1、Designation: D 7229 08Standard Test Method forPreparation and Determination of Bulk Specific Gravity ofDense-Graded Cold Mix Asphalt (CMA) Specimens byMeans of Superpave Gyratory Compactor1This standard is issued under the fixed designation D 7229; the number immediately following the designation in
2、dicates the year oforiginal adoption or, in the case of revision, 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 test method concerns the preparatio
3、n and compac-tion of cylindrical specimens of dense-graded cold mix asphalt(CMA) using the Superpave gyratory compactor (SGC).1.2 This test method is applicable for road mixes or plantmixes prepared at ambient temperatures.1.3 This test method also refers to the determination of thebulk specific gra
4、vity of the compacted CMA.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 A precision and bias statement for this test method hasnot been developed at this time. Therefore, this test methodshould not be used for acceptan
5、ce or rejection of a material forpurchasing purposes.1.6 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 and health practices and determine the applica-bility o
6、f regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C 566 Test Method for Total Evaporable Moisture Contentof Aggregate by DryingD8 Terminology Relating to Materials for Roads and Pave-mentsD 977 Specification for Emulsified AsphaltD 1188 Test Method for Bulk Specific Gr
7、avity and Densityof Compacted Bituminous Mixtures Using CoatedSamplesD 2041 Test Method for Theoretical Maximum SpecificGravity and Density of Bituminous Paving MixturesD 2397 Specification for Cationic Emulsified AsphaltD 2489 Practice for Estimating Degree of Particle Coatingof Bituminous-Aggregat
8、e MixturesD 2726 Test Method for Bulk Specific Gravity and Densityof Non-Absorptive Compacted Bituminous MixturesD 3203 Test Method for Percent Air Voids in CompactedDense and Open Bituminous Paving MixturesD 3628 Practice for Selection and Use of Emulsified As-phaltsD 4215 Specification for Cold-Mi
9、xed, Cold-Laid Bitumi-nous Paving MixturesD 6752 Test Method for Bulk Specific Gravity and Densityof Compacted Bituminous Mixtures Using AutomaticVacuum Sealing MethodD 6925 Test Method for Preparation and Determination ofthe Relative Density of Hot Mix Asphalt (HMA) Speci-mens by Means of the Super
10、pave Gyratory CompactorD 6934 Test Method for Residue by Evaporation of Emul-sified AsphaltD 6998 Practice for Evaluating Aggregate Coating usingEmulsified Asphalts3. Terminology3.1 DefinitionsDefinitions are in accordance with Termi-nology D8.3.2 Definitions of Terms Specific to This Standard:3.2.1
11、 dense-graded aggregate emulsified asphalt coldmixturesmixtures of dense-graded aggregate and emulsifiedasphalt uniformly mixed at or near ambient temperature.3.2.2 dense-graded cold mix asphalt (CMA)emulsifiedasphalt that has been mixed with aggregate, dry, and com-pacted by a suitable compacting d
12、evice.1This test method is under the jurisdiction of ASTM Committee D04 on Roadand Paving Materials and is the direct responsibility of Subcommittee D04.27 onCold Mix Asphalts.Current edition approved Dec. 1, 2008. Published December 2008. Originallyapproved in 2006. Last previous edition approved i
13、n 2006 as D 7229 06.2For 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.1Copyright ASTM International, 100 Barr H
14、arbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.3 nominal maximum aggregate/sieve sizeone sievesize larger than the first sieve to retain more than 10 %.4. Significance and Use4.1 This test method is used to prepare specimens fordetermination of the bulk specific gravit
15、y of a cured compactedspecimen. It covers modifications to Test Method D 6925 forpreparation of CMA by means of the SGC.4.2 This test method is useful for monitoring the density ofthe specimen during the compaction process. It is suitable forlaboratory design and field control of CMA.4.3 Local end-u
16、se specifications should be developed toestablish conformance to the job and user requirements.5. Apparatus5.1 Superpave Gyratory CompactorAn electrohydyaulicor electromechanical compactor with a ram and ram heads asdescribed in Test Method D 6925.6. Materials6.1 Aggregates3Dense-graded aggregates m
17、eeting the re-quirements of Specification D 4215 are among those suitablefor emulsified asphalt cold mixtures or further guidance shouldbe obtained from the Cold Mix Manual.6.2 EmulsionsTwo types of emulsified asphalt are usedfor producing dense-graded emulsified asphalt cold mixturesand their selec
18、tion are described in Practice D 3628. These aredesignated as slow-setting and medium-setting emulsions.Medium-setting emulsions are used with aggregates that do nothave excessive amounts passing the 0.075-mm sieve. Slow-setting emulsions are normally used with the more denseaggregates with larger a
19、mounts passing the 0.075-mm sieve.Specifications for these emulsions are given in SpecificationsD 977 and D 2397.7. Procedure7.1 Determination of Trial Emulsion ContentIf needed, asimple formula for base mixtures and one for surface mixturesis used. These formulas are based on the percentage ofaggre
20、gate passing the 4.75-mm sieve and, in most cases, givea satisfactory starting point.7.1.1 Determine the residue content of the emulsion to beused by Test Method D 6934 or another suitable acceptableprocedure.7.1.2 Estimate the initial emulsified asphalt content basedon the dry weight of aggregate a
21、s follows:47.1.2.1 Base Mixtures:E 50.06B 1 0.01C! 3 100A(1)7.1.2.2 Surface Mixtures:E 50.07B 1 0.03C! 3 100A(2)where:A = percent residue of the emulsion by distillation or othersuitable procedure (see 7.1.1),B = percent of dry aggregate passing the 4.75-mm sieve,C = 100 B (dry aggregate retained on
22、 the 4.75-mm sieveand above), andE = percent emulsified asphalt based on dry weight ofaggregate.7.2 Coating TestPreliminary evaluation of the emulsifiedasphalt selected for mixture preparation is accomplishedthrough a coating test. The trial emulsion content as deter-mined in 7.1 is combined with th
23、e wet job aggregate correctedto dry weight. Coating is visually estimated by the user assatisfactory or unsatisfactory for the intended use of the mix(surface mixtures require a greater degree of coating than dobase mixtures). Local end-use specifications or agreementbetween user and supplier should
24、 be developed to determinethe degree of coating. If the degree of coating is consideredsatisfactory, proceed to making the mix. If the coating isconsidered unsatisfactory, select another grade of emulsion asdescribed in Practice D 3628 and start over from 7.1.NOTE 1As a general guideline, aggregates
25、 not exceeding 20 %passing the 0.075-mm sieve can be used for the slow-setting emulsions,and aggregates with less than 10 % passing the 0.075-mm sieve are usedfor the medium-setting emulsions. Local end-use specifications should bedeveloped to finalize these requirements since aggregates vary fromre
26、gion to region.NOTE 2Coating may be quantitatively calculated by using the proce-dure described in Practice D 2489.NOTE 3The emulsified asphalt/job aggregate coating test in TestMethod D 6998 can be used for this screening process.7.3 Preparation of Test SpecimensPrepare a specimenusing the emulsion
27、 content determined in 7.1. If the mixture inthe coating tests (7.2) appears to be dry, start with the trialemulsion content (7.1). Conversely, if the mixture appears rich,reduce the emulsion content.NOTE 4A trial emulsion content of 8 % emulsion is a good startingpoint. Other trial blends can be 1
28、% higher or 1 % lower. Other trial blendswould then be 9, 8, and 7 % of emulsion content, respectively. A normaldifference between the emulsion content levels is 1 %, which is a residualdifference of 0.65 % for an emulsion with a 65 % residue content.7.4 Preparation of Aggregates:7.4.1 Determine the
29、 moisture content of the aggregatefollowing Test Method C 566.7.4.2 Weigh the appropriate amount of wet job aggregate,corrected to dry aggregate weight to obtain a compactedspecimen height of 115 6 5 mm, into suitable mixing bowls foreach individual batch. Care must be taken so that the aggregatefor
30、 each batch is representative of the project aggregate. Ifnecessary, the aggregate maybe dried and separated into sizesthen reblended into individual batch sizes. If this is done, waterequivalent to stockpile moisture must be added to each batchand the mixture covered to prevent loss of moisture for
31、 about24 h before mixing with emulsion.NOTE 5It may be necessary to produce a trial specimen to achievethis height requirement. Generally, 4500 to 4700 g of aggregate arerequired.7.4.3 If premixing water is required, pour the predeterminedamount (from section 7.2) onto the aggregate and hand mix for
32、3Asphalt Cold Mix Manual, Asphalt Institute, Manual Series No. 14 (MS-14),3rd Edition, 1997.4A Basic Asphalt Emulsion Manual, Asphalt Institute, Asphalt EmulsionManufactures Association, Manual Series No. 19 (MS- 9), 3rd Edition.D722908260 s or until uniform. As an option, mechanical mixing may beus
33、ed. This must be done just before the addition and mixingwith the emulsified asphalt.7.4.4 Weigh a predetermined amount of emulsion (fromsection 7.2) and add to the wet aggregate. Mix thoroughly for60 s until the aggregates are coated. As an option, mechanicalmixing may be used. Excessive mixing wil
34、l cause the mix tostrip.7.4.5 Place the emulsion mix in a pan and dry in aforced-draft oven for 3.0 6 0.1hat306 0.1C.7.5 Compaction:7.5.1 Prepare the sample for compaction as described in thisprocedure and follow the densification procedure of Section 8of Test Method D 6925.7.5.2 Place the base plat
35、e and a paper disk in the bottom ofthe mold.7.5.3 Place the mixture into the mold in one lift. Care shouldbe taken to avoid segregation in the mold. After all the mix isin the mold, level the mix, and place another paper disk andupper plate (if required) on top of the leveled material.7.5.4 Load the
36、 charged mold into the compactor and centerthe loading ram.7.5.5 Apply a constant vertical pressure of 600 6 60 kPa forthe first five gyrations and 600 6 18 kPa during the remainderof the compaction process as described in Test Method D 6925.7.5.6 Allow the compaction to proceed to the desirednumber
37、 of gyrations based on end-use requirement.NOTE 6Note that this process of loading, densification, and unloadingof the CMA is similar to the HMA process described in sections 6.1through 6.11 of Test Method D 6925, except temperatures, handling times,and aging requirements are different.NOTE 7Present
38、 practice is to use 33 6 3 gyrations. Previous roundrobin between five laboratories indicated that above 40 gyrations nofurther height reduction of the compacted mix was observed.7.5.7 Extrude the sample from the mold and weigh. Placethe compacted specimen in the forced air-draft oven set at 306 1C
39、and cure for 20 6 0.1 h.NOTE 8The curing protocol in this standard represents only a practicebeing followed by some practitioners and was used in a round-robinencompassing five laboratories. It is not intended to cover or simulate thelarge spectrum of varying field practices and pavement performance
40、conditions. In the application of this standard the user may define adifferent curing protocol that better represents the local field practice; onethat better simulates the expected short and long term conditions affectingthe mixture properties.7.6 Densification:7.6.1 Determine the bulk specific gra
41、vity of the extrudedspecimen as described in Test Methods D 1188, D 2726 orD 6752.7.6.2 Determine the bulk density by dividing the weight ofthe specimen in air by its calculated volume, determined basedon geometric measurements (height and mold diameter).Db5WaHA; A 5p3D2/4 (3)where:Db= measured bulk
42、 density of a compacted mixture speci-men,D = diameter of specimen,Wa= specimen weight in air,H = height of compacted specimen, andA = area of cylindrical specimen.7.6.3 Other volumetric properties such as voids, voids filled,and voids in the mineral aggregate are determined followingthe appropriate
43、 Test Methods D 2041 and D 3203 and thecalculations described in Asphalt Institute Manual MS-2.58. Report8.1 Report the following information:8.1.1 Date and time of specimen preparation;8.1.2 Specimen identification including grade of emulsion;8.1.3 Percentage of emulsified asphalt in specimen to th
44、enearest 0.1 %;8.1.4 Mass of the specimen to the nearest 0.1 g;8.1.5 Bulk specific gravity of the compacted specimen(Gmb) by Test Methods D 1188, D 2726,orD 6752 to thenearest 0.001; and8.1.6 Height of the compacted specimen after each gyration(hx) to the nearest 0.1 mm if required.9. Precision and
45、Bias9.1 The between-laboratory reproducibility of this testmethod is underway and will be available on or beforeDecember 1, 2012. A preliminary study between five labora-tories, using one emulsion and one set of aggregates and threeemulsion content of a single mix and two replicates, indicatedthat a
46、 single-operator precision greater than 1 % of the meanshould be considered suspect and for between-laboratoryprecision greater than 3 % of the mean should be consideredsuspect. This test method should not be used for acceptance orrejection of a material for purchasing purposes.9.2 BiasNo informatio
47、n can be presented on the bias ofthe procedure because no material having an accepted refer-ence value is available.10. Keywords10.1 aggregates; cold mix asphalt; compaction; emulsifiedasphalt; emulsions; gyratory; medium-setting emulsions; slow-setting emulsions5Mix Design Methods for Asphalt Concr
48、ete and other Hot-mix types, AsphaltInstitute, Manual Series No. 2 (MS-2) 6th Edition, 1995.D7229083ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that dete
49、rmination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, w
