ASTM C566-1997(2004) Standard Test Method for Total Evaporable Moisture Content of Aggregate by Drying《用干燥法测定集料总含水量的标准试验方法》.pdf

1、Designation: C 566 97 (Reapproved 2004)Standard Test Method forTotal Evaporable Moisture Content of Aggregate by Drying1This standard is issued under the fixed designation C 566; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the

2、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. Scope1.1 This test method covers the

3、determination of the per-centage of evaporable moisture in a sample of aggregate bydrying both surface moisture and moisture in the pores of theaggregate. Some aggregate may contain water that is chemi-cally combined with the minerals in the aggregate. Such wateris not evaporable and is not included

4、 in the percentagedetermined by this test method.1.2 The values stated in SI units are to be regarded as thestandard. The values stated in parentheses are provided forinformation only.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is ther

5、esponsibility 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. For specificprecautionary statements, see 5.3.1, 7.2.1, and 7.3.1.2. Referenced Documents2.1 ASTM Standards:2C 29/C 29M Test Metho

6、d for Bulk Density (Unit Weight)and Voids in AggregateC 125 Terminology Relating to Concrete and ConcreteAggregatesC 127 Test Method for Density, Relative Density (SpecificGravity), and Absorption of Coarse AggregateC 128 Test Method for Density, Relative Density (SpecificGravity), and Absorption of

7、 Fine AggregateC 670 Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction MaterialsD 75 Practice for Sampling AggregatesE 11 Specification for Wire Cloth and Sieves for TestingPurposes2.2 Other Document:National Research Council Report SHRP-P-61933. Terminology3.1 De

8、finitions:3.1.1 For definitions of terms used in this test method, referto Terminology C 125.4. Significance and Use4.1 This test method is sufficiently accurate for usualpurposes, such as adjusting batch quantities of ingredients forconcrete. It will generally measure the moisture in the testsample

9、 more reliably than the sample can be made to representthe aggregate supply. In cases where the aggregate itself isaltered by heat, or where more refined measurement is re-quired, the test should be conducted using a ventilated,controlled temperature oven.4.2 Large particles of coarse aggregate, esp

10、ecially thoselarger than 50 mm (2 in.), will require greater time for themoisture to travel from the interior of the particle to thesurface. The user of this test method should determine by trialif rapid drying methods provide sufficient accuracy for theintended use when drying large size particles.

11、5. Apparatus5.1 BalanceA balance or scale accurate, readable, andsensitive to within 0.1 % of the test load at any point within therange of use. Within any interval equal to 10 % of the capacityof the balance or scale used to determine mass, the loadindication shall be accurate within 0.1 % of the d

12、ifference inmasses.5.2 Source of HeatA ventilated oven capable of maintain-ing the temperature surrounding the sample at 110 6 5C (2306 9F). Where close control of the temperature is not required(see 4.1), other suitable sources of heat may be used, such as anelectric or gas hot plate, electric heat

13、 lamps, or a ventilatedmicrowave oven.5.3 Sample ContainerA container not affected by the heat,of sufficient volume to contain the sample without danger ofspilling, and of such shape that the depth of sample will notexceed one fifth of the least lateral dimension.1This test method is under the juris

14、diction of ASTM Committee C09 onConcrete and Concrete Aggregates and is the direct responsibility of SubcommitteeC09.20 on Normal Weight Aggregates.Current edition approved February 1, 2004. Published March 2004. Originallyapproved in 1965. Last previous edition approved in 1997 as C 566 97.2For ref

15、erenced 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 Document Summary page onthe ASTM website.3Available from the National Research Council, 2101 Constitution Ave.

16、, N.W.,Washington, DC 20418.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.3.1 PrecautionWhen a microwave oven is used, thecontainer shall be nonmetallic.NOTE 1Except for testing large samples, an ordinary frying pan issuitable fo

17、r use with a hot plate, or any shallow flat-bottomed metal panis suitable with heat lamps or oven. Note the precaution in 5.3.1.5.4 StirrerA metal spoon or spatula of convenient size.6. Sampling6.1 Sample in accordance with Practice D 75, except for thesample size.6.2 Secure a sample of the aggregat

18、e representative of themoisture content in the supply being tested and having a massnot less than the amount listed in Table 1. Protect the sampleagainst loss of moisture prior to determining the mass.7. Procedure7.1 Determine the mass of the sample to the nearest 0.1 %.7.2 Dry the sample thoroughly

19、 in the sample container bymeans of the selected source of heat, exercising care to avoidloss of any particles. Very rapid heating may cause someparticles to explode, resulting in loss of particles. Use acontrolled temperature oven when excessive heat may alter thecharacter of the aggregate, or wher

20、e more precise measurementis required. If a source of heat other than the controlledtemperature oven is used, stir the sample during drying toaccelerate the operation and avoid localized overheating. Whenusing a microwave oven, stirring of the sample is optional.7.2.1 CautionWhen using a microwave o

21、ven, occasion-ally minerals are present in aggregates that may cause thematerial to overheat and explode. If this occurs it can damagethe microwave oven.7.3 When a hot plate is used, drying can be expedited by thefollowing procedure. Add sufficient anhydrous denatured alco-hol to cover the moist sam

22、ple. Stir and allow suspendedmaterial to settle. Decant as much of the alcohol as possiblewithout losing any of the sample. Ignite the remaining alcoholand allow it to burn off during drying over the hot plate.7.3.1 WarningExercise care to control the ignition op-eration to prevent injury or damage

23、from the burning alcohol.7.4 The sample is thoroughly dry when further heatingcauses, or would cause, less than 0.1 % additional loss in mass.7.5 Determine the mass of the dried sample to the nearest0.1 % after it has cooled sufficiently not to damage the balance.8. Calculation8.1 Calculate total ev

24、aporable moisture content as follows:p 5 100 W 2 D!/D (1)where:p = total evaporable moisture content of sample, percent,W = mass of original sample, g, andD = mass of dried sample, g.8.2 Surface moisture content is equal to the differencebetween the total evaporable moisture content and the absorp-t

25、ion, with all values based on the mass of a dry sample.Absorption may be determined in accordance with TestMethod C 127 or Test Method C 128.9. Precision and Bias9.1 Precision:9.1.1 The within-laboratory single operator standard devia-tion for moisture content of aggregates has been found to be0.28

26、% (Note 2). Therefore, results of two properly conductedtests by the same operator in the same laboratory on the sametype of aggregate sample should not differ by more than 0.79 %(Note 2) from each other.9.1.2 The between-laboratory standard deviation for mois-ture content of aggregates has been fou

27、nd to be 0.28 % (Note2). Therefore, results of properly conducted tests from twolaboratories on the same aggregate sample should not differ bymore than 0.79 % (Note 2) from each other.9.1.3 Test data used to derive the above precision indiceswere obtained from samples dried to a constant mass in adr

28、ying oven maintained at 110 6 5C. When other dryingprocedures are used, the precision of the results may besignificantly different than that indicated above.NOTE 2These numbers represent, respectively, the 1s and 2s limits asdescribed in Practice C 670.9.2 Bias:9.2.1 When experimental results are co

29、mpared with knownvalues from accurately compounded specimens, the followinghas been derived.9.2.1.1 The bias of moisture tests on one aggregate materialhas been found to have a mean of +0.06 %. The bias ofindividual test values from the same aggregate material hasbeen found with 95 % confidence to l

30、ie between 0.07 %and +0.20 %.9.2.1.2 The bias of moisture tests on a second aggregatematerial has been found to have a mean of +0.01 %. The biasof individual test values from the same aggregate material hasbeen found with 95 % confidence to lie between 0.14 %and +0.14 %.9.2.1.3 The bias of moisture

31、tests overall on both aggregatematerials has been found to have a mean of +0.03 %. The biasof individual test values overall from both aggregate materialshas been found with 95 % confidence to lie between 0.12 %and +0.18 %.9.2.2 Test data used to derive the above bias statementswere obtained from sa

32、mples dried to a constant mass in aTABLE 1 Sample Size for AggregateNominal Maximum Sizeof Aggregate, mm (in.)AMass of Normal WeightAggregate Sample, min, kgB4.75 (0.187) (No. 4) 0.59.5 (38) 1.512.5 (12)219.0 (34)325.0 (1) 437.5 (112)650 (2) 863 (212)1075 (3) 1390 (312 6100 (4) 25150 (6) 50ABased on

33、 sieves meeting Specification E 11.BDetermine the minimum sample mass for lightweight aggregate by multiplyingthe value listed by the dry-loose unit mass of the aggregate in kg/m3(determinedusing Test Method C 29/C 29M) and dividing by 1600.C 566 97 (2004)2drying oven maintained at 110 6 5C. When ot

34、her dryingprocedures are used, the bias of the results may be significantlydifferent than that indicated above.NOTE 3These precision and bias statements were derived fromaggregate moisture data provided by 17 laboratories participating in theSHRP Soil Moisture Proficiency Sample Program which is ful

35、ly describedin the National Research Council Report SHRP-P-619. The samples testedwhich relate to these statements were well-graded mixtures of fine andcoarse aggregate with moisture contents ranging from air dry to saturatedsurface dry.10. Keywords10.1 aggregate; drying; moisture contentASTM Intern

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39、ards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).C 566 97 (2004)3