1、Designation: D7759 12 D7759 12aStandard Guide forNuclear Surface Moisture and Density Gauge Calibration1This standard is issued under the fixed designation D7759; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last rev
2、ision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope Scope*1.1 This guide describes the process and objective of calibrating the density system of a nuclear surface moisture and dens
3、itygauge, or formulating the mathematical relationship between the density system response (the “density count”) of a nuclear surfacemoisture and density gauge and the corresponding density value of the density standard upon which the density system responsewas observed.1.2 This guide describes the
4、process and objective of calibrating the water content system of a nuclear surface moisture anddensity gauge, or formulating the mathematical relationship between the water content system response (the “water content count”)of a nuclear surface moisture and density gauge and the corresponding water
5、mass per unit volume value of the water contentstandard upon which the water content system response was observed.1.3 This guide describes the process and objective of verifying the density system of a nuclear surface moisture and densitygauge.1.4 This guide describes the process and objective of ve
6、rifying the water content system of a nuclear surface moisture anddensity gauge.1.5 This guide describes two mathematical processes by which the gauge measurement precision may be computed ormeasured.1.6 This guide offers guidance for developing and reporting estimates of uncertainties in measuremen
7、ts made with gauges thathave undergone calibration or verification.1.7 All observed and calculated values shall confirm to the guide for significant digits and rounding established in PracticeD6026.1.8 This guide does not purport to address all of the safety concerns, if any, associated with its use
8、. It is the responsibility ofthe user of this guide to establish appropriate safety and health practices and determine the applicability of regulatory limitationsprior to use.1.9 This guide offers an organized collection of information or a series of options and does not recommend specific course of
9、action. This document cannot replace education or experience and should be used in conjunction with professional judgment. Notall aspects of this guide may be applicable in all circumstances. This ASTM standard is not intended to represent or replace thestandard of care by which the adequacy of a gi
10、ven professional service must be judged, nor should this document be appliedwithout consideration of a projects many unique aspects. The word “Standard” in the title of this document means only that thedocument has been approved through the ASTM consensus process.2. Referenced Documents2.1 ASTM Stan
11、dards:2D653 Terminology Relating to Soil, Rock, and Contained FluidsD2216 Test Methods for Laboratory Determination of Water (Moisture) Content of Soil and Rock by MassD6026 Practice for Using Significant Digits in Geotechnical DataD6938 Test Method for In-Place Density and Water Content of Soil and
12、 Soil-Aggregate by Nuclear Methods (Shallow Depth)D7013 Guide for Nuclear Surface Moisture and Density Gauge Calibration Facility Setup1 This practice is under the jurisdiction of ASTM Committee D18 on Soil and Rock and is the direct responsibility of Subcommittee D18.08 on Special and ConstructionC
13、ontrol Tests.Current edition approved Feb. 1, 2012Nov. 1, 2012. Published March 2012December 2012. Originally approved in 2012. Last previous edition approved in 2012 asD775912. DOI: 10.1520/D7759-12.10.1520/D7759-12a.2 For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact
14、ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been m
15、ade to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A
16、 Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13. Terminology3.1 DefinitionsSee Terminology D653 for general definitions.3.2 Definitions of Terms Specific to This Standar
17、d:3.2.1 coverage factor3, na number larger than one by which a combined standard measurement uncertainty is multiplied toobtain an expanded measurement uncertainty.3.2.2 definitional uncertainty3, nthe component of measurement uncertainty resulting from the finite amount of detail in thedefinition o
18、f the measurand. The “measurand” in the case of a nuclear surface moisture density gauge, is typically either in-placedensity or water mass per unit volume.3.2.3 density system calibration, nthe method by which the values of the fit parameters in the equation that relates the densitysystem response
19、(the “density count”) of a nuclear gauge and the corresponding density value of the density standard upon whichthat density system response was observed are computed. In addition, the uncertainty of measurements taken with gaugescalibrated by the specific method must be known at representative densi
20、ty values that span the range of densities for which thecalibration is valid.3.2.4 density system verification, na set of operations or processes, or both, by which, for each density standard used in theprocess, the in-place density value(s) measured by the nuclear gauge on the density standard is r
21、elated to the corresponding value(s)of the standard or standards. In addition, the uncertainty of measurements taken with gauges that meets the established verificationcriterion or criteria must be known at representative densities that span the range of densities for which the verification is valid
22、.3.2.5 detector, na device to detect and measure radiation.3.2.6 expanded measurement uncertainty3, nproduct of a combined standard measurement uncertainty and a coverage factorlarger than one.3.2.7 gamma (radiation) source, na sealed source of radioactive material that emits gamma radiation as it d
23、ecays.3.2.8 in-place density, nthe total mass (solids plus water) per total volume of soil or soil-aggregates measured in place.3.2.9 measurement uncertainty3, nnon-negative parameter characterizing the dispersion of the quantity values being attributedto a measurand. The “measurand” in the case of
24、a nuclear surface moisture density gauge, is typically either in-place density orwater mass per unit volume.3.2.10 neutron (radiation) source, na sealed source of radioactive material that emits neutron radiation as it decays.3.2.11 nuclear gauge, na device containing one or more radioactive sources
25、 used to measure certain properties of soil andsoil-aggregates.3.2.12 prepared standards, ndensity or water content measurement standards prepared of soil, solid rock, concrete, andengineered materials, that have density or water content values, or both, that are established and known to a specified
26、 uncertainty.3.2.13 source rod, na metal rod attached to a nuclear gauge in which a radioactive source or a detector is housed. The rodcan be lowered to specified depths for testing.3.2.14 standard measurement uncertainty3, nmeasurement uncertainty expressed as a standard deviation.3.2.15 test count
27、, N, nthe measured output of a detector for a specific type of radiation for a given test.3.2.16 Type A Uncertainty Evaluation3, nevaluation of a component of measurement uncertainty by a statistical analysis ofmeasured quantity values obtained under defined measurement conditions.3.2.17 Type B Unce
28、rtainty Evaluation3, nevaluation of a component of measurement uncertainty by means other than a TypeA Evaluation.3.2.18 volumetric water content, nthe volume of water as a percent of the total volume of soil or rock material.3.2.19 water content, nthe ratio of the mass of water contained in the por
29、e spaces of soil or soil-aggregate, to the solid massof particles in that material, expressed as a percentage (this is sometimes referred to in some scientific fields as gravimetric watercontent to differentiate it from volumetric water content).3.2.20 water content system calibration, nthe method b
30、y which the values of the fit parameters in the equation that relates thewater content system response (the “water content count”) of a nuclear gauge and the corresponding water mass per unit volumevalue of the water content standard upon which that water content system response was observed are com
31、puted. In addition, theuncertainty of measurements taken with the gauges calibrated by the specific method must be known at representative water massper unit volume values that span the range of water mass per unit volume values for which the calibration is valid.3.2.21 water content system verifica
32、tion, na set of operations or processes, or both, by which, for each water content standardused in the process, the in-place water mass per unit volume value(s) measured by the nuclear gauge on water content standard3 JCGM 200:2008: International Vocabulary of MetrologyBasic and General Concepts and
33、 Associated Terms (VIM). 2008: Joint Document Committee for Guides inMetrology.D7759 12a2is related to the corresponding value(s) of these standards. In addition, the uncertainty of measurements taken with gauges thatmeets the established verification criterion or criteria must be known at represent
34、ative water mass per unit volume values that spanthe range of water mass per unit volume values for which the verification is valid.3.2.22 water mass per unit volume, nthe ratio of the mass of water contained in the pore spaces of a soil or soil-aggregateto the total volume occupied by that soil or
35、rock material.4. Summary of Practice4.1 The objectives of the practice are as follows:4.1.1 The objective of density system calibration is to formulate a mathematical equation, or density calibration equation, thatrelates the gauge density system response (the “density count”) to the soil-equivalent
36、 density of the standard on which this responseis elicited. The maximum uncertainties of subsequent gauge density readings shall be determined for the calibration process thatis used. The standards used for the determination of uncertainty shall be representative of the range of densities for which
37、the gaugewill be used.4.1.2 The objective of density system verification is to evaluate the current density calibration equation for the gauge anddetermine if a new calibration is required. The verification method will be based upon relating, at the pertinent density or densitiesfor the specific met
38、hod, the density value of a known density standard to the density measured by the gauge. The maximumuncertainties of subsequent gauge density readings shall be determined for the verification method used. The standards used forthe determination of uncertainty shall be representative of the range of
39、densities for which the gauge will be used.4.1.3 The objective of water content system calibration is to formulate a mathematical equation, or water content calibrationequation, that relates the gauge water content system response (the “water content count”) to the water mass per unit volume valueof
40、 the standard on which this response is elicited. The uncertainties of subsequent gauge water mass per unit volume readings forlow and high shall be known for, at a minimum, a water mass per unit volume standards used for thelevel within 32 kg/m3determination (2.0 lbm/ft3of uncertainty shall be dete
41、rmined for the calibration process that is used. The low and high ) of the upperextreme of the water mass per unit volume standards shall span the range of water masscalibration range (typically 300 kg/m3 perunit(18.7 lbm/ft3 volume values for which the gauge will be used.) or higher).4.1.4 The obje
42、ctive of water content system verification is to evaluate the current water content system calibration equation forthe gauge and determine if a new calibration is required. This evaluation will be based upon relating, at the pertinent water massper unit volume values for the specific method, the wat
43、er mass per unit volume value of a known water mass per unit volumestandard to the water mass per unit volume value measured by the gauge. The uncertainties of subsequent gauge water mass perunit volume readings for low and high shall be known for, at a minimum, a water mass per unit volume standard
44、s used for thelevelwithin 32 kg/m3 determination (2.0 lbm/ft3of uncertainty shall be determined for the calibration process that is used. The low andhigh ) of the upper extreme of the water mass per unit volume standards shall span the range of water masscalibration range(typically 300 kg/m3 per uni
45、t(18.7 lbm/ft3 volume values for which the gauge will be used.) or higher).4.1.5 The density calibration equation relates the in-place density value measured by the gauge on a test site (the “independentvariable”) with the density test count measured by the gauge on the test site (the “dependent var
46、iable”) is typically exponentialor polynomial in form, with three fit coefficients.4.2 Historically, the most successful methods for calibrating the density system of a gauge is done by taking gauge densityreadings on three or more density standards, combining the independent and dependent variables
47、 into data pairs, and using aleast-squares or Newton-Rafson fitting algorithm with these data pairs to compute the fit coefficients. These density standards haveunique density values that span the range of densities for which the gauge will be used.4.2.1 The density system calibration of a gauge is
48、not necessarily limited to the process described in 4.2. However, for anymethod that is used in the density system calibration process, one must know the uncertainties of the in-place density readingsmeasured by devices calibrated in this manner over the range of density values for which the gauge w
49、ill be used.4.2.2 For any method that is used in the density system verification process, one must know the uncertainties of the in-placedensity readings measured by devices calibrated in this manner over the range of density values for which the gauge will be used.4.2.3 The water content calibration equation that relates the in-place water mass per unit volume value measured by the gaugeon a test site (the “independent variable”) with the water content test count measured by the gauge on the test site (the “dependentvariable”) is typically linear in form,
