1、Designation: D 6928 08Standard Test Method forResistance of Coarse Aggregate to Degradation by Abrasionin the Micro-Deval Apparatus1This standard is issued under the fixed designation D 6928; the number immediately following the designation indicates the year oforiginal adoption or, in the case of r
2、evision, 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 covers a procedure for testing coarseaggregate for resistance to abrasion using
3、 the Micro-Devalapparatus.1.2 The values stated in SI units are to be regarded as thestandard.1.3 The text of this method references notes and footnoteswhich provide explanatory material. These notes and footnotes(excluding those in tables and figures) shall not be consideredas requirements of the t
4、est method.1.4 This procedure may involve hazardous materials, opera-tions, and equipment. This standard does not purport toaddress all of the safety concerns, if any, associated with itsuse. It is the responsibility of the user of this standard toestablish appropriate safety and health practices an
5、d deter-mine the applicability of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C 136 Test Method for Sieve Analysis of Fine and CoarseAggregatesC 670 Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction MaterialsE11 Specification for
6、 Wire Cloth and Sieves for TestingPurposes3. Terminology3.1 Definitions:3.1.1 constant mass, nthe condition of a test sample driedat a temperature of 110 6 5C such that it will not lose morethan 0.1 % moisture after2hofdrying.3.1.1.1 DiscussionSuch a condition of dryness can beverified by determinin
7、g the mass of the sample before and aftersuccessive 2-h drying periods. In lieu of such a determination,samples may be considered to have reached constant masswhen they have been dried at a temperature of 110 6 5C foran equal or longer period than that previously found adequatefor producing the desi
8、red constant mass condition under equalor heavier loading conditions of the oven.4. Summary of Test Method4.1 The Micro-Deval Test is a measure of abrasion resis-tance and durability of mineral aggregates resulting from acombination of actions including abrasion and grinding withsteel balls in the p
9、resence of water. A sample with standardgrading is initially soaked in water for not less than one hour.The sample is then placed in a jar mill with 2.0 L of water andan abrasive charge consisting of 5000 g of 9.5-mm diametersteel balls. The jar, aggregate, water, and charge are revolved at100 rpm f
10、or up to 2 h, depending on the particle size. Thesample is then washed and oven dried. The loss is the amountof material passing the 1.18-mm sieve expressed as a percentby mass of the original sample.5. Significance and Use5.1 The Micro-Deval abrasion test is a test of coarseaggregate to determine a
11、brasion loss in the presence of waterand an abrasive charge. Many aggregates are more susceptibleto abrasion when wet than dry, and the use of water in this testincorporates this reduction in resistance to degradation incontrast to some other tests, which are conducted on dryaggregate. The test resu
12、lts are helpful in evaluating thetoughness/abrasion resistance of coarse aggregate subject toabrasion when adequate information is not available fromservice records.5.2 The Micro-Deval abrasion test is useful for detectingchanges in properties of aggregate produced from an aggregatesource as part of
13、 a quality control or quality assurance process.6. Apparatus6.1 Micro-Deval Abrasion Machine, a jar rolling mill ca-pable of running at 100 6 5 rpm (Fig. 1).1This test method is under the jurisdiction of ASTM Committee D04 on Roadand Paving Materials and is the direct responsibility of Subcommittee
14、D04.51 onAggregate Tests.Current edition approved Feb. 1, 2008. Published March 2008. Originallyapproved in 2003. Last previous edition approved in 2006 as D 6928 06.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual B
15、ook 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.FIG. 1 Micro-Deval Abrasion Machine and Container (dimensions in mm)D6928082NOTE
16、 1Micro-Deval abrasion machine fitted with a counter may beused if the test is conducted on the basis of number of revolutions (Clause9.4.2).6.2 Containers, stainless steel Micro-Deval abrasion jarshaving an apporiximate 5-L capacity, a locking cover andgasket capable of sealing the jar and making i
17、t water-tight.External diameter of the abrasion jar shall be 194-mm to202-mm and the internal height shall be 170-mm to 177-mm.The inside and outside surfaces of the jars shall be smooth andhave no significant ridges or indentations (Fig. 1).6.3 Abrasive ChargeMagnetic stainless steel balls arerequi
18、red. These shall have a diameter of 9.5 6 0.5 mm. Eachjar requires a charge of 5000 6 5 g of balls.6.4 Sieves, with square openings, and of the following sizesconforming to Specification E11specifications: 19.0 mm, 16.0mm, 12.5 mm, 9.5 mm, 6.7 mm, 6.3 mm, 4.75 mm, 1.18 mm.6.5 Oven, capable of mainta
19、ining a temperature of 110 65C.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 theSoils and Aggregates Section, Materials Engineering MaterialsOffice, Ministry of Transportation, 1201 Wils
20、on Avenue,Downsview, Ontario, Canada M3M1J8. Fax: 1-416-235-4101.7.2 Calibration AggregateAn adequate supply of aggre-gate, established by the Laboratory to use for calibration of thetest method (see 11.1).8. Test Sample8.1 The test sample shall be washed and oven-dried at 1106 5C to constant mass,
21、separated into individual size fractionsin accordance with Test Method C 136, and recombined tomeet the grading as shown in 8.2, 8.3,or8.4. In sections 8.3and 8.4, the 6.7-mm sieve can be used in place of the 6.3-mmsieve when specified.8.2 Aggregate for the test sample shall consist of materialpassi
22、ng 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 where the maximum nominal size of the coarseaggregate is 12.5 mm, a sample of 1500 6 5 g
23、 shall beprepared as 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 coarseaggregate is 9.5 mm or less, a sample 1500 6 5 g shall beprepared as follows:Passing Retained Mass9.5-mm 6.3-mm 750 g6.3-mm 4.75-mm 7
24、50 g9. Test Procedure9.1 Prepare a representative 1500 6 5 g test sample. Weighthe sample and record the Mass, A, to the nearest 1.0 g.9.2 Immerse the test sample in 2.0 6 0.05 L of tap water ata temperature 20 6 5C for a minimum of 1 h either in theMicro-Deval container or some other suitable conta
25、iner.9.3 Place the test sample in the Micro-Deval abrasioncontainer with 5000 6 5 g steel balls and the water used in 9.2to immerse the sample. Install the cover and place theMicro-Deval container on the machine.9.3.1 Run the machine at 100 6 5 rpm for 2 h 6 1 min forthe grading shown in 8.2. For th
26、e grading shown in 8.3, run themachine for 105 6 1 min. For the grading shown in 8.4, run themachine for 95 6 1 min.9.3.2 If a revolution counter is available; run the machinefor 12 000 6 100 revolutions for the grading shown in 8.2; forthe grading shown in 8.3, run the machine for 10 500 6 100revol
27、utions; For the grading shown in 8.4, run the machine for9500 6 100 revolutions.9.4 Carefully pour the test sample and steel balls over a4.75-mm sieve superimposed on a 1.18-mm sieve. Take care toremove the entire test sample from the stainless steel jar. Washand manipulate the retained material on
28、the sieve with waterusing a hand held water hose and the hand until the washingsare clear and all material smaller than 1.18 mm passes thatsieve. Remove the stainless steel balls using a magnet or othersuitable means. Discard material smaller than 1.18 mm.9.5 Combine the material retained on the 4.7
29、5 mm and 1.18mm sieves, being careful not to lose any material.9.6 Oven dry the test sample to constant mass at 110 6 5C.9.7 Weigh the test sample to the nearest 1.0 g. Record theMass, B.10. Calculation10.1 Calculate the Micro-Deval abrasion loss, as follows, tothe nearest 0.1 %.Percent Loss 5 A 2 B
30、! / A 3 100 (1)11. Use of the Calibration Aggregate11.1 Calibration AggregateThe Laboratory will establishan adequate supply of material to use for calibration of the testmethod.Asuitable material with a loss of between 10 and 25 %shall be established. From this material 10 samples shall betaken ran
31、domly and tested. At the same time 10 samples ofreference aggregate from Brechin Quarry No. 2 (see 7.1) shallalso be tested. Provided the mean loss and variation of theBrechin Quarry No. 2 aggregate is within the allowed toleranceof 11.1.1, the mean value and range obtained with the supplyof the in-
32、house calibration aggregate shall be used thereafter.At any time a new supply of the in-house calibration aggregateis required, the calibration procedure shall be conducted.11.1.1 The mean loss of the Brechin Quarry No. 2 referenceaggregate (see 7.1) in multi-laboratory study of the Micro-Deval test
33、 is 19.1 %. For continued acceptance of data,individual reference material test data must fall within therange 17.5 to 20.7 % loss for 95 % of the time.11.1.2 When test data of the calibration aggregate is outsidethe limits, an investigation as to the probable cause shall beconducted. The equipment
34、shall be re-calibrated and the testingtechnique re-examined to detect non-conformance with the testprocedure.D692808311.2 Every 10 samples, but at least every week in which asample is tested, a sample of the calibration aggregate shallalso be tested. The material shall be taken from a stock supplyan
35、d prepared according to 8.2. When 20 samples of calibrationmaterial have been tested, and the results show satisfactoryvariation, the frequency of testing may be changed to aminimum of one sample every month.11.3 Trend Chart UseThe percent loss of the last twentysamples of calibration material shall
36、 be plotted on a trend chartin order to monitor the variation in results (Fig. 2).12. Report12.1 The report shall include the following:12.1.1 The maximum size of the aggregate tested and thegrading used.12.1.2 The percent loss of the test sample to one decimalplace.12.1.3 The percent loss of the ca
37、libration aggregate, testedclosest to the time at which the aggregate was tested, to thenearest 0.1 %.12.1.4 The percent loss of the last twenty samples ofcalibration aggregate on a trend chart.13. Precision and Bias313.1 PrecisionFor 19.0-mm maximum size aggregatewith abrasion losses in the range f
38、rom 5 % to 20 %, the singleoperator coefficient of variation has been found to be 3.4 %.4Therefore, results of two properly conducted tests on samplesof the same aggregate by the same operator using the sameequipment are not expected to differ by more than 9.6 %4oftheir average, 95 % of the time. Th
39、e multilaboratory coefficientof variation has been found to be 5.6%.4Therefore, the resultsof two properly conducted tests by different laboratories onsamples of the same aggregate are not expected to differ bymore than 15.8 %4of their average, 95 % of the time.13.2 BiasThe procedure in this test me
40、thod for measuringresistance to abrasion has no bias because the resistance toabrasion can only be defined in terms of the test method.14. Keywords14.1 abrasion resistance; coarse aggregate; micro deval3Supporting data pending being filed at ASTM International Headquarters.4These numbers represent,
41、respectively, the (1s %) and (d2s %) limits asdescribed in Practice C 670.D6928084APPENDIX(Nonmandatory Information)X1. INTERPRETATION OF TEST RESULTSX1.1 In studies of the performance of aggregates in thistest,5,6,7the limits in Table X1.1 have been found useful forseparating aggregates of satisfac
42、tory performance from thoseof fair or poor performance. The use of a single test by itself forestimating likely aggregate performance is not as useful asusing a combination of tests which measure complementaryproperties. Further discussion on this topic will be found inRogers5and Lang et al.75Rogers
43、, C., “Canadian Experience with the Micro-Deval Test for Aggregates,”Advances in Aggregates and Armourstone Evaluation, Latham, J. P., ed., GeologicalSociety, London, Engineering Geology Special Publications, 13, 1998, pp. 139-147.6Kandhal, P. S., Parker Jr., F., “Aggregate Tests Related to Asphalt
44、ConcretePerformance in Pavements,” Final Report Prepared for National CooperativeHighway Research Program, Transportation Research Board, Washington, May1997.7Lang, A. P., Range, P. H., Fowler, D. W. and Allen, J. J., “Prediction of CoarseAggregate Performance by Micro-Deval and Other Soundness, Str
45、ength, andIntrinsic Particle Property Tests,” Transportation Research Record, Journal of theTransportation Research Board, No. 2026, 2007, pp. 38.FIG. 2 Micro-Deval Abrasion Trend Chart for Brechin Quarry No.2 Aggregate SamplesD6928085ASTM International takes no position respecting the validity of a
46、ny 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 infringement of such rights, are entirely their own responsibility.This standard is subject to re
47、vision 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. You
48、r comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copy
49、righted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).TABLE X1.1ApplicationMaximum Micro-DevalAbrasion Loss (%)Granular sub-base 30AGranular base 25AOpen graded base course 17AStructural Concrete 17A21BConcrete Pavement 13AAsphalt concrete base course and secondary roa
