1、Designation: D 6607 00 (Reapproved 2005)Standard Practice forInclusion of Precision Statement Variation in SpecificationLimits1This standard is issued under the fixed designation D 6607; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisi
2、on, the 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.1. Scope1.1 This practice covers a method of determining rationalspecification limits by inclusion of the precisi
3、on of the testmethod used in the specification.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 all of thesafety concerns, if any, associated with its use. It is theresponsibilit
4、y 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:2C 670 Practice for Preparing PrecisionAnd Bias StatementsFor Test Methods For Construction Materials
5、C 802 Practice For Conducting An Interlaboratory TestProgram To Determine The Precision Of Test Methods ForConstruction MaterialsD 2172 Test Methods for Quantitative Extraction Of Bitu-men From Bituminous Paving MixturesD 2726 Test Method for Bulk Specific Gravity and Densityof Non-Absorptive Compac
6、ted Bituminous MixturesE 177 Practice for Use Of The Terms Precision And Bias InASTM Test Methods2.2 Federal Highway Administration Report:FHWA Report HI-93047 Materials Control andAcceptanceQuality Assurance, Federal Highway Ad-ministration, May 199333. Terminology3.1 For definitions of terms used
7、in this practice, consultPractice E 177.4. Significance and Use4.1 Each test method has a limited precision. Even if a testis performed as carefully and as correctly as possible on amaterial which is as homogeneous as can be obtained, the testwill still vary from one to another. A widely used measur
8、e ofthe variation of the test results from a test method is thestandard deviation (s). In an ASTM standard test, the standarddeviation of the test method can be found in the Precision andBias statement for the test. The “Blue Book,” Form and Stylefor ASTM Standards, requires that all test methods in
9、cludePrecision and Bias statements. Practice C 670 and PracticeC 802 provide guidance for determination of these values.4.2 If the precision of a test method is low and the precisionof the test has not been properly considered in a materialspecification, a uniform material with the right quality may
10、 stillbe rejected most of the time because of the wide variation ofthe test results. In order to have rational specification limits, theprecision of the test used should be properly included in aspecification.4.3 This practice provides a guideline for proper inclusionof precision of the test method
11、in a rational specification.5. Procedure5.1 Determine the effective standard deviation (sX)ofthetest results due to the combined effects of materials variationand test variation using Eq 1:sX5 sM21sT2! (1)where:sM= standard deviation of test property due to materialvariation (see Note 1), andsT= sta
12、ndard deviation of test property due to test method(see Note 2).NOTE 1sMis the expected standard deviation of the material propertywhen the material is produced in a properly controlled process.Astandarddeviation which is representative of the acceptable variation of the1This guide is under the juri
13、sdiction of Committee D04 on Road and PavingMaterials and is the direct responsibility of Subcommittee D04.94 on StatisticalProcedures and Evaluation of Data.Current edition approved June 1, 2005. Published June 2005. Originallyapproved in 2000. Last previous edition approved in 2000 as D 6607 00.2F
14、or 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.3Available from National Technical Information Service (NTIS),
15、U.S. Depart-ment of Commerce, 5285 Port Royal Rd., Springfield, VA 22161.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.material can be used. It can be calculated from the data obtained fromproperly produced materials.NOTE 2sTis the
16、 standard deviation as given in the precisionstatement for the test method used to measure the test property.5.2 Determine the standard deviation of the mean of the testresults (s3) using Eq 2:s35s3/ =n (2)where:n = number of tests performed.5.3 For a two-ended specification (with both a minimumand
17、maximum limits), the specification limits for the averagetest value from n test ( x ) should be the following: Za /2s3# 3 # 1 Za /2s3(3)where: = target propertyZa/2= critical number of standard deviations for (1a)confidence interval. (See Table 1 for values of Za /2 for different specified confidenc
18、e intervals.)5.4 For a one-ended specification (with only a maximum orminimum limit), the specification limit for the average testvalue from n test ( x ) should be the following:3 $ Zas3with a minimum limit! (4)or3 # 1 Zas3with a maximum limit! (5)APPENDIXESX1. First Example of the Application of Pr
19、ecision Limits to Specification WritingX1.1 Problem StatementX1.1.1 A specification is to be written for the asphaltcontent of an asphalt mixture with aggregate water absorptioncapacity of less than 1.25 %. Three reflux asphalt extractiontests are to be run and the average of three test results is t
20、o beused for acceptance purpose. The target asphalt content is6.2 %. It is assumed that the contractor can reasonably controlthe asphalt content with a standard deviation of 0.20 % (seeNote X1.1).NOTE X1.1Typical standard deviations of different material proper-ties can be found in FHWA Report HI-93
21、047. The typical range ofstandard deviation of asphalt content was given as 0.15 % 0.30 %.X1.2 Precision statement for Test Methods D 2172(Method BReflux) is given in Table X1.1.X1.3 The combined standard deviation of the measuredasphalt content:sx5 = 0.221 0.232! 5 0.305 % (X1.1)X1.4 The standard d
22、eviation of the mean of three testresults:sx5 0.305 / = 3 5 0.176 % (X1.2)X1.5 Specification limits using a 95 % confidence interval:5 6.2 % 6 Za/20.176 %!5 6.2 % 6 1.96 0.176 %!5 6.2 % 6 0.3 % (X1.3)X2. Second ExampleX2.1 Problem StatementX2.1.1 A specification is to be written for the asphaltconte
23、nt of the asphalt mixture as described in Example 1.However, the average of seven test results (instead of three testresults) is to be used.X2.2 The combined standard deviation of the measuredasphalt content is the same as in Example 1:sx5 = 0.221 0.232! 5 0.305 % (X2.1)X2.3 The standard deviation o
24、f the mean of seven testresults:sx5 0.305 / = 75 0.115 % (X2.2)X2.4 Specification limits using a 95 % confidence interval:5 6.2 % 6 1.96 0.115 %!5 6.2 % 6 0.2 % (X2.3)TABLE 1 Z Values for Different Confidence LevelsConfidence Level (1 a): 90 % 95 % 97.5 % 99.0 %Za/2(Two-End Specification) 1.645 1.96
25、0 2.243 2.575Za(One-End Specification) 1.282 1.645 1.960 2.327TABLE X1.1 Mixes with Agg. of Water Absorption 1.25 %StandardDeviationAcceptable Range ofTwo Test ResultsSingle-Operator 0.19 % .054 %Multi-Operator 0.23 % 0.65 %D 6607 00 (2005)2X3. Third ExampleX3.1 Problem StatementX3.1.1 A specificati
26、on is to be written for the compacteddensity of an asphalt mixture with non-absorptive aggregate.The target density is 2.365 g/cm3. Five density measurementsin accordance with Test Method D 2726 are to be made, andthe average test result is to be used for acceptance purposes. Itis assumed that the c
27、ontractor can control the density of themixture with a standard deviation of 0.02 g/cm3.X3.2 Precision statement for Test Method D 2726 is inTable X3.1.X3.3 The combined standard deviation of the measureddensity:sx5 = 0.20021 0.02692!5 0.0335 g/cm3(X3.1)X3.4 The standard deviation of the mean of fiv
28、e test results:sx5 0.0335 / = 5!5 0.0150 g/cm3(X3.2)X3.5 Specification limit using a 95 % confidence interval:Minimum average measured density5 2.365 Za0.015!5 2.365 1.65 0.115!35 2.340 g/cm (X3.3)X3.6 With this specification, a contractor who compacts theasphalt mixture to an average density of 2.3
29、56 g/cm3wouldmeet the specification 95 % of the time.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent ri
30、ghts, 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 every five years andif not revised, either reapproved or withdrawn. Your comments are invited either fo
31、r 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 technical committee, which you may attend. If you feel that your comments have not received a fair hearin
32、g 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 ma
33、y 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).TABLE X3.1 Precision Statement ValuesStandardDeviationAcceptable Range ofTwo Test ResultsSingle-Operator Precision 0.0124 0.035Multi-Operator Precision 0.0269 0.076D 6607 00 (2005)3
