ASTM D6780/D6780M-19
(Test Method)Standard Test Methods for Water Content and Density of Soil In situ by Time Domain Reflectometry (TDR)
Standard Test Methods for Water Content and Density of Soil In situ by Time Domain Reflectometry (TDR)
SIGNIFICANCE AND USE
5.1 This test method can be used to determine the density and water content of naturally occurring soils and of soils placed during the construction of earth embankments, road fills, and structural backfills.
5.2 Time domain reflectometry (TDR) measures the apparent dielectric constant (Procedure A) and the apparent dielectric constant, first voltage drop and long term voltage (V1 and Vf) (Procedure B) of soil. The apparent dielectric constant is affected significantly by the water content and density of soil, and to a lesser extent by the chemical composition of soil and pore water, and by temperature. The first voltage drop and long term voltage (V1 and Vf) are affected significantly by the water content, density, and the chemical composition of the in situ pore water, and to a lesser extent the chemical composition of the soil solids. This test method measures the gravimetric water content.
5.3 Soil and pore water characteristics are accounted for in Procedure A with two calibration constants and for Procedure B with five calibration constants. The two soil constants for Procedure A are determined for a given soil by performing compaction tests in a special mold as described in Annex A2. The five soil constants for Procedure B are determined in conjunction with compaction testing in accordance with specified compaction procedures, for example, Test Method D698 as described in Annex A3. Both Procedures A and B use Test Method D2216 to determine the water contents.
5.4 When following Procedure A, the water content is the average value over the length of the cylindrical mold and the density is the average value over the length of the multiple-rod probe embedded in the soil. When following Procedure B, the water content and density is the average values over the length of the multiple-rod embedded in the soil.
Note 1: The quality of the result produced by this standard is dependent on the competence of the personnel performing it, and the suitability of th...
SCOPE
1.1 This test method may be used to determine the water content of soils and the density of soils in place using Time Domain Reflectometry.
1.2 This test method applies to soils that have 30 % or less by weight of their particles retained on the 19.0-mm [3/4-in.] sieve.
1.3 This test method is suitable for use as a means of acceptance for compacted fill or embankments.
1.4 This test method is not appropriate for frozen soils or soils at temperatures over 40°C [100°F] and may not be suitable for organic soils, highly plastic soils, or extremely dense soils.
1.5 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026.
1.5.1 The method used to specify how data are collected, calculated, or recorded in this standard is not directly related to the accuracy to which the data can be applied in design or other uses, or both. How one applies the results obtained using this standard is beyond its scope.2
1.6 Two alternative procedures are provided to determine the water content and the density of soil in situ:
1.6.1 Procedure A
involves two tests in the field, an in situ test and a test in a mold containing material excavated from the in situ test location. The apparent dielectric constant is determined in both tests.
1.6.2 Procedure B
involves only an in situ test by incorporating the first voltage drop and long term voltage (V1 and Vf ) in addition to the apparent dielectric constant. While the bulk electrical conductivity can be determined from these measurements, it is not needed for the determination of water content and density.
1.7 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non...
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This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation:D6780/D6780M −19
Standard Test Methods for
Water Content and Density of Soil In situ by Time Domain
1
Reflectometry (TDR)
This standard is issued under the fixed designation D6780/D6780M; the number immediately following the designation indicates the
year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last
reapproval. A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* electrical conductivity can be determined from these
measurements, it is not needed for the determination of water
1.1 This test method may be used to determine the water
content and density.
content of soils and the density of soils in place using Time
1.7 Units—The values stated in either SI units or inch-
Domain Reflectometry.
pound units are to be regarded separately as standard. The
1.2 This test method applies to soils that have 30% or less
values stated in each system may not be exact equivalents;
3
by weight of their particles retained on the 19.0-mm [ ⁄4-in.]
therefore,eachsystemshallbeusedindependentlyoftheother.
sieve.
Combining values from the two systems may result in non-
1.3 This test method is suitable for use as a means of
conformance with the standard. For additional information
acceptance for compacted fill or embankments.
consult SI10.
1.4 This test method is not appropriate for frozen soils or
1.8 This standard does not purport to address all of the
soils at temperatures over 40°C [100°F] and may not be safety concerns, if any, associated with its use. It is the
suitable for organic soils, highly plastic soils, or extremely
responsibility of the user of this standard to establish appro-
dense soils. priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
1.5 All observed and calculated values shall conform to the
1.9 This international standard was developed in accor-
guidelines for significant digits and rounding established in
dance with internationally recognized principles on standard-
Practice D6026.
ization established in the Decision on Principles for the
1.5.1 The method used to specify how data are collected,
Development of International Standards, Guides and Recom-
calculated,orrecordedinthisstandardisnotdirectlyrelatedto
mendations issued by the World Trade Organization Technical
theaccuracytowhichthedatacanbeappliedindesignorother
Barriers to Trade (TBT) Committee.
uses, or both. How one applies the results obtained using this
2
standard is beyond its scope.
2. Referenced Documents
1.6 Two alternative procedures are provided to determine 3
2.1 ASTM Standards:
the water content and the density of soil in situ:
D653Terminology Relating to Soil, Rock, and Contained
1.6.1 Procedure A involves two tests in the field, an in situ
Fluids
testandatestinamoldcontainingmaterialexcavatedfromthe
D698Test Methods for Laboratory Compaction Character-
in situ test location. The apparent dielectric constant is deter- 3
istics of Soil Using Standard Effort (12,400 ft-lbf/ft (600
mined in both tests. 3
kN-m/m ))
1.6.2 Procedure B involves only an in situ test by incorpo-
D1557Test Methods for Laboratory Compaction Character-
3
rating the first voltage drop and long term voltage (V and V )
1 f
istics of Soil Using Modified Effort (56,000 ft-lbf/ft
in addition to the apparent dielectric constant. While the bulk 3
(2,700 kN-m/m ))
D2216TestMethodsforLaboratoryDeterminationofWater
(Moisture) Content of Soil and Rock by Mass
1
D2487Practice for Classification of Soils for Engineering
ThistestmethodisunderthejurisdictionofASTMCommitteeD18onSoiland
Rock and is the direct responsibility of Subcommittee D18.08 on Special and
Purposes (Unified Soil Classification System)
Construction Control Tests.
D3740Practice for Minimum Requirements for Agencies
Current edition approved Aug. 1, 2019. Published September 2019. Originally
approved in 2002. Last previous edition approved in 2012 as D6780/D6780M–12.
DOI: 10.1520/D6780_D6780M-19.
2 3
“TheWaterContentandDensityofSoilInsitubyTimeDomainReflectometry For referenced ASTM standards, visit the ASTM website, www.astm.org, or
apparatus and procedures are covered by a patent. If you are aware of an contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
alternative(s) to the patented item, please attach to your ballot return a description Standards volume information, refer to the standard’s Document Summary page on
of the alternatives. All suggestions will be considered by the committee.” the ASTM website.
*A Summary of Changes section appears at the end of this standard
...
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 made to the previous version. Because
it 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 version
of the standard as published by ASTM is to be considered the official document.
Designation: D6780/D6780M − 12 D6780/D6780M − 19
Standard Test MethodMethods for
Water Content and Density of Soil In situ by Time Domain
1
Reflectometry (TDR)
This standard is issued under the fixed designation D6780/D6780M; the number immediately following the designation indicates the
year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last
reapproval. A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This test method may be used to determine the water content of soils and the in situ density of soils using a TDR apparatus.in
place using Time Domain Reflectometry.
3
1.2 This test method applies to soils that have 30 % or less by weight of their particles retained on the 19.0-mm [ ⁄4-in.] sieve.
1.3 This test method is suitable for use as a means of acceptance for compacted fill or embankments.
1.4 This test method is not appropriate for frozen soils or soils at temperatures over 40°C [100°F] and may not be suitable for
organic andsoils, highly plastic soils, or extremely dense soils.
1.5 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice
D6026.
1.5.1 The method used to specify how data are collected, calculated, or recorded in this standard is not directly related to the
accuracy to which the data can be applied in design or other uses, or both. How one applies the results obtained using this standard
2
is beyond its scope.
1.6 Two alternative procedures are provided.provided to determine the water content and the density of soil in situ:
1.6.1 Procedure A involves two tests in the field, an in situ test and a test in a mold containing material excavated from the in
situ test location. The apparent dielectric constant is determined in both tests.
1.6.2 Procedure B involves only an in situ test by incorporating the first voltage drop and long term voltage (V and V ) in
1 f
addition to the apparent dielectric constant. While the bulk electrical conductivity can be determined from these measurements,
it is not needed for the determination of water content and density.
1.7 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated
in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values
from the two systems may result in non-conformance with the standard. For additional information consult SI10.
1.8 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.9 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
3
2.1 ASTM Standards:
D653 Terminology Relating to Soil, Rock, and Contained Fluids
3 3
D698 Test Methods for Laboratory Compaction Characteristics of Soil Using Standard Effort (12,400 ft-lbf/ft (600 kN-m/m ))
1
This test method is under the jurisdiction of ASTM Committee D18 on Soil and Rock and is the direct responsibility of Subcommittee D18.08 on Special and Construction
Control Tests.
Current edition approved May 15, 2012Aug. 1, 2019. Published August 2012September 2019. Originally approved in 2002. Last previous edition approved in 20052012
as D6780 – 05.D6780/D6780M – 12. DOI: 10.1520/D6780_D6780M-12.10.1520/D6780_D6780M-19.
2
“The Water Content and Density of Soil In situ by Time Domain Reflectometry apparatus and procedures are covered by a patent. If you are aware of an alternative(s)
to the patented item, please attach to your ballot return a description of the alternatives. All suggestions will be considered by the committee.”
3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
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...
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