1、Designation: D7428 081D7428 15Standard Test Method forResistance of Fine Aggregate to Degradation by Abrasion inthe Micro-Deval Apparatus1This standard is issued under the fixed designation D7428; the number immediately following the designation indicates the year oforiginal adoption or, in the case
2、 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 NOTEResearch report footnote was added editorially to Section 13 in March 2009.1. Scope1.1 This test m
3、ethod covers a procedure for testing fine aggregate for resistance to abrasion using the Micro-Deval apparatus.1.2 The values stated in SI units are to be regarded as the standard.1.2 The text of this method references notes and footnotes which provide explanatory material. These notes and footnotes
4、(excluding those in tables and figures) shall not be considered as requirements of the test method.1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.4 This standard does not purport to address all of the safety concerns, i
5、f any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C88 Test Method for Soundness of Aggregates by Us
6、e of Sodium Sulfate or Magnesium SulfateC117 Test Method for Materials Finer than 75-m (No. 200) Sieve in Mineral Aggregates by WashingC136 Test Method for Sieve Analysis of Fine and Coarse AggregatesC670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction Material
7、sD6928 Test Method for Resistance of Coarse Aggregate to Degradation by Abrasion in the Micro-Deval ApparatusE11 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 5C such tha
8、t it will not lose more than0.1 % moisture 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 w
9、hen they have been dried at atemperature of 110 6 5C 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 Test is a measure of abrasion res
10、istance and durability of mineral aggregates resulting from a combinationof actions including abrasion and grinding with steel balls in the presence of water. A 500-g sample with standard grading is1 This test method is under the jurisdiction ofASTM Committee D04 on Road and Paving Materials and is
11、the direct responsibility of Subcommittee D04.51 on AggregateTests.Current edition approved Feb. 1, 2008Jan. 1, 2015. Published March 2008February 2015. Originally approved in 2008. Last previous edition approved in 2008 asD7428 081. DOI: 10.1520/D7428-08E01.10.1520/D7428-15.2 For referencedASTM sta
12、ndards, 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 to provide the user of an
13、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 versionof the standard as publish
14、ed 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 States1initially soaked in water for not less than one hour. The sample is then placed in a jar mill with 0.75 L of water and an abrasivecha
15、rge consisting of 1250 g of 9.5-mm diameter steel balls. The jar, aggregate, water, and charge are revolved at 100 rpm for 15minutes. The sample is then washed and oven dried. The loss is the amount of material passing the 75 m sieve expressed as apercent by mass of the original sample.5. Significan
16、ce and Use5.1 The Micro-Deval abrasion test is a test of fine aggregate to determine abrasion loss in the presence of water and an abrasivecharge. Many aggregates are more susceptible to abrasion when wet than dry, and the use of water in this test incorporates thisreduction in resistance to degrada
17、tion. The test results are helpful in evaluating the toughness/abrasion resistance of fine aggregatesubject to abrasion when adequate information is not available from service records. This test is suitable for measuring the amountof weak, soft material such as shale or shaley carbonate in fine aggr
18、egate. Materials that give a low loss in this test are unlikelyto exhibit significant degradation during handling, mixing or placing. There is a relationship between drying shrinkage of cementmortar and Micro-Deval abrasion loss of fine aggregate, with higher loss materials resulting in higher dryin
19、g shrinkage.Descriptions of the development of the test and the relationship with other properties have been published.3,4,55.2 The Micro-Deval abrasion test on fine aggregate is useful for detecting changes in properties of aggregate produced froman aggregate source as part of a quality control or
20、quality assurance process.5.3 The Micro-Deval abrasion test on fine aggregate, in contrast to the version on coarse aggregate, has a significant correlationwith the Magnesium Sulfate soundness loss of fine aggregate. The Micro-Deval test on fine aggregate has better precision than thesulfate soundne
21、ss test, is quicker, and may be used in place of that test. Advice on specific values for selection of aggregate willbe found in the appendix.6. Apparatus6.1 Micro-Deval Abrasion Machine, a jar rolling mill as specified in Test Method D6928.6.2 Containers, stainless steel Micro-Deval abrasion jars a
22、s specified in Test Method D6928.6.3 Abrasive ChargeMagnetic stainless steel balls are required. These shall have a diameter of 9.5 6 0.5 mm. Each jarrequires a charge of 1250 6 5 g of balls.NOTE 1Prior to use, new containers and new steel balls should be conditioned. Conditioning is accomplished by
23、 running the equipment with a chargeof 500 g of silica sand with 750 ml of water for a period of four hours. From time to time it may be necessary to recondition the containers and steelballs. The need for this will be indicated by significant reduction in loss with the calibration material. It has
24、been found that reconditioning is usuallyneeded when the equipment has been used for testing carbonate coarse aggregate in the coarse aggregate version of the test (Test Method D6928), whichmay lead to polishing of the inside of the container and ball surfaces. The conditioning process gives the con
25、tainers and balls a “frosted” surface, whichpromotes tumbling of the balls and aggregate inside the container, rather than sliding when the containers are rotated. When silica rich fine aggregatesare tested, the need for reconditioning may be reduced or eliminated provided the calibration aggregate
26、gives satisfactory results. For this reason, it isgood practice to not use containers used for testing coarse aggregate in the fine aggregate version of the test.6.4 Sieves, with square openings, and of the following sizes conforming to Specification E11 specifications: 6.7 or 6.3 mm, 4.75mm, 2.36 m
27、m, 1.18 mm, 0.600600 m, 300 m, 150 m, 75 m.6.5 Oven, capable of maintaining a temperature of 110 6 5C.6.6 Balance, or scale accurate to 0.1 g.7. Supplies7.1 Laboratory Reference AggregateA supply of standard “Standard Sutherland Micro-Deval Fine Aggregate”Aggregate.”6available from the Soils andAggr
28、egates Section, Materials Engineering Materials Office, Ministry of Transportation, 1201 WilsonAvenue, Downsview, Ontario, Canada M3M1J8. Fax: 1-416-235-4101. The material shall be prepared as follows:3 Rogers, C., “Canadian Experience with the Micro-Deval Test for Aggregates,” Advances in Aggregate
29、s and Armourstone Evaluation, Latham, J. P., ed., GeologicalSociety, London, Engineering Geology Special Publications, 13, 1998, pp. 139-147.4 Rogers, C. A., Bailey, M. L., and Price, B., “Micro-Deval Test for Evaluating the Quality of Fine Aggregate for Concrete and Asphalt,” Transportation Researc
30、h Board,Washington, DC, Record 1301, 1991, pp. 68-76.5 Rogers, C., Lane, B., and Senior, S., “The Micro-Deval Abrasion Test for Coarse and Fine Aggregate in Asphalt Pavement,” Proceedings of Annual Symposium ofInternational Center for Aggregate Research, Austin, TX, April, 2003. Also published as On
31、tario Ministry of Transportation Report, Materials Engineering and ResearchOffice Report MERO 006.6 Available from the Soils andAggregates Section, Materials Engineering Materials Office, Ministry of Transportation, 1201 WilsonAvenue, Downsview, Ontario, CanadaM3M1J8.D7428 152Passing Retained Mass4.
32、75-mm 2.36-mm 40 g2.36-mm 1.18-mm 115 g1.18-mm 0.600-m 180 g1.18-mm 600-m 180 g0.600-m 0.300-m 120 g600-m 300-m 120 g0.300-m 150-m 38 g300-m 150-m 38 g150-m 75-m 7 g7.2 Calibration AggregateAn adequate supply of aggregate, established by the Laboratory to use for calibration of the testmethod (see 1
33、1.1).8. Test Sample8.1 The test sample shall be washed over a 75-m sieve following Test Method C117 and oven-dried at 110 6 5C to constantmass, separated into individual size fractions in accordance with Test Method C136, and recombined to meet the grading shownin 8.2.8.2 Aggregate for the test samp
34、le shall consist of material passing the 4.75-mm sieve, retained on the 75-m sieve with aFineness Modulus of 2.8 (Note 2). An oven dried sample of 500 6 5 g shall be prepared as follows:Passing Retained Mass4.75-mm 2.36-mm 50 g2.36-mm 1.18-mm 125 g1.18-mm 0.600-m 125 g1.18-mm 600-m 125 g0.600-m 0.30
35、0-m 100 g600-m 300-m 100 g0.300-m 150-m 75 g300-m 150-m 75 g150-m 75-m 25 gNOTE 2Fine aggregates that have a fine grading give a slightly higher Micro-Deval Abrasion loss than those with a coarser grading from the samesource. The effect of grading is small when the mean loss is less than about 20 %.
36、 For materials of low loss, which easily meet applicable specificationrequirements, it may be practical to test material without preparing to the grading given above for routine quality control purposes. When desired, othergrading may be used but the use of such grading should be reported.9. Test Pr
37、ocedure9.1 Prepare a representative 500 6 5 g test sample in accordance with Section 8. Weigh the test sample and record the Mass,A, to the nearest 0.1 g.9.2 Immerse the test sample in 0.75 6 0.05 L of tap water at a temperature 20 6 5C for a minimum of 1 h either in theMicro-Deval container or some
38、 other suitable container.9.3 Add 1250 6 5 g steel balls to the prepared test sample and the water used to immerse the sample. Install the cover and placethe Micro-Deval container on the machine. If another suitable container was used to immerse the sample, transfer the entire testsample and the wat
39、er to the Micro-Deval abrasion jar and add the steel balls.9.4 Run the machine at 100 6 5 rpm for 15 min 6 5 s. If a revolution counter is available; run the machine for 1500 6 10revolutions.9.5 Carefully pour the sample and steel balls over a 6.3 or 6.7-mm sieve into a suitable container. container
40、 (Note 3). Take careto remove the entire sample from the stainless steel jar and that no aggregate is lost. Wash the steel balls retained on the sieve sothat no aggregate adheres. The steel balls shall be removed from the sieve after washing. Wash the fine aggregate, recovered inthe container placed
41、 below the 6.3 or 6.7-mm sieve, following Test Method C117 until the washings are clear and all materialsmaller than 75 m passes that sieve.NOTE 3Sieves with 6.7 or 6.3 mm2 openings have been found acceptable for this purpose.9.6 Oven dry the washed sample to constant mass at 110 6 5C.9.7 Weigh the
42、oven dry sample to the nearest 0.1 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 Calibration Aggregate11.1 Calibration AggregateThe Laboratory will establish an adequate supply of materi
43、al to use for calibration of the testmethod. A suitable material with a loss of between 10 and 25 % shall be established. From this material 10 samples shall be takenD7428 153randomly and tested. At the same time 10 samples of “Standard Sutherland Micro-Deval Fine Aggregate” (see 7.1) shall also bet
44、ested. Provided the mean loss and variation of the “Standard Sutherland Micro-Deval Fine Aggregate” are within allowedtolerance given below in 11.1.1, the mean value and range obtained with the supply of the in-house calibration aggregate shall beused thereafter. At any time a new supply of the in-h
45、ouse calibration aggregate is required, the calibration procedure shall beconducted.11.1.1 The mean loss of the “Standard Sutherland Micro-Deval Fine Aggregate” (see 7.1) in multi-laboratory study of theMicro-Deval test is 16.8 %. For continued acceptance of data, individual test data must fall with
46、in the range 15.2 to 18.4 % lossfor 95 % of the time.11.1.2 When test data of the calibration aggregate is outside the limits established in 11.1, an investigation as to the probablecause shall be conducted. The equipment shall be re-calibrated and the testing technique examined to detect non-confor
47、mance withthe test procedure.11.2 Every 10 samples, but at least every week in which a sample is tested, a sample of the calibration aggregate shall also betested. The material shall be taken from a stock supply and prepared according to 8.2. When 20 samples of calibration materialhave been tested,
48、and the results show satisfactory variation, the frequency of testing may be changed to a minimum of one sampleevery month.11.3 Trend Chart UseThe percent loss of the last twenty samples of calibration material shall be plotted on a trend chart inorder to monitor the variation in results (Fig. 1).12
49、. Report12.1 The report shall include the following:12.1.1 The grading used if different from that specified.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 which the aggregate was tested, to the nearest0.1 %.12.1.4 The percent loss of the last twenty samples of calibration aggregate on a trend chart.FIG. 1 Micro-Deval Abrasion Trend Chart for Calibration Aggregate SamplesD7428 15413. Precision and Bias713.1 PrecisionFor fin
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