ASTM C1556-03
(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
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 the 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: C 1556 – 03
Standard Test Method for
Determining the Apparent Chloride Diffusion Coefficient of
Cementitious Mixtures by Bulk Diffusion
This standard is issued under the fixed designation C 1556; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.1 For definitions of terms used in this test method, refer
to Terminology C 125.
1.1 This test method covers the laboratory determination of
3.2 Definitions of Terms Specific to This Standard:
the apparent chloride diffusion coefficient for hardened cemen-
3.2.1 apparent chloride diffusion coeffıcient, D , n—a chlo-
titious mixtures. a
ride transport parameter calculated from acid-soluble chloride
1.2 The values stated in SI units are to be regarded as the
profile data obtained from saturated specimens exposed to
standard.
chloride solutions, without correction for chloride binding, that
1.3 This standard does not purport to address all of the
provides an indication of the ease of chloride penetration into
safety concerns, if any, associated with its use. It is the
cementitious mixtures.
responsibility of the user of this standard to establish appro-
3.2.2 chloride binding, v—the chemical process by which
priate safety and health practices and determine the applica-
chloride ion is removed from solution and incorporated into
bility of regulatory limitations prior to use.
cementitious binder hydration products.
2. Referenced Documents
3.2.2.1 Discussion—Chloride binding is primarily associ-
ated with hydration products formed by the aluminate phase of
2.1 ASTM Standards:
cement and mixtures containing ground granulated blast fur-
C 31/C 31M Practice for Making and Curing Concrete Test
nace slag.
Specimens in the Field
3.2.3 chloride penetration, v—the ingress of chloride ions
C 42/C 42M Test Method for Obtaining and Testing Drilled
due to exposure to external sources.
Cores and Sawed Beams of Concrete
3.2.4 exposure liquid, n—the sodium chloride solution in
C 125 Terminology Relating to Concrete and Concrete
which test specimens are stored prior to obtaining a chloride
Aggregates
profile.
C 192/C 192M Practice for Making and Curing Concrete in
3.2.5 exposure time, n—the time that the test specimen is
the Laboratory
stored in the solution containing chloride ion.
C 670 Practice for Preparing Precision and Bias Statements
3.2.6 initial chloride-ion content, C , n—the ratio of the
for Test Methods for Construction Materials i
mass of chloride ion to the mass of concrete for a test specimen
C 1152/C 1152M Test Method for Acid-Soluble Chloride in
that has not been exposed to external chloride sources.
Mortar and Concrete
3.2.7 profile grinding, v—the process of grinding off and
C 1202 Test Method for Electrical Indication of Concrete’s
collecting a powder sample in thin successive layers from a test
Ability to Resist Chloride-ion Penetration
specimen using a dry process.
2.2 NORDTEST Standards:
3.2.8 surface chloride content, C , n—the theoretical ratio
NT BUILD 443, Approved 1995-11, Concrete, Hardened: s
of the mass of chloride ion to the mass of concrete at the
Accelerated Chloride Penetration (in English)
interface between the exposure liquid and the test specimen.
3. Terminology
4. Summary of Test Method
3.1 Definitions:
4.1 Obtain a representative sample of the cementitious
mixture prior to exposure to chloride ion. Separate each sample
1 into a test specimen and an initial chloride-ion content speci-
This test method is under the jurisdiction of ASTM Committee C09 on
men. Crush the initial chloride-ion content specimen and
Concrete and Concrete Aggregates and is the direct responsibility of Subcommittee
C09.66 on Concrete’s Resistance to Fluid Penetration.
determine the initial acid-soluble chloride-ion content. Seal all
Current edition approved Jan. 10, 2003. Published February 2003.
sides of the test specimen, except the finished surface, with a
Annual Book of ASTM Standards, Vol 04.02.
3 suitable barrier coating. Saturate the sealed specimen in a
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 calcium hydroxide solution, rinse with tap water, and then
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C1556–03
place in a sodium chloride solution. After a specified exposure 5.5 The apparent chloride diffusion coefficient is commonly
time, the test specimen is removed from the sodium chloride used in chloride ingress models based on Fick’s second law of
solution and thin layers are ground off parallel to the exposed diffusion. The apparent diffusion coefficient determined by this
face of the specimen. The acid-soluble chloride content of each method includes chemically bound chloride, so proper use of
layer is determined. The apparent chloride diffusion coefficient the apparent chloride diffusion coefficient to predict chloride
and the projected surface chloride-ion concentration are then ingress requires consideration of chloride binding.
calculated using the initial chloride-ion content, and at least six
5.6 The resistance to chloride penetration is affected by such
related values for chloride-ion content and depth below the factors as the environment, finishing, mixture composition,
exposed surface.
workmanship, curing, and age.
5. Significance and Use
6. Apparatus
5.1 This test method is applicable to cementitious mixtures
6.1 Balance, accurate to at least 60.01 g.
that have not been exposed to external chloride ions, other than
6.2 Thermometer, accurate to at least 61.0°C.
the negligible quantity of chloride ion exposure from sample
6.3 Controlled Temperature Laboratory or Chamber. The
preparation using potable water, prior to the test.
laboratory or chamber shall maintain the temperature of a
5.2 The calculation procedure described in this test method
water bath at 23 6 2°C.
is applicable only to laboratory test specimens exposed to a
6.4 Plastic Container, with tight-fitting lid. Select a con-
sodium chloride solution as described in this test method. This
tainer size in accordance with provisions in 9.1.2.
calculation procedure is not applicable to specimens exposed to
6.5 Equipment for grinding off and collecting powder from
cyclic wetting and drying.
concrete, mortar, or grout specimens in layers of approximately
5.3 In most cases, the value of the apparent chloride
2 mm thickness. Refer to Figs. 1 and 2 for examples of
diffusion coefficient for cementitious mixtures changes over
satisfactory equipment (see Note 2).
time (see Note 1). Therefore, apparent diffusion coefficients
obtained at early ages may not be representative of perfor-
NOTE 2—A lathe or milling machine equipped with a short-barrel
mance in service.
carbide-tipped, or diamond-tipped, core drill bit has been found satisfac-
tory for profile grinding.
NOTE 1—The rate of change of the apparent diffusion coefficient for
cementitious mixtures containing pozzolans or blast-furnace slag is
6.6 Resealable Polyethylene Bags, 200- to 300-mm wide by
typically different than that for mixtures containing only portland cement.
250- to 300-mm long, and sheet thickness not less than 0.1
mm.
5.4 The apparent chloride diffusion coefficient is used in
Fick’s second law of diffusion to estimate chloride penetration 6.7 Equipment for crushing concrete, mortar or grout. Suit-
into cementitious mixtures that are in a saturated condition. able equipment is described in Test Method C 1152/C 1152M.
FIG. 1 Profile Grinding Using a Milling Machine
C1556–03
FIG. 2 Profile Grinding Using a Lathe
6.8 Equipment for chloride analysis as described in Test 8.2 Unless otherwise specified, provide 28 days of labora-
Method C 1152/C 1152M. tory standard moist curing in accordance with Practice C 31/
6.9 Slide Caliper, accurate to at least 6 0.1 mm. C 31M or C 192/C 192M prior to sample preparation for
immersion in the exposure liquid.
7. Reagents and Materials 8.2.1 Describe any variance from standard curing practice
in the report.
7.1 Distilled or De-ionized Water.
8.3 For drilled cores obtained according to Test Method
7.2 Calcium Hydroxide [Ca(OH) ], technical grade.
C 42/C 42M, prepare the test specimen by cutting off the
7.3 Calcium Hydroxide Solution, saturated, (approx. 3 g/L).
outermost 75 mm of the core. The test specimen thus obtained
7.4 Sodium Chloride [NaCl], technical grade.
has one face that is the original finished surface, and the other
7.5 Exposure Liquid—An aqueous NaCl solution prepared
face that is a sawn surface as shown in Fig. 3.
with a concentration of 165 6 1 g NaCl per L of solution.
8.4 For specimens prepared in accordance with Practice
7.6 Two-component Polyurethane or Epoxy-resin Based
C 31/C 31M or C 192/C 192M, the test specimen is prepared
Paint, capable of forming a barrier membrane that is resistant
by cutting parallel to the finished surface. The top 75 mm is
to chloride ion diffusion.
used as the test specimen (see Fig. 3).
8.5 From the remainder of the drilled core, or molded
8. Test Specimens
specimen, cut a slice that is at least 20-mm thick. Use this slice
8.1 Drilled cores, molded cylinders, or molded cubes are
to determine the initial chloride-ion content, C .
i
acceptable test specimens. One sample consists of at least two
test specimens representative of the cementitious mixture
under test (see Note 3). Specimens must be free of defects such
as voids or cracks visible to the unaided eye (see Note 4). 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 3—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 4—Specimens with voids deeper than the profile layer thickness
can increase the apparent rate of chloride penetration, and increases test
variability. FIG. 3 Sketch of Specimens Obtained from a Typical Sample
C1556–03
8.6 Rinse the specimens with tap water immediately after chamber or room maintained at 23 6 2°C. Record the start date
cutting. Scrub the surface with a stiff nylon brush, and rinse and start time to the nearest hour.
again. Prior to sealing specimen surfaces, air dry until no
9.1.2 It is permitted to place multiple specimens in a single
moisture can be removed from the surface with a dry paper
container as long as the specimens are placed in the container
towel (see Note 5).
such that the entire exposure surface is unobstructed. Maintain
8.6.1 Exposure specimens must be surface-dry but inter-
the exposed surface area to exposure liquid volume ratio within
nally moist prior to sealing. This condition is satisfied by
the range of 50 6 30 cm /L (see Note 7).
standard moist-cured specimens allowed to air dry for no more
NOTE 7—The volume of exposure liquid required for nominal 100-mm
than 24 h in laboratory air maintained at 23 6 2°C and 50 6
diameter cylinder or core exposure specimens is approximately one liter
3 % RH.
per specimen.
NOTE 5—Specimens cured in a saturated calcium hydroxide water bath
9.1.3 The specimens must remain in the exposure liquid for
are normally covered by residual lime particles. If this residue is not
at least 35 days (see Note 8).
removed and test specimens are allowed to temporarily dry in air, a
calcium carbonate layer can form on the surface of the specimen. This
NOTE 8—The exposure time should be extended for mixtures such as
carbonate layer may interfere with the test result, which is why cleansing
those that are more mature, were made with low w/cm, or high-
and rinsing with tap water after cutting or removal from the saturated
performance mixtures containing supplementary cementitious materials.
calcium hydroxide water bath is required.
9.1.4 If evaporation of water from the exposure liquid or a
8.7 Seal all sides of the exposure specimen except for the
container leak allows the specimen surface to dry during the
finished surface following the procedure described in Test
exposure time, the test is not valid (see Note 9).
Method C 1202.
8.8 Determine the initial mass of the test specimen when the
NOTE 9—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 the exposure time to the nearest hour.
hydroxide water bath at 23 6 2°C in a tightly closed plastic
9.2 Profile Grinding:
container. The container must be filled to the top to prevent
9.2.1 Remove the test specimen from the exposure liquid,
carbonation. After 24 h of immersion, remove the specimen,
rinse with tap water, and dry for at least 24 h in laboratory air
blot the surface dry with a paper towel, and determine the mass
maintained at 23 6 2°C and 50 6 3 % RH.
of the specimen in the surface-dry condition.
9.2.2 If a delay between exposure and grinding longer than
8.10 The test specimen is immersed in a saturated calcium
24 h is expected, place the specimens in watertight resealable
hydroxide water bath until the mass does not change by more
polyethylene bags prior to grinding.
than 0.1 % in 24 h (see Note 6). An acceptable alternative
9.2.3 Obtain the powder samples by grinding off material in
procedure is to vacuum saturate the specimens with saturated
calcium hydroxide solution using a vacuum chamber similar to layers parallel to the exposed surface. Do not grind closer than
5 mm from the edge of the specimen to avoid edge effects and
the system described in Test Method C 1202.
disturbances from the coating.
NOTE 6—Typically, the mass of moist-cured specimens stabilizes
9.2.4 For the minimum exposure time of 35 days, grind off
within 48 h.
eight layers in accordance with Table 1. For longer exposure
9. Procedure
times, select depth increments such that a minimum of 6 points
span the range from 1 mm below the exposed surface to a depth
9.1 Exposure:
with a chloride-ion content equal to, or slightly greater than,
9.1.1 Remove the saturated test specimen from the calcium
the initial chloride-ion con
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