1、Designation: D6857/D6857M 11D6857/D6857M 17Standard Test Method forMaximum Specific Gravity and Density of BituminousPaving Asphalt Mixtures Using Automatic Vacuum SealingMethod1This standard is issued under the fixed designation D6857/D6857M; the number immediately following the designation indicat
2、es 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
3、maximum specific gravity of and density of uncompacted bituminous pavingasphalt mixtures at 25C 77F.25 C 77 F.1.2 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 sh
4、all be used independently of the other. Combining values from thetwo systems may result in non-conformancenonconformance with the standard.1.3 The text of this standard references notes and footnotes which provide explanatory material. These notes and footnotes(excluding those in tables and figures)
5、 shall not be considered as requirements of the standard.1.4 This 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 applicabilit
6、y of regulatorylimitations prior to use.1.5 This international standard 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 Tra
7、de Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2C670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction MaterialsD979D979/D979M Practice for Sampling Bituminous Paving MixturesD2041D2041/D2041M Test Method for
8、 Theoretical Maximum Specific Gravity and Density of Bituminous Paving MixturesD3666 Specification for Minimum Requirements for Agencies Testing and Inspecting Road and Paving MaterialsD4753 Guide for Evaluating, Selecting, and Specifying Balances and Standard Masses for Use in Soil, Rock, and Const
9、ructionMaterials TestingE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test MethodE1547 Terminology Relating to Industrial and Specialty ChemicalsD3666 Specification for Minimum Requirements for Agencies Testing and Inspecting Road and Paving Materials3. Termin
10、ology3.1 The terms specific gravityspecific gravity and densitydensity used in this test method are in accordance with theTerminology E1547.3.2 Definitions:3.2.1 density, as determined by this test methodthe mass of a cubic meter of the material at 25C25 C in SI units, or the massof a cubic foot of
11、the material at 77F77 F in inch-pound units.3.2.2 residual pressure, as employed by this test methodthe pressure in a vacuum chamber when vacuum is applied.1 This test method is under the jurisdiction of ASTM Committee D04 on Road and Paving Materials and is the direct responsibility of Subcommittee
12、 D04.21 on SpecificGravity and Density of BituminousAsphalt Mixtures.Current edition approved June 1, 2011June 1, 2017. Published July 2011June 2017. Originally approved in 2003. Last previous edition approved in 20092011 asD6857 09.D6857/D6857M 11. DOI: 10.1520/D6857_D6857M-11.10.1520/D6857_D6857M-
13、17.2 For referencedASTM standards, 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.This document is not an ASTM standard and is intended only
14、 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 changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versio
15、nof 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. United States13.2.3 specific gravity, as determined by this test methodthe ratio of a given mass of material at 25C 77F2
16、5 C 77 F tothe mass of an equal volume of water at the same temperature.4. Summary of Test Method4.1 Aweighed sample of oven-dry pavingasphalt mixture in the loose condition at room temperature is placed inside a speciallydesigned channel bag. The bag containing the sample is placed inside another b
17、ag and placed inside a vacuum chamber. Air isevacuated from the sample to an absolute pressure of 6.0 mm Hg 6 Torr and is automatically sealed. The bags containing thesample are removed from the vacuum chamber and placed inside a large water tank equipped with scales for weighing the sampleunder wat
18、er. While completely submerged, the bag is cut open by scissors to allow the water to enter the bag. Since the sampleis under complete vacuum, water will be forced around all the accessible areas of the sample. The difference in weight in air andsuspended weight in water will provide the sample volu
19、me after correcting for the bag influence. The dry weight and the volumecan be used to calculate the maximum specific gravity of the sample. This method is a rapid technique for determination ofmaximum specific gravity that minimizes the exposure of bituminous asphalt mixture samples to water during
20、 testing and reducesthe chance of water absorption.NOTE 1For porous aggregates, if water absorption correction is not performed on the maximum specific gravities obtained using this test method,the results may be higher than the results obtained by Test Method D2041D2041/D2041M. Without aggregate wa
21、ter absorption correction, air voidscalculated based on these results may be higher.5. Significance and Use5.1 The maximum specific gravities and densities of bituminous paving asphalt mixtures are intrinsic properties whose valuesare influenced by the composition of the mixture in terms of types an
22、d amounts of aggregates and bituminousasphalt materials.5.1.1 They are used to calculate values for percent air voids in compacted bituminous paving asphalt mixtures.5.1.2 They provide target values for the compaction of pavingasphalt mixtures.5.1.3 They are essential when calculating the amount of
23、bitumen asphalt binder absorbed by the internal porosity of theindividual aggregate particles in a bituminous paving an asphalt mixture.NOTE 2The personnel and equipment used in performing quality of the results produced by this standard are dependent on the competence of thepersonnel performing the
24、 procedure and the capability, calibration, and maintenance of the equipment used.Agencies that meet 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 s
25、tandard are cautioned that compliance with Specification D3666 alone does not completely ensure reliable 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
26、 factors.6. Apparatus6.1 Balance, with ample capacity, and with sufficient sensitivity to enable maximum specific gravity of specimens to becalculated to at least four significant figures, that is, to at least three decimal places. It shall be equipped with a suitable apparatusto permit weighing the
27、 specimen while it is suspended in water. The suspension wire attached to the scales should break the surfaceof the water at a single point and should have a maximum diameter of 3 mm 0.125 in. The balance shall conform toSpecificationGuide D4753 as a class GP2 balance.NOTE 3Since there are no more s
28、ignificant figures in the quotient (maximum specific gravity) than appear in either the dividend (the mass of thespecimen in 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 thatthe balance must have a sensitivi
29、ty capable of providing both mass and volume values to at least four figures. For example, a sensitivity of 0.1 g 0.00022lb would provide 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 when the specific gravityis 2.300.6.2 Water Bath, with
30、 minimum dimensions (Length Width Depth) of 610 by 460 by 460 mm 24 by 18 by 18 in. ora cylindrical container with a minimum diameter of 460 mm 18 in. 18 in. and minimum depth of 460 mm 18 in., 18 in., forcompletely submerging the specimen in water while suspended.NOTE 4Setting the water tank at wai
31、st level will enable the user to conduct this test while standing and will significantly simplify the weighingoperations.6.3 Vacuum Chamber,3, with with a 0.93 kW (1.25 hp)1.25 hp pump capable of evacuating a sealed and enclosed chamber to5.6 mm 5.6 mm Hg 6 Torr. The chamber shall be large enough to
32、 seal samples as large as 2200 g 4.85 lb. The device shallautomatically seal the plastic bag and exhaust air back into the chamber in a controlled manner to ensure proper conformance ofthe plastic to the asphalt mixture. The air exhaust and vacuum operation time should be calibrated at the factory p
33、rior to initialuse. The air exhaust system should be calibrated to bring the chamber to atmospheric pressure in 80 to 150 s, after the completionof the vacuum operation. The vacuum system should be provided with a latch to control the chamber door opening.3 The sole source of supply of the apparatus
34、 and the method known to the committee at this time is InstroTek, Inc., Raleigh, NC. If you are aware of alternative suppliers,please provide this information to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee,1 which youmay att
35、end.D6857/D6857M 1726.4 Absolute Vacuum Measurement Gauge, independent of the vacuum sealing device which may be placed directly inside thechamber to verify vacuum performance and the chamber door sealing condition of the unit. The gauge shall be capable of readingpressure to 3 mm Hg 3 Torr.6.5 Plas
36、tic Bags, consisting of inner plastic bag (internal bag) having random channels built into one side of the bag, withminimum and maximum bag opening sizes of 305 mm 12 in. 12 in. and 340 mm 13.5 in., respectively, and outer plastic bag(external bag) with minimum and maximum opening sizes of 375 mm 14
37、.75 in. and 394 mm 15.5 in., respectively. The bagsshall be of plastic material that will not adhere to asphalt film, is puncture resistant, and is impermeable to air. Each bag shall havea minimum thickness of 0.100 mm 0.004 in. and maximum thickness of 0.152 mm 0.006 in. The combined apparent speci
38、ficgravity of the two bags shall be provided by the manufacturer.NOTE 5Protect the plastic bags during storage. Rough handling, storing in close proximity to sharp objects, near aggregates, or inside drawers willdamage the plastic bags. Refer to manufacturers the manufacturers procedures for safe ha
39、ndling and storage of bags.6.6 Holder, for water displacement of the sample having no sharp edges.6.7 Filler Plates, to position the sample and the bags in the same plane as the sealing bar.6.8 Bag Cutting Bag-Cutting Knife, or scissors.6.9 Thermometric Device, a temperature measuring temperature-me
40、asuring device readable to 0.5C 1F0.5 C 1 F andaccurate to 0.3C 0.5F0.3 C 0.5 F for monitoring the temperature of the water bath.6.10 Laboratory Oven, Laboratory oven, capable of heating the asphalt sample to 110 6 5C5 C 230 6 9F9 F7. Sampling7.1 Obtain the sample in accordance with Practice D979D97
41、9/D979M.7.2 The size of the sample shall conform to the following requirements. Samples larger than 2200 g 4.85 lb may be tested in15002000 g 3.31-4.41 1500 to 2000 g 3.31 to 4.41 lb portions at a time.Size of Largest Particle ofAggregate in Mixture, mm in.Minimum Sample Size,g50.0 2 600013.2337.5 1
42、.5 40008.8225.0 1 25005.5119.0 0.75 20004.4112.5 0.5 15003.319.5 0.375 15003.314.75 0.187 15003.318. Procedure8.1 Separate the particles of the sample of pavingasphalt mixture by hand, taking care to avoid fracturing the aggregate, so thatthe particles of the fine aggregate portion are not larger th
43、an 6.3 mm 6.3 mm 14 in. If a sample of pavingasphalt mixture is notsufficiently soft to be separated manually, place it in a flat pan,pan and warm it in an oven until it can be separated as described.8.2 Unless the pavingasphalt mixture has been prepared in a laboratory using oven-dry aggregates, ov
44、en dry aggregates,oven-dry the sample to a constant mass at a temperature of 110 6 5C5 C 230 6 9F.9 F. Other methods of drying can beused as long as the sample achieves a constant mass (mass repeats within 0.1 %). This drying, and any required warming forparticle separation as described in 8.1, shou
45、ld be combined as a single operation to minimize reheating effects.8.3 Cool the sample to room temperature and record the weight. (Refer to columnColumn B of the data collection table. SeeTable X1.1 in the Appendix).Appendix.)8.4 Set the vacuum sealing machine according to the manufacturesmanufactur
46、ers recommendation to create 99 % of absolutevacuum for a minimum of five minutes5 min inside the chamber.NOTE 6For asphalt mixturemixtures that contain polymers, follow manufacturers the manufacturers recommendations.8.5 If after examining the external bag there are no punctures or cuts, weigh one
47、channel (internal) and one examined nonchannel (external) bag.8.6 Record the combined weight of the bags in columnColumn A of the attached data collection table.8.7 Place the sample in the internal bag. Ensure that no sample is lost during this transfer.8.8 Place the empty external bag inside the va
48、cuum chamber.8.9 Place the internal bag containing the sample with the channel side (rough side) down into the external bag. The rough sideis placed under the sample to protect against trapped air and to help in the evacuation of the air from the bag.8.10 Spread the sample so that it is evenly distr
49、ibuted within the internal bag. Do not spread the sample by squeezing down onthe sample from outside the bag.D6857/D6857M 1738.11 Push in the opening of the internal bag away from the opening of the external bag to prevent the opening of the internalbag from being sealed. Make sure that the opening of the internal bag is flat and that the opening is not restricted by a fold in thebag.8.12 Place the opening of the external
