1、Designation: D7064/D7064M 08 (Reapproved 2013)Standard 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
2、year of last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers the mix design of open-gradedfriction course (OGFC) using the superpave gyratory compac-t
3、or (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 design. Where applicable, Specification D366
4、6should 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; therefore, eachsystem shall be used indepe
5、ndently 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 standard to establish appro-priate safety an
6、d 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 (SpecificGravity), and Absorption of Coarse
7、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 of FineAggregate (as Influenced by Particle Shape, Su
8、rfaceTexture, 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 Soils andFine AggregateD3203 Test Method
9、 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 MaterialsD4791 Test Method for Flat Par
10、ticles, 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 AsphaltBinderD6390 Test Method for Determin
11、ation 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 Bituminous Paving Mixtures Using AutomaticVacuum
12、 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 for Materials and Construction of Open-G
13、raded Friction Course Plant Mixtures2.2 AASHTO Standards:3R30Mixture Conditioning of Hot Mix Asphalt (HMA)T 283 Resistance of Compacted Bituminous Mixture to1This practice is under the jurisdiction of ASTM Committee D04 on Road andPaving Materials and is the direct responsibility of Subcommittee D04
14、.23 onPlant-Mixed Bituminous Surfaces and Bases.Current edition approved Dec. 1, 2013. Published February 2014. Originallyapproved in 2004. Last previous edition approved in 2008 as D7064/D7064M 081. DOI: 10.1520/D7064_D7064M-08R13.2For referenced ASTM standards, visit the ASTM website, www.astm.org
15、, orcontact ASTM Customer 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, Wa
16、shington, DC 20001,http:/www.transportation.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1Moisture-Induced Damage32.3 Other References:TRB Synthesis 284NCAT Report No. 2001-01 Design, Construction, and Per-formance of New-Genera
17、tion 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 themixture is to provide a free
18、-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 percent of thetotal volume of
19、 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 descriptions of aggregate,
20、 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 aggregate may be retained on
21、 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 additive, npolymer, crumb rubb
22、er, 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 aggregategradings from the sel
23、ected 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 6.0and 6.5 % (generally higher
24、 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 standard aggregate gradin
25、g 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 specimensare compacted using 50 gyrations of a SGC or other suitablecompactor at t
26、hree asphalt contents. The design asphalt contentis selected on the basis of satisfactory conformance with therequirements of Section 12.4.4 Evaluating Moisture SusceptibilityThe moisture sus-ceptibility of the designed mixture shall be evaluated using theAASHTO T 283 test method. If the mixture fai
27、ls 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 OGFC mixtures that will provi
28、de 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. Materials include aggregates,
29、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 from crushing in accordance w
30、ith 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 voids content of least 40 % w
31、hentested 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 that the material to be tested be
32、separated 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 expected functionalperformance of
33、 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 temperature) thannormally used at the l
34、ocation 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 exceeding95. This is determined by
35、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 08 (2013)26.1.4 Selection of AdditivesEither a cellulose fiber or amineral fiber
36、 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 stabilizer additiveused should
37、 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 initially re-quired: four samples at eac
38、h 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 theoretical maximum d
39、ensity 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 separate theaggregates by dry
40、-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 temperature to which the
41、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 modifiedasphalt or asph
42、alt-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 the purpose ofcoating (
43、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 change is to be madein
44、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 to a temperature not ex
45、ceeding 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. Thestabilizing additive should be d
46、ry-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 mixes without fibers. The
47、 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 manufactureror supplier of the add
48、itives 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 prevent loss of the mi
49、xduring 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 AASHTO R30 and then compacted using 50
