1、Designation: D 7064 04Standard Practice forOpen-Graded Friction Course (OGFC) Mix Design1This standard is issued under the fixed designation D 7064; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A numbe
2、r 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 standard practice covers the mix design of open-graded friction course (OGFC) using the superpave gyratorycompactor (SGC) or other sui
3、table forms of compaction. TheOGFC mix design is based on the volumetric properties of themix in terms of air voids, and the presence of stone-on-stonecontact. Information found in Guide D 6932 should be re-viewed before starting the mix design. Where applicable,Specification D 3666 should be applie
4、d as a minimum foragencies testing and inspecting road and paving materials.1.2 The values stated in SI units are to be regarded asstandard. The inch-pound units in parentheses are for informa-tion only.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with
5、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:2C 29/C 29M Test Method for Unit Weight and Voids inAggregateC 127 Tes
6、t Method for Density, Relative Density (SpecificGravity), and Absorption of Coarse AggregateC 131 Test Method for Resistance to Degradation of Small-Size Coarse Aggregate by Abrasion and Impact in the LosAngeles MachineC 136 Test Method for Sieve Analysis of Fine and CoarseAggregatesC 1252 Test Meth
7、ods for Uncompacted Void Content ofFine Aggregate (as Influenced by Particle Shape, SurfaceTexture, and Grading)D 946 Specification for Penetration-Graded Asphalt Ce-ment for Use in Pavement ConstructionD 2041 Test Method for Theoretical Maximum SpecificGravity and Density of Bituminous Paving Mixtu
8、resD 2419 Test Method for Sand Equivalent Value of Soils andFine AggregateD 3203 Test Method for Percent Air Voids in CompactedDense and Open Bituminous Paving MixturesD 3381 Specification for Viscosity-Graded Asphalt Cementfor Use in Pavement ConstructionD 3666 Specification for Minimum Requirement
9、s for Agen-cies testing and Inspecting Bituminous Paving MaterialsD 4791 Test Method for Flat Particles, Elongated Particles,or Flat and Elongated Particles in Coarse AggregateD 5821 Test Method for Determining the Percentage ofFractured Particles in Coarse AggregateD 6114 Specification for Asphalt-
10、Rubber BinderD 6373 Specification for Performance Graded AsphaltBinderD 6390 Test Method for Determination of Draindown Char-acteristics in Uncompacted Asphalt MixturesD 6752 Test Method for Bulk Specific Gravity and Densityof Compacted Bituminous Mixtures Using AutomaticVacuum Sealing MethodD 6857
11、Test Method for Maximum Specific Gravity andDensity of Bituminous Paving Mixtures Using AutomaticVacuum Sealing MethodD 6932 Guide for Materials and Construction of OpenGraded Friction Course Plant Mixtures2.2 AASHTO Standards:R 30 Mixture Conditioning of Hot Mix Asphalt (HMA)3T 283 Resistance of Co
12、mpacted Bituminous Mixture toMoisture-Induced Damage3T 312 Preparing and Determining the Density of Hot-MixAsphalt (HMA) Specimens by means of the SuperpaveGyratory Compactor32.3 Other References:TRB Synthesis 284NCAT Report No. 2001-01 Design, Construction, and Per-formance of New-Generation Open-G
13、raded FrictionCourses3. Terminology3.1 Definitions of Terms Specific to This Standard:1This practice is under the jurisdiction of ASTM Committee D04 on Road andPaving Materials and is the direct responsibility of Subcommittee D04.23 onPlant-Mixed Bituminous Surfaces and Bases.Current edition approve
14、d Aug. 1, 2004. Published August 2004.2For 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 ASTM website.3Available from America
15、n Association of State Highway and TransportationOfficials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washington, DC 20001.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.1 open-graded friction course (OGFC), nspecial typeof ho
16、t mix asphalt surface mixture used for reducing hydro-planing and potential for skidding, where the function of themixture 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
17、smallpockets of air between the coated aggregate particles through-out a compacted paving mixture, expressed as a percent 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 a
18、ggregate, air voids, asphalt, and fiber, ifused.3.1.4 nominal maximum size of aggregate, nin specifica-tions for, or 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
19、 sieve opening through which all of the aggregatemay, but need not, pass so that a stated maximum proportion ofthe aggregate may be retained on that sieve. A sieve opening sodesignated is the nominal maximum aggregate size.3.1.5 maximum aggregate size, nin specifications for, ordescriptions of aggre
20、gate, the smallest sieve opening throughwhich the entire amount of aggregate is required to pass.3.1.6 stabilizing additive, 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 SelectionAgg
21、regates, asphalt, and additivesthat meet specification are selected.4.2 Select Optimum GradingAt least three trial aggregategradings 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 isd
22、etermined in accordance with Test Method C 29/C 29M. Foreach trial grading, an initial trial asphalt content between 6.0and 6.5 % (generally higher for asphalt-rubber SpecificationD 6114) is selected and at least two specimens are compactedusing 50 gyrations of the SGC (AASHTO T 312) or othersuitabl
23、e compactor. An optimum grading is selected to ensurestone-on-stone contact.NOTE 1If a 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 Aspha
24、lt Content SelectionReplicate speci-mens are compacted using 50 gyrations of a SGC or 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 moist
25、ure sus-ceptibility of the designed mixture shall be evaluated using theAASHTO T 283 test 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 requiremen
26、t.5. Significance and Use5.1 The procedure described in this practice is used todesign 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
27、 The first step in the mix design process is to selectmaterials suitable for the OGFC. 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 C 131. Crushed gravel (if used) mu
28、st have atleast 90 % particles with two faces and 95 % particles with oneface resulting from crushing in accordance with Test MethodD 5821. 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 M
29、ethodD 4791.6.1.2 Selection of Fine AggregateThe fine aggregateshould have an uncompacted voids content of least 40 % whentested in accordance with Test Methods C 1252, Method C. Itis important that the aggregate be clean. The sand equivalentvalue of the fine aggregate passing the No. 8 (2.36 mm) si
30、eve,according to Test Method D 2419, should be at least 45 % orgreater. It is recommended that the material to be tested beseparated on the No. 8 (2.36 mm) sieve because of the coarsegrading of the aggregate. It is also very important to removeany coatings or fines adhering to the coarse material.6.
31、1.3 Asphalt Grade SelectionThe asphalt grade selectionis based on environment, traffic, and expected functionalperformance of the OGFC. The preferred specified asphaltgrade should meet Specification D 6373, however other gradesof asphalt, such as viscosity-graded Specification D 3381 orpenetration g
32、raded Specification D 946 may be suitable. Apg-grade, one or two grades stiffer (at high temperature) 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 asp
33、halt cements is permitted provided that theselected asphalt grade has a PG temperature range exceeding95C. This is determined by subtracting the low from the highspecification temperature grade for example, PG 70-28 =70-(-28) = 98. A value less than 95C may be used ifsatisfactory performance has bee
34、n noted with the selected PGgrade.6.1.4 Selection of AdditivesEither a cellulose 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
35、the dosage rate of the fiberstabilized additive. The dosage rate of fiber stabilizer 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 drai
36、ndown.D70640427. Test Specimens7.1 Numbers of SamplesTwelve samples are initiallyrequired: 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 gradi
37、ng are compacted. Theremaining sample of each trial grading is then used todetermine the theoretical maximum density according to TestMethod D 2041 or Test Method D 6857.NOTE 3For some polymer modified asphalt and asphalt-rubber, thetypical asphalt content may be higher; see Appendix X1.7.2 Preparat
38、ion of AggregatesDry aggregates to a con-stant mass at 105 to 110C (220 to 230F) and separate theaggregates by dry-sieving into the desired size fractions (TestMethod C 136).7.3 Determination of Mixing and Compaction Tempera-tures:7.3.1 The temperature to which an asphalt must be heated toproduce a
39、viscosity of 170 6 20 cSt shall be the mixingtemperature.7.3.2 The temperature to which the asphalt must be heatedto produce a viscosity 280 6 30 cSt shall be the compactiontemperature.7.3.3 However, while the temperatures shown in 7.3.1 and7.3.2 will work for most unmodified asphalt, the selectedte
40、mperatures may need to be changed for polymer modifiedasphalt 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 u
41、sed.7.4.2 An initial batch shall be mixed for the 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 clo
42、th orwashed clean with solvent, except when a change 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 t
43、he aggregate in each pan; place in an ovenset to a temperature not exceeding the mixing temperatureestablished in 7.3 by more than approximately 28C (50F).Heat the asphalt to the established mixing temperature. Thestabilizing additive or fiber (if used), should be added to theheated aggregate prior
44、to the introduction of the asphalt. Thestabilizing 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 increase
45、d surface area added by the fiber, comparedto mixes 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
46、 to the procedure recommended by the manufactureror 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 crate
47、r formed inthe aggregate blend. Exercise care to 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
48、 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 AASHTOPP2 and then comp
49、acted using 50 gyrations of the SGC orother compactor providing equivalent compacted density.8. Selection of Trial Gradings8.1 Three trial gradings should be selected to be within therecommended master range of grading shown in Table 1, or agrading shown in Appendix X1 or a grading that has demon-strated good performance. The three trial gradings shouldgenerally fall along the coarse and fine limits of the gradingrange, along with one falling in the middle. These trial gradingsare obtained by adjusting the amount of fine and coarseaggregate in each blend.N
