1、Designation: C 131 06Standard Test Method forResistance to Degradation of Small-Size Coarse Aggregateby Abrasion and Impact in the Los Angeles Machine1This standard is issued under the fixed designation C 131; the number immediately following the designation indicates the year oforiginal adoption or
2、, in the case of revision, 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.This standard has been approved for use by agencies of the Department of Defense.1. Scope*
3、1.1 This test method covers a procedure for testing sizes ofcoarse aggregate smaller than 37.5 mm (112 in.) for resistanceto degradation using the LosAngeles testing machine (Note 1).NOTE 1A procedure for testing coarse aggregate larger than 19.0 mm(34 in.) is covered in Test Method C 535.1.2 The va
4、lues stated in SI units are to be regarded as thestandard. The inch-pound values given in parentheses are forinformation only.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish ap
5、pro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2A 6/A 6M Specification for General Requirements forRolled Structural Steel Bars, Plates, Shapes, and SheetPilingC 125 Terminology Relating to Conc
6、rete and ConcreteAggregatesC 136 Test Method for Sieve Analysis of Fine and CoarseAggregatesC 535 Test Method for Resistance to Degradation of Large-Size Coarse Aggregate by Abrasion and Impact in the LosAngeles MachineC 670 Practice for Preparing Precision and Bias Statementsfor Test Methods for Co
7、nstruction MaterialsC 702 Practice for Reducing Samples of Aggregate toTesting SizeD75 Practice for Sampling AggregatesE11 Specification for Wire Cloth and Sieves for TestingPurposes3. Terminology3.1 DefinitionsFor definitions of terms used in this testmethod, refer to Terminology C 125.4. Summary o
8、f Test Method4.1 This test is a measure of degradation of mineral aggre-gates of standard gradings resulting from a combination ofactions including abrasion or attrition, impact, and grinding ina rotating steel drum containing a specified number of steelspheres, the number depending upon the grading
9、 of the testsample. As the drum rotates, a shelf plate picks up the sampleand the steel spheres, carrying them around until they aredropped to the opposite side of the drum, creating an impact-crushing effect. The contents then roll within the drum with anabrading and grinding action until the shelf
10、 plate picks up thesample and the steel spheres, and the cycle is repeated. Afterthe prescribed number of revolutions, the contents are removedfrom the drum and the aggregate portion is sieved to measurethe degradation as percent loss.5. Significance and Use5.1 This test has been widely used as an i
11、ndicator of therelative quality or competence of various sources of aggregatehaving similar mineral compositions. The results do notautomatically permit valid comparisons to be made betweensources distinctly different in origin, composition, or structure.Assign specification limits with extreme care
12、 in considerationof available aggregate types and their performance history inspecific end uses.6. Apparatus6.1 Los Angeles MachineA Los Angeles machine, con-forming in all essential characteristics to the design shown inFig. 1, shall be used. The machine shall consist of a hollowsteel cylinder, wit
13、h a wall thickness of not less than 12.4 mm(Note 2) closed at both ends, conforming to the dimensionsshown in Fig. 1, having an inside diameter of 711 6 5mm(281This test method is under the jurisdiction of ASTM Committee C09 onConcrete and Concrete Aggregates and is the direct responsibility of Subc
14、ommitteeC09.20 on Normal Weight Aggregates.Current edition approved August 1, 2006. Published August 2006. Originallyapproved in 1937. Last previous edition approved in 2003 as C 131-03.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceas
15、tm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United S
16、tates.6 0.2 in.), and an inside length of 508 6 5mm(206 0.2 in.).The interior surface of the cylinder shall be free from protru-sions disrupting the path of the sample and steel spheres exceptfor the shelf described below. The cylinder shall be mounted onstub shafts attached to the ends of the cylin
17、der but not enteringit, and shall be mounted in such a manner that it rotates withthe axis in a horizontal position within a tolerance in slope of1 in 100. An opening in the cylinder shall be provided for theintroduction of the test sample. A suitable, dust-tight covershall be provided for the openi
18、ng with means for bolting thecover in place. The cover shall be so designed as to maintainthe cylindrical contour of the interior surface unless the shelf isso located that the charge will not fall on the cover, or come incontact with it during the test. A removable steel shelfextending the full len
19、gth of the cylinder and projecting inward89 6 2 mm (3.5 6 0.1 in.) shall be mounted on the interiorcylindrical surface of the cylinder, in such a way that a planecentered between the large faces coincides with an axial plane.The shelf shall be of such thickness and so mounted, by boltsor other suita
20、ble means, as to be firm and rigid. The position ofthe shelf (Note 3) shall be such that the sample and the steelspheres shall not impact on or near the opening and its cover,and that the distance from the shelf to the opening, measuredalong the outside circumference of the cylinder in the direction
21、of rotation, shall be not less than 1270 mm (50 in.). Inspect theshelf periodically to determine that it is not bent eitherlengthwise or from its normal radial position with respect to thecylinder. If either condition is found, repair or replace the shelfbefore further tests are conducted.NOTE 2This
22、 is the minimum tolerance permitted on 12.7 mm (12 in.)rolled steel plate as described in Specification A 6/A 6M.NOTE 3The use of a shelf of wear-resistant steel, rectangular in crosssection and mounted independently of the cover, is preferred. However, ashelf consisting of a section of rolled angle
23、, properly mounted on theinside of the cover plate, may be used provided the direction of rotation issuch that the charge will be caught on the outside face of the angle.6.1.1 The machine shall be so driven and so counterbal-anced as to maintain a substantially uniform peripheral speed(Note 4). If a
24、n angle is used as the shelf, the direction ofrotation shall be such that the charge is caught on the outsidesurface of the angle.NOTE 4Back-lash or slip in the driving mechanism is very likely tofurnish test results which are not duplicated by other Los Angelesmachines producing constant peripheral
25、 speed.Inch Equivalentsmmin.6.41412.71225.4189312102415261907125082071128127050FIG. 1 Los Angeles Testing MachineC1310626.2 Sieves, conforming to Specification E11.6.3 BalanceA balance or scale accurate within 0.1 % oftest load over the range required for this test.6.4 ChargeThe charge shall consist
26、 of steel spheres aver-aging approximately 46.8 mm (12732 in.) in diameter and eachhaving a mass of between 390 and 445 g.6.4.1 The charge, (Note 5) depending upon the grading ofthe test sample as described in Section 8, shall be as follows:GradingNumber ofSpheresMass ofCharge, gA 12 5000 6 25B 11 4
27、584 6 25C 8 3330 6 20D 6 2500 6 15NOTE 5Steel ball bearings 46.0 mm (11316 in.) and 47.6 mm (178 in.)in diameter, having a mass of approximately 400 and 440 g each,respectively, are readily available. Steel spheres 46.8 mm (12732 in.) indiameter having a mass of approximately 420 g may also be obtai
28、nable.The charge may consist of a mixture of these sizes conforming to the masstolerances of 6.4 and 6.4.1.7. Sampling7.1 Obtain the field sample in accordance with PracticeD75, and reduce the field sample to adequate sample size inaccordance with Practice C 702.8. Test Sample Preparation8.1 Wash th
29、e reduced sample and oven dry at 110 6 5C(230 6 9 F) to substantially constant mass (see 9.1.1),separate into individual size fractions, and recombine to thegrading of Table 1 most nearly corresponding to the range ofsizes in the aggregate as furnished for the work. Record themass of the sample prio
30、r to test to the nearest 1 g.9. Procedure9.1 Place the test sample and the charge in the Los Angelestesting machine and rotate the machine at a speed of 30 to 33r/min for 500 revolutions (Note 6).After the prescribed numberof revolutions, discharge the material from the machine andmake a preliminary
31、 separation of the sample on a sieve coarserthan the 1.70-mm (No. 12) sieve. Sieve the finer portion on a1.70-mm sieve in a manner conforming to Test Method C 136.Wash the material coarser than the 1.70-mm (No. 12) sieve andoven-dry at 110 6 5 C (230 6 9 F) to substantially constantmass (see 9.1.1),
32、 and determine the mass to the nearest 1 g(Note 7).9.1.1 If the aggregate is essentially free of adherent coatingsand dust, the requirement for washing after the test is optional.However, in the case of referee testing, the washing procedureshall be performed.NOTE 6Valuable information concerning th
33、e uniformity of the sampleunder test may be obtained by determining the loss after 100 revolutions.The loss should be determined by dry sieving the material on the 1.70-mmsieve without washing. The ratio of the loss after 100 revolutions to theloss after 500 revolutions should not greatly exceed 0.2
34、0 for material ofuniform hardness. When this determination is made, take care to avoidlosing any part of the sample; return the entire sample, including the dustof fracture, to the testing machine for the final 400 revolutions required tocomplete the test.NOTE 7Elimination of washing after test will
35、 seldom reduce themeasured loss by more than about 0.2 % of the original sample mass.10. Calculation10.1 Calculate the loss (difference between the originalmass and the final mass of the test sample) as a percentage ofthe original mass of the test sample. Report this value as thepercent loss (Note 8
36、).NOTE 8The percent loss determined by this test method has no knownconsistent relationship to the percent loss for the same material whentested by Test Method C 535.11. Report11.1 Report the following information:11.1.1 Identification of the aggregate as to source, type, andnominal maximum size;11.
37、1.2 Grading designation from Table 1 used for the test;and11.1.3 Loss by abrasion and impact of the sample expressedto the nearest 1 % by mass.12. Precision and Bias12.1 For nominal 19.0-mm (34-in.) maximum size coarseaggregate with percent losses in the range of 10 to 45 %, themultilaboratory coeff
38、icient of variation has been found to be4.5 %.3Therefore, results of two properly conducted testsfrom two different laboratories on samples of the same coarseaggregates are not expected to differ from each other by more3These numbers represent, respectively, the (1s%) and (d2s%) limits asdescribed i
39、n Practice C 670.TABLE 1 Gradings of Test SamplesSieve Size (Square Openings) Mass of Indicated Sizes, gPassing Retained onGradingABCD37.5mm(112 in.) 25.0 mm (1 in.) 1 250 6 25 . . .25.0mm(1in.) 19.0mm(34 in.) 1 250 6 25 . . .19.0mm(34 in.) 12.5 mm (12 in.) 1 250 6 10 2 500 6 10 . .12.5mm(12 in.) 9.
40、5 mm (38 in.) 1 250 6 10 2 500 6 10 . .9.5mm(38 in.) 6.3 mm (14 in.) . . 2 500 6 10 .6.3mm(14 in.) 4.75-mm (No. 4) . . 2 500 6 10 .4.75-mm (No. 4) 2.36-mm (No. 8) . . . 5 000 6 10Total 5 000 6 10 5 000 6 10 5 000 6 10 5 000 6 10C131063than 12.7 %3(95 % probability) of their average. The single-opera
41、tor coefficient of variation has been found to be2.0 %.3Therefore, results of two properly conducted tests bythe same operator on the same coarse aggregate are notexpected to differ from each other by more than 5.7 % (95 %probability) of their average.312.2 BiasSince there is no accepted reference m
42、aterialsuitable for determining the bias for this procedure, no state-ment on bias is being made.13. Keywords13.1 abrasion; aggregate (coarse; small size); degradation;impact; Los Angeles machineAPPENDIX(Nonmandatory Information)X1. MAINTENANCE OF SHELFX1.1 The shelf of the Los Angeles machine is su
43、bject tosevere surface wear and impact. With use, the working surfaceof the shelf is peened by the balls and tends to develop a ridgeof metal parallel to and about 32 mm (114 in.) from the junctionof the shelf and the inner surface of the cylinder. If the shelf ismade from a section of rolled angle,
44、 not only may this ridgedevelop but the shelf itself may be bent longitudinally ortransversely from its proper position.X1.2 The shelf should be inspected periodically to deter-mine that it is not bent either lengthwise or from its normalradial position with respect to the cylinder. If either condit
45、ionis found, the shelf should be repaired or replaced before furthertests are made. The influence on the test result of the ridgedeveloped by peening of the working face of the shelf is notknown. However, for uniform test conditions, it is recom-mended that the ridge be ground off if its height exce
46、eds 2 mm(0.1 in.).SUMMARY OF CHANGESCommittee C09 has identified the location of selected changes to this test method since the last issue,C 131 03, that may impact the use of this test method. (Approved August 1, 2006)(1) Revised 6.1.ASTM International takes no position respecting the validity of a
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48、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
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