1、Designation: D7064/D7064M 081Standard Practice forOpen-Graded Friction Course (OGFC) Mix Design1This standard is issued under the fixed designation D7064/D7064M; the number immediately following the designation indicates theyear of original adoption or, in the case of revision, the year of last revi
2、sion. A number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.Updated X2.2.1 and X2.3.1.6 editorially in December 20101. Scope1.1 This practice covers the mix design of open-gradedfriction course (OGFC
3、) using the superpave gyratory compac-tor (SGC) or other suitable forms of compaction. The OGFCmix design is based on the volumetric properties of the mix interms of air voids, and the presence of stone-on-stone contact.Information found in Guide D6932 should be reviewed beforestarting the mix desig
4、n. Where applicable, Specification D3666should be applied as a minimum for agencies testing andinspecting road and paving materials.1.2 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; the
5、refore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this stand
6、ard 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:2C29/C29M Test Method for Bulk Density (“Unit Weight”)and Voids in AggregateC127 Test Method for Density, Relative Density (Spec
7、ificGravity), and Absorption of Coarse AggregateC131 Test Method for Resistance to Degradation of Small-Size Coarse Aggregate by Abrasion and Impact in the LosAngeles MachineC136 Test Method for Sieve Analysis of Fine and CoarseAggregatesC1252 Test Methods for Uncompacted Void Content ofFine Aggrega
8、te (as Influenced by Particle Shape, SurfaceTexture, and Grading)D946 Specification for Penetration-Graded Asphalt Cementfor Use in Pavement ConstructionD2041 Test Method for Theoretical Maximum SpecificGravity and Density of Bituminous Paving MixturesD2419 Test Method for Sand Equivalent Value of S
9、oils andFine AggregateD3203 Test Method for Percent Air Voids in CompactedDense and Open Bituminous Paving MixturesD3381 Specification for Viscosity-Graded Asphalt Cementfor Use in Pavement ConstructionD3666 Specification for Minimum Requirements for Agen-cies Testing and Inspecting Road and Paving
10、MaterialsD4791 Test Method for Flat Particles, Elongated Particles,or Flat and Elongated Particles in Coarse AggregateD5821 Test Method for Determining the Percentage ofFractured Particles in Coarse AggregateD6114 Specification for Asphalt-Rubber BinderD6373 Specification for Performance Graded Asph
11、altBinderD6390 Test Method for Determination of Draindown Char-acteristics in Uncompacted Asphalt MixturesD6752 Test Method for Bulk Specific Gravity and Densityof Compacted Bituminous Mixtures Using AutomaticVacuum Sealing MethodD6857 Test Method for Maximum Specific Gravity andDensity of Bituminou
12、s Paving 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 CompactorD6926 Practice for Preparation of Bituminous SpecimensUsing Marshall ApparatusD6932 Guide f
13、or Materials and Construction of Open-Graded Friction Course Plant Mixtures2.2 AASHTO Standards:3R30Mixture Conditioning of Hot Mix Asphalt (HMA)1This practice is under the jurisdiction of ASTM Committee D04 on Road andPaving Materials and is the direct responsibility of Subcommittee D04.23 onPlant-
14、Mixed Bituminous Surfaces and Bases.Current edition approved Aug. 1, 2008. Published August 2008. Originallyapproved in 2004. Last previous edition approved in 2004 as D7064 04. DOI:10.1520/D7064_D7064M-08.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer
15、Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards 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:/w
16、ww.transportation.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.T 283 Resistance of Compacted Bituminous Mixture toMoisture-Induced Damage32.3 Other References:TRB Synthesis 284NCAT Report No. 2001-01 Design, Construction, and
17、Per-formance of New-Generation Open-Graded FrictionCourses3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 open-graded friction course (OGFC), nspecial typeof hot mix asphalt surface mixture used for reducing hydro-planing and potential for skidding, where the function of themi
18、xture is to provide a free-draining layer that permits surfacewater to migrate laterally through the mixture to the edge of thepavement.3.1.2 air voids (Va), nthe total volume of the smallpockets of air between the coated aggregate particles through-out a compacted paving mixture, expressed as a per
19、cent of thetotal volume of the compacted specimen.3.1.3 voids in coarse aggregate (VCA), nthe volume inbetween the coarse aggregate particles, where this volumeincludes filler, fine aggregate, air voids, asphalt, and fiber, ifused.3.1.4 nominal maximum size of aggregate, nin specifica-tions for, or
20、descriptions of aggregate, the smallest sieveopening through which the entire amount of aggregate ispermitted to pass.3.1.4.1 DiscussionSpecifications on aggregates usuallystipulate a sieve opening through which all of the aggregatemay, but need not, pass so that a stated maximum proportion ofthe ag
21、gregate may be retained on that sieve.Asieve opening sodesignated is the nominal maximum aggregate size.3.1.5 maximum aggregate size, nin specifications for, ordescriptions of aggregate, the smallest sieve opening throughwhich the entire amount of aggregate is required to pass.3.1.6 stabilizing addi
22、tive, npolymer, crumb rubber, orfibers, or both, used to minimize draindown of the asphaltduring transport and placement of the OGFC.4. Summary of Practice4.1 Materials SelectionAggregates, asphalt, and additivesthat meet specification are selected.4.2 Select Optimum GradingAt least three trial aggr
23、egategradings from the selected aggregate stockpiles are blended.Gradings for OGFC are based on volume. The dry-rodded unitweight for the coarse aggregate for each trial grading isdetermined in accordance with Test Method C29/C29M. Foreach trial grading, an initial trial asphalt content between 6.0a
24、nd 6.5 % (generally higher for asphalt-rubber SpecificationD6114) is selected and at least two specimens are compactedusing 50 gyrations of the Superpave Gyratory Compactor(SGC) (Test Method D6925) or other suitable compactor. Anoptimum grading is selected to ensure stone-on-stone contact.NOTE 1If a
25、 standard aggregate grading and asphalt content has beensuccessfully used, three trial gradings may not be necessary. Examples ofcommonly used gradings and asphalt contents are shown in Appendix X1.4.3 Design Asphalt Content SelectionReplicate speci-mens are compacted using 50 gyrations of a SGC or
26、othersuitable compactor at three asphalt contents. The designasphalt content is selected on the basis of satisfactory conform-ance with the requirements of Section 12.4.4 Evaluating Moisture SusceptibilityThe moisture sus-ceptibility of the designed mixture shall be evaluated using theAASHTO T 283 t
27、est method. If the mixture fails the selectedmoisture susceptibility requirement, it is suggested that appro-priate modifiers such as liquid anti-strip, or hydrated lime, orboth are evaluated to meet the requirement.5. Significance and Use5.1 The procedure described in this practice is used todesign
28、 OGFC mixtures that will provide good performance interms of permeability (tending to reduce hydroplaning andpotential for skidding), and durability when subjected to highvolumes of traffic.6. Material Selection6.1 The first step in the mix design process is to selectmaterials suitable for the OGFC.
29、 Materials include aggregates,asphalt, and additives.6.1.1 Selection of Coarse AggregateCoarse aggregateshould have abrasion values of less than 30 % in accordancewith Test Method C131. Crushed gravel (if used) must have atleast 90 % particles with two faces and 95 % particles with oneface resulting
30、 from crushing in accordance with Test MethodD5821. The percentage of flat and elongated particles shouldnot exceed 10 %, with a ratio of 5:1 in maximum to minimumdimension, respectively in accordance with Test MethodD4791.6.1.2 Selection of Fine AggregateThe fine aggregateshould have an uncompacted
31、 voids content of least 40 % whentested in accordance with Test Methods C1252, Method C. It isimportant that the aggregate be clean. The sand equivalentvalue of the fine aggregate passing the 2.36 mm No. 8 sieve,according to Test Method D2419, should be at least 45 % orgreater. It is recommended tha
32、t the material to be tested beseparated on the 2.36 mm No. 8 sieve because of the coarsegrading of the aggregate. It is also very important to removeany coatings or fines adhering to the coarse material.6.1.3 Asphalt Grade SelectionThe asphalt grade selectionis based on environment, traffic, and exp
33、ected functionalperformance of the OGFC. The preferred specified asphaltgrade should meet Specification D6373, however other gradesof asphalt, such as viscosity-graded Specification D3381 orpenetration graded Specification D946 may be suitable. APG-grade, one or two grades stiffer (at high temperatu
34、re) thannormally used at the location of the pavement, has been shownto perform successfully. Mixes with modified asphalt cementshave shown significant improvement in performance. The useof modified asphalt cements is permitted provided that theselected asphalt grade has a PG temperature range excee
35、ding95. This is determined by subtracting the low from the highspecification temperature grade (for example, PG 70 28 = 70 (28) = 98). A value less than 95 may be used if satisfactoryperformance has been noted with the selected PG grade.D7064/D7064M 08126.1.4 Selection of AdditivesEither a cellulose
36、 fiber or amineral fiber may be used to minimize draindown. Typically adosage rate of 0.3 % by mixture mass (or weight of total mix)is used but the draindown target of 0.3 % maximum should bethe acceptance guideline for the dosage rate of the fiberstabilized additive. The dosage rate of fiber stabil
37、izer additiveused should be in the range listed in 12.8.NOTE 2For some mixes which use polymer-modified asphalt orasphalt rubber, fiber additives may not be required or necessary to obtaingood performance or control draindown.7. Test Specimens7.1 Numbers of SamplesTwelve samples are initiallyrequire
38、d: four samples at each of the three trial gradings. Eachsample is mixed with the trial asphalt content (typicallybetween 6.0 and 6.5 % for neat liquid asphalts), and three ofthe four samples for each trial grading are compacted. Theremaining sample of each trial grading is then used todetermine the
39、 theoretical maximum density according to TestMethod D2041 or Test Method D6857.NOTE 3For some polymer modified asphalt and asphalt-rubber, thetypical asphalt content may be higher; see Appendix X1.7.2 Preparation of AggregatesDry aggregates to a con-stant mass at 105 to 110C 220 to 230F and separat
40、e theaggregates by dry-sieving into the desired size fractions (TestMethod C136).7.3 Determination of Mixing and Compaction Tempera-tures:7.3.1 The temperature to which an asphalt must be heated toproduce a viscosity of 0.00017 6 0.00002 m2/s 170 6 20 cStshall be the mixing temperature.7.3.2 The tem
41、perature to which the asphalt must be heatedto produce a viscosity 0.00028 6 0.00003 m2/s 280 6 30 cStshall be the compaction temperature.7.3.3 However, while the temperatures shown in 7.3.1 and7.3.2 will work for most unmodified asphalt, the selectedtemperatures may need to be changed for polymer m
42、odifiedasphalt or asphalt-rubber. For polymer modified asphalt andasphalt-rubber, the manufacturer or supplier guidelines formixing and compaction temperatures should be followed.7.4 Preparation of Mixtures:7.4.1 A mechanical mixing apparatus shall be used.7.4.2 An initial batch shall be mixed for t
43、he purpose ofcoating (buttering) the mixture bowl and stirrers. This batchshall be wasted after mixing and the sides of the bowl andstirrers shall be cleaned of mixture residue by scraping with asmall limber spatula. The bowl shall not be wiped with cloth orwashed clean with solvent, except when a c
44、hange is to be madein the asphalt or at the end of a design.7.4.3 For each test specimen, weigh into separate pans theamount of each size fraction required to produce a batch ofaggregate that will result in a compacted specimen of thecorrect size. Mix the aggregate in each pan; place in an ovenset t
45、o a temperature not exceeding the mixing temperatureestablished in 7.3 by more than approximately 28C 80F.Heat the asphalt to the established mixing temperature. Thestabilizing additive or fiber (if used), should be added to theheated aggregate prior to the introduction of the asphalt. Thestabilizin
46、g additive should be dry-mixed thoroughly with theheated aggregate. This procedure is needed to ensure an evendistribution of the stabilizing additive during the laboratorymixing process. Slightly longer mixing times may be requireddue to the increased surface area added by the fiber, comparedto mix
47、es without fibers. The supplier recommended mixingtemperature should compensate for this stiffening.NOTE 4For polymer modified asphalt and asphalt-rubber, the addi-tives should be incorporated into the liquid asphalt and thoroughlyinteracted according to the procedure recommended by the manufacturer
48、or supplier of the additives before the asphalt is mixed with the aggregate.7.4.4 Form a crater in the dry blended aggregate and to thisadd stabilizing fiber additive if used, and then add the weighedpreheated required amount of asphalt into the crater formed inthe aggregate blend. Exercise care to
49、prevent loss of the mixduring subsequent handling. At this point, the temperature ofthe aggregate and asphalt shall be within the limits of themixing temperature established in 7.3. Mix the aggregate andasphalt rapidly until thoroughly coated.7.5 Size and Shape of Compacted SpecimensSpecimendiameter shall be 100 mm 4 in. and nominal height shall be63.5 mm 2.5 in.7.6 Compaction of SpecimensThe compaction tempera-ture is determined in accordance with 7.3. Laboratory samplesof OGFC are short-term aged in accordance with AASHTOR30and th
