ASTM C1556-11a(2016)
(Test Method)Standard Test Method for Determining the Apparent Chloride Diffusion Coefficient of Cementitious Mixtures by Bulk Diffusion
Standard Test Method for Determining the Apparent Chloride Diffusion Coefficient of Cementitious Mixtures by Bulk Diffusion
SIGNIFICANCE AND USE
5.1 This test method is applicable to cementitious mixtures that have not been exposed to external chloride ions, other than the negligible quantity of chloride ion exposure from sample preparation using potable water, prior to the test.
5.2 The calculation procedure described in this test method is applicable only to laboratory test specimens exposed to a sodium chloride solution as described in this test method. This calculation procedure is not applicable to specimens exposed to chloride ions during cyclic wetting and drying.
Note 1: The diffusion of ionic species in concrete occurs within the fluid-filled pores, cracks and void spaces. The concentration and valence of other ionic species in the pore fluid also influence the rate of chloride diffusion, and therefore, the apparent diffusion coefficient as determined by this test procedure.
5.3 In most cases, the value of the apparent chloride diffusion coefficient for cementitious mixtures changes over time (see Note 2). Therefore, apparent diffusion coefficients obtained at early ages may not be representative of performance in service.
Note 2: The rate of change of the apparent diffusion coefficient for cementitious mixtures containing pozzolans or blast-furnace slag is typically different than that for mixtures containing only portland cement.
5.4 The apparent chloride diffusion coefficient is used in Fick's second law of diffusion to estimate chloride penetration into cementitious mixtures that are in a saturated condition.
5.5 The apparent chloride diffusion coefficient is commonly used in chloride ingress models based on Fick's second law of diffusion. The apparent diffusion coefficient determined by this method includes bound chloride, so proper use of the apparent chloride diffusion coefficient to predict chloride ingress requires consideration of chloride binding.
5.6 The resistance to chloride penetration is affected by such factors as the environment, finishing, mixture composition, w...
SCOPE
1.1 This test method covers the laboratory determination of the apparent chloride diffusion coefficient for hardened cementitious mixtures.
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.
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Designation: C1556 − 11a (Reapproved 2016)
Standard Test Method for
Determining the Apparent Chloride Diffusion Coefficient of
Cementitious Mixtures by Bulk Diffusion
This standard is issued under the fixed designation C1556; 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.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* 2.2 NORDTEST Standards:
NT BUILD 443Approved 1995-11, Concrete, Hardened:
1.1 This test method covers the laboratory determination of
Accelerated Chloride Penetration (in English)
theapparentchloridediffusioncoefficientforhardenedcemen-
titious mixtures.
3. Terminology
1.2 The values stated in SI units are to be regarded as
3.1 Definitions:
standard. No other units of measurement are included in this
3.1.1 For definitions of terms used in this test method, refer
standard.
to Terminology C125.
1.3 This standard does not purport to address all of the
3.2 Definitions of Terms Specific to This Standard:
safety concerns, if any, associated with its use. It is the
3.2.1 apparent chloride diffusion coeffıcient, D,n—a chlo-
a
responsibility of the user of this standard to establish appro-
ride transport parameter calculated from acid-soluble chloride
priate safety and health practices and determine the applica-
profile data obtained from saturated specimens exposed to
bility of regulatory limitations prior to use.
chloridesolutions,withoutcorrectionforchloridebinding,that
provides an indication of the ease of chloride penetration into
2. Referenced Documents
cementitious mixtures.
2.1 ASTM Standards:
3.2.2 chloride binding, v—the chemical process by which
C31/C31MPractice for Making and Curing Concrete Test
chloride ion is removed from solution and incorporated into
Specimens in the Field
cementitious binder hydration products.
C42/C42MTest Method for Obtaining and Testing Drilled
3.2.2.1 Discussion—Chloride binding is primarily associ-
Cores and Sawed Beams of Concrete
ated with hydration products formed by the aluminate phase of
C125Terminology Relating to Concrete and Concrete Ag-
cement and mixtures containing ground granulated blast fur-
gregates
nace slag.
C192/C192MPractice for Making and Curing ConcreteTest
3.2.3 chloride penetration, v—the ingress of chloride ions
Specimens in the Laboratory
due to exposure to external sources.
C670Practice for Preparing Precision and Bias Statements
for Test Methods for Construction Materials 3.2.4 exposure liquid, n—the sodium chloride solution in
C1152/C1152MTest Method for Acid-Soluble Chloride in which test specimens are stored prior to obtaining a chloride
profile.
Mortar and Concrete
C1202Test Method for Electrical Indication of Concrete’s
3.2.5 exposure time, n—the time that the test specimen is
Ability to Resist Chloride Ion Penetration
stored in the solution containing chloride ion.
3.2.6 initial chloride-ion content, C ,n—the ratio of the
i
massofchlorideiontothemassofconcreteforatestspecimen
This test method is under the jurisdiction of ASTM Committee C09 on
Concrete and ConcreteAggregatesand is the direct responsibility of Subcommittee
that has not been exposed to external chloride sources.
C09.66 on Concrete’s Resistance to Fluid Penetration.
3.2.7 profile grinding, v—the process of grinding off and
Current edition approved April 1, 2016. Published May 2016. Originally
approved in 2003. Last previous edition approved in 2011 as C1556 – 11a. DOI: collectingapowdersampleinthinsuccessivelayersfromatest
10.1520/C1556-11AR16.
specimen using a dry process.
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 Published by NORDTEST, P.O. Box 116 FIN-02151 ESPOO Finland, Project
the ASTM website.
1154-94, e-mail: nordtest @vtt.fi, website: http://www.vtt.fi/nordtest
*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
C1556 − 11a (2016)
3.2.8 surface chloride content, C,n—thetheoreticalratioof 6. Apparatus
s
themassofchlorideiontothemassofconcreteattheinterface
6.1 Balance, accurate to at least 60.01 g.
between the exposure liquid and the test specimen.
6.2 Thermometer, accurate to at least 61.0 °C.
4. Summary of Test Method
6.3 Controlled Temperature Laboratory or Chamber. The
4.1 Obtain a representative sample of the cementitious laboratory or chamber shall maintain the temperature of a
mixturepriortoexposuretochlorideion.Separateeachsample
water bath at 23 6 2 °C.
into a test specimen and an initial chloride-ion content speci-
6.4 Plastic Container, with tight-fitting lid. Select a con-
men. Crush the initial chloride-ion content specimen and
tainer size in accordance with provisions in 9.1.2.
determine the initial acid-soluble chloride-ion content. Seal all
6.5 Equipment for grinding off and collecting powder from
sides of the test specimen, except the finished surface, with a
concrete,mortar,orgroutspecimensinlayersofapproximately
suitable barrier coating. Saturate the sealed specimen in a
2 mm thickness. Refer to Figs. 1 and 2 for examples of
calcium hydroxide solution, rinse with tap water, and then
satisfactory equipment (see Note 3).
place in a sodium chloride solution.After a specified exposure
NOTE 3—A lathe or milling machine equipped with a short-barrel
time, the test specimen is removed from the sodium chloride
carbide-tipped, or diamond-tipped, core drill bit has been found satisfac-
solution and thin layers are ground off parallel to the exposed
tory for profile grinding.
faceofthespecimen.Theacid-solublechloridecontentofeach
6.6 Resealable Polyethylene Bags,200-to300-mmwideby
layer is determined.The apparent chloride diffusion coefficient
250- to 300-mm long, and sheet thickness not less than 0.1
and the projected surface chloride-ion concentration are then
mm.
calculatedusingtheinitialchloride-ioncontent,andatleastsix
6.7 Equipment for crushing concrete, mortar or grout. Suit-
related values for chloride-ion content and depth below the
able equipment is described in Test Method C1152/C1152M.
exposed surface.
6.8 Equipment for chloride analysis as described in Test
5. Significance and Use
Method C1152/C1152M.
5.1 This test method is applicable to cementitious mixtures
6.9 Slide Caliper, accurate to at least 6 0.1 mm.
thathavenotbeenexposedtoexternalchlorideions,otherthan
the negligible quantity of chloride ion exposure from sample
7. Reagents and Materials
preparation using potable water, prior to the test.
7.1 Distilled or De-ionized Water.
5.2 The calculation procedure described in this test method
7.2 Calcium Hydroxide [Ca(OH) ], technical grade.
is applicable only to laboratory test specimens exposed to a
sodium chloride solution as described in this test method. This
7.3 Calcium Hydroxide Solution, saturated, (approx. 3 g/L).
calculationprocedureisnotapplicabletospecimensexposedto
7.4 Sodium Chloride [NaCl], technical grade.
chloride ions during cyclic wetting and drying.
7.5 Exposure Liquid—An aqueous NaCl solution prepared
NOTE 1—The diffusion of ionic species in concrete occurs within the
with a concentration of 165 6 1 g NaCl per L of solution.
fluid-filled pores, cracks and void spaces. The concentration and valence
of other ionic species in the pore fluid also influence the rate of chloride
7.6 Two-component Polyurethane or Epoxy-resin Based
diffusion, and therefore, the apparent diffusion coefficient as determined
Paint, capable of forming a barrier membrane that is resistant
by this test procedure.
to chloride ion diffusion.
5.3 In most cases, the value of the apparent chloride
diffusion coefficient for cementitious mixtures changes over
8. Test Specimens
time (see Note 2). Therefore, apparent diffusion coefficients
8.1 Drilled cores, molded cylinders, or molded cubes are
obtained at early ages may not be representative of perfor-
acceptable test specimens. One sample consists of at least two
mance in service.
test specimens representative of the cementitious mixture
NOTE 2—The rate of change of the apparent diffusion coefficient for
undertest(seeNote4).Specimensmustbefreeofdefectssuch
cementitious mixtures containing pozzolans or blast-furnace slag is
as voids or cracks visible to the unaided eye (see Note 5). The
typically different than that for mixtures containing only portland cement.
minimum dimension across the finished surface of each test
5.4 The apparent chloride diffusion coefficient is used in
specimen must be at least 75 mm, but not less than three times
Fick’s second law of diffusion to estimate chloride penetration
the nominal maximum aggregate particle size. The specimen
into cementitious mixtures that are in a saturated condition.
depth must be at least 75 mm.
5.5 The apparent chloride diffusion coefficient is commonly
NOTE 4—The material between the exposed surface and the outermost
used in chloride ingress models based on Fick’s second law of
layer of reinforcement is often of interest because it is here that the
diffusion.Theapparentdiffusioncoefficientdeterminedbythis protectionagainstchloridepenetrationisneeded.Furthermore,thequality
of the material in this particular area can deviate from that in the rest of
method includes bound chloride, so proper use of the apparent
the system, as this region is often affected by construction practices.
chloride diffusion coefficient to predict chloride ingress re-
NOTE 5—Specimens with voids deeper than the profile layer thickness
quires consideration of chloride binding.
can increase the apparent rate of chloride penetration, and increases test
variability.
5.6 Theresistancetochloridepenetrationisaffectedbysuch
factors as the environment, finishing, mixture composition, 8.2 Unless otherwise specified, provide 28 days of labora-
workmanship, curing, and age. tory standard moist curing in accordance with Practice C31/
C1556 − 11a (2016)
FIG. 1 Profile Grinding Using a Milling Machine
FIG. 2 Profile Grinding Using a Lathe
C31M or C192/C192M prior to sample preparation for immer- 8.3 For drilled cores obtained according to Test Method
sion in the exposure liquid.
C42/C42M, prepare the test specimen by cutting off the
8.2.1 Describe any variance from standard curing practice
outermost 75 mm of the core. The test specimen thus obtained
in the report.
C1556 − 11a (2016)
has one face that is the original finished surface, and the other blotthesurfacedrywithapapertowel,anddeterminethemass
face that is a sawn surface as shown in Fig. 3. of the specimen in the surface-dry condition.
8.4 For specimens prepared in accordance with Practice 8.10 The test specimen is immersed in a saturated calcium
C31/C31M or C192/C192M, the test specimen is prepared by hydroxide water bath until the mass does not change by more
cutting parallel to the finished surface. The top 75 mm is used than 0.1% in 24 h (see Note 7). An acceptable alternative
as the test specimen (see Fig. 3). procedure is to vacuum saturate the specimens with saturated
calciumhydroxidesolutionusingavacuumchambersimilarto
8.5 From the remainder of the drilled core, or molded
the system described in Test Method C1202.
specimen,cutaslicethatisatleast20-mmthick.Usethisslice
NOTE7—Typically,themassofmoist-curedspecimensstabilizeswithin
to determine the initial chloride-ion content, C either by
i
48 h.
crushingtheentiresliceorbygrindingoffalayeratleast2-mm
thick.Alternately,iftheprofilefromthediffusiontestspecimen
9. Procedure
is ground deep enough such that the last 2 successive layers
9.1 Exposure:
taken have chloride contents within 0.01 % by mass of
9.1.1 Remove the saturated test specimen from the calcium
concrete of each other, it is permitted to extrapolate the best-fit
hydroxide water bath, immediately rinse the specimen surface
equationofthechlorideprofiletoobtaintheinitialchloride-ion
with tap water, place the specimen in the exposure container,
content, C.
i
fill the container with the exposure liquid, and then seal the
8.6 Rinse the specimens with tap water immediately after
container. Place the container in a temperature-controlled
cutting. Scrub the surface with a stiff nylon brush, and rinse
chamberorroommaintainedat23 62°C.Recordthestartdate
again. Prior to sealing specimen surfaces, air dry until no
and start time to the nearest hour.
moisture can be removed from the surface with a dry paper
9.1.2 It is permitted to place multiple specimens in a single
towel (see Note 6).
container as long as the specimens are placed in the container
8.6.1 Exposure specimens must be surface-dry but inter-
such that the entire exposure surface is unobstructed. Maintain
nally moist prior to sealing. This condition is satisfied by
theexposedsurfaceareatoexposureliquidvolumeratiowithin
standard moist-cured specimens allowed to air dry for no more
the range of 50 6 30 cm /L (see Note 8).
than 24 h in laboratory air maintained at 23 6 2 °C and 50 6
NOTE 8—The volume of exposure liquid required for nominal 100-mm
3% RH.
diameter cylinder or core exposure specimens is approximately one liter
per specimen.
NOTE 6—Specimens cured in a saturated calcium hydroxide water bath
are normally covered by residual lime particles. If this residue is not
9.1.3 The specimens must remain in the exposure liquid for
removed and test specimens are allowed to temporarily dry in air, a
at least 35 days (see Note 9).
calcium carbonate layer can form on the surface of the specimen. This
carbonate layer may interfere with the test result, which is why cleansing
NOTE 9—The exposure time should be extended for mixtures such as
and rinsing with tap water after cutting or removal from the saturated
those that are more mature, were made with low w/cm, or high-
calcium hydroxide water bath is required.
performance mixtures containing supplementary cementitious materials.
8.7 Seal all sides of the exposure specimen except for the
9.1.4 If evaporation of water from the exposure liquid or a
finished surface following the procedure described in Test
container leak allows the specimen surface to dry during the
Method C1202.
exposure time, the test is not valid (see Note 10).
8.8 Determinetheinitialmassofthetestspecimenwhenthe
NOTE 10—It is suggested to monitor the mass of the sealed container if
coating has hardened.
evaporation of water from the exposure solution is expected.
8.9 Immerse the test specimen in the saturated calcium
9.1.5 Record t
...
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: C1556 − 11a C1556 − 11a (Reapproved 2016)
Standard Test Method for
Determining the Apparent Chloride Diffusion Coefficient of
Cementitious Mixtures by Bulk Diffusion
This standard is issued under the fixed designation C1556; 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 laboratory determination of the apparent chloride diffusion coefficient for hardened cementitious
mixtures.
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
2.1 ASTM Standards:
C31/C31M Practice for Making and Curing Concrete Test Specimens in the Field
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
C1152/C1152M Test Method for Acid-Soluble Chloride in Mortar and Concrete
C1202 Test Method for Electrical Indication of Concrete’s Ability to Resist Chloride Ion Penetration
2.2 NORDTEST Standards:
NT BUILD 443 Approved 1995-11, Concrete, Hardened: Accelerated Chloride Penetration (in English)
3. Terminology
3.1 Definitions:
3.1.1 For definitions of terms used in this test method, refer to Terminology C125.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 apparent chloride diffusion coeffıcient, D ,n—a chloride transport parameter calculated from acid-soluble chloride profile
a
data obtained from saturated specimens exposed to chloride solutions, without correction for chloride binding, that provides an
indication of the ease of chloride penetration into cementitious mixtures.
3.2.2 chloride binding, v—the chemical process by which chloride ion is removed from solution and incorporated into
cementitious binder hydration products.
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. 15, 2011April 1, 2016. Published January 2012May 2016. Originally approved in 2003. Last previous edition approved in 2011 as C1556
– 11.11a. DOI: 10.1520/C1556-11A.10.1520/C1556-11AR16.
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.
Published by NORDTEST, P.O. Box 116 FIN-02151 ESPOO Finland, Project 1154-94, e-mail: nordtest @vtt.fi, website: http://www.vtt.fi/nordtest
3.2.2.1 Discussion—
Chloride binding is primarily associated with hydration products formed by the aluminate phase of cement and mixtures containing
ground granulated blast furnace slag.
*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
C1556 − 11a (2016)
3.2.3 chloride penetration, v—the ingress of chloride ions due to exposure to external sources.
3.2.4 exposure liquid, n—the sodium chloride solution in which test specimens are stored prior to obtaining a chloride profile.
3.2.5 exposure time, n—the time that the test specimen is stored in the solution containing chloride ion.
3.2.6 initial chloride-ion content, C ,n—the ratio of the mass of chloride ion to the mass of concrete for a test specimen that
i
has not been exposed to external chloride sources.
3.2.7 profile grinding, v—the process of grinding off and collecting a powder sample in thin successive layers from a test
specimen using a dry process.
3.2.8 surface chloride content, C ,n—the theoretical ratio of the mass of chloride ion to the mass of concrete at the interface
s
between the exposure liquid and the test specimen.
4. Summary of Test Method
4.1 Obtain a representative sample of the cementitious mixture prior to exposure to chloride ion. Separate each sample into a
test specimen and an initial chloride-ion content specimen. Crush the initial chloride-ion content specimen and determine the initial
acid-soluble chloride-ion content. Seal all sides of the test specimen, except the finished surface, with a suitable barrier coating.
Saturate the sealed specimen in a calcium hydroxide solution, rinse with tap water, and then place in a sodium chloride solution.
After a specified exposure time, the test specimen is removed from the sodium chloride solution and thin layers are ground off
parallel to the exposed face of the specimen. The acid-soluble chloride content of each layer is determined. The apparent chloride
diffusion coefficient and the projected surface chloride-ion concentration are then calculated using the initial chloride-ion content,
and at least six related values for chloride-ion content and depth below the exposed surface.
5. Significance and Use
5.1 This test method is applicable to cementitious mixtures that have not been exposed to external chloride ions, other than the
negligible quantity of chloride ion exposure from sample preparation using potable water, prior to the test.
5.2 The calculation procedure described in this test method is applicable only to laboratory test specimens exposed to a sodium
chloride solution as described in this test method. This calculation procedure is not applicable to specimens exposed to chloride
ions during cyclic wetting and drying.
NOTE 1—The diffusion of ionic species in concrete occurs within the fluid-filled pores, cracks and void spaces. The concentration and valence of other
ionic species in the pore fluid also influence the rate of chloride diffusion, and therefore, the apparent diffusion coefficient as determined by this test
procedure.
5.3 In most cases, the value of the apparent chloride diffusion coefficient for cementitious mixtures changes over time (see Note
2). Therefore, apparent diffusion coefficients obtained at early ages may not be representative of performance in service.
NOTE 2—The rate of change of the apparent diffusion coefficient for cementitious mixtures containing pozzolans or blast-furnace slag is typically
different than that for mixtures containing only portland cement.
5.4 The apparent chloride diffusion coefficient is used in Fick’s second law of diffusion to estimate chloride penetration into
cementitious mixtures that are in a saturated condition.
5.5 The apparent chloride diffusion coefficient is commonly used in chloride ingress models based on Fick’s second law of
diffusion. The apparent diffusion coefficient determined by this method includes bound chloride, so proper use of the apparent
chloride diffusion coefficient to predict chloride ingress requires consideration of chloride binding.
5.6 The resistance to chloride penetration is affected by such factors as the environment, finishing, mixture composition,
workmanship, curing, and age.
6. Apparatus
6.1 Balance, accurate to at least 60.01 g.
6.2 Thermometer, accurate to at least 61.0 °C.
6.3 Controlled Temperature Laboratory or Chamber. The laboratory or chamber shall maintain the temperature of a water bath
at 23 6 2 °C.
6.4 Plastic Container, with tight-fitting lid. Select a container size in accordance with provisions in 9.1.2.
6.5 Equipment for grinding off and collecting powder from concrete, mortar, or grout specimens in layers of approximately 2
mm thickness. Refer to Figs. 1 and 2 for examples of satisfactory equipment (see Note 3).
NOTE 3—A lathe or milling machine equipped with a short-barrel carbide-tipped, or diamond-tipped, core drill bit has been found satisfactory for profile
grinding.
6.6 Resealable Polyethylene Bags, 200- to 300-mm wide by 250- to 300-mm long, and sheet thickness not less than 0.1 mm.
6.7 Equipment for crushing concrete, mortar or grout. Suitable equipment is described in Test Method C1152/C1152M.
6.8 Equipment for chloride analysis as described in Test Method C1152/C1152M.
C1556 − 11a (2016)
FIG. 1 Profile Grinding Using a Milling Machine
FIG. 2 Profile Grinding Using a Lathe
6.9 Slide Caliper, accurate to at least 6 0.1 mm.
7. Reagents and Materials
7.1 Distilled or De-ionized Water.
7.2 Calcium Hydroxide [Ca(OH) ], technical grade.
C1556 − 11a (2016)
7.3 Calcium Hydroxide Solution, saturated, (approx. 3 g/L).
7.4 Sodium Chloride [NaCl], technical grade.
7.5 Exposure Liquid—An aqueous NaCl solution prepared with a concentration of 165 6 1 g NaCl per L of solution.
7.6 Two-component Polyurethane or Epoxy-resin Based Paint, capable of forming a barrier membrane that is resistant to
chloride ion diffusion.
8. Test Specimens
8.1 Drilled cores, molded cylinders, or molded cubes are acceptable test specimens. One sample consists of at least two test
specimens representative of the cementitious mixture under test (see Note 4). Specimens must be free of defects such as voids or
cracks visible to the unaided eye (see Note 5). The minimum dimension across the finished surface of each test specimen must
be at least 75 mm, but not less than three times the nominal maximum aggregate particle size. The specimen depth must be at least
75 mm.
NOTE 4—The material between the exposed surface and the outermost layer of reinforcement is often of interest because it is here that the protection
against chloride penetration is needed. Furthermore, the quality of the material in this particular area can deviate from that in the rest of the system, as
this region is often affected by construction practices.
NOTE 5—Specimens with voids deeper than the profile layer thickness can increase the apparent rate of chloride penetration, and increases test
variability.
8.2 Unless otherwise specified, provide 28 days of laboratory standard moist curing in accordance with Practice C31/C31M or
C192/C192M prior to sample preparation for immersion in the exposure liquid.
8.2.1 Describe any variance from standard curing practice in the report.
8.3 For drilled cores obtained according to Test Method C42/C42M, prepare the test specimen by cutting off the outermost 75
mm of the core. The test specimen thus obtained has one face that is the original finished surface, and the other face that is a sawn
surface as shown in Fig. 3.
8.4 For specimens prepared in accordance with Practice C31/C31M or C192/C192M, the test specimen is prepared by cutting
parallel to the finished surface. The top 75 mm is used as the test specimen (see Fig. 3).
8.5 From the remainder of the drilled core, or molded specimen, cut a slice that is at least 20-mm thick. Use this slice to
determine the initial chloride-ion content, C either by crushing the entire slice or by grinding off a layer at least 2-mm thick.
i
Alternately, if the profile from the diffusion test specimen is ground deep enough such that the last 2 successive layers taken have
chloride contents within 0.01 % by mass of concrete of each other, it is permitted to extrapolate the best-fit equation of the chloride
profile to obtain the initial chloride-ion content, C .
i
8.6 Rinse the specimens with tap water immediately after cutting. Scrub the surface with a stiff nylon brush, and rinse again.
Prior to sealing specimen surfaces, air dry until no moisture can be removed from the surface with a dry paper towel (see Note
6).
8.6.1 Exposure specimens must be surface-dry but internally moist prior to sealing. This condition is satisfied by standard
moist-cured specimens allowed to air dry for no more than 24 h in laboratory air maintained at 23 6 2 °C and 50 6 3 % RH.
NOTE 6—Specimens cured in a saturated calcium hydroxide water bath are normally covered by residual lime particles. If this residue is not removed
and test specimens are allowed to temporarily dry in air, a calcium carbonate layer can form on the surface of the specimen. This carbonate layer may
interfere with the test result, which is why cleansing and rinsing with tap water after cutting or removal from the saturated calcium hydroxide water bath
is required.
8.7 Seal all sides of the exposure specimen except for the finished surface following the procedure described in Test Method
C1202.
8.8 Determine the initial mass of the test specimen when the coating has hardened.
FIG. 3 Sketch of Specimens Obtained from a Typical Sample
C1556 − 11a (2016)
8.9 Immerse the test specimen in the saturated calcium hydroxide water bath at 23 6 2°C in a tightly closed plastic container.
The container must be filled to the top to prevent carbonation. After 24 h of immersion, remove the specimen, blot the surface dry
with a paper towel, and determine the mass of the specimen in the surface-dry condition.
8.10 The test specimen is immersed in a saturated calcium hydroxide water bath until the mass does not change by more than
0.1 % in 24 h (see Note 7). An acceptable alternative procedure is to vacuum saturate the specimens with saturated calcium
hydroxide solution using a vacuum chamber similar to the system described in Test Method C1202.
NOTE 7—Typically, the mass of moist-cured specimens stabilizes within 48 h.
9. Procedure
9.1 Exposure:
9.1.1 Remove the saturated test specimen from the calcium hydroxide water bath, immediately rinse the specimen surface with
tap water, place the specimen in the exposure container, fill the container with the exposure liquid, and then seal the container. Place
the container in a temperature-controlled chamber or room maintained at 23 6 2°C. Record the start date and start time to the
nearest hour.
9.1.2 It is permitted to place multiple specimens in a single container as long as the specimens are placed in the container such
that the entire exposure surface is uno
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