1、Designation: D6928 10Standard 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 case of rev
2、ision, 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 coarseaggregate for resistance to abrasion using th
3、e Micro-Devalapparatus.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 The text of this method references notes and footnoteswhich provide explanatory material. These notes and footnotes(excluding those in tables and fig
4、ures) shall not be consideredas requirements of the test 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 t
5、oestablish appropriate safety and health practices and deter-mine the applicability of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C136 Test Method for Sieve Analysis of Fine and CoarseAggregatesC670 Practice for Preparing Precision and Bias Statementsfor Test Meth
6、ods for Construction MaterialsE11 Specification for Woven Wire Test Sieve Cloth and TestSieves3. 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
7、 a condition of dryness can beverified by determining 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
8、that previously found adequatefor producing the desired 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 incl
9、uding abrasion and grinding withsteel balls in the presence 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, a
10、ggregate, water, and charge are revolved at100 rpm for 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 abras
11、ion test is a test of coarseaggregate to determine abrasion 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
12、, which are conducted on dryaggregate. The test results 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 a
13、ggregate produced from an aggregatesource as part of 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 Materia
14、ls and is the direct responsibility of Subcommittee D04.51 onAggregate Tests.Current edition approved June 1, 2010. Published June 2010. Originallyapproved in 2003. Last previous edition approved in 2008 as D6928 081. DOI:10.1520/D6928-10.2For referenced ASTM standards, visit the ASTM website, www.a
15、stm.org, 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.FIG. 1
16、Micro-Deval Abrasion Machine and Container (dimensions in mm)D6928 102NOTE 1Micro-Deval abrasion machine fitted with a counter may beused if the test is conducted on the basis of number of revolutions (Section9.3.2).6.2 Containers, stainless steel Micro-Deval abrasion jarshaving an apporiximate 5-L
17、capacity, a locking cover andgasket capable of sealing the jar and making it 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 inden
18、tations (Fig. 1).6.3 Abrasive ChargeMagnetic stainless steel balls arerequired. 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 E11 specifications: 19.0 mm, 16.0mm, 1
19、2.5 mm, 9.5 mm, 6.7 mm, 6.3 mm, 4.75 mm, 1.18 mm.6.5 Oven, capable of maintaining 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,
20、Materials Engineering MaterialsOffice, Ministry of Transportation, 1201 Wilson 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
21、The test sample shall be washed and oven-dried at 1106 5C to constant mass, separated into individual size fractionsin accordance with Test Method C136, and recombined to meetthe grading as shown in 8.2, 8.3,or8.4. In sections 8.3 and 8.4,the 6.7-mm sieve can be used in place of the 6.3-mm sievewhen
22、 specified.8.2 Aggregate for the test sample shall consist of materialpassing 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 max
23、imum nominal size of the coarseaggregate is 12.5 mm, a sample of 1500 6 5 g 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 bep
24、repared as follows:Passing Retained Mass9.5-mm 6.3-mm 750 g6.3-mm 4.75-mm 750 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 min
25、imum of 1 h either in theMicro-Deval container or some other suitable container.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
26、 machine at 100 6 5 rpm for 2 h 6 1 min forthe grading shown in 8.2. For the 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
27、 in 8.2; forthe grading shown in 8.3, run the machine for 10 500 6 100revolutions; For the grading shown in 8.4, run the machine for9500 6 100 revolutions.9.4 Carefully pour the test sample and the steel balls over a4.75mm sieve superimposed on a 1.18mm sieve. Take careto remove the entire test samp
28、le from the stainless steel jar.Wash and manipulate the retained material on the sieve withwater using a hand held water hose and the hand until thewashings are clear and material smaller than 1.18 mm passesthat sieve. Discard material smaller than 1.18mm. Remove thestainless steel balls as describe
29、d in 9.5.9.5 Remove the steel balls using one of the followingoptions:9.5.1 Option 1,Wet method for removing steel balls fromsampleRemove the stainless steel balls from the sampleimmediately after washing using a magnet or other suitablemeans, being careful not to lose any material. Combine themater
30、ial retained on the 4.75-mm and 1.18-mm sieves. Oven-dry the test sample to a constant mass at 110 6 5C.9.5.2 Option 2, Dry method for removing steel balls fromsampleCombine the material retained on the 4.75-mm and1.18-mm sieves and steel balls, being careful not to lose anymaterial. Oven dry the te
31、st sample and steel balls to a constantmass at 110 6 5C. Remove the steel balls from the dry sampleusing a magnet or other suitable means.NOTE 2Extreme care must be taken if using the wet method forremoving the steel balls. The surface tension of the water may cause smallpieces of the aggregate to a
32、dhere to the balls. The wet method for removalis allowed to expedite additional testing for laboratories with a limitedsupply of balls. Otherwise, the dry method may be used to eliminate thispotential source of error. However, care should still be taken whenremoving the balls to avoid loss of aggreg
33、ate.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! / A 3 100 (1)11. Use of the Calibration Aggregate11.1 Cal
34、ibration 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 %D6928 103shall be established. From this material 10 samples shall betaken randomly and tested. At the same time 10 samples ofre
35、ference 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-house calibration aggregate shall be used thereaft
36、er.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 is 19.1 %. For continued acceptance of data,indiv
37、idual 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 shall be re-calibrated and the testingtechnique re
38、-examined to detect non-conformance with the testprocedure.11.2 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 supplyand prepared according to 8.2. When 20 samples of calibratio
39、nmaterial 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 be plotted on a trend chartin order to monitor the variat
40、ion 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 calibration aggregate, testedclosest to the time at which th
41、e 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 from 5 % to 20 %, the singleoperator coefficient of variati
42、on 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. The multilaboratory coefficientof variation has been found t
43、o 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.3Supporting data have been filed at ASTM International Headquarters and maybe obtained by reques
44、ting Research Report RR:D04-1029.4These numbers represent, respectively, the (1s %) and (d2s %) limits asdescribed in Practice C670.FIG. 2 Micro-Deval Abrasion Trend Chart for Brechin Quarry No.2 Aggregate SamplesD6928 10413.2 BiasThe procedure in this test method for measuringresistance to abrasion
45、 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 devalAPPENDIX(Nonmandatory Information)X1. INTERPRETATION OF TEST RESULTSX1.1 In studies of the performance of aggregates in thistest,5,6,7the
46、limits in Table X1.1 have been found useful forseparating aggregates of satisfactory 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.
47、 Further discussion on this topic will be found inRogers5and Lang et al.75Rogers, 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, p
48、p. 139-147.6Kandhal, P. S., Parker Jr., F., “Aggregate Tests Related to Asphalt 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., “P
49、rediction of CoarseAggregate Performance by Micro-Deval and Other Soundness, Strength, andIntrinsic Particle Property Tests,” Transportation Research Record, Journal of theTransportation Research Board, No. 2026, 2007, pp. 38.D6928 105ASTM 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 infringement of such rights, are entirely their own re
