ASTM D7064/D7064M-21

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Designation: D7064/D7064M − 08 (Reapproved 2013) D7064/D7064M − 21
Standard Practice for
Open-Graded Friction Course (OGFC) Mix Asphalt Mixture
Design
This standard is issued under the fixed designation D7064/D7064M; the number immediately following the designation indicates the
year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last
reapproval. A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This practice covers the mix design of open-graded friction course (OGFC) using the superpave gyratory compactorSuperpave
Gyratory Compactor (SGC) or other suitable forms of compaction. The OGFC mix asphalt mixture design is based on the
volumetric properties of the mix asphalt mixture in terms of air voids,voids and the presence of stone-on-stone contact. Information
found in Guide D6932D6932/D6932M should be reviewed before starting the mix design. Where applicable, Specification D3666
should be applied as a minimum for agencies testing and inspecting road and paving materials.
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the
two systems may result in non-conformancenonconformance with the standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
C29/C29M Test Method for Bulk Density (“Unit Weight”) and Voids in Aggregate
C127 Test Method for Relative Density (Specific Gravity) and Absorption of Coarse Aggregate
C131C131/C131M Test Method for Resistance to Degradation of Small-Size Coarse Aggregate by Abrasion and Impact in the
Los Angeles Machine
C136C136/C136M Test Method for Sieve Analysis of Fine and Coarse Aggregates
C1252 Test Methods for Uncompacted Void Content of Fine Aggregate (as Influenced by Particle Shape, Surface Texture, and
Grading)
D946D946/D946M Specification for Penetration-Graded Asphalt Binder for Use in Pavement Construction
D2041D2041/D2041M Test Method for Theoretical Maximum Specific Gravity and Density of Asphalt Mixtures
D2419 Test Method for Sand Equivalent Value of Soils and Fine Aggregate
D3203D3203/D3203M Test Method for Percent Air Voids in Compacted Asphalt Mixtures
This practice is under the jurisdiction of ASTM Committee D04 on Road and Paving Materials and is the direct responsibility of Subcommittee D04.23 on Plant-Mixed
Asphalt Surfaces and Bases.
Current edition approved Dec. 1, 2013May 1, 2021. Published February 2014May 2021. Originally approved in 2004. Last previous edition approved in 20082013 as
ε1
D7064/D7064M – 08 (2013). . DOI: 10.1520/D7064_D7064M-08R13.10.1520/D7064_D7064M-21.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7064/D7064M − 21
D3381D3381/D3381M Specification for Viscosity-Graded Asphalt Binder for Use in Pavement Construction
D3666 Specification for Minimum Requirements for Agencies Testing and Inspecting Road and Paving Materials
D4791 Test Method for Flat Particles, Elongated Particles, or Flat and Elongated Particles in Coarse Aggregate
D5821 Test Method for Determining the Percentage of Fractured Particles in Coarse Aggregate
D6114D6114/D6114M Specification for Asphalt-Rubber Binder
D6373 Specification for Performance-Graded Asphalt Binder
D6390 Test Method for Determination of Draindown Characteristics in Uncompacted Asphalt Mixtures
D6752D6752/D6752M Test Method for Bulk Specific Gravity and Density of Compacted Asphalt Mixtures Using Automatic
Vacuum Sealing Method
D6857D6857/D6857M Test Method for Maximum Specific Gravity and Density of Asphalt Mixtures Using Automatic Vacuum
Sealing Method
D6925 Test Method for Preparation and Determination of the Relative Density of Asphalt Mix Specimens by Means of the
Superpave Gyratory Compactor
D6926 Practice for Preparation of Asphalt Mixture Specimens Using Marshall Apparatus
D6932D6932/D6932M Guide for Materials and Construction of Open-Graded Friction Course Plant Asphalt Mixtures
2.2 AASHTO Standards:
R 30 Mixture Conditioning of Hot Mix Asphalt (HMA)
T 283 Resistance of Compacted Bituminous Mixture to Moisture-Induced Damage
2.3 Other References:
TRB Synthesis 284
NCAT Report No. 2001-01 Design, Construction, and Performance of New-Generation Open-Graded Friction Courses
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 open-graded friction course (OGFC), n—special type of hot mix asphalt surface mixture used for reducing hydroplaning and
potential for skidding, where the function of the mixture is to provide a free-draining layer that permits surface water to migrate
laterally through the mixture to the edge of the pavement.
3.1.1 air voids (V ), n—the total volume of the small pockets of air between the coated aggregate particles throughout a compacted
a
paving mixture, expressed as a percent of the total volume of the compacted specimen.
3.1.2 voids in coarse aggregate (VCA),maximum aggregate size, n—the volume in between in specifications for, or descriptions
of aggregate, the coarse aggregate particles, where this volume includes filler, fine aggregate, air voids, asphalt, and fiber, if
used.smallest sieve opening through which the entire amount of aggregate is required to pass.
3.1.3 nominal maximum size of aggregate, n—in specifications for, or descriptions of aggregate, the smallest sieve opening
through which the entire amount of aggregate is permitted to pass.
3.1.3.1 Discussion—
Specifications on aggregates usually stipulate a sieve opening through which all of the aggregate may, but need not, pass so that
a stated maximum proportion of the aggregate may be retained on that sieve. A sieve opening so designated is the nominal
maximum aggregate size.
3.1.4 maximum aggregate size, open-graded friction course (OGFC), n—in specifications for, or descriptions of aggregate,special
type of asphalt the smallest sieve opening through which the entire amount of aggregate is required to pass.surface mixture used
for reducing hydroplaning and potential for skidding, where the function of the asphalt mixture is to provide a free-draining layer
that permits surface water to migrate laterally through the asphalt mixture to the edge of the pavement.
3.1.5 stabilizing additive, n—polymer, crumb rubber, or fibers, or both,others, used to minimize draindown meet the minimum
draindown requirements of the asphaltmix during transport and placement of the OGFC.placement.
3.1.6 voids in coarse aggregate (VCA), n—the volume in between the coarse aggregate particles, where this volume includes filler,
fine aggregate, air voids, asphalt, and fiber, if used.
Available from American Association of State Highway and Transportation Officials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washington, DC 20001,
http://www.transportation.org.
D7064/D7064M − 21
3.1.7 warm mix technology (WMT), n—a technology which is incorporated in the asphalt binder and allows for sufficient reduction
to the asphalt mixture temperature such that it meets the minimum draindown requirements.
4. Summary of Practice
4.1 Materials Selection—Aggregates, asphalt, and additives that meet specification are selected.
4.2 Select Optimum Grading—At least three trial aggregate gradings from the selected aggregate stockpiles are blended. Gradings
for OGFC are based on volume. The dry-rodded unit weight for the coarse aggregate for each trial grading is determined in
accordance with Test Method C29/C29M. For each trial grading, an initial trial asphalt content between 6.0 and 6.5 % (generally
higher for asphalt-rubber Specification D6114D6114/D6114M) is selected and at least two specimens are compacted using 50
gyrations of the Superpave Gyratory Compactor (SGC) (Test Method D6925) or other suitable compactor. An optimum grading
is selected to ensure stone-on-stone contact.
NOTE 1—If a standard aggregate grading and asphalt content has been successfully used, three trial gradings may not be necessary. Examples of commonly
used gradings and asphalt contents are shown in Appendix X1.
4.3 Design Asphalt Content Selection—Replicate specimens are compacted using 50 gyrations of a SGC or other suitable
compactor at three asphalt contents. The design asphalt content is selected on the basis of satisfactory conformance with the
requirements of Section 12.
4.4 Evaluating Moisture Susceptibility—The moisture susceptibility of the designed mixture shall be evaluated using the
AASHTO T 283 test method. If the mixture fails the selected moisture susceptibility requirement, it is suggested that appropriate
modifiers such as liquid anti-strip,anti-strip or hydrated lime, or both, are evaluated to meet the requirement.
5. Significance and Use
5.1 The procedure described in this practice is used to design OGFC asphalt mixtures that will provide good performance in terms
of permeability (tending to reduce hydroplaning and potential for skidding),skidding) and durability when subjected to high
volumes of traffic.
6. Material Selection
6.1 The first step in the asphalt mix design process is to select materials suitable for the OGFC. Materials include aggregates,
asphalt, and additives.
6.1.1 Selection of Coarse Aggregate—Coarse aggregate should have abrasion values of less than 30 % in accordance with Test
Method C131C131/C131M. Crushed gravel (if used) must have at least 90 % particles with two faces and 95 % particles with one
face resulting from crushing in accordance with Test Method D5821. The percentage of flat and elongated particles should not
exceed 10 %, with a ratio of 5:1 in maximum to minimum dimension, respectively, in accordance with Test Method D4791.
6.1.2 Selection of Fine Aggregate—The fine aggregate should have an uncompacted voids content of least 40 % when tested in
accordance with Test Methods C1252, Method C. It is important that the aggregate be clean. The sand equivalent value of the fine
aggregate passing the 2.36 mm [No. 8] sieve, according to Test Method D2419, should be at least 45 % or greater. It is
recommended that the material to be tested be separated on the 2.36 mm [No. 8] sieve because of the coarse grading of the
aggregate. It is also very important to remove any coatings or fines adhering to the coarse material.
6.1.3 Asphalt Grade Selection—The asphalt grade selection is based on environment, traffic, and expected functional performance
of the OGFC. The preferred specified asphalt grade should meet Specification D6373, however; however, other grades of
asphalt,asphalt such as viscosity-graded Specification D3381D3381/D3381M or penetration graded penetration-graded Specifi-
cation D946D946/D946M may be suitable. A PG-grade, performance grade (PG), one or two grades stiffer (at high temperature)
than normally used at the location of the pavement, has been shown to perform successfully. Mixes Asphalt mixes with modified
asphalt cementsbinders have shown significant improvement in performance. The use of modified asphalt cementsbinders is
permitted provided that the selected asphalt grade has a PG temperature range exceeding 95. This is determined by subtracting the
low from the high specification temperature grade (for example, PG 70 – 28 = 70 – (–28) = 98). A value less than 95 may be used
if satisfactory performance has been noted with the selected PG grade.PG.
D7064/D7064M − 21
6.1.4 Selection of Additives—Either a cellulose fiber or a mineral fiber fiber, a mineral fiber, or a warm mix technology (see 6.1.4.1)
may be used to minimize draindown. Typically, a fiber dosage rate of 0.3 % by mixture mass (or weight of total mix) is used but
the draindown target of 0.3 % maximum should be the acceptance guideline for the dosage rate of the fiber stabilized additive. The
dosage rate of fiber stabilizer additive used should be in the range listed in 12.8.
NOTE 2—For some mixes which use polymer-modified asphalt or asphalt-rubber, fiber additives may not be required or necessary to obtain good
performance or control draindown.
6.1.4.1 Use of Warm Mix Technology—A WMT may be blended into the asphalt binder at an asphalt terminal or asphalt plant so
that the asphalt mixture temperature may be reduced to meet the requirements listed in 12.8. A typical warm asphalt mixture
temperature reduction of 30 to 50 °C from hot asphalt mixtures is normal.
NOTE 2—For some mixes which use polymer-modified asphalt or asphalt rubber, fiber additives may not be required or necessary to obtain good
performance or control draindown.
7. Test Specimens
7.1 Numbers of Samples—Twelve samples are initially required: four samples at each of the three trial gradings. Each sample is
mixed with the trial asphalt content (typically between 6.0 and 6.5 % for neat liquid asphalts), and three of the four samples for
each trial grading are compacted. The remaining sample of each trial grading is then used to determine the theoretical maximum
density according to Test Method D2041D2041/D2041M or Test Method D6857D6857/D6857M.
NOTE 3—For some polymer modified polymer-modified asphalt and asphalt-rubber, the typical asphalt content may be higher; see Appendix X1.
7.2 Preparation of Aggregates—Dry aggregates to a constant mass at 105 to 110°C110 °C [220 to 230°F]230 °F] and separate the
aggregates by dry-sieving into the desired size fractions (Test Method C136C136/C136M).
7.3 Determination of Mixing and Compaction Temperatures:
7.3.1 The temperature to which an asphalt must be heated to produce a viscosity of 0.00017 6 0.00002 m /s [170 6 20 cSt] shall
be the mixing temperature.
7.3.2 The temperature to which the asphalt must be heated to produce a viscosity 0.00028 6 0.00003 m /s [280 6 30 cSt] shall
be the compaction temperature.
7.3.3 However, while the temperatures shown in 7.3.1 and 7.3.2 will work for most unmodified asphalt, asphalt binder, the selected
temperatures may need to be changed for polymer modified polymer-modified asphalt binder or asphalt-rubber. For polymer
modified polymer-modified asphalt binder and asphalt-rubber, the manufacturer or supplier guidelines for mixing and compaction
temperatures should be followed.
7.4 Preparation of Mixtures: Asphalt Mixture(s):
7.4.1 A mechanical mixing apparatus shall be used.
7.4.2 An initial batch shall be mixed for the purpose of coating (buttering) the mixture bowl and stirrers. This batch shall be wasted
after mixing and the sides of the bowl and stirrers shall be cleaned of asphalt mixture residue by scraping with a small limber
spatula. The bowl shall not be wiped with cloth or washed clean with solvent, except when a change is to be made in the asphalt
or at the end of a design.
7.4.3 For each test specimen, weigh into separate pans the amount of each size fraction required to produce a batch of aggregate
that will result in a compacted specimen of the correct size. Mix the aggregate in each pan; place in an oven set to a temperature
not exceeding the mixing temperature established in 7.3 by more than approximately 28°C [80°F].28 °C [80 °F]. Heat the asphalt
to the established mixing temperature. The stabilizing additive or fiber (if used),used) should be added to the heated aggregate prior
to the introduction of the asphalt. The stabilizing additive should be dry-mixed thoroughly with the heated aggregate. This
procedure is needed to ensure an even distribution of the stabilizing additive during the laboratory mixing process. Slightly longer
mixing times may be required due to the increased surface area added by the fiber, compared to mixes without fibers. The supplier
D7064/D7064M − 21
recommended supplier-recommended mixing temperature should compensate for this stiffening. In the case of a warm mix
technology, it should be added to the asphalt binder and homogenized prior to mixing the warm mix technology modified asphalt
binder with the aggregate.
NOTE 4—For polymer modified polymer-modified asphalt binder and asphalt-rubber, the additives should be incorporated into the liquid asphalt and
thoroughly interacted according to the procedure recommended by the manufacturer or supplier of the additives before the asphalt is mixed with the
aggregate. In the case of a warm mix technology, it should be added to the asphalt binder and homogenized prior to mixing the warm mix technology
modified asphalt binder with the aggregate.
7.4.4 Form a crater in the dry blended aggregate and to this add stabilizing fiber additive, if used, and then add the weighed
preheated required amount of asphalt binder (with or without the warm mix technology) into the crater formed in the aggregate
blend. Exercise care to prevent loss of the mix during subsequent handling. At this point, the temperature of the aggregate and
asphalt binder shall be within the limits of the mixing temperature established in 7.3. Mix the aggregate and asphalt binder rapidly
until thoroughly coated.
7.5 Size and Shape of Compacted Specimens—Specimen diameter shall be 100 mm [4 in.] and nominal height shall be 63.5 mm
[2.5 in.].
7.6 Compaction of Specimens—The compaction temperature is determined in accordance with 7.3. Laboratory samples of OGFC
are short-term aged in accordance with AASHTO R 30 R 30 and then compacted using 50 gyrations ofin the SGC or other
compactor providing equivalent compacted density.
8. Selection of Trial Gradings
8.1 Three trial gradings shoul
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