ASTM C1876-24

Standard Test Method for Bulk Electrical Resistivity or Bulk Conductivity of Concrete

SIGNIFICANCE AND USE
5.1 The electrical resistivity of a concrete is the opposition to the movement of ions under an applied electric field. The electrical conductivity of a concrete is a measure of how readily the ions in the pore solution can be transported through the concrete under an applied electric field (the higher the conductivity, the greater the rate of transport). The electrical resistivity or conductivity is a material property that depends upon the pore volume, the pore structure (size and connectivity), the pore solution composition, the degree of saturation of the concrete specimen, and the specimen’s temperature. Concrete mixture characteristics that are known to affect concrete electrical resistivity, as well as resistance to chloride ion penetration, include water-cementitious materials ratio, pozzolans, slag cement, the presence of polymeric admixtures, air-entrainment, aggregate type, aggregate volume fraction, degree of consolidation, curing method, and age.  
5.2 The bulk electrical resistivity of concrete is the inverse of its bulk electrical conductivity. Bulk electrical conductivity can also be measured by Test Method C1760, which uses the apparatus described in Test Method C1202. This test method, however, uses apparatus specifically designed to measure bulk conductivity or bulk resistivity.  
5.3 The purpose of conditioning in a simulated pore solution is to bring the specimen to a level of near complete saturation of the capillary and gel pores. When comparing two different concrete specimens, it is important to condition both specimens as close as possible to a comparable saturation state, using the same solution for conditioning, so that values can be compared in a meaningful way. This is particularly true for using the measured resistivity or conductivity, along with other information, to estimate the diffusivity.  
5.4 The bulk electrical resistivity or conductivity of concrete can provide a rapid indication of its resistance to chloride ion penetrati...
SCOPE
1.1 This test method covers the determination of the bulk electrical resistivity or conductivity of molded specimens or cored sections of hardened concrete after immersion in water saturated with a simulated pore solution in order to provide a rapid indication of its resistance to the penetration of fluids and dissolved aggressive ions.  
1.2 The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard. If required results obtained from another standard are not reported in the same system of units as used by this standard, it is permitted to convert those results using the conversion factors found in the SI Quick Reference Guide.2  
1.3 The text of this standard references notes and footnotes that provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of this standard.  
1.4 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. (Warning—Fresh hydraulic cementitious mixtures are caustic and may cause chemical burns to skin and tissue upon prolonged exposure.)3 For specific warning statement see 8.1.2.  
1.5 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-Dec-2023
• ICS: 91.100.10 - Cement. Gypsum. Lime. Mortar
• Technical Committee: C09 - Concrete and Concrete Aggregates
• Drafting Committee: C09.66 - Concrete's Resistance to Fluid Penetration

Relations

• Replaces: ASTM C1876-23 - Standard Test Method for Bulk Electrical Resistivity or Bulk Conductivity of Concrete
• Effective Date: 01-Jan-2024
• Refers: ASTM C31/C31M-24a - Standard Practice for Making and Curing Concrete Test Specimens in the Field
• Effective Date: 01-Apr-2024
• Refers: ASTM C670-24a - Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
• Effective Date: 01-Feb-2024
• Refers: ASTM C670-24 - Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
• Effective Date: 01-Jan-2024
• Refers: ASTM C31/C31M-24 - Standard Practice for Making and Curing Concrete Test Specimens in the Field
• Effective Date: 01-Jan-2024
• Refers: ASTM C31/C31M-23 - Standard Practice for Making and Curing Concrete Test Specimens in the Field
• Effective Date: 01-Jun-2023
• Refers: ASTM C39/C39M-21 - Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens
• Effective Date: 01-Mar-2021
• Refers: ASTM C670-15 - Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
• Effective Date: 15-Jun-2015

Overview

ASTM C1876-24 is the Standard Test Method for Bulk Electrical Resistivity or Bulk Conductivity of Concrete, developed by ASTM International. This method provides a reliable, rapid approach to measuring the electrical resistivity or conductivity of hardened concrete specimens-either molded or cored-after immersion in a water solution simulating concrete pore conditions. By assessing bulk electrical resistivity and conductivity, this standard offers key insight into the material property governing the movement of ions through concrete, which is essential for evaluating the durability of concrete, particularly its resistance to the ingress of water and dissolved aggressive ions such as chlorides.

Key Topics

• Electrical Resistivity and Conductivity: Measures the opposition and ease, respectively, with which ions move through saturated concrete under an applied electric field.
• Influencing Factors: Bulk electrical resistivity/conductivity depends on variables such as pore structure, saturation level, pore solution composition, specimen temperature, mix proportions, water-cementitious ratio, admixtures, aggregate properties, degree of consolidation, curing regime, and specimen age.
• Rapid Durability Assessment: Provides a quick indication of concrete’s resistance to chloride ion and fluid penetration, supporting performance-based durability specifications.
• Specimen Conditioning: Ensures comparable moisture saturation across specimens using a standardized pore solution, enabling meaningful comparison between different concrete batches.
• Testing Procedure: Utilizes specialized apparatus and electrodes with precise verification requirements to measure resistivity or conductivity, following strict preparation, conditioning, and measurement protocols.

Applications

The ASTM C1876-24 standard is widely used in the construction and civil engineering sectors for:

• Evaluating Concrete Durability: Results can rapidly indicate the concrete's ability to resist chloride ion penetration, a critical factor in the longevity of reinforced structures exposed to deicing salts or marine environments.
• Quality Control for Concrete Production: Assists concrete producers and specifiers in qualifying admixtures, supplementary cementitious materials, and novel mix designs by correlating electrical properties with permeability and expected service life.
• Performance-Based Specifications: Supports the adoption of performance requirements by agencies and owners seeking resilient infrastructure, reducing the reliance on prescriptive specifications.
• Correlation with Other Tests: Shows strong correlation with other ASTM methods, such as C1202 for chloride penetration resistance and C1556 for diffusion, supporting comprehensive durability testing programs.
• Research and Material Development: Facilitates development and comparative studies of new concrete materials, mix designs, and admixtures by providing quantifiable, reproducible electrical property data.

Related Standards

Understanding and applying ASTM C1876-24 is often complemented by the following ASTM standards:

• ASTM C1202 - Test Method for Electrical Indication of Concrete’s Ability to Resist Chloride Ion Penetration
• ASTM C1556 - Test Method for Determining the Apparent Chloride Diffusion Coefficient of Cementitious Mixtures by Bulk Diffusion
• ASTM C31/C31M - Practice for Making and Curing Concrete Test Specimens in the Field
• ASTM C39/C39M - Test Method for Compressive Strength of Cylindrical Concrete Specimens
• ASTM C42/C42M - Test Method for Obtaining and Testing Drilled Cores and Sawed Beams of Concrete
• ASTM C125 - Terminology Relating to Concrete and Concrete Aggregates

Practical Value

By following ASTM C1876-24, laboratories, agencies, and contractors can:

• Obtain rapid, repeatable measurements of concrete resistivity/conductivity, providing early-stage data for decision-making.
• Support service life modeling, material optimization, and specification compliance for critical infrastructure.
• Reduce long-term maintenance risks by verifying material resistance to aggressive environments.
• Harmonize data reporting and comparison by adhering to SI units and standardized protocols.

For professionals seeking efficient, standardized assessment of fluid and ion penetrability in concrete, ASTM C1876-24 is a critical tool supporting both quality assurance and innovative concrete technology development.

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: C1876 − 24
Standard Test Method for
Bulk Electrical Resistivity or Bulk Conductivity of Concrete
This standard is issued under the fixed designation C1876; 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* 2. Referenced Documents
2.1 ASTM Standards:
1.1 This test method covers the determination of the bulk
C31/C31M Practice for Making and Curing Concrete Test
electrical resistivity or conductivity of molded specimens or
Specimens in the Field
cored sections of hardened concrete after immersion in water
C39/C39M Test Method for Compressive Strength of Cylin-
saturated with a simulated pore solution in order to provide a
drical Concrete Specimens
rapid indication of its resistance to the penetration of fluids and
C42/C42M Test Method for Obtaining and Testing Drilled
dissolved aggressive ions.
Cores and Sawed Beams of Concrete
1.2 The values stated in SI units are to be regarded as the
C125 Terminology Relating to Concrete and Concrete Ag-
standard. No other units of measurement are included in this
gregates
standard. If required results obtained from another standard are
C192/C192M Practice for Making and Curing Concrete Test
not reported in the same system of units as used by this
Specimens in the Laboratory
standard, it is permitted to convert those results using the
C670 Practice for Preparing Precision and Bias Statements
conversion factors found in the SI Quick Reference Guide.
for Test Methods for Construction Materials
1.3 The text of this standard references notes and footnotes C1202 Test Method for Electrical Indication of Concrete’s
Ability to Resist Chloride Ion Penetration
that provide explanatory material. These notes and footnotes
(excluding those in tables and figures) shall not be considered C1556 Test Method for Determining the Apparent Chloride
Diffusion Coefficient of Cementitious Mixtures by Bulk
as requirements of this standard.
Diffusion
1.4 This standard does not purport to address all of the
C1760 Test Method for Bulk Electrical Conductivity of
safety concerns, if any, associated with its use. It is the
Hardened Concrete (Withdrawn 2021)
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
3. Terminology
mine the applicability of regulatory limitations prior to use.
3.1 Definitions:
(Warning—Fresh hydraulic cementitious mixtures are caustic
3.1.1 For definitions of terms used in this standard, refer to
and may cause chemical burns to skin and tissue upon
3 Terminology C125.
prolonged exposure.) For specific warning statement see
3.2 Definitions of Terms Specific to This Standard:
8.1.2.
3.2.1 bulk electrical resistivity, n—material property that
1.5 This international standard was developed in accor-
quantifies how strongly the material opposes the flow of
dance with internationally recognized principles on standard-
electrical charge when an electric field is applied using
ization established in the Decision on Principles for the
electrodes placed on opposite faces of a test specimen; mea-
Development of International Standards, Guides and Recom-
sured in units of ohm-meter.
mendations issued by the World Trade Organization Technical
3.2.2 bulk electrical conductivity, n—material property that
Barriers to Trade (TBT) Committee.
quantifies how strongly the material permits the flow of
electrical charge when an electric field is applied using
electrodes placed on opposite faces of a test specimen; mea-
This test method is under the jurisdiction of ASTM Committee C09 on
sured in units of milli-siemens per meter (mS/m).
Concrete and Concrete Aggregates and is the direct responsibility of Subcommittee
C09.66 on Concrete’s Resistance to Fluid Penetration.
Current edition approved Jan. 1, 2024. Published February 2024. Originally
approved in 2019. Last previous edition approved 2023 as C1876–23. DOI: For referenced ASTM standards, visit the ASTM website, www.astm.org, or
10.1520/C1876-24 contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Annex A in Form and Style for ASTM Standards, www.astm.org/COMMIT/ Standards volume information, refer to the standard’s Document Summary page on
Blue_Book.pdf. the ASTM website.
3 5
Section on Safety Precautions, Manual of Aggregate and Concrete Testing, The last approved version of this historical standard is referenced on
Annual Book of ASTM Standards, Vol. 04.02. www.astm.org.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1876 − 24
3.2.2.1 Discussion—Bulk electrical conductivity is the re- Method C1202 (1, 2, 3). Bulk electrical resistivity results have
ciprocal of bulk electrical resistivity. shown good correlation with bulk diffusion determined using
Test Method C1556 on companion molded cylinders from the
4. Summary of Test Method same concrete mixtures (4).
4.1 The electrical resistance or conductance of a hardened
6. Interferences
concrete cylindrical specimen conditioned in accordance with
6.1 If this test method is used to compare different concrete
this test method is determined on at least two specimens
mixtures, the results can be misleading if certain admixtures
obtained from cores or cast in cylindrical molds, the ends are
containing water-soluble ionic compounds, such as calcium
prepared, the dimensions measured, and then submerged in a
nitrite and calcium nitrate, are present in one of the concrete
simulated pore solution for at least 6 days, or from time of
mixtures. Chemical admixtures such as calcium nitrite can
demolding in the case of molded cylinders. While the specimen
contribute to a lower electrical resistivity because they increase
is in the solution, the bulk resistivity or conductivity test device
the conductivity of the pore solution (Note 1). This effect can
is verified over the expected range of resistivity or conductiv-
be independent of the overall quality of the concrete because it
ity. Then the specimen is placed in the test device. In some
has been shown in long-term bulk diffusion tests that concretes
testing apparatus, the voltage and current are measured such
with calcium nitrite can perform as well as control mixtures
that the resistivity or conductivity can then be calculated. In
without the admixture and lower conductivity.
other testing apparatus, the resistivity or conductivity is calcu-
lated directly once specimen dimensions are input. NOTE 1—Similarly, other admixtures containing water-soluble ionic
compounds might affect the results of this test method. Long-term
chloride ion diffusion tests are recommended if an admixture effect is
5. Significance and Use
suspected. Alternately, this interference can be minimized by expressing
results as a formation factor (see Appendix X1).
5.1 The electrical resistivity of a concrete is the opposition
6.2 Because the test results are a function of the electrical
to the movement of ions under an applied electric field. The
electrical conductivity of a concrete is a measure of how resistance or conductance of the specimen, the presence of
reinforcing steel, metal fibers, or other embedded electrically
readily the ions in the pore solution can be transported through
conductive materials, including some types of aggregates, may
the concrete under an applied electric field (the higher the
yield unrepresentative results, as these will result in higher
conductivity, the greater the rate of transport). The electrical
conductivity than a concrete of similar quality but with no
resistivity or conductivity is a material property that depends
embedded conductive material. The test is not applicable to
upon the pore volume, the pore structure (size and
specimens containing reinforcing steel positioned longitudi-
connectivity), the pore solution composition, the degree of
nally that provide a continuous electrical path between the two
saturation of the concrete specimen, and the specimen’s tem-
ends of the specimen, and it is not applicable to specimens
perature. Concrete mixture characteristics that are known to
containing discrete metallic fibers.
affect concrete electrical resistivity, as well as resistance to
chloride ion penetration, include water-cementitious materials
6.3 Leaching of ions from the pore solution of concrete is
ratio, pozzolans, slag cement, the presence of polymeric
known to affect measured resistivity or conductivity values.
admixtures, air-entrainment, aggregate type, aggregate volume
Even standard curing in water saturated with calcium hydrox-
fraction, degree of consolidation, curing method, and age.
ide can influence the resistivity of the solution inside the pores
of the concrete as potassium and sodium hydroxides are
5.2 The bulk electrical resistivity of concrete is the inverse
leached out. As such, concrete cylinders and cores are im-
of its bulk electrical conductivity. Bulk electrical conductivity
mersed in simulated pore solution for at least 6 days prior to
can also be measured by Test Method C1760, which uses the
testing.
apparatus described in Test Method C1202. This test method,
however, uses apparatus specifically designed to measure bulk
6.4 The level of saturation of the concrete has a major
conductivity or bulk resistivity.
impact on resistivity or conductivity because the electric
current is mainly conducted through the liquid in the pores.
5.3 The purpose of conditioning in a simulated pore solution
Achieving full saturation is difficult, so while not perfect, the
is to bring the specimen to a level of near complete saturation
conditioning procedures used in this test method provide a
of the capillary and gel pores. When comparing two different
methodology for achieving a high and reproducible level of
concrete specimens, it is important to condition both specimens
saturation without allowing excessive leaching of alkalis.
as close as possible to a comparable saturation state, using the
6.5 Because concrete has a capacitive component, its elec-
same solution for conditioning, so that values can be compared
trical response is characterized by a magnitude and a phase
in a meaningful way. This is particularly true for using the
difference that is a function of the AC frequency. This may
measured resistivity or conductivity, along with other
have an effect on the measured test result. The desired quantity
information, to estimate the diffusivity.
is the magnitude of the impedance that is measured at the
5.4 The bulk electrical resistivity or conductivity of con-
frequency that yields the minimum phase difference between
crete can provide a rapid indication of its resistance to chloride
ion penetration and resistance to penetration of other fluids.
Resistivity or conductivity measurements have shown good
The boldface numbers in parentheses refer to the list of references at the end of
correlations with other electrical indication tests including Test this standard.
C1876 − 24
the applied voltage and the measured current; that is, the 7.6 Specimen Holder, for tests to be conducted horizontally,
system is behaving most like a resistor. A number of commer- sufficiently large enough to support the cylindrical specimen
cial devices operate at a single fixed frequency, typically during testing. The specimen holder shall be made of rigid
between 10 Hz and 1 kHz. The degree to which a limited plastic or other similar electrically non-conductive material.
frequency range impacts the result has been found to be no
NOTE 5—Two vertically oriented V-notch plates fixed to a base plate
more than 5 % (5).
provides a suitable specimen holder.
6.6 Electrical resistivity or conductivity is temperature
7.7 Non-Electrically Conductive Surface, for tests to be
dependent, so perform all tests on concrete specimens condi-
conducted vertically, such as a rubber or plastic base or mat of
tioned within 62 ºC (5, 6).
at least 3 mm thickness and having a cross-sectional area larger
than that of the plate electrodes. The test device is placed on
6.7 The thin sponges, saturated with conductive fluid, that
top of this non-conductive mat or base.
connect the test specimen to the plate electrodes, can provide a
small amount of resistance (7). However, if both electrodes are
7.8 Ruler, 300 mm to 380 mm in length divided into 1 mm
clamped tightly to the test specimen, the resistance is minimal
graduations.
and can be neglected.
7.9 Saw, for trimming ends of cores. The saw shall have a
diamond or silicon-carbide cutting edge and shall be capable of
7. Apparatus
cutting cores without introducing cracks or dislodging aggre-
7.1 Bulk Resistivity or Conductivity Test Device, capable of
gate particles.
supplying an ac voltage across the entire cross-section of the
specimen, measuring the current passing through the specimen
8. Reagents and Materials
to three significant digits, and measuring the voltage drop
8.1 Simulated Pore Solution Saturated with Calcium
across the ends of the specimen to three significant digits. The
Hydroxide—Add 7.6 g of dry NaOH, 10.64 g of dry KOH, and
test device shall meet the verification requirements in Section
2.0 g of dry Ca(OH) to a 1 L container and add deionized
11. 2
water to the 1 L mark. Use reagent grade chemicals conforming
NOTE 2—Several test devices are commercially available, but the
to the specifications of the Committee on Analytical Reagents
voltage, frequency, and wave form used are different with each device.
of the American Chemical Society where such specifications
Some devices display resistivity or conductivity based directly on speci-
are available.
men geometry while others may display the electrical resistance of the
specimen. In this test method, different devices may be used as long as
NOTE 6—Sufficient solution can be made in an 18 to 20 L bucket using
they meet the verification requirements in Section 11.
13 250 g deionized water, 102.6 g NaOH, 143.9 g KOH, and 27 g
7.2 Stainless Steel Electrically Conductive Plate Electrodes,
Ca(OH) . No correction for purity of reagents is made.
NOTE 7—This simulated pore solution has been found to minimize the
made with at least the same nominal diameter (Note 3) as the
potential for leaching of alkalis and calcium hydroxide from the test
ends of the specimens to be tested and between 6 mm and 8
specimens and minimize changes to the electrical conductivity of the pore
mm thick. Plate electrodes shall be fitted with connectors that
solution. The conductivity and resistivity of this pore solution has been
allow connection to the electrical cables. Plate electrodes are
found to be 7874 mS/m and 0.127 ohm-m, respectively. Compositions and
permitted to be larger than the specimen diameter or cross- conductivities of pore solutions in different concretes and at different ages
will vary but it is not practical to match pore solution compositions to
section.
those of each concrete being tested.
NOTE 3—Rectangular specimens, such as cubes or prisms, may also be
8.1.1 Bring the simulated pore solution to room temperature
measured using electrodes of at least the same size as the cross-section to
prior to use.
be tested.
8.1.2 Warning—Before using NaOH and KOH, review the
7.3 Electrical Cables, for connecting the plate electrodes to
following: (1) the safety precautions for using NaOH and
the test device. Two insulated cables or one insulated cable
KOH; (2) first aid for burns; and (3) the emergency response to
with two conductors made of 18 AWG stranded copper wire
spills, as described in the manufacturer’s Material Safety Data
have been found to be satisfactory. The ends of the cables shall
Sheets or other reliable safety literature. NaOH and KOH as
be suitable for connecting to the test device and the plate
well as solutions made with them can cause very severe burns
electrodes.
and injury to unprotected skin and eyes. Suitable personal
7.4 Set of Verification Resistors, including at least two
protective equipment should always be used when making the
precision resistors, with tolerances no greater than 60.1 % of
solution and when placing and removing specimens from the
their nominal value, that cover the potential range of resistivity
pore solution. These should include full-face shields, rubber
values for the concrete mixtures to be tested. Use of a
aprons, and gloves impervious to NaOH and KOH. Gloves
cylindrical verification cell containing multiple precision
should be checked periodically for pin holes.
resistors, such as provided by some equipment suppliers, is
also suitable for this purpose.
NOTE 4—It is recommended that the precision resistors cover the range
Reagent Chemicals, American Chemical Society Specifications, American
from 100 ohm to 100 kohm.
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
listed by the American Chemical Society, see Analar Standards for Laboratory
7.5 Sponges, or other alkali-resistant absorbent material
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
with at least the same dimensions as the cross-sections of the
and National Formulary, U.S. Pharmacopeial Convention,Inc. (USPC), Rockville,
ends of the test specimen. MD.
C1876 − 24
8.2 Conductive Fluid—An electrically conductive liquid is 35 mm to 40 mm of solution (Note 9). The simulated pore
applied to sponges and each electrode to ensure electrical solution shall be maintained at a temperat
...

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: C1876 − 23 C1876 − 24
Standard Test Method for
Bulk Electrical Resistivity or Bulk Conductivity of Concrete
This standard is issued under the fixed designation C1876; 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 determination of the bulk electrical resistivity or conductivity of molded specimens or cored
sections of hardened concrete after immersion in water saturated with a simulated pore solution in order to provide a rapid
indication of its resistance to the penetration of fluids and dissolved aggressive ions.
1.2 The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard.
If required results obtained from another standard are not reported in the same system of units as used by this standard, it is
permitted to convert those results using the conversion factors found in the SI Quick Reference Guide.
1.3 The text of this standard references notes and footnotes that provide explanatory material. These notes and footnotes
(excluding those in tables and figures) shall not be considered as requirements of this standard.
1.4 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. (Warning—Fresh hydraulic cementitious mixtures are caustic and may cause chemical burns
to skin and tissue upon prolonged exposure.) For specific warning statement see 8.1.2.
1.5 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
2.1 ASTM Standards:
C31/C31M Practice for Making and Curing Concrete Test Specimens in the Field
C39/C39M Test Method for Compressive Strength of Cylindrical Concrete Specimens
C42/C42M Test Method for Obtaining and Testing Drilled Cores and Sawed Beams of Concrete
C125 Terminology Relating to Concrete and Concrete Aggregates
C192/C192M Practice for Making and Curing Concrete Test Specimens in the Laboratory
C670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
C1202 Test Method for Electrical Indication of Concrete’s Ability to Resist Chloride Ion Penetration
C1556 Test Method for Determining the Apparent Chloride Diffusion Coefficient of Cementitious Mixtures by Bulk Diffusion
This test method is under the jurisdiction of ASTM Committee C09 on Concrete and Concrete Aggregates and is the direct responsibility of Subcommittee C09.66 on
Concrete’s Resistance to Fluid Penetration.
Current edition approved Dec. 1, 2023Jan. 1, 2024. Published December 2023February 2024. Originally approved in 2019. Last previous edition approved 20192023 as
C1876–19. DOI: 10.1520/C1876-23–23. DOI: 10.1520/C1876-24
Annex A in Form and Style for ASTM Standards, www.astm.org/COMMIT/Blue_Book.pdf.
Section on Safety Precautions, Manual of Aggregate and Concrete Testing, Annual Book of ASTM Standards, Vol. 04.02.
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.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1876 − 24
C1760 Test Method for Bulk Electrical Conductivity of Hardened Concrete (Withdrawn 2021)
3. Terminology
3.1 Definitions:
3.1.1 For definitions of terms used in this standard, refer to Terminology C125.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 bulk electrical resistivity, n—material property that quantifies how strongly the material opposes the flow of electrical charge
when an electric field is applied using electrodes placed on opposite faces of a test specimen; measured in units of ohm-meter.
3.2.2 bulk electrical conductivity, n—material property that quantifies how strongly the material permits the flow of electrical
charge when an electric field is applied using electrodes placed on opposite faces of a test specimen; measured in units of
milli-siemens per meter (mS/m).
3.2.2.1 Discussion—
Bulk electrical conductivity is the reciprocal of bulk electrical resistivity.
4. Summary of Test Method
4.1 The electrical resistance or conductance of a hardened concrete cylindrical specimen conditioned in accordance with this test
method is determined on at least two specimens obtained from cores or cast in cylindrical molds, the ends are prepared, the
dimensions measured, and then submerged in a simulated pore solution for at least 6 days, or from time of demolding in the case
of molded cylinders. While the specimen is in the solution, the bulk resistivity or conductivity test device is verified over the
expected range of resistivity or conductivity. Then the specimen is placed in the test device. In some testing apparatus, the voltage
and current are measured such that the resistivity or conductivity can then be calculated. In other testing apparatus, the resistivity
or conductivity is calculated directly once specimen dimensions are input.
5. Significance and Use
5.1 The electrical resistivity of a concrete is the opposition to the movement of ions under an applied electric field. The electrical
conductivity of a concrete is a measure of how readily the ions in the pore solution can be transported through the concrete under
an applied electric field (the higher the conductivity, the greater the rate of transport). The electrical resistivity or conductivity is
a material property that depends upon the pore volume, the pore structure (size and connectivity), the pore solution composition,
the degree of saturation of the concrete specimen, and the specimen’s temperature. Concrete mixture characteristics that are known
to affect concrete electrical resistivity, as well as resistance to chloride ion penetration, include water-cementitious materials ratio,
pozzolans, slag cement, the presence of polymeric admixtures, air-entrainment, aggregate type, aggregate volume fraction, degree
of consolidation, curing method, and age.
5.2 The bulk electrical resistivity of concrete is the inverse of its bulk electrical conductivity. Bulk electrical conductivity can also
be measured by Test Method C1760, which uses the apparatus described in Test Method C1202. This test method, however, uses
apparatus specifically designed to measure bulk conductivity or bulk resistivity.
5.3 The purpose of conditioning in a simulated pore solution is to bring the specimen to a level of near complete saturation of the
capillary and gel pores. When comparing two different concrete specimens, it is important to condition both specimens as close
as possible to a comparable saturation state, using the same solution for conditioning, so that values can be compared in a
meaningful way. This is particularly true for using the measured resistivity or conductivity, along with other information, to
estimate the diffusivity.
5.4 The bulk electrical resistivity or conductivity of concrete can provide a rapid indication of its resistance to chloride ion
penetration and resistance to penetration of other fluids. Resistivity or conductivity measurements have shown good correlations
with other electrical indication tests including Test Method C1202 (1, 2, 3). Bulk electrical resistivity results have shown good
correlation with bulk diffusion determined using Test Method C1556 on companion molded cylinders from the same concrete
mixtures (4).
The last approved version of this historical standard is referenced on www.astm.org.
The boldface numbers in parentheses refer to the list of references at the end of this standard.
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6. Interferences
6.1 If this test method is used to compare different concrete mixtures, the results can be misleading if certain admixtures
containing water-soluble ionic compounds, such as calcium nitrite and calcium nitrate, are present in one of the concrete mixtures.
Chemical admixtures such as calcium nitrite can contribute to a lower electrical resistivity because they increase the conductivity
of the pore solution (Note 1). This effect can be independent of the overall quality of the concrete because it has been shown in
long-term bulk diffusion tests that concretes with calcium nitrite can perform as well as control mixtures without the admixture
and lower conductivity.
NOTE 1—Similarly, other admixtures containing water-soluble ionic compounds might affect the results of this test method. Long-term chloride ion
diffusion tests are recommended if an admixture effect is suspected. Alternately, this interference can be minimized by expressing results as a formation
factor (see Appendix X1).
6.2 Because the test results are a function of the electrical resistance or conductance of the specimen, the presence of reinforcing
steel, metal fibers, or other embedded electrically conductive materials, including some types of aggregates, may yield
unrepresentative results, as these will result in higher conductivity than a concrete of similar quality but with no embedded
conductive material. The test is not applicable to specimens containing reinforcing steel positioned longitudinally that provide a
continuous electrical path between the two ends of the specimen, and it is not applicable to specimens containing discrete metallic
fibers.
6.3 Leaching of ions from the pore solution of concrete is known to affect measured resistivity or conductivity values. Even
standard curing in water saturated with calcium hydroxide can influence the resistivity of the solution inside the pores of the
concrete as potassium and sodium hydroxides are leached out. As such, concrete cylinders and cores are immersed in simulated
pore solution for at least 6 days prior to testing.
6.4 The level of saturation of the concrete has a major impact on resistivity or conductivity because the electric current is mainly
conducted through the liquid in the pores. Achieving full saturation is difficult, so while not perfect, the conditioning procedures
used in this test method provide a methodology for achieving a high and reproducible level of saturation without allowing
excessive leaching of alkalis.
6.5 Because concrete has a capacitive component, its electrical response is characterized by a magnitude and a phase difference
that is a function of the AC frequency. This may have an effect on the measured test result. The desired quantity is the magnitude
of the impedance that is measured at the frequency that yields the minimum phase difference between the applied voltage and the
measured current; that is, the system is behaving most like a resistor. A number of commercial devices operate at a single fixed
frequency, typically between 10 Hz and 1 kHz. The degree to which a limited frequency range impacts the result has been found
to be no more than 5 % (5).
6.6 Electrical resistivity or conductivity is temperature dependent, so perform all tests on concrete specimens conditioned within
62 ºC (5, 6).
6.7 The thin sponges, saturated with conductive fluid, that connect the test specimen to the plate electrodes, can provide a small
amount of resistance (7). However, if both electrodes are clamped tightly to the test specimen, the resistance is minimal and can
be neglected.
7. Apparatus
7.1 Bulk Resistivity or Conductivity Test Device, capable of supplying an ac voltage across the entire cross-section of the specimen,
measuring the current passing through the specimen to three significant digits, and measuring the voltage drop across the ends of
the specimen to three significant digits. The test device shall meet the verification requirements in Section 11.
NOTE 2—Several test devices are commercially available, but the voltage, frequency, and wave form used are different with each device. Some devices
display resistivity or conductivity based directly on specimen geometry while others may display the electrical resistance of the specimen. In this test
method, different devices may be used as long as they meet the verification requirements in Section 11.
7.2 Stainless Steel Electrically Conductive Plate Electrodes, made with at least the same nominal diameter (Note 3) as the ends
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of the specimens to be tested and between 6 mm and 8 mm thick. Plate electrodes shall be fitted with connectors that allow
connection to the electrical cables. Plate electrodes are permitted to be larger than the specimen diameter or cross-section.
NOTE 3—Rectangular specimens, such as cubes or prisms, may also be measured using electrodes of at least the same size as the cross-section to be tested.
7.3 Electrical Cables, for connecting the plate electrodes to the test device. Two insulated cables or one insulated cable with two
conductors made of 18 AWG stranded copper wire have been found to be satisfactory. The ends of the cables shall be suitable for
connecting to the test device and the plate electrodes.
7.4 Set of Verification Resistors, including at least two precision resistors, with tolerances no greater than 60.1 % of their nominal
value, that cover the potential range of resistivity values for the concrete mixtures to be tested. Use of a cylindrical verification
cell containing multiple precision resistors, such as provided by some equipment suppliers, is also suitable for this purpose.
NOTE 4—It is recommended that the precision resistors cover the range from 100 ohm to 100 kohm.
7.5 Sponges, or other alkali-resistant absorbent material with at least the same dimensions as the cross-sections of the ends of the
test specimen.
7.6 Specimen Holder, for tests to be conducted horizontally, sufficiently large enough to support the cylindrical specimen during
testing. The specimen holder shall be made of rigid plastic or other similar electrically non-conductive material.
NOTE 5—Two vertically oriented V-notch plates fixed to a base plate provides a suitable specimen holder.
7.7 Non-Electrically Conductive Surface, for tests to be conducted vertically, such as a rubber or plastic base or mat of at least
3 mm thickness and having a cross-sectional area larger than that of the plate electrodes. The test device is placed on top of this
non-conductive mat or base.
7.8 Ruler, 300 mm to 380 mm in length divided into 1 mm graduations.
7.9 Saw, for trimming ends of cores. The saw shall have a diamond or silicon-carbide cutting edge and shall be capable of cutting
cores without introducing cracks or dislodging aggregate particles.
8. Reagents and Materials
8.1 Simulated Pore Solution Saturated with Calcium Hydroxide—Add 7.6 g of dry NaOH, 10.64 g of dry KOH, and 2.0 g of dry
Ca(OH) to a 1 L container and add deionized water to the 1 L mark. Use reagent grade chemicals conforming to the specifications
of the Committee on Analytical Reagents of the American Chemical Society where such specifications are available.
NOTE 6—Sufficient solution can be made in an 18 to 20 L bucket using 13 250 g deionized water, 102.6 g NaOH, 143.9 g KOH, and 27 g Ca(OH) . No
correction for purity of reagents is made.
NOTE 7—This simulated pore solution has been found to minimize the potential for leaching of alkalis and calcium hydroxide from the test specimens
and minimize changes to the electrical conductivity of the pore solution. The conductivity and resistivity of this pore solution has been found to be 7874
mS/m and 0.127 ohm-m, respectively. Compositions and conductivities of pore solutions in different concretes and at different ages will vary but it is
not practical to match pore solution compositions to those of each concrete being tested.
8.1.1 Bring the simulated pore solution to room temperature prior to use.
8.1.2 Warning—Before using NaOH and KOH, review the following: (1) the safety precautions for using NaOH and KOH; (2)
first aid for burns; and (3) the emergency response to spills, as described in the manufacturer’s Material Safety Data Sheets or other
reliable safety literature. NaOH and KOH as well as solutions made with them can cause very severe burns and injury to
unprotected skin and eyes. Suitable personal protective equipment should always be used when making the solution and when
Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by
the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National
Formulary, U.S. Pharmacopeial Convention,Inc. (USPC), Rockville, MD.
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placing and removing specimens from the pore solution. These should include full-face shields, rubber aprons, and gloves
impervious to NaOH and KOH. Gloves should be checked periodically for pin holes.
8.2 Conductive Fluid—An electrically conductive liquid is applied to sponges and each electrode to ensure electrical contact with
the surface of the concrete. Follow the apparatus manufacturer’s instructions regarding the composition and use of a conductive
fluid.
NOTE 8—Water saturated with respect to calcium hydroxide has been found to be a suitable conductive fluid for saturating the sponges. Alternatively, the
simulated pore solution described in 8.1, or a conductive fluid supplied by the manufacturer of the equipment is also suitable. The use of distilled or
deionized water is not recommended due to its low electrical conductivity. Tap water may be acceptable, if determined to
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