1、Designation: D6752/D6752M 11D6752/D6752M 17Standard Test Method forBulk Specific Gravity and Density of CompactedBituminousAsphalt Mixtures Using Automatic VacuumSealing Method1This standard is issued under the fixed designation D6752/D6752M; the number immediately following the designation indicate
2、s theyear of original adoption or, in the case of revision, the 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 test method covers the determination of b
3、ulk specific gravity of compacted bituminousasphalt mixtures by the vacuumsealing method.1.2 This method can be used for compacted cylindrical and cubical bituminous laboratory and field asphalt mixture specimens.1.3 The bulk specific gravity of the compacted bituminousasphalt mixtures may be used i
4、n calculating the unit weight of themixture.1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in eachsystem may not be exact equivalent; therefore, each system shall be used independently of the other. Combining values from thet
5、wo systems may result in non-conformancenonconformance with the standard.1.5 The text of this standard references notes and footnotes which provide explanatory material. These notes and footnotes(excluding those in tables and figures) shall not be considered as requirements of the standard.1.6 This
6、standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatoryrequirements prior to use.1.7 This international st
7、andard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Re
8、ferenced Documents2.1 ASTM Standards:2C670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction MaterialsD8 Terminology Relating to Materials for Roads and PavementsD2726D2726/D2726M Test Method for Bulk Specific Gravity and Density of Non-Absorptive Compacted Bitum
9、inous MixturesD3203D3203/D3203M Test Method for Percent Air Voids in Compacted Dense and Open Bituminous Paving Asphalt MixturesD3666 Specification for Minimum Requirements for Agencies Testing and Inspecting Road and Paving MaterialsD4753 Guide for Evaluating, Selecting, and Specifying Balances and
10、 Standard Masses for Use in Soil, Rock, and ConstructionMaterials TestingD5361D5361/D5361M Practice for Sampling Compacted BituminousAsphalt Mixtures for Laboratory TestingD7227D7227/D7227M Practice for Rapid Drying of Compacted Asphalt Specimens Using Vacuum Drying Apparatus2.2 AASHTO Standards:3M3
11、23 Standard Specification for Superpave Mix Design3. Terminology3.1 For definitions of terms used in this standard, refer to Terminology D8.1 This test method is under the jurisdiction of ASTM Committee D04 on Road and Paving Materials and is the direct responsibility of Subcommittee D04.21 on Speci
12、ficGravity and Density of Asphalt Mixtures.Current edition approved June 1, 2011June 1, 2017. Published July 2011June 2017. Originally approved in 2002. Last previous edition approved in 20092011 asD6752 09.D6752/D6752M 11. DOI: 10.1520/D6752_D6752M-11.10.1520/D6752_D6752M-17.2 For referencedASTM st
13、andards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available from the American Association of State Highway Transportation Officials
14、(AASHTO), 441 N. Capitol Street, NW, Washington, DC 20001.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all change
15、s accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. Unit
16、ed States14. Significance and Use4.1 The results obtained from this method can be used to determine the unit weight of compacted bituminous mixturesasphaltmixtures, and in conjunction with Test Method D3203D3203/D3203M, to obtain percent air voids. These values in turn may beused in determining the
17、relative degree of compaction.4.2 Since specific gravity has no units, it must be converted to density in order to do calculations that require units. Thisconversion is made by multiplying the specific gravity at a given temperature by the density of water at the same temperature.4.3 This method can
18、 be used for 100 mm 4 in. and 150 mm 6 in. diameter cylindrical as well as cubical asphalt mixturespecimens to correct for inconsistencies in sample weight determinations resulting from drainage of water from samples andinaccuracy in saturated surface dry weight of absorptive coarse and open graded
19、mixes. MixesAsphalt mixes such as Stone MatrixAsphaltstone matrix asphalt (SMA), porous friction course, and coarse graded mixes with significant surface texture andinterconnected voids can be tested with this method. Follow manufacturer recommendation for appropriate bag sizes to be utilizedwith cu
20、bical and abnormally shaped samples.4NOTE 1The personnel and equipment used in performing quality of the results produced by this standard are dependent on the competence of thepersonnel performing the procedure and the capability, calibration, and maintenance of the equipment used.Agencies that mee
21、t the criteria of SpecificationD3666this test can be evaluated in accordance with Practice are generally considered capable of competent and objective testing, sampling, inspection,etc. Users of this standard are cautioned that compliance with Specification D3666 alone does not completely ensure rel
22、iable results. Reliable resultsdepend on many factors; following the suggestions of Specification D3666. or some similar acceptable guideline provides a means of evaluating andcontrolling some of those factors.5. Apparatus5.1 Balance, with ample capacity, and with sufficient sensitivity to enable bu
23、lk specific gravity of specimens to be calculatedto at least four significant figures, that is, to at least three decimal places. It shall be equipped with a suitable apparatus to permitweighing the specimen while it is suspended in water. The balance shall conform to Guide D4753 as a class GP2 bala
24、nce.NOTE 2Since there are no more significant figures in the quotient (bulk specific gravity) than appear in either the dividend (the mass of the specimenin air) or in the divisor (the volume of the specimen, obtained from the difference in mass of the specimen in air and in water), this means that
25、the balancemust have a sensitivity capable of providing both mass and volume values to at least four figures. For example, a sensitivity of 0.1 g 0.00022 lb wouldprovide four significant figures for the determination of a mass in the range from 130.0 to 999.9 g 0.29 to 2.20 lb 2.20 lb when the speci
26、fic gravityis 2.300.5.2 Water Bath, with minimum dimensions (Length(length Widthwidth Depth)depth) of 610 by 460 by 460 mm 24 by18 by 18 in. or a large cylindrical container, for completely submerging the specimen in water while suspended, equipped withan overflow outlet for maintaining a constant w
27、ater level.NOTE 3It is preferable to keep the water temperature constant by using a temperature controlled temperature-controlled heater. Also, to reduce thechance for the bag to touch the sides of the water tank, it is preferable to elevate the water tank to a level at which the sample can be place
28、d on theweighing mechanism while standing up, and the placement of the sample and the bag in the water tank can easily be inspected.5.3 Cushioned holder,Holder, for water displacement of the sample, having no sharp edges.NOTE 4To avoid accidental puncture of the plastic bags in the water bath, plast
29、ic coated plastic-coated cushioned holders have been found to workwell for this test method.5.4 Vacuum Chamber, with a 0.93 kW (1.25 hp)1.25 hp pump capable of evacuating a sealed and enclosed chamber to aminimum pressure of 10 mm Hg (10 Torr)10 Torr in less than 60 s, when at sea level. The chamber
30、 shall be large enough to sealsamples of 150 mm 6 in. wide by 350 mm 14 in. long by 150 mm 6 in. thick. The device shall automatically seal the plasticbag and exhaust air back into the chamber in a controlled manner to ensure proper conformance of the plastic to the asphaltspecimen. The air exhaust
31、and vacuum operation time should be calibrated at the factory prior to initial use. The air exhaust systemshould be calibrated to bring the chamber to atmospheric pressure in 80 to 120 s, after the completion of the vacuum operation.The vacuum system should be provided with a latch to control the ch
32、amber door opening.5.5 A Vacuum Measurement Gauge, independent of the vacuum sealing device that could be placed directly inside the chamber,to verify vacuum performance and the chamber door sealing condition of the unit. The gauge shall be capable of reading 3 mmHg (3 Torr)3 Torr pressure.5.6 Plast
33、ic Bags, used with the vacuum device shall be one of the two following sizes. The smaller bags shall have a minimumopening of 241 mm 9.50 in. and maximum opening of 260 mm 10.25 in. and the larger bags shall have a minimum of 375 mm14.75 in. and a maximum opening of 394 mm 15.5 in. The bags shall be
34、 of plastic material that will not adhere to asphalt film,is puncture resistant, is capable of withstanding sample temperatures of up to 70C 158F,70 C 158 F, is impermeable towater, and contains no air channels for evacuation of air from the bag. The bags shall have a minimum thickness of 0.100 mm4
35、Bulk specific gravity determined by this method may be lower than the results obtained by Test Method D2726D2726/D2726M. As a result, air voids determined fromthese bulk specific gravity values may be higher than the air voids values determined using Test Method D2726D2726/D2726M. These differences
36、may be more pronouncedfor coarse aggregate mixtures. Users of this method are cautioned to evaluate any alteration in percent asphalt content or aggregate gradations for mix designs with a knownpositive performance history.D6752/D6752M 1720.004 in. and maximum thickness of 0.152 mm 0.006 in. The app
37、arent specific gravity for the bags shall be provided by themanufacturer. The apparent specific gravity provided for each size bag shall account for the different sample weights and bagweight used during testing.5.7 Specimen Sliding Plate, used within the chamber for reduction of friction on the pla
38、stic bags.5.8 Bag Cutting Bag-Cutting Knife, or scissors.6. Sampling6.1 Test specimens may be molded from laboratory prepared laboratory-prepared samples or taken from bituminousasphaltpavement in the field. Field samples should be obtained in accordance with Practice D5361D5361/D5361M.7. Test Speci
39、mens7.1 It is recommended, (1) that the diameter of cylindrically molded or cored specimens, or the length of the sides of sawedspecimens be at least equal to four times the maximum size of the aggregate; and (2) that the thickness of specimens be at leastone and one half one-half times the maximum
40、size of the aggregate. Pavement specimens are to be taken by such means as coring,sawing of blocks, and so forth.7.2 Take care to avoid distortion, bending, or cracking of specimens during and after removal from pavement or mold. Storespecimens in a safe, cool place.7.3 Specimens shall be free of fo
41、reign materials,materials such as sealcoat, tack coat, foundation material, soil, paper, or foil.When any of these materials areis visually evident, theyit shall be removed. Sealcoat, tackcoat, or irregular surfaces that may resultin the plastic bag not complying with the sample shall be removed by
42、sawing the bottom or the top faces, or both, of the sample.7.4 If desired, specimens may be separated from other pavement layers by sawing or other suitable means.7.5 Use a brush or a soft sanding block to break sharp edges around the top and bottom corners of the sample.8. Procedure8.1 This procedu
43、re can be used for compacted field and laboratory specimens. Specifically, use this procedure,procedure if theasphalt mix is absorptive as determined by Test Method D2726D2726/D2726M and for coarse and open graded mixes. For asphaltmixes such as Stone Matrix Asphaltstone matrix asphalt (SMA), porous
44、 friction course, and coarse graded mixes with significantsurface texture and interconnected voids, follow the procedure outlined in this section for determination of bulk specific gravity.8.2 Mass of Unsealed Specimen:8.2.1 Laboratory Prepared Laboratory-Prepared SpecimensDetermine the mass of the
45、specimen after it has cooled to roomtemperature. Designate this mass as A.8.2.2 Cores and Specimens Containing MoistureDry the specimen and designate this mass as A. Vacuum drying drying,Practice D7227D7227/D7227M, or other approved methods may be used to dry the sample to constant mass.8.3 Mass of
46、Sealed Specimen:8.3.1 Select an appropriate size bag. For all 100 mm 4 in. diameter samples and samples with 150 mm 6 in. diameter andless than 75 mm 3 in. thickness, use the bag with smaller opening size as specified in 4.65.6. For 150 mm 6 in. samples withgreater than 50 mm 2 in. thickness, use th
47、e larger opening size bags as specified in 4.65.6. For samples that weigh more than5500 g 12.1 lb or abnormally shaped samples, use manufacturers recommendation for appropriate bag size and configuration.NOTE 5Protect the bag during storage. Rough handling, storing in proximity to sharp objects such
48、 as tools, aggregate, or inside drawers will damagethe plastic bag. Refer to manufacturers recommendation for handling and safe storage.8.3.2 Inspect an appropriate size bag for holes or irregularities, record the bag mass and place a bag inside the vacuum chamberon top of the specimen sliding plate
49、.8.3.3 Gently open the bag and place the specimen in the plastic bag on top of the specimen sliding plate, being careful to handlethe bag in such a manner that would prevent a puncture. Avoid dropping or impacting the bag, and follow manufacturersrecommendations for handling the specimens and the bags.8.3.4 Allow the vacuum chamber to remove the air from the chamber and the plastic bag. The vacuum chamber shallautomatically seal the bag once the air is removed.8.3.5 Exhaust air into the chamber until the
