Significance and Use
Each test method has a limited precision. Even if a test is performed as carefully and as correctly as possible on a material which is as homogeneous as can be obtained, the test will still vary from one to another. A widely used measure of the variation of the test results from a test method is the standard deviation (σ). In an ASTM standard test, the standard deviation of the test method can be found in the Precision and Bias statement for the test. The “Blue Book,” Form and Style for ASTM Standards, requires that all test methods include Precision and Bias statements. Practice C670 and Practice C802 provide guidance for determination of these values.
If the precision of a test method is low and the precision of the test has not been properly considered in a material specification, a uniform material with the right quality may still be rejected most of the time because of the wide variation of the test results. In order to have rational specification limits, the precision of the test used should be properly included in a specification.
This practice provides a guideline for proper inclusion of precision of the test method in a rational specification.
1.1 This practice covers a method of determining rational specification limits by inclusion of the precision of the test method used in the specification.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
C670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
C802 Practice for Conducting an Interlaboratory Test Program to Determine the Precision of Test Methods for Construction Materials
D2172 Test Methods for Quantitative Extraction of Bitumen From Bituminous Paving Mixtures
D2726 Test Method for Bulk Specific Gravity and Density of Non-Absorptive Compacted Bituminous Mixtures
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
Federal Highway Administration Report
FHWAReportHI-93&ndas Materials Control and Acceptance--Quality Assurance, Federal Highway Administration, May 1993 Available from National Technical Information Service (NTIS), U.S. Department of Commerce, 5285 Port Royal Rd., Springfield, VA 22161.
Precision; Specification preparation; Inclusion (of precision statement variation); Pavement surfaces--specifications
ICS Number Code 19.020 (Test conditions and procedures in general)
ASTM International is a member of CrossRef.
Citing ASTM Standards
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