ASTM D3744 D3744M-2011a Standard Test Method for Aggregate Durability Index《集料耐久率的标准试验方法》.pdf

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1、Designation: D3744/D3744M 11aStandard Test Method forAggregate Durability Index1This standard is issued under the fixed designation D3744/D3744M; the number immediately following the designation indicates theyear of original adoption or, in the case of revision, the year of last revision. A number i

2、n parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of a durabilityindex of an aggregate. The calculated durability index is avalue indicating the relati

3、ve resistance of an aggregate toproduction of detrimental clay-like fines when subjected to theprescribed mechanical methods of degradation.1.2 UnitsThe values stated in either SI units or inch-pound units are to be regarded separately as standard. Thevalues stated in each system may not be exact eq

4、uivalents;therefore, each system shall be used independently of the other.Combining values from the two systems may result in non-conformance with the standard.1.2.1 Measurements of volume and mass are only given inSI units because they are the only units typically used inpractice when performing th

5、is test method.1.2.2 Measurements in Section 11, Section 15, Equation 3,Equation 4, Table 1, and Figure 2 are only given in inch-poundunits because the equipment used in these sections is onlymanufactured using the inch-pound system.1.3 This standard does not purport to address all of thesafety conc

6、erns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C127 Test Method for Density, Relative

7、Density (SpecificGravity), and Absorption of Coarse AggregateC136 Test Method for Sieve Analysis of Fine and CoarseAggregatesC702 Practice for Reducing Samples of Aggregate to Test-ing SizeD75 Practice for Sampling AggregatesD2419 Test Method for Sand Equivalent Value of Soils andFine AggregateD3666

8、 Specification for Minimum Requirements for Agen-cies Testing and Inspecting Road and Paving MaterialsD4753 Guide for Evaluating, Selecting, and SpecifyingBalances and Standard Masses for Use in Soil, Rock, andConstruction Materials TestingE11 Specification for Woven Wire Test Sieve Cloth and TestSi

9、eves3. Summary of Test Method3.1 This test method was developed to permit prequalifica-tion of aggregates proposed for use in the construction oftransportation facilities. Basically, the test establishes an ag-gregates resistance to generating fines when agitated in thepresence of water. Separate an

10、d different test procedures areused to evaluate the coarse and the fine portions of a material.3.2 A sample of coarse aggregate is prepared to a specificgrading and then washed in a mechanical washing vessel for a2-min agitation time. After discarding the minus 4.75-mm (No.4) material, dry the washe

11、d test sample.3.3 The coarse aggregate test sample is then agitated in themechanical washing vessel for a period of 10 min. A represen-tative portion of the resulting wash water and minus 75-m(No. 200) size fines is collected and mixed with a stockcalcium chloride solution and placed in a plastic cy

12、linder.Aftera 20-min sedimentation time, the level of the sediment columnis read. The height of the sediment value is then used tocalculate the durability index of the coarse aggregate (Dc).3.4 The fine aggregate sample is prepared by washing aspecific quantity of the material in the mechanical wash

13、ingvessel for a 2-min agitation period. All minus 75-m (No. 200)size material is washed from the sample through a 75-m (No.200) sieve and discarded. The plus 75-m (No. 200) fraction isdried.3.5 The fine aggregate test sample is tested by the StandardSand Equivalent Test Method (Test Method D2419) ex

14、cept formodifications to the test sample preparation and duration of theshaking time. The mechanical shaker method is required. Ashaking time of 10 min instead of 45 s is used.3.6 This test method includes procedures for testing aggre-gates exhibiting a wide range in specific gravity, includinglight

15、weight and porous coarse aggregates, and also procedures1This test method is 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 Dec. 1, 2011. Published December 2011. Originallyap

16、proved in 1979. Last previous edition approved in 2011 asD3744 11. DOI:10.1520/D3744_D3744_D3744M11A2For referenced 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 Do

17、cument Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.for testing small maximum size aggregate which is too fine totest as a coarse aggregate and too coarse to consider as a fineaggregate, such as a p

18、ea gravel or a very coarse sand.3.7 The durability index for coarse aggregate (Dc) or for fineaggregate (Df) is calculated, as applicable, by appropriateequations presented in the method. The durability index of awell-graded aggregate containing both coarse and fine fractionsis defined as the lowest

19、 of the two values, Dcor Df, obtained bythe test. This value is recommended to be the controlling valuefor specification purposes.4. Significance and Use4.1 This test method assigns an empirical value to therelative amount, fineness, and character of clay-like materialthat may be generated in an agg

20、regate when subjected tomechanical degradation.4.2 The procedure has been used in limited geographicalareas of the United States and the results have been correlatedwith aggregate performance in various construction applica-tions, including: aggregate base, permeable material for back-fill, fine con

21、crete aggregate, and riprap for rock slope protec-tion.3,44.3 A minimum durability index is permitted to be specifiedto prohibit the use of an aggregate in various constructionapplications that is prone to degradation, resulting in genera-tion of clay-like fines.4.4 This test method provides a rapid

22、 test for evaluation ofthe quality of a new aggregate source. Research has indicatedit may also be suitable for use instead of the sodium sulfatesoundness test for evaluating the durability characteristics offine aggregate for use in portland-cement concrete, therebyreducing the need for time-consum

23、ing and expensive sound-ness tests.34.5 Although the application of this method has beenlimited to aggregates for specific construction uses, the possi-bility exists for expanding the application of this method tocontrol the quality of aggregates used in other areas ofconstruction, such as aggregate

24、s for use in bituminous pavingmixtures, coarse aggregate for use in portland-cement concrete,and aggregate for use as railroad ballast.NOTE 1The text of this test method references notes and footnoteswhich provide explanatory material. These notes and footnotes (excludingthose in tables and figures)

25、 shall not be considered as requirements of thetest method.NOTE 2The quality of the results produced by this standard aredependent on the competence of the personnel performing the procedureand the capability, calibration, and maintenance of the equipment used.Agencies that meet the criteria of Prac

26、tice D3666 are generally consideredcapable of competent and objective testing/sampling/inspection/etc. Usersof this standard are cautioned that compliance with Practice D3666 alonedoes not completely assure reliable results. Reliable results depend onmany factors; following the suggestions of Practi

27、ce D3666 or somesimilar acceptable guideline provides a means of evaluating and control-ling some of those factors.5. Apparatus5.1 Mechanical Washing Vessel (Pot)A flat-bottomed,straight-sided cylindrical vessel similar to the design shown inFig. 1 with a volume of approximately 7 liters and innerdi

28、ameter of approximately 200 mm 8 in. The vessel lid mustbe equipped with a rubber gasket or another means ofpreventing leaks during agitation.5.2 Collection PanAround pan (at least 230 mm 9 in. indiameter and approximately 100 mm 4 in. deep), suitable tocollect the wash water from the washed sample.

29、 The pan shallhave vertical or nearly vertical sides and shall be equipped asnecessary to hold the wire mesh of a 200-mm 8-in. diametersieve at least 75 mm 3 in. above the bottom. An adaptor thatwill not allow loss of fines or wash water may be used to nestthe sieve with the container, or the sieve

30、may be nested with ablank sieve frame resting in the bottom of the pan.5.3 AgitatorA mechanical device designed to hold thewash vessel in an upright position while subjecting it to alateral reciprocating motion of 45 6 6mm134 614 in. at arate of 285 6 10 complete cycles per minute. Fig. 2 shows aTyl

31、er portable sieve shaker modified to meet these require-ments.5.4 All equipment required to perform the Test for SandEquivalent Value of Soils and Fine Aggregate (Test MethodD2419).5.5 SievesThe sieves shall conform to Specification E11.5.6 BalanceA balance having a minimum capacity of 500g and meet

32、ing the requirements of Guide D4753, Class GP5.5.7 OvenAn oven capable of maintaining a temperatureof 110 6 5C 230 6 10F.5.8 Graduated CylinderA 1000-mL graduated cylinder5.9 FunnelA funnel of sufficient size to allow for transferof wash water from the collection pan to the graduatedcylinder.6. Reag

33、ents and Materials6.1 Calcium Chloride SolutionsUse stock and workingcalcium chloride solutions as specified in the Reagents andMaterials section of Test Method D2419.6.2 WaterUse distilled or demineralized water for thenormal performance of this test method. The test results arelikely to be affecte

34、d by certain minerals dissolved in water.However, if it is determined that local tap water is of suchpurity that it does not affect the test results, the use of tap wateris permissible in place of distilled or demineralized water. Forreferee purposes, distilled or demineralized water shall be usedfo

35、r all steps in the test.7. Temperature Control7.1 This test method is normally performed without stricttemperature control; however, for referee purposes, retest thematerial with the temperature of the distilled or demineralizedwater and the working calcium chloride solution at 22 6 3C72 6 5F.8. Sam

36、pling8.1 Obtain samples of the aggregate to be tested in accor-dance with Practice D75.3Hamilton, R. D., Smith, R. E., and Sherman, G. B., “Factors Influencing theDurability ofAggregates,” Research Report 633476, State of California, Division ofHighways, Materials and Research Department, June 1971.

37、4Hveem, F. N., and Smith, T. N., “Durability of Aggregates,” Research Report,State of California, Division of Highways, Materials and Research Department,January 1964.D3744/D3744M 11a29. Initial Sample Preparation9.1 Dry aggregate samples sufficiently to permit a completeseparation on the 4.75-mm (N

38、o. 4) sieve and to develop afree-flowing condition in the portion passing the sieve. Performdrying by any method that does not heat the aggregate inexcess of 60C 140F or cause degradation of the particles.Sunlight, ovens, or forced drafts of warm air are the mostcommonly used sources of heat.9.2 If

39、the sample contains an appreciable amount of clay,turn the aggregate frequently during the drying process toobtain even drying throughout and prevent the formation ofhard clay lumps.9.3 Break up any hard clods and remove coatings of finesfrom the coarse aggregate particles by any means that will not

40、appreciably reduce the natural individual particle sizes.9.4 Determine the sample grading by sieving in accordancewith Test Method C136 on 19.0, 12.5, 9.5, 4.75, 2.36, and1.18-mm (34 ,12 , and38-in. and Nos. 4, 8, and 16) sieves.Discard any material that is retained on the 19.0-mm (34-in.)sieve.9.5

41、Determine the test procedures to be used for establishingthe durability index of the aggregate based upon the grading ofthe aggregate as determined in 9.4.9.5.1 If less than 10 % of the aggregate passes the 4.75-mm(No. 4) sieve, test coarse aggregate (Procedure A) only.9.5.2 If less than 10 % of the

42、 aggregate is coarser than the4.75-mm (No. 4) sieve, test fine aggregate (Procedure B) only.9.5.3 When both coarse and fine aggregate fractions areeach present in quantities equal to or greater than 10 % and ifthe percent passing the 1.18-mm (No. 16) sieve is greater than10 %, use both Procedures A

43、and B on the appropriateaggregate sizes. If the percent passing the 1.18-mm (No. 16)sieve is less than or equal to 10 %, use Procedure A orProcedure C.FIG. 1 Mechanical Washing VesselD3744/D3744M 11a39.5.4 If most of the aggregate (75 to 80 %) is retainedbetween the 9.5 and 1.18-mm (38-in. and No. 1

44、6) sieves, useProcedure C only.PROCEDURE ACOARSE AGGREGATE10. Test Sample Preparation10.1 Prepare a 2550 6 25-g (air-dry) preliminary testsample using the grading given below:Aggregate Size Air Dry Mass, g19.0to12.5mm(34 to12 in.) 1070 6 1012.5 to 9.5 mm (12 to38 in.) 570 6 109.5to4.75mm(38 in. to N

45、o. 4) 910 6 52550 6 25For materials with less than 10 % in any of the size fractionsgiven in 10.1, prepare the test sample using the actualpercentage for the deficient fraction and proportionally in-crease the mass of the remaining fractions to obtain the 2550 gtest sample. Two examples follow.Examp

46、le 1Less than 10 % in 19.0 to 12.5 mm (34 to12 in.) fractionAggregate Size Percent Calculation Air Dry Mass, g19.0to12.5mm(34 to12 in.) 6 0.06 3 2550 153 6 1012.5 to 9.5 mm (12 to38 in) 26 570 (2550 153) 923 6 10570 + 9109.5to4.75mm(38 to No. 4) 68 910 (2550 153) 1474 6 5570 + 910Totals 100 2550 6 2

47、5Example 2Less than 10 % in two fractionsAggregate Size Percent Calculation Air DryMass, g19.0to12.5mm(34 to12 in.) 4 0.04 3 2550 102 6 1012.5 to 9.5 mm (12 to38 in) 7 0.07 3 2550 179 6 109.5to4.75mm(38 to No. 4) 89 2550 (102 + 179) 2269 6 5Totals 100 2550 6 2510.2 Place the preliminary test sample

48、in the mechanicalwashing vessel and add 1000 6 5 ml of distilled or deminer-alized water.10.3 Because of the low specific gravity or high absorptionrate, or both, of some aggregates, the proportions of aggregateto water will not provide the intended interparticle abrasion.Testing of these materials

49、will require adjustment of the testspecimen mass or volume of both wash and test water, or both.10.3.1 Wash all materials that are not completely inundatedwhen 1000 ml of water are added to the test sample and testwith adjusted sample masses and water volumes.10.3.2 Determine the bulk, oven-dry specific gravity, andpercentage of absorption of the aggregate in accordance withTest Method C127.10.3.3 Adjust the total mass of the test sample using thefollowing equation:FIG. 2 Modification of Tyler Portable Si