ASTM D7229-2006 Standard Test Method for Preparation and Determination of the Bulk Specific Gravity of Dense-Graded Cold Mix Asphalt (CMA) Specimens by Means of the Superpave Gyrat.pdf

1、Designation: D 7229 06Standard Test Method forPreparation and Determination of the Bulk Specific Gravityof Dense-Graded Cold Mix Asphalt (CMA) Specimens byMeans of the Superpave Gyratory Compactor1This standard is issued under the fixed designation D 7229; the number immediately following the design

2、ation indicates 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method concerns the p

3、reparation 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 spe

4、cific gravity of the compacted CMA.1.4 The values given in SI units are to be considered thestandard.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 acceptance or rejection of a material forpurchasing purpo

5、ses.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 of regulatory limitations prior to use.2. Referenc

6、ed 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 Gravity and Densityof Compacted Bituminous Mixtures

7、 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-Aggregate MixturesD 2726 Test Method for Bulk Specific Gr

8、avity 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-Mixed, Cold-Laid Bitumi-nous Paving MixturesD 6752

9、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 Superpave Gyratory CompactorD 6934 Test Method for Res

10、idue 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 dense-graded aggregate emulsified asphalt coldmi

11、xturesmixtures 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 device.3.2.3 nominal maximum aggregate/sieve sizeo

12、ne 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 gravity of a cured compactedspecimen. It covers modifications to Test Method D 6925 forpreparation of CMA by means of the S

13、GC.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 July 1, 2006. Published July 2006.2For referenced ASTM standards, visit the ASTM website, www.astm.org

14、, 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 Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.2 This test

15、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-use specifications should be developed toestablish conformance to the job and user requirements.5. Apparatus5.1 Superpave Gyratory Comp

16、actorAn electrohydyaulicor electromechanical compactor with a ram and ram heads asdescribed in Test Method D 6925.6. Materials6.1 Aggregates3Dense-graded aggregates meeting the re-quirements of Specification D 4215 are among those suitablefor emulsified asphalt cold mixtures or further guidance shou

17、ldbe obtained from the Cold Mix Manual.6.2 EmulsionsTwo types of emulsified asphalt are usedfor producing dense-graded emulsified asphalt cold mixturesand their selection are described in Practice D 3628. These aredesignated as slow-setting and medium-setting emulsions.Medium-setting emulsions are u

18、sed 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 amounts passing the 0.075-mm sieve.Specifications for these emulsions are given in SpecificationsD 977 and D 2397.7. Procedure7.1 Deter

19、mination of Trial Emulsion ContentIf needed, asimple formula for base mixtures and one for surface mixturesis used. These formulas are based on the percentage ofaggregate passing the 4.75-mm sieve and, in most cases, givea satisfactory starting point.7.1.1 Determine the residue content of the emulsi

20、on 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 as 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 resi

21、due 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 the 4.75-mm sieveand above), andE = percent emulsified asphalt based on dry weight ofaggregate.7.2 Coating TestPreliminary evaluation

22、 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 the wet job aggregate correctedto dry weight. Coating is visually estimated by the user assatisfactory or unsatisfactory for the intende

23、d 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 be developed to determinethe degree of coating. If the degree of coating is consideredsatisfactory, proceed to making the mix. If the

24、 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 not exceeding 20 %passing the 0.075-mm sieve can be used for the slow-setting emulsions,and aggregates with less than 10 % passing th

25、e 0.075-mm sieve are usedfor the medium-setting emulsions. Local end-use specifications should bedeveloped to finalize these requirements since aggregates vary fromregion to region.NOTE 2Coating may be quantitatively calculated by using the proce-dure described in Practice D 2489.NOTE 3The emulsifie

26、d 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 content determined in 7.1. If the mixture inthe coating tests (7.2) appears to be dry, start with the trialemulsion content (7.1). Co

27、nversely, 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 % higher or 1 % lower. Other trial blendswould then be 9, 8, and 7 % of emulsion content, respectively. A normaldifference between the

28、 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 moisture content of the aggregatefollowing Test Method C 566.7.4.2 Weigh the appropriate amount of wet job aggregate,corrected to dry

29、 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 each batch is representative of the project aggregate. Ifnecessary, the aggregate maybe dried and separated into sizesthen reblended

30、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 about24 h before mixing with emulsion.NOTE 5It may be necessary to produce a trial specimen to achievethis height requirement. Genera

31、lly, 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 for60 s or until uniform. As an option, mechanical mixing may beused. This must be done just before the addition and mixingwith the emuls

32、ified 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 will cause the mix tostrip.3Asphalt Cold Mix Manual, Asphalt Institute, Ma

33、nual 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.D72290627.4.5 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.

34、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 plate 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 segregatio

35、n 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 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

36、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 of gyrations based on end-use requirement.NOTE 6Note that this process of loading, densification, and unloadingof the CMA is similar

37、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 practice is to use 33 6 3 gyrations. Previous roundrobin between five laboratories indicated that above 40 gyrations nofurther height

38、 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 and cure for 20 6 0.1 h.NOTE 8The curing protocol in this standard represents only a practicebeing followed by some practitioners and

39、was used in a round-robinencompassing five laboratories. It is not intended to cover or simulate thelarge spectrum of varying field practices and pavement performanceconditions. In the application of this standard the user may define adifferent curing protocol that better represents the local field

40、practice; onethat better simulates the expected short and long term conditions affectingthe mixture properties.7.6 Densification:7.6.1 Determine the bulk specific gravity of the extrudedspecimen as described in Test Methods D 1188, D 2726 orD 6752.7.6.2 Determine the bulk density by dividing the wei

41、ght 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 density of a compacted mixture speci-men,D = diameter of specimen,Wa= specimen weight in air,H = height of compacted specimen, andA =

42、 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 Test Methods D 2041 and D 3203 and thecalculations described in Asphalt Institute Manual MS-25.8. Report8.1 Report the following info

43、rmation: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 thenearest 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 Meth

44、ods 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 Bias9.1 The between-laboratory reproducibility of this testmethod is underway and will be available on or before October,2007. A preli

45、minary study between five laboratories, using oneemulsion and one set of aggregates and three emulsion contentof a single mix and two replicates, indicated that a single-operator precision greater than 1 % of the mean should beconsidered suspect and for between-laboratory precisiongreater than 3 % o

46、f the mean should be considered suspect.9.2 BiasNo information 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

47、; slow-setting emulsionsASTM 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 determination of the validity of any such patent rights, and the riskof infringe

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