ASTM G57-20

Standard Test Method for Measurement of Soil Resistivity Using the Wenner Four-Electrode Method

SIGNIFICANCE AND USE
5.1 Measurement of soil resistivity is used for assessment and control of corrosion of buried structures. Soil resistivity is used both for the estimation of expected corrosion rates and for the design of cathodic protection systems. As an essential design parameter for cathodic protection systems, it is important to take as many measurements as necessary so as to get a sufficiently representative characterization of the soil environment to which the entire buried structure will be exposed.
SCOPE
1.1 This test method covers the equipment and procedures for the measurement of soil resistivity, both in situ and for samples removed from the ground, for use in assessment and control of corrosion of buried structures.  
1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard. Soil resistivity values are reported in ohm-centimeter.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 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.

General Information

• Status: Published
• Publication Date: 31-Oct-2020
• ICS: 93.020 - Earthworks. Excavations. Foundation construction. Underground works
• Technical Committee: G01 - Corrosion of Metals
• Drafting Committee: G01.10 - Corrosion in Soils

Standards Content (Sample)

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: G57 − 20
Standard Test Method for
Measurement of Soil Resistivity Using the Wenner Four-
1
Electrode Method
This standard is issued under the fixed designation G57; the number immediately following the designation indicates the year of original
adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
3
1. Scope 2.2 UNS Standards:
UNS Designation S30400 and S30403
1.1 This test method covers the equipment and procedures
UNS Designation S31600 and S31603
for the measurement of soil resistivity, both in situ and for
samples removed from the ground, for use in assessment and
3. Terminology
control of corrosion of buried structures.
3.1 Definitions:
1.2 The values stated in SI units are to be regarded as
3.1.1 four-electrode soil box, n—anon-conductivecontainer
standard. The values given in parentheses after SI units are
of known internal dimensions with four electrodes for measur-
provided for information only and are not considered standard.
ing a substance’s resistivity.
Soil resistivity values are reported in ohm-centimeter.
3.1.2 saturated soil, n—soil whose entire soil porosity is
1.3 This standard does not purport to address all of the
filled with water.
safety concerns, if any, associated with its use. It is the
3.1.3 soil resistance meter, n—an instrument capable of
responsibility of the user of this standard to establish appro-
measuring soil resistance.
priate safety, health, and environmental practices and deter-
3.1.4 soil resistivity, n—the electrical resistance between
mine the applicability of regulatory limitations prior to use.
opposite faces of a unit cube of material, typically expressed in
1.4 This international standard was developed in accor-
ohm-meter, ohm-cm, or similar units; the reciprocal of con-
dance with internationally recognized principles on standard-
ductivity
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
3.2 The terminology used herein, if not specifically defined
mendations issued by the World Trade Organization Technical
otherwise, shall be in accordance with Terminology G193.
Barriers to Trade (TBT) Committee.
Definitions provided herein and not given in Terminology
G193 are limited only to this test method.
2. Referenced Documents
3.3 Discussion—Resistivity measurements indicate the rela-
2
2.1 ASTM Standards:
tive ability of a medium to carry electrical currents. When a
D1193 Specification for Reagent Water
metallic structure is immersed in a conductive medium, the
E691 Practice for Conducting an Interlaboratory Study to
ability of the medium to carry current will influence the
Determine the Precision of a Test Method
magnitude of galvanic currents and cathodic protection cur-
G187 Test Method for Measurement of Soil Resistivity
rents. The degree of electrode polarization will also affect the
Using the Two-Electrode Soil Box Method
size of such currents.
G193 Terminology and Acronyms Relating to Corrosion
4. Summary of Test Method
1
This test method is under the jurisdiction of ASTM Committee G01 on
4.1 The Wenner four-electrode method requires that four
Corrosion of Metals and is the direct responsibility of Subcommittee G01.10 on
metal electrodes be placed with equal separation in a straight
Corrosion in Soils.
line in the surface of the soil to a depth not exceeding 5 % of
Current edition approved Nov. 1, 2020. Published December 2020. Originally
approved in 1978. Last previous edition approved in 2012 as G57–06 (2012). DOI: the minimum separation of the electrodes. The electrode
10.1520/G0057-20.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
3
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Metals and Alloys in the Unified Numbering System (UNS), 13th Edition,
Standards volume information, refer to the standard’s Document Summary page on developed jointly by ASTM International, West Conshohocken, PA, and SAE
the ASTM website. International, Warrendale, PA, 2017.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
G57−20
FIG. 1 Typical Connections for Use of Soil Box with Various Types of Instruments
separation should be selected with consideration of the soil where:
strata of interest. The resulting resistivity measurement repre-
b = outer electrode spacing, ft,
sents the average resistivity of a hemisphere of soil of a radius
a = inner electrode
...

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: G57 − 06 (Reapproved 2012) G57 − 20
Standard Test Method for
Field Measurement of Soil Resistivity Using the Wenner
1
Four-Electrode Method
This standard is issued under the fixed designation G57; 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 covers the equipment and procedures for the field measurement of soil resistivity, both in situ and for samples
removed from the ground, for use in the assessment and control of corrosion of buried structures.
1.2 To convert cm (metric unit) to metre (SI unit), divide by 100.The values stated in SI units are to be regarded as standard. The
values given in parentheses after SI units are provided for information only and are not considered standard. Soil resistivity values
are reported in ohm-centimeter.
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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.4 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
2
2.1 ASTM Standards:
D1193 Specification for Reagent Water
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
G187 Test Method for Measurement of Soil Resistivity Using the Two-Electrode Soil Box Method
G193 Terminology and Acronyms Relating to Corrosion
3
2.2 UNS Standards:
UNS Designation S30400 and S30403
UNS Designation S31600 and S31603
3. Terminology
3.1 Definitions:
1
This test method is under the jurisdiction of ASTM Committee G01 on Corrosion of Metals and is the direct responsibility of Subcommittee G01.10 on Corrosion in
Soils.
Current edition approved May 1, 2012Nov. 1, 2020. Published June 2012December 2020. Originally approved in 1978. Last previous edition approved in 20062012 as
G57–06. –06 (2012). DOI: 10.1520/G0057-06R12. 10.1520/G0057-20.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
3
Metals and Alloys in the Unified Numbering System (UNS), 13th Edition, developed jointly by ASTM International, West Conshohocken, PA, and SAE International,
Warrendale, PA, 2017.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
G57 − 20
3.1.1 four-electrode soil box, n—a non-conductive container of known internal dimensions with four electrodes for measuring a
substance’s resistivity.
3.1.2 saturated soil, n—soil whose entire soil porosity is filled with water.
3.1.3 soil resistance meter, n—an instrument capable of measuring soil resistance.
3.1.4 resistivity—soil resistivity, n—the electrical resistance between opposite faces of a unit cube of material; the reciprocal of
conductivity. Resistivity is used in preference to conductivity as an expression of the electrical character of soils (and waters) since
it is expressed in whole numbers.material, typically expressed in ohm-meter, ohm-cm, or similar units; the reciprocal of
conductivity
2.1.1.1 Discussion—
Resistivity measurements indicate the relative ability of a medium to carry electrical currents. When a metallic structure is
immersed in a conductive medium, the ability of the medium to carry current will influence the magnitude of galvanic currents
and cathodic protection currents. The degree of electrode polarization will also affect the size of such currents.
3.2 The terminology used herein, if not specifically defined otherwise, shall be in accordance with Terminology G193. Definitions
provided herein and not given in Terminology G193 are limited only to this test method.
3.3 Discussion—Resistivity measurements indicate the relative ability of a medium to carry electrical cur
...