1、Designation: D 6928 06Standard 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 method covers a procedure for testing coarseaggregate for resistance to abrasion using the
3、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 test m
4、ethod.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 and det
5、er-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 Wire
6、 Cloth and Sieves for TestingPurposes3. Terminology3.1 Definitions:3.1.1 constant mass, ntest samples dried at a temperatureof 110 6 5C to a condition such that it will not lose more than0.1 % moisture after2hofdrying. Such a condition of drynesscan be verified by weighing the sample before and afte
7、rsuccessive 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 desired constant mass condition under equalo
8、r 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 presence of water. A sample with standard
9、grading 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 for up to 2 h, depending on the particle
10、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 abrasion loss in the presence of waterand
11、 an abrasive charge. Many aggregates are more susceptiblewhen wet than dry, and the use of water in this test incorporatesthis reduction in resistance in degradation in contrast to someother tests, which are conducted on dry aggregate. The testresults are helpful in evaluating the toughness/abrasion
12、 resis-tance of coarse aggregate subject to abrasion when adequateinformation is not available from service records.5.2 The Micro-Deval abrasion test is useful for detectingchanges in properties of aggregate produced from an aggregatesource as part of a quality control or quality assurance process.6
13、. Apparatus6.1 Micro-Deval Abrasion Machine, a jar rolling mill ca-pable of running at 100 6 5 rpm (Fig. 1).6.2 Containers, stainless steel Micro-Deval abrasion jarshaving a 5-L capacity with a rubber ring in the rotary lockingcover. External diameter of 194-mm to 202-mm. Internal1This test method i
14、s under the jurisdiction of ASTM Committee D04 on Roadand Paving Materials and is the direct responsibility of Subcommittee D04.51 onAggregate Tests.Current edition approved Jan. 1, 2006. Published January 2006. Originallyapproved in 2003. Last previous edition approved in 2003 as D 6928 03.2For ref
15、erenced ASTM standards, visit the ASTM website, www.astm.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, We
16、st Conshohocken, PA 19428-2959, United States.height of 170-mm to 177-mm. The inside and outside surfacesof the jars shall be smooth and have no observable ridges orindentations (Fig. 1).6.3 Abrasive ChargeMagnetic stainless steel balls arerequired. These shall have a diameter of 9.5 6 0.5 mm. Eachj
17、ar 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 maintaining a temperature of 110 65C.6.6 Balance, or scale ac
18、curate 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, Engineering Materials Office,Ministry of Transportation, 1201 Wilson Avenue, Downsview,Ontario, Canada M3M1J8. Fax: 1-416-235-4101.
19、7.2 Calibration AggregateAn adequate supply of aggre-gate, established by the Laboratory to use for calibration of thetest method (see 11.1).FIG. 1 Micro-Deval Abrasion Machine and ContainerD69280628. Test Sample8.1 The test sample shall be washed and oven-dried at 1106 5C to constant mass, separate
20、d 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 shall consist of material passingthe 19.0-mm
21、sieve, retained on the 9.5-mm sieve. An ovendried 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 shall beprepar
22、ed 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 750 g9. Test Pro
23、cedure9.1 Prepare a representative 1500 6 5 g sample. Weigh thesample and record the Mass, A, to the nearest 1.0 g.9.2 Immerse the sample in 2.0 6 0.05 L of tap water at atemperature 20 6 5C for a minimum of 1 h either in theMicro-Deval container or some other suitable container.9.3 Place the sample
24、 in the Micro-Deval abrasion containerwith 5000 6 5 g steel balls and the water used in 9.2 to saturatethe sample. Install the cover and place the Micro-Devalcontainer on the machine.9.4 Run the machine at 100 6 5 rpm for 2 h 6 1 min for thegrading shown in 8.2. For the grading shown in 8.3, run hem
25、achine for 105 6 1 min. For the grading shown in 8.4, run themachine for 95 6 1 min.9.5 Carefully pour the sample and steel balls over a4.75-mm sieve superimposed on a 1.18-mm. Take care toremove the entire sample from the stainless steel jar. Wash andmanipulate the retained material on the sieve wi
26、th water usinga hand held water hose and the hand until the washings areclear and all material smaller than 1.18 mm passes that sieve.Remove the stainless steel balls using a magnet or othersuitable means. Discard material smaller than 1.18 mm.9.6 Combine the material retained on the 4.75 mm and 1.1
27、8mm sieves, being careful not to lose any material.9.7 Oven dry the sample to constant mass at 110 6 5C.9.8 Weigh the sample to the nearest 1.0 g. Record the Mass,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
28、 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 15 and 25 %shall be established. From this material 10 samples shall betaken randomly and tested. At t
29、he 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 allowed tolerance of11.1.1, the mean value obtained with the supply of the in-housecalibration aggregate shall be
30、 used thereafter. At any time anew supply is required, the calibration procedure shall beconducted.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,individual reference material
31、 test data must fall within therange 17.5 to 20.7 % loss for 95 % of the time.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 8.2.11.3 Trend
32、Chart UseThe percent loss of the last twentysamples of control material shall be plotted on a trend chart inorder 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
33、loss of the test sample to one decimalplace.12.1.3 The percent loss of the calibration 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 Bias13.1 Pr
34、ecisionThe multi-laboratory precision has beenfound to vary over the range of values obtained in this test. Thefigures given in column 2 are the coefficients of variation thathave been found to be appropriate for the materials describedin Column 1. The figures given in Column 3 are that limits thats
35、hould not be exceeded by the difference between the results oftwo properly conducted tests expressed as a percent of theirmean.AggregateAbrasionLoss (%)Coefficientof Variation(% of mean)AAcceptable Rangeof Two Results(% of mean)A5 10.0 2812 6.4 1817 5.6 1621 5.3 15AThese numbers represent, respectiv
36、ely, the (1s %) and (d2s %) limits asdescribed in Practice C 670.D692806313.2 BiasThe procedure in this test method 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
37、; micro devalAPPENDIX(Nonmandatory Information)X1. INTERPRETATION OF TEST RESULTSX1.1 In studies of the performance of aggregates in thistest,3,4the limits in Table X1.1 have been found useful forseparating aggregates of satisfactory performance from thoseof fair or poor performance.3Rogers, C., “Ca
38、nadian 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. 139-147.4Kandhal, P. S., Parker Jr., F., “Aggregate Tests Related to Asphalt ConcreteP
39、erformance in Pavements,” Final Report Prepared for National CooperativeHighway Research Program, Transportation Research Board, Washington, May1997.FIG. 2 Micro-Deval Abrasion Trend Chart for Brechin Quarry No.2 Aggregate SamplesD6928064ASTM International takes no position respecting the validity o
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43、opyrighted 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
44、.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 17AConcrete Pavement 13AAsphalt concrete base course and secondary road surface course 21AAsphalt con
45、crete surface course 17A18BARogers, 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.BKandhal, P. S., Parker Jr., F., “Aggregate Tests Related to Asphalt Concrete Performance in Pavements,” Final Report Prepared for National Cooperative HighwayResearch Program, Transportation Research Board, Washington, May 1997.D6928065
