsThe values stated in SI units are to be regardedas standard. No other units of measurement are inclu
4、ded in thisstandard.1.3 The text of this standard references notes and footnoteswhich provide explanatory material. These notes and footnotes(excluding those in tables and figures) shall not be consideredas requirements of the standard.1.4 This standard does not purport to address all of thesafety c
5、oncerns, 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:2D979/D979M Practice for Sampling Bit
6、uminous PavingMixturesD1188 Test Method for Bulk Specific Gravity and Density ofCompacted Bituminous Mixtures Using Coated SamplesD2041 Test Method for Theoretical Maximum SpecificGravity and Density of Bituminous Paving MixturesD2726 Test Method for Bulk Specific Gravity and Densityof Non-Absorptiv
7、e Compacted Bituminous MixturesD3666 Specification for Minimum Requirements for Agen-cies Testing and Inspecting Road and Paving MaterialsD6752 Test Method for Bulk Specific Gravity and Densityof Compacted Bituminous Mixtures Using AutomaticVacuum Sealing MethodD6857 Test Method for Maximum Specific
8、 Gravity andDensity of Bituminous Paving Mixtures Using AutomaticVacuum Sealing MethodD7460 Test Method for Determining Fatigue Failure ofCompacted Asphalt Concrete Subjected to Repeated Flex-ural BendingE644 Test Methods for Testing Industrial Resistance Ther-mometers2.2 AASHTO Standards:3AASHTO T
9、321 Method of Test for Determining the FatigueLife of Compacted Asphalt Mixtures Subjected to Re-peated Flexural BendingAASHTO T 324 Method of Test for Hamburg Wheel-TrackTesting of Compacted Hot Mix Asphalt (HMA)AASHTO M 323 Specification for Superpave VolumetricMix Design2.3 Additional Resources:4
10、Asphalt Institute MS-2 Asphalt Mix Design Methods3. Terminology3.1 Definitions:3.1.1 rolling compactora device that uses a segment or arcof a circle composed of metal to compact asphalt mixture intoa slab.3.1.2 rolling compactor footthe portion of the device thatconsists of the segment or arc of a c
11、ircle composed of metalattached to the loading frame that rotates across the surface ofthe asphalt mixture.3.1.3 rolling compactor traythe portion of the device thatthe mold rests on during compaction. The tray can be stationaryor can move horizontally to facilitate compaction.3.2 Definitions of Ter
12、ms Specific to This Standard:3.2.1 lab mix lab compacted (LMLC) asphalt mixasphaltmix samples that are prepared in the laboratory by weighing1This practice is under the jurisdiction of ASTM Committee D04 on Road andPaving Materials and is the direct responsibility of Subcommittee D04.20 onMechanical
13、 Tests of Asphalt Mixtures.Current edition approved Dec. 1, 2016. Published December 2016. DOI:10.1520/D807916.2For 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 s
14、tandards Document Summary page onthe ASTM website.3Available from American Association of State Highway and TransportationOfficials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washington, DC 20001,http:/www.transportation.org.4Available from Asphalt Institute at: http:/bookstore.asphaltinstitute.or
15、g/catalog/book/ms-2-asphalt-mix-design-methods.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Dec
16、ision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organiziation Technical Barriers to Trade (TBT) Committee.1and blending each constituent and then compacting the blendedmix using a laboratory compaction apparatus.3.2.1.1 Discussi
17、onLMLC typically occurs during the as-phalt mix design phase.3.2.2 plant mix laboratory compacted (PMLC) asphaltmixasphalt mix samples that are manufactured in a produc-tion plant, sampled prior to compaction, then immediatelycompacted using a laboratory compaction apparatus.3.2.2.1 DiscussionPMLC s
18、pecimens are often used forquality control testing. Asphalt mix is not permitted to coolsubstantially and it may be necessary to place the mix in alaboratory oven to equilibrate the mix to the compactiontemperature before molding.3.2.3 reheated plant mix lab compacted (RPMLC) asphaltmixasphalt mix s
19、amples that are manufactured in a produc-tion plant, sampled prior to compaction, allowed to cool toroom temperature, then reheated in a laboratory oven andcompacted using a laboratory compaction apparatus.3.2.3.1 DiscussionRPMLCs are often used for qualityacceptance and verification testing. The re
20、heating time shouldbe as short as possible to obtain uniform temperature to avoidartificially aging the specimens. Asphalt mix conditioning,reheat temperature, and time should be defined in the appli-cable specification.4. Summary of Practice4.1 A sample of loose asphalt mix is compacted in anautoma
21、tic apparatus by the combination of vertical displace-ments of a segmented rolling compactor foot and horizontalmovements of a rolling compactor foot relative to the compac-tor tray to produce a slab of compacted asphalt with a targettheoretical density (that is, based on the geometric volume ofthe
22、specimen).5. Significance and Use5.1 Asphalt slabs compacted with the rolling compactor canbe used to obtain specimens for further testing, including bulkspecific gravity following Test Methods D1188, D2726, andD6752, fatigue performance characteristics following TestMethod D7460 or AASHTO T 321, an
23、d Hamburg wheel-tracktesting following AASHTO T 324.5.2 Specimens to perform other standard tests could also beobtained, as long as their volume is contained within thevolume of a slab.NOTE 1The quality of the results produced by this standard aredependent on the competence of the personnel performi
24、ng the procedureand the capability, calibration, and maintenance of the equipment used.Agencies that meet the criteria of Specification D3666 are generallyconsidered capable of competent and objective testing, sampling,inspection, etc. Users of this practice are cautioned that compliance withSpecifi
25、cation D3666 alone does not completely ensure reliable results.Reliable results depend on many factors following the suggestions ofSpecification D3666 or some similar acceptable guideline that provides ameans of evaluating and controlling some of those factors.6. Apparatus6.1 Segmented Rolling Compa
26、ctorA compactor capableof fabricating asphalt slabs comprised of the following systemcomponents: (1) reaction frame, (2) fully integrated loadingsystem, including loading rams, controller, and data acquisitionto record loads applied, height measurements, and number ofcycles, and (3) segmented rollin
27、g compactor foot and mold.The compactor must comply with the following specifications:6.1.1 Vertical load divided by the width of the moldperpendicular to the rolling direction is adjustable by the userup to at least 75 kg cm.NOTE 2The vertical load should be measured and controlled to anaccuracy of
28、 65 % of the applied load. The loading system used to achievethe required load can be electromechanical, pneumatic, or hydraulic.6.1.2 The capability to perform at least four load cyclesevery minute.6.1.3 The compactor must be capable of producing com-pacted slabs with minimum dimensions of 300 6 5
29、mm long,260 6 5 mm wide, and with a minimum height measured at thecenter of the slab of 38 mm.6.1.4 The controller must also be capable of automaticallyterminating the compaction run after meeting one of threetermination criteria: sample height, number of loading cycles,or target density. The contro
30、ller shall state that the compactionis finished and the termination criterion (height, cycles, ortheoretical density) shall be recorded.NOTE 3Since the dimensions of the mold and the mass of the mixtureare known, the theoretical density can be calculated.6.1.5 The reaction frame shall be rigid and c
31、apable ofsustaining the maximum forces generated during the compac-tion process. It shall also be able to sustain the reaction forcesbeing applied to the mold.6.1.6 The loading system (see Fig. 1) shall consist of a1. Rolling compactor foot 4. Mold2. Pivot 5. Rolling compactor tray3. Linear loading
32、point 6. SampleFIG. 1 Example Schematic of a Rolling CompactorD8079 162controlled vertical axis loading system capable of applying acompressive load to the mix during compaction. The systemshall be able to control the height of the rolling compactor footusing displacement or vertical load. The syste
33、m can use leverarms, electric motors, pneumatics, hydraulics, or a combinationthereof to control the height or load of the rolling compactorfoot.6.1.7 The machine shall be designed such that the rollingcompactor foot movement ensures constant distance betweenthe foot and bottom of the mold along eac
34、h cycle.6.2 Mold PlatesWear plates used on top and bottom of thespecimen and rolling compactor foot. All mold plates and therolling compactor foot shall be fabricated from metal strongenough to withstand the applied forces. The mold bottom plateshall be flat (0.5 mm over 300 mm).6.3 ThermometerA pla
35、tinum resistance thermometer(PRT), thermocouple, or dial-type thermometer with a range ofat least 10 C to 232 C. Calibrate the thermometer system(probe and readout) in accordance with Test Methods E644.Corrections shall be applied to ensure accurate measurementswithin 63 C.6.4 BalanceAt least one ba
36、lance with a minimum capacityof 8000 g, with a sensitivity of 0.1 g.6.5 OvenAt least one forced draft oven, capable of heatingthe asphalt binder, aggregates, and equipment to the compac-tion temperature specified by the asphalt binder manufacturer,and thermostatically controlled to 63 C. If short te
37、rm ovenaging is going to be conducted on the mix, an additional forceddraft oven capable of maintaining 63 C must be available foruse.6.6 MiscellaneousMiscellaneous equipment may include:flat bottom metal pans for heating aggregate and asphalt mixes;scoops; containers for heating asphalt binders; mi
38、xing spoons;spatulas; tine rake; protective gloves for handling hot equip-ment; portable aids to lift moderately heavy items in alaboratory setting; and mechanical mixers.7. Preparation of Apparatus7.1 Follow manufacturers recommendations for turning onthe rolling compactor.7.2 Place the mold in the
39、 oven at the selected compactiontemperature at least 30 min prior to loading the mix in thecompactor.7.3 Heat or coat any tools with an asphalt release agent toprevent mix from adhering to the tools.8. Preparation and Conditioning of the Loose Mix8.1 To prepare and condition the mix prior to compact
40、ion,follow local and national standards for preparation of samplesand adjust the quantities of materials such that the total mass ofthe mix produced in the laboratory or obtained from a plant issufficient to produce the required compacted specimen volumeand a companion loose mix sample suitable to d
41、etermine thetheoretical maximum specific gravity of the asphalt mixaccording to Test Methods D2041 or D6857.NOTE 4The total mass will depend on the target density of the slaband the slab width, length, and height. For typical asphalt mixes, weightsbetween 10 and 90 kg have been used to make slabs.8.
42、1.1 To obtain a sufficient mass of asphalt mix for PMLCor RPMLC mixes, use Practice D979/D979M. Otherwise, forLMLC mixes, prepare a sufficient quantity of asphalt mix usingAASHTO M 323 or Asphalt Institute MS-2.9. Procedure9.1 Preparation and Filling the Mold:9.1.1 Distribute the total mass to be us
43、ed during compactionin equal amounts in separate pans. Record the total mass to beplaced in the mold.NOTE 5Pans with net weights of asphalt mix between 5 kg and 7 kgare manageable during the compaction process.9.1.2 Heat mix to compaction temperature.9.1.3 Remove heated mold from oven and place it i
44、n a safeand convenient location.9.1.4 Transfer the loose mix from the pans into the mold.9.1.5 With a scoop, place 1.0 to 2.0 kg of mix in smallmounds evenly spaced throughout the mold to reduce segre-gation and to prevent low and high density areas. Spread outthe mounds with a spatula or tine rake
45、for each layer. Use avibrating motion with a spatula or rake to settle the mix and fitit within the mold.NOTE 6If the asphalt mix contains fiber reinforcement, follow thefiber manufacturers instructions for molding the sample to avoid fiberorientation bias.9.1.6 Once all the mix has been placed, spr
46、ead the surface ofmix such that it is approximately level with a spatula or tinerake.9.2 Compaction of a Specimen:9.2.1 Slide the mold and asphalt mix onto the rollingcompactor tray and lock the mold to the frame following themanufacturers instructions.9.2.2 Enter the number of cycles and height or
47、density toterminate the test. Load cycle is the horizontal linear move-ment of the rolling compactor foot or mold that allows therolling compactor foot to move from the edge of the compac-tion mold to the opposing edge and then return to the startinginitial edge. Select whether the rolling compactor
48、 foot will belowered by incremental height or load. Enter other specimeninformation as required in the rolling compactor software.NOTE 7Experienced operators can complete steps 9.1.3 9.2.2 in lessthan 5 min. To maintain temperature, the process should take no longerthan 10 min.9.2.3 Follow the manuf
49、acturers instructions to start thesample compaction. When the required vertical load or dis-placement is applied to the sample, compaction takes placeuntil one of the selected termination criteria, sample height,number of loading cycles, or target density, is achieved.9.2.4 When a termination criterion is achieved, the rollingcompactor foot is removed vertically to avoid further compac-tion.9.2.5 When the termination criteria cannot be achieved, therolling compactor should have software controls in place toterminate the compaction.D8079 1639.3 R
