1、Designation: D6928 10D6928 17Standard Test Method forResistance of Coarse Aggregate to Degradation by Abrasionin the Micro-Deval Apparatus1This standard is issued under the fixed designation D6928; the number immediately following the designation indicates the year oforiginal adoption or, in the cas
2、e 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 covers a procedure for testing coarse aggregate for resistance to abrasion
3、 using the Micro-Deval apparatus.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 The text of this method references notes and footnotes which provide explanatory material. These notes and footnotes(excluding those in t
4、ables and figures) shall not be considered as requirements of the test method.1.4 This procedure may involve hazardous materials, operations, and equipment. This standard does not purport to address allof the safety concerns, if any, associated with its use. It is the responsibility of the user of t
5、his standard to establish appropriatesafety and health practices and determine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles f
6、or the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2C136 Test Method for Sieve Analysis of Fine and Coarse AggregatesC670 Practice for Preparing Precisio
7、n and Bias Statements for Test Methods for Construction MaterialsE11 Specification for Woven Wire Test Sieve Cloth and Test Sieves3. Terminology3.1 Definitions:3.1.1 constant mass, nthe condition of a test sample dried at a temperature of 110 6 5C5 C such that it will not lose morethan 0.1 % moistur
8、e after 2 h of drying.3.1.1.1 DiscussionSuch a condition of dryness can be verified by determining the mass of the sample before and after successive 2-h drying periods.In lieu of such a determination, samples may be considered to have reached constant mass when they have been dried at atemperature
9、of 110 6 5C5 C for an equal or longer period than that previously found adequate for producing the desired constantmass condition under equal or heavier loading conditions of the oven.4. Summary of Test Method4.1 The Micro-Deval Testtest is a measure of abrasion resistance and durability of mineral
10、aggregates resulting from acombination of actions including abrasion and grinding with steel balls in the presence of water. A sample with standard gradingis initially soaked in water for not less than one hour.1 h. The sample is then placed in a jar mill with 2.0 Lof water and an abrasivecharge con
11、sisting of 5000 g of 9.5-mm diameter steel balls. The jar, aggregate, water, and charge are revolved at 100 rpm for up1 This test method is under the jurisdiction ofASTM Committee D04 on Road and Paving Materials and is the direct responsibility of Subcommittee D04.51 on AggregateTests.Current editi
12、on approved June 1, 2010April 1, 2017. Published June 2010April 2017. Originally approved in 2003. Last previous edition approved in 20082010 as D6928 0810.1. DOI: 10.1520/D6928-10.10.1520/D6928-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service a
13、t 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 to provide the user of an ASTM standard an indication of what changes have been made to the previous ver
14、sion. 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 versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM Internatio
15、nal, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1to 2 h, depending on the particle size. The sample is then washed and oven dried. The loss is the amount of material passing the1.18-mm sieve expressed as a percent by mass of the original sample.5. Significance
16、 and Use5.1 The Micro-Deval abrasion test is a test of coarse aggregate to determine abrasion loss in the presence of water and anabrasive charge. Many aggregates are more susceptible to abrasion when wet than dry, and the use of water in this test incorporatesthis reduction in resistance to degrada
17、tion in contrast to some other tests, which are conducted on dry aggregate. The test resultsare helpful in evaluating the toughness/abrasion resistance of coarse aggregate subject to abrasion when adequate information isnot available from service records.5.2 The Micro-Deval abrasion test is useful f
18、or detecting changes in properties of aggregate produced from an aggregate sourceas part of a quality control or quality assurance process.6. Apparatus6.1 Micro-Deval Abrasion Machine, a jar rolling mill capable of running at 100 6 5 rpm (Fig. 1).NOTE 1Micro-Deval abrasion machine fitted with a coun
19、ter may be used if the test is conducted on the basis of number of revolutions (Section(see9.3.2).6.2 Containers, stainless steel Micro-Deval abrasion jars having an apporiximate 5-L capacity, a locking cover and gasketcapable of sealing the jar and making it water-tight.watertight. External diamete
20、r of the abrasion jar shall be 194-mm194 mm to202-mm202 mm and the internal height shall be 170-mm170 mm to 177-mm.177 mm. The inside and outside surfaces of the jarsshall be smooth and have no significant ridges or indentations (Fig. 1).6.3 Abrasive ChargeMagnetic stainless steel balls are required
21、. These shall have a diameter of 9.5 6 0.5 mm. Each jarrequires a charge of 5000 6 5 g of balls.6.4 Sieves, with square openings, and of the following sizes conforming to Specification E11 specifications: 19.0 mm, 16.0 mm,16.0 mm, 12.5 mm, 9.5 mm, 6.7 mm, 6.3 mm, 4.75 mm, and 1.18 mm.6.5 Oven, capab
22、le of maintaining a temperature of 110 6 5C.5 C.6.6 Balance, or scale accurate to 1.0 g.7. Supplies7.1 Laboratory Reference AggregateA supply of standard “Brechin Quarry No. 2” coarse aggregate available from the Soilsand Aggregates Section, Materials Engineering Materials Office, Ministry of Transp
23、ortation, 1201 Wilson Avenue, Downsview,Ontario, Canada M3M1J8. Fax: 1-416-235-4101.7.1 CalibrationReference AggregateAn adequate supply of aggregate, established by the Laboratorylaboratory to use forcalibrationverification of the consistency of the test method (see 11.1).8. Test Sample8.1 The test
24、 sample shall be washed and oven-dried oven dried at 110 6 5C5 C to constant mass, separated into individualsize fractions in accordance with Test Method C136, and recombined to meet the grading as shown in 8.2, 8.3, or 8.4. In sections8.3 and 8.4, the 6.7-mm sieve can be used in place of the 6.3-mm
25、 sieve when specified.8.2 Aggregate for the test sample shall consist of material passing the 19.0-mm sieve, retained on the 9.5-mm sieve. Anoven-dried sample of 1500 6 5 g shall be prepared as follows:Passing Retained Mass19.0-mm 16.0-mm 375 g16.0-mm 12.5-mm 375 g12.5-mm 9.5-mm 750 g8.3 In a case w
26、here the maximum nominal size of the coarse aggregate is 12.5 mm, a sample of 1500 6 5 g shall be preparedas follows:Passing Retained Mass12.5-mm 9.5-mm 750 g9.5-mm 6.3-mm 375 g6.3-mm 4.75-mm 375 g8.4 In a case where the maximum nominal size of the coarse aggregate is 9.5 mm or less, a sample 1500 6
27、 5 g shall be preparedas follows:Passing Retained Mass9.5-mm 6.3-mm 750 g6.3-mm 4.75-mm 750 gD6928 172NOTE 1Dimensions are in millimeters.FIG. 1 Micro-Deval Abrasion Machine and Container (dimensions in mm)D6928 1739. Test Procedure9.1 Prepare a representative 1500 6 5 g 5-g test sample. Weigh the s
28、ample and record the Mass,mass, A, to the nearest 1.0 g.9.2 Immerse the test sample in 2.0 6 0.05 L of tap water at a temperature of 20 6 5C5 C for a minimum of 1 h either in theMicro-Deval container or some other suitable container.9.3 Place the test sample in the Micro-Deval abrasion container wit
29、h 500065 g steel balls and the water used in 9.2 to immersethe sample. Install the cover and place the Micro-Deval container on the machine.9.3.1 Run the machine at 100 6 5 rpm for 2 h 6 1 min for the grading shown in 8.2. For the grading shown in 8.3, run themachine for 105 6 1 min. For the grading
30、 shown in 8.4, run the machine for 95 6 1 min.9.3.2 If a revolution counter is available;available, run the machine for 12 000 6 100 revolutions for the grading shown in 8.2;for. For the grading shown in 8.3, run the machine for 10 500 6 100 revolutions;revolutions. For the grading shown in 8.4, run
31、the machine for 9500 6 100 revolutions.9.4 Carefully pour the test sample and the steel balls over a 4.75mm4.75-mm sieve superimposed on a 1.18mm1.18-mmsieve. Take care to remove the entire test sample from the stainless steel jar. Wash and manipulate the retained material on the sievewith water usi
32、ng a hand held hand-held water hose and the hand until the washings are clear and material smaller than 1.18 mmpasses that sieve. Discard material smaller than 1.18mm. 1.18 mm. Remove the stainless steel balls as described in 9.5.9.5 Remove the steel balls using one of the following options:9.5.1 Op
33、tion 1, Wet method for removing steel balls from sampleMethod for Removing Steel Balls from SampleRemove thestainless steel balls from the sample immediately after washing using a magnet or other suitable means, being careful not to loseany material. Combine the material retained on the 4.75-mm and
34、1.18-mm sieves. Oven-dry the test sample to a constant mass at110 6 5C.5 C.9.5.2 Option 2, Dry method for removing steel balls from sampleMethod for Removing Steel Balls from SampleCombinethe material retained on the 4.75-mm and 1.18-mm sieves and steel balls, being careful not to lose any material.
35、 Oven dry the testsample and steel balls to a constant mass at 110 6 5C.5 C. Remove the steel balls from the dry sample using a magnet or othersuitable means.NOTE 2Extreme care must be taken if using the wet method for removing the steel balls. The surface tension of the water may cause small pieces
36、of the aggregate to adhere to the balls. The wet method for removal is allowed to expedite additional testing for laboratories with a limited supply of balls.Otherwise, the dry method may be used to eliminate this potential source of error. However, care should still be taken when removing the balls
37、 to avoidloss of aggregate.9.6 Oven dry the test sample to constant mass at 110 6 5C.5 C.9.7 Weigh the test sample to the nearest 1.0 g. Record the mass, B.10. Calculation10.1 Calculate the Micro-Deval abrasion loss, as follows, to the nearest 0.1 %.Percent Loss5A 2B!/A 3100 (1)11. Use of the Calibr
38、ationReference Aggregate11.1 CalibrationReference AggregateThe Laboratorylaboratory will establish an adequate supply of material to use forcalibrationverification of the consistency of the test method. A suitable material with a loss of between 10 and 25 % shall beestablished. From this material 10
39、ten samples shall be taken randomly and tested. At the same time 10 samples of referenceaggregate from Brechin Quarry No. 2 (see 7.1) shall also be tested. Provided the mean loss and variation of the Brechin QuarryNo. 2 aggregate is within the allowed tolerance of 11.1.1, the mean value and range ob
40、tained with the supply of the in-housecalibration aggregate shall be used thereafter. At any time a new supply of the in-house calibration reference aggregate (7.1) isrequired, the calibration this procedure shall be conducted.11.1.1 The mean loss of the Brechin Quarry No. 2 reference aggregate (see
41、value and range (62 standard deviations) obtainedfrom the supply 7.1) in multi-laboratory study of the Micro-Deval test is 19.1 %. For continued acceptance of data, individualreference material test data must fall within the range 17.5 to 20.7 % loss for 95 % of the time.of the reference aggregate s
42、hall bedetermined from the ten samples.11.1.2 When test data of the calibrationreference aggregate is outside the limits,range, an investigation as to the probable causeshall be conducted. The equipment shall be re-calibrated and the testing technique re-examined to detect non-conformancenonconforma
43、nce with the test procedure.11.2 Every 10ten samples, but at least every week in which a sample is tested, a sample of the calibrationreference aggregateshall also be tested. The material shall be taken from a stock supply and prepared according to 8.2. When 20 samples of calibrationmaterial have be
44、en tested, and the results show satisfactory variation, the frequency of testing may be changed to a minimum ofone sample every month.D6928 17411.3 Trend Chart UseThe percent loss of the last twenty20 samples of calibrationreference material shall be plotted on a trendchart in order to monitor the v
45、ariation in results (Fig. 2).12. Report12.1 The report shall include the following:12.1.1 The maximum size of the aggregate tested and the grading used.12.1.2 The percent loss of the test sample to one decimal place.12.1.3 The percent loss of the calibration aggregate, tested closest to the time at
46、which the aggregate was tested, to the nearest0.1 %.12.1.4 The percent loss of the last twenty20 samples of calibration aggregate on a trend chart.13. Precision and Bias313.1 PrecisionFor 19.0-mm maximum size aggregate with abrasion losses in the range from 5 % to 20 %, the single operatorsingle-ope
47、rator coefficient of variation has been found to be 3.4 %.4 Therefore, results of two properly conducted tests on samplesof the same aggregate by the same operator using the same equipment are not expected to differ by more than 9.6 %4 of theiraverage, 95 % of the time. The multilaboratory coefficie
48、nt of variation has been found to be 5.6%.4 Therefore, the results of twoproperly conducted tests by different laboratories on samples of the same aggregate are not expected to differ by more than 15.8 %4of their average, 95 % of the time.13.2 BiasThe procedure in this test method for measuring resi
49、stance to abrasion has no bias because the resistance to abrasioncan only be defined in terms of the test method.3 Supporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:D04-1029. Contact ASTM CustomerService at serviceastm.org.4 These numbers represent, respectively, the (1s %) and (d2s %) limits as described in Practice C670.FIG. 2 Micro-Deval Abrasion Trend Chart for Brechin Quarry No.2 Aggregate SamplesReference AggregateD6928 17514. Keywords14.1 abrasion resistance; coar
copyright@ 2008-2019 麦多课文库（www.mydoc123.com）网站版权所有
备案/许可证编号：苏ICP备17064731号-1