ASTM D3744-2003 Standard Test Method for Aggregate Durability Index《集料耐久性指数的标准测试方法》.pdf

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1、Designation: D 3744 03Standard Test Method forAggregate Durability Index1This standard is issued under the fixed designation D 3744; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses

2、 indicates the year of last reapproval. Asuperscript epsilon (e) 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 relative resistanc

3、e of an aggregate toproduction of detrimental clay-like fines when subjected to theprescribed mechanical methods of degradation.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.3 This standard does not purport to address a

4、ll of thesafety concerns, 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:C 136 Test Method fo

5、r Sieve Analysis of Fine and CoarseAggregates2D 75 Practice for Sampling Aggregates3D 2419 Test Method for Sand Equivalent Value of Soils andFine Aggregate3D 4753 Guide for Evaluating, Selecting, and SpecifyingBalances and Scales for Use in Soil, Rock, and Construc-tion Materials Testing4E 11 Specif

6、ication for Wire Cloth and Sieves for TestingPurposes53. 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

7、when agitated in thepresence of water. Separate and 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 discardin

8、g the minus 4.75-mm (No.4) material, dry the washed 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 stockca

9、lcium chloride solution and placed in a plastic cylinder. 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 aspeci

10、fic quantity of the material in the mechanical washingvessel 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 Standar

11、dSand Equivalent Test Method (Test Method D 2419) except 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 exhibit

12、ing a wide range in specific gravity, includinglightweight and porous coarse aggregates, and also proceduresfor 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 gravel or a very coarse sand.3.7 The durabi

13、lity 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 the two values, Dcor Df, obtained bythe te

14、st. This value is recommended to be the controlling valuefor specification purposes.1This 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 July 10, 2003. Publishe

15、d September 2003. Originallyapproved in 1979. Last previous edition approved in 1997 as D 3744 97.2Annual Book of ASTM Standards, Vol 04.02.3Annual Book of ASTM Standards, Vol 04.03.4Annual Book of ASTM Standards, Vol 04.08.5Annual Book of ASTM Standards, Vol 14.02.1Copyright ASTM International, 100

16、 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.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 aggregate when subjected tomechanical degradation.4.

17、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 aggregate, and riprap for rock slope protec

18、-tion.6,74.3 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 for evaluation ofthe quality of a new aggre

19、gate 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 and expensive sound-ness tests.64.5 Although

20、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 use in bituminous pavingmixtures, coarse ag

21、gregate for use in portland-cement concrete,and aggregate for use as railroad ballast.5. Apparatus5.1 Mechanical Washing Vessel (Pot)A flat-bottomed,straight-sided cylindrical vessel conforming to the specifica-tions and dimensions shown in Fig. 1.5.2 Collection PanA round pan (at least 230 mm (9 in

22、.) indiameter and approximately 100 mm (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 an 203-mm (8-in.) diametersieve at least 75 mm (3 in.) above the bottom. An a

23、daptor thatwill not allow loss of fines or wash 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 ala

24、teral reciprocating motion at a rate of 285 6 10 completecycles per minute. The reciprocating motion shall be producedby means of an eccentric in the base of the carrier and thelength of the stroke shall be 44.5 6 0.6 mm (1.75 6 0.025 in.).The clearance between the cam and follower of the eccentrics

25、hall be 0.25 to 1.02 mm (0.001 to 0.004 in.). 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 MethodD 2419).5.5 SievesThe sieves shall conform to Specification E 1

26、1.5.6 BalanceA balance having a minimum capacity of 500g and meeting the requirements of Guide D 4753, Class GP5.6. Reagents and Materials6.1 Calcium Chloride SolutionsUse stock and workingcalcium chloride solutions as specified in the Reagents andMaterials section of Test Method D 2419.6.2 WaterUse

27、 distilled or demineralized water for thenormal performance 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 permis

28、sable in place of distilled or demineralized water. 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

29、the temperature of the distilled or demineralizedwater and the working calcium chloride solution at 22 6 3C(72 6 5F).8. Sampling8.1 Obtain samples of the aggregate to be tested in accor-dance with Practice D 75.9. Initial Sample Preparation9.1 Dry aggregate samples sufficiently to permit a completes

30、eparation on the 4.75-mm (No. 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.The use of sunlight, ovens, or forced drafts of warm air are themo

31、st common drying methods.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 of finesfrom the coarse aggregate part

32、icles by any means that will notappreciably reduce the natural individual particle sizes.9.4 Determine the sample grading by sieving in accordancewith Test Method C 136 on the 19.0, 12.5, 9.5, 4.75, 2.36, and1.18-mm (34 ,12 ,38-in. and Nos. 4, 8, and 16) sieves. Discardany material that is retained

33、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, test coarse aggregate (Procedure A) o

34、nly.6Hamilton, R. D., Smith, R. E., and Sherman, G. B., “Factors Influencing theDurability of Aggregates,” Research Report 633476, State of California, Division ofHighways, Materials and Research Department, June 1971.7Hveem, F. N., and Smith, T. N., “Durability of Aggregates,” Research Report,State

35、 of California, Division of Highways, Materials and Research Department,January 1964.D37440329.5.2 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 equ

36、al to or greater than 10 % and ifthe percent passing 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 aggre

37、gate (75 to 80 %) is retainedbetween the 9.5 and 1.18-mm (38-in. and No. 16) 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, g19.0 to 12.5 mm (34 t

38、o12 in.) 1070 6 1012.5 to 9.5 mm (12 to38 in.) 570 6 109.5 to 4.75 mm (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 actualSI Equivalentin. mm in. mm in. mm91732 242.1 758 193.714 6.4858 219.1 312 88.9

39、116 1.683364 216.3 212 64.8132 0.7972932 200.834 19.0164 0.4072732 199.2NOTE 1The gasket shall be18 in. neoprene rubber, having an inside diameter of 72732 6164 in. and an outside diameter of 83364 6164 in.NOTE 2The pot shall be a flat bottom, straight-sided, cylindrical vessel with a capacity of ap

40、proximately 2 gal. The top edge shall be flared outwardto form a seat for the gasket and lid.NOTE 3Three trunk clamps are required and shall be placed at one-third intervals. The clamps shall be attached to the pot by rivets or welds so thatthe pot remains watertight. When fitted with the18-in. gask

41、et and clamped in place, the lid shall form a watertight seal with the flared edge of the pot.NOTE 4The vessel shall be 20-gage stainless steel, unless otherwise noted. All dimensions shall be within 6132 in., unless otherwise noted.FIG. 1 Mechanical Washing VesselD3744033percentage for the deficien

42、t fraction and proportionally in-crease the mass of the remaining 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, g19.0 to 12.5 mm (34 to12 in.) 6 0.06 3 2550 153 6 1012.5

43、 to 9.5 mm (12 to38 in.) 26 570 2550 2 153!570 1 910923 6 109.5 to 4.75 mm (38 to No. 4) 68 910 2550 2 153!570 1 9101474 6 5Totals 100 2550 6 25Example 2Less than 10 % in two fractionsAggregate Size Percent Calculation Air DryMass, g19.0 to 12.5 mm (34 to12 in.) 4 0.04 3 2550 102 6 1012.5 to 9.5 mm

44、(12 to38 in.) 7 0.07 3 2550 179 6 109.5 to 4.75 mm (38 to No. 4) 89 2550 (102 + 179) 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 absorption

45、rate, or both, of some aggregates, the proportions of aggregateto water will not provide 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 in

46、undatedwhen 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 C 127.10.3.3 Adjust the total mass of the test sample using

47、 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 10.1.10.3.4 Adjust the volume of test water using the followingequation:Adj

48、usted water 5 1000 1 A 3 W! 2 50 (2)where:A = absorption of aggregate, % (expressed as a decimalfraction), andW = mass of oven-dried test sample, g.10.4 Clamp the vessel lid in place, and secure the vessel inthe sieve shaker. Begin agitation after a time of 60 6 10 s haselapsed from the introduction

49、 of the wash water. Agitate thevessel in the sieve shaker for 120 6 5s.10.5 After the 2-min agitation time is completed, removethe vessel from the shaker, unclamp the lid and pour thecontents onto a 4.75-mm (No. 4) sieve. Rinse any remainingfines from the vessel onto the sieve and direct water (from aFIG. 2 Modification of Tyler Portable Sieve ShakerD3744034flexible hose attached to a faucet) onto the aggregate until thewater passing through the sieve comes out clear.10.6 Dry the fraction retained on the 4.75-mm (No