ASTM C70-2006 Standard Test Method for Surface Moisture in Fine Aggregate《细集料表面湿度的标准试验方法》.pdf

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1、Designation: C 70 06American Association StateHighway and Transportation Officials StandardAASHTO No.: T142Standard Test Method forSurface Moisture in Fine Aggregate1This standard is issued under the fixed designation C 70; the number immediately following the designation indicates the year of origi

2、naladoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscriptepsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Def

3、ense.1. Scope*1.1 This test method covers field determination of theamount of surface moisture in fine aggregate by displacementin water.1.2 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 e

4、stablish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1.3 The values stated in SI units are to be regarded as thestandard. The values in parentheses are provided for informa-tion purposes only.2. Referenced Documents2.1 ASTM Standar

5、ds:2C 128 Test Method for Density, Relative Density (SpecificGravity), and Absorption of Fine AggregateC 566 Test Method for Total Evaporable Moisture Contentof Aggregate by DryingC 670 Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction Materials3. Significance and

6、 Use3.1 This test method is not widely used. However, it is aconvenient procedure for field or plant determination ofmoisture content of fine aggregate if specific gravity values areknown and if drying facilities are not available. It can be usedto adjust the aggregate mass for moisture content and

7、todetermine surface moisture contribution to mixing water inportland cement concrete.3.2 The accuracy of the test method depends upon accurateinformation on the bulk specific gravity of the material in asaturated surface-dry condition.4. Apparatus4.1 Balance, having a capacity of 2 kg or more and se

8、nsitiveto 0.5 g or less.4.2 FlaskA suitable container or flask, preferably of glassor noncorrosive metal. The container may be a pycnometer, avolumetric flask, a graduated volumetric flask, or other suitablemeasuring device. The volume of the container shall be fromtwo to three times the loose volum

9、e of the sample. Thecontainer shall be so designed that it can be filled to the mark,or the volume of its contents read, within 0.5 mL or less.5. Sample5.1 Select a representative sample of the fine aggregate to betested for surface moisture content. It shall weigh not less than200 g. Larger samples

10、 will yield more accurate results.6. Procedure6.1 The surface water content may be determined either bymass or volume. In each case the test shall be made at atemperature range of 18 to 29C (65 to 85F).6.2 Determination by MassDetermine the mass of thecontainer, in grams, filled to the mark with onl

11、y water. Beforeplacing the sample into the container, adjust the level of thewater so that it will be sufficient to cover the sample withoutgoing over the original mark. Introduce the weighed sample offine aggregate into the container and remove the entrained air.Fill the container to the original m

12、ark, and determine the massin grams. Calculate the amount of water displaced by thesample, as follows:Md5 Mc1 Ms2 M (1)where:Md= mass of water displaced by the sample, g,Mc= mass of container filled to the mark with water, g,Ms= mass of sample, g, andM = mass of container and sample, filled to the m

13、ark withwater, g.6.3 Determination by VolumeMeasure a volume of water,in millilitres, sufficient to cover the sample and place in thecontainer. Introduce the weighed sample of fine aggregate intothe container and remove the entrained air. Determine thecombined volume of the sample and the water by d

14、irect reading1This test method is under the jurisdiction of ASTM Committee C09 onConcrete and Concrete Aggregates and is the direct responsibility of SubcommitteeC09.20 on Normal Weight Aggregates.Current edition approved Feb. 15, 2006. Published March 2006. Originallyapproved in 1970. Last previous

15、 edition approved in 2001 as C 70 94(2001).2For 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 Document Summary page onthe ASTM website.1*A Summary of Cha

16、nges section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.when a graduated flask is used. When a pycnometer orvolumetric flask of known volume is used, fill the container tothe known volume mark

17、with an additional measured volumeof water. The flask or pycnometer volume is then equal to thecombined volume of sample and water. Calculate the amountof water displaced by the sample, as follows:Vs5 V22 V1(2)where:Vs= volume of water displaced by the sample, mL,V2= combined volume of sample and wa

18、ter, mL, andV1= total volume of water in the flask or pycnometerrequired to cover the sample and bring the level up tothe known volume mark, mL.7. Calculation7.1 Calculate the percentage of surface moisture in terms ofthe saturated surface-dry fine aggregate (see Appendix X1), asfollows:P 5 Md2 Vd!/

19、Ms2 Md!# 3 100 (3)where:P = surface moisture in terms of saturated surface-dryfine aggregate, %,Vd= mass of the sample (Msin 6.2) divided by the bulkspecific gravity of the fine aggregate in a saturatedsurface-dry condition, determined as prescribed inTest Method C 128, andMd= mass of water displace

20、d, g, andMs= mass of sample, g7.2 Calculate the percentage of surface moisture in terms ofdry aggregate if the absorption of the aggregate is known asfollows:Pd5 P1 1 Pa/100!# (4)where:Pd= surface moisture in terms of dry fine aggregate, %,andPa= absorption of the fine aggregate, %, determined inacc

21、ordance with Test Method C 128.Total moisture content, on a dry aggregate basis, is the sumof the surface moisture, Pd, and the absorption, Pa.8. Report8.1 Report surface moisture test results as determined bythis method to the nearest 0.1 %.9. Precision and Bias9.1 This procedure is estimated to be

22、 less precise thanproperly conducted moisture content tests by drying (TestMethod C 566). Accurate specific gravity information is essen-tial to the bias of this method. Test Method C 566 can be usedto verify the level of bias.9.2 PrecisionThese estimates of precision are based onresults from the AA

23、SHTO Materials Reference Laboratory(AMRL) Proficiency Sample Program, of testing conducted onFine Aggregate Proficiency Sample Numbers 99 and 100. Theprecision limits are based on test results submitted by 144laboratories that tested two fine aggregate test samples ofapproximately 500 g mass with av

24、erage surface moisturecontents of 2.323 % and 2.075 % respectively.9.2.1 Single-Operator PrecisionThe single-operator stan-dard deviation of a single test result has been found to be0.50 %.3Therefore, results of two properly conducted tests bythe same operator should not differ by more than 1.39 %.9

25、.2.2 Multilaboratory PrecisionThe multilaboratory stan-dard deviation of a single test result has been found to be0.82 %.3Therefore, results of two properly conducted tests indifferent laboratories on the same material should not differ bymore than 2.31 %.39.3 BiasSince there is no accepted referenc

26、e materialsuitable for determining the bias of this test procedure, nostatement on bias (other than that in 9.1) is made.10. Keywords10.1 fine aggregate; fine aggregate moisture; surfacemoistureAPPENDIX(Nonmandatory Information)X1. DEVELOPMENT OF EQUATIONSX1.1 These equations are readily derived fro

27、m basicrelationships. For convenience express P in terms of the ratior, that is, the ratio of the mass of surface moisture to the massof the saturated, surface-dry sample. It follows that:r 5Ms2 Ms/1 1 r!#Ms/1 1 r!(X1.1)X1.1.1 If G is bulk specific gravity of the saturated, surface-dry fine aggregat

28、e, thenMd5MsG1 1 r!1 Ms2Ms1 1 r(X1.2)where the first term gives the water displaced by thesaturated surface-dry fine aggregate and the second that dis-placed by the surface moisture.3These numbers represent, respectively, the (1s) and d2s) limits as described inPractice C 670.C70062X1.1.2 From Eq X1

29、.2:Ms1 1 r5Md2 Ms1G2 1(X1.3)By definition,Ms5 VdG (X1.4)X1.1.3 Substituting for Ms/(1 + r) and Msin Eq X1.1 andsimplifying,r 5 Md2 Vd!/Ms2 Md! (X1.5)SUMMARY OF CHANGESCommittee C09 has identified the location of selected changes to this test method since the last issue,C 70 94(2001), that may impact

30、 the use of this test method. (Approved February 15, 2006)(1) Added new paragraph 1.3.(2) Revised paragraph 6.1.(3) Changed “weight” to “mass” throughout.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard.

31、Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed ev

32、ery 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. Your comments will receive careful consideration at a meeting of theresponsible tech

33、nical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, 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).C70063