ASTM D3744 D3744M-2011 Standard Test Method for Aggregate Durability Index《集料耐久性指数的标准试验方法》.pdf

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1、Designation: D3744/D3744M 11Standard 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 in

2、 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 relativ

3、e 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 equ

4、ivalents;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 thi

5、s 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 conce

6、rns, 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 D

7、ensity (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 TestSie

9、ves3. 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 and

10、 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 washed

11、 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 cyl

12、inder.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 washi

13、ngvessel 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) exc

14、ept 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, includinglightw

15、eight 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 June 1, 2011. Published July 2011. Originally approv

16、edin 1979. Last previous edition approved in 2003 asD3744 03. DOI: 10.1520/D3744_D3744_D3744M112For 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 Documen

17、t 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 pea gr

18、avel 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 of t

19、he 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 aggregat

20、e 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 concrete

21、 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 test

22、 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-consuming a

23、nd 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 aggregates for

24、 use in bituminous pavingmixtures, coarse aggregate for use in portland-cement concrete,and aggregate for use as railroad ballast.NOTE 1The quality of the results produced by this standard aredependent on the competence of the personnel performing the procedureand the capability, calibration, and ma

25、intenance of the equipment used.Agencies that meet the criteria of Practice 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. Reli

26、able results depend onmany factors; following the suggestions of Practice 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 de

27、sign shown inFig. 1 with a volume of approximately 7 liters and innerdiameter 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

28、 4 in. deep), suitable tocollect the wash water from the washed sample. 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 wa

29、sh water may be used to nestthe sieve with the container, or the sieve 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

30、 in. at arate of 285 6 10 complete cycles per minute. Fig. 2 shows aTyler 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 Specificat

31、ion E11.5.6 BalanceA balance having a minimum capacity of 500g and meeting 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 transfe

32、rof wash water from the collection pan to the graduatedcylinder.6. Reagents 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 pe

33、rformance of this test method. The test results arelikely to be affected 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

34、. Forreferee purposes, distilled or demineralized water shall be usedfor 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 demineralizedw

35、ater and the working calcium chloride solution at 22 6 3C72 6 5F.8. Sampling8.1 Obtain samples of the aggregate to be tested in accor-dance with Practice D75.9. Initial Sample Preparation9.1 Dry aggregate samples sufficiently to permit a completeseparation on the 4.75-mm (No. 4) sieve and to develop

36、 a3Hamilton, 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 1971.4Hveem, F. N., and Smith, T. N., “Durability of Aggregates,” Research Report,State of

37、 California, Division of Highways, Materials and Research Department,January 1964.D3744/D3744M 112free-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 force

38、d drafts of warm air are the mostcommonly used sources of heat.9.2 If 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

39、of finesfrom the coarse aggregate particles by any means that will notappreciably 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.D

40、iscard any material that is retained on the 19.0-mm (34-in.)sieve.9.5 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, t

41、est coarse aggregate (Procedure A) only.9.5.2 If less than 10 % of the 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

42、the 1.18-mm (No. 16) sieve is greater than10 %, use both Procedures A 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.9.5.4 If most of the aggregate (75 to 80 %) is retainedbetween the 9.5 and 1.18

43、-mm (38-in. and No. 16) sieves, useProcedure C only.FIG. 1 Mechanical Washing VesselD3744/D3744M 113PROCEDURE 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.)

44、1070 6 1012.5 to 9.5 mm (12 to38 in.) 570 6 109.5to4.75mm(38 in. to No. 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

45、 fractions to obtain the 2550 gtest sample. Two examples follow.Example 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 + 9109.5to4.75m

46、m(38 to No. 4) 68 910 (2550 153) 1474 6 5570 + 910Totals 100 2550 6 25Example 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

47、) 2269 6 5Totals 100 2550 6 2510.2 Place the preliminary test sample 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 pr

48、ovide the intended interparticle abrasion.Testing of these materials 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 sam

49、ple 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.FIG. 2 Modification of Tyler Portable Sieve ShakerD3744/D3744M 11410.3.3 Adjust the total mass of the test sample using thefollowing equation:Adjusted sample mass, g 5specific gravity of aggregate2.653 W (1)where:W = mass of oven-dried test sample, g.Adjust the mass of material in each size fraction proportion-ally to the masses specified in 10