ASTM G180-04
(Test Method)Standard Test Method for Initial Screening of Corrosion Inhibiting Admixtures for Steel in Concrete
Standard Test Method for Initial Screening of Corrosion Inhibiting Admixtures for Steel in Concrete
SIGNIFICANCE AND USE
This test method provides a means for assessing corrosion-inhibiting concrete admixtures.
This test method is useful for development of admixtures intended to reduce corrosion of reinforcing steel in concrete.
This test method is useful in determining the corrosivity of admixtures toward steel reinforcing if the admixture sample is compared to a control without admixtures.
Good performance, a reduction in corrosion rate versus chloride alone by at least one order of magnitude in this test, is a strong indication that an admixture is a corrosion inhibitor. However, poor performance requires additional testing to determine if the admixture improves corrosion resistance.
This method is a screening test and shall not be used to predict performance in the field. However, it is useful to determine which admixtures shall be included into long-term evaluation programs.
The filtering process makes this test not suitable for the evaluation of emulsions.
SCOPE
1.1 This test method describes a procedure for determining the effects of chemical admixtures on the corrosion of metals in concrete. This test method can be used to evaluate materials intended to inhibit chloride-induced corrosion of steel in concrete. It can also be used to evaluate the corrosivity of admixtures by themselves or in a chloride environment. This test is not applicable for emulsions.
1.2 Units—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:G180–04
Standard Test Method for
Initial Screening of Corrosion Inhibiting Admixtures for
Steel in Concrete
This standard is issued under the fixed designation G 180; 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. Terminology
1.1 This test method describes a procedure for determining 3.1 Definitions—For definitions of terms used in this prac-
theeffectsofchemicaladmixturesonthecorrosionofmetalsin tice see Terminology G 15.
concrete. This test method can be used to evaluate materials
4. Significance and Use
intended to inhibit chloride-induced corrosion of steel in
concrete. It can also be used to evaluate the corrosivity of 4.1 This test method provides a means for assessing
corrosion-inhibiting concrete admixtures.
admixtures by themselves or in a chloride environment. This
test is not applicable for emulsions. 4.2 This test method is useful for development of admix-
tures intended to reduce corrosion of reinforcing steel in
1.2 Units—The values stated in SI units are to be regarded
as standard. No other units of measurement are included in this concrete.
4.3 This test method is useful in determining the corrosivity
standard.
1.3 This standard does not purport to address all of the of admixtures toward steel reinforcing if the admixture sample
is compared to a control without admixtures.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 4.4 Good performance, a reduction in corrosion rate versus
chloride alone by at least one order of magnitude in this test, is
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. a strong indication that an admixture is a corrosion inhibitor.
However, poor performance requires additional testing to
2. Referenced Documents
determine if the admixture improves corrosion resistance.
2.1 ASTM Standards: 4.5 This method is a screening test and shall not be used to
C 150 Specification for Portland Cement predict performance in the field. However, it is useful to
C 670 Practice for Preparing Precision Statements for Test determine which admixtures shall be included into long-term
Methods for Construction Materials evaluation programs.
D 632 Specification for Sodium Chloride 4.6 The filtering process makes this test not suitable for the
E 691 Practice for Conducting an Interlaboratory Study to evaluation of emulsions.
Determine the Precision of a Test Method
5. Apparatus
G 3 PracticeforConventionsApplicabletoElectrochemical
5.1 The test cell as described in Test Method G 5.
Measurements in Corrosion Testing
G 5 Test Method for Making Potentiostatic and Potentiody- 5.2 Potentiostat, as described in Test Method G 5, capable
of varying potential at a constant scan rate and measuring the
namic Anodic Polarization Measurements
G 15 Terminology Relating to Corrosion and Corrosion resulting current.
5.3 A method of recording the varying potential and result-
Testing
G 59 Test Method for Conducting Potentiodynamic Polar- ing current is needed.
5.4 Electrode holder such as described in Fig. 3 of Test
ization Resistance Measurements
Method G 5.
5.5 Electrodes:
This test method is under the jurisdiction of ASTM Committee G01 on
5.5.1 Workingelectrode,preparedfroma12.7mmlengthof
Corrosion of Metals and is the direct responsibility of Subcommittee G01.14 on
9.5 mm diameter rod stock. Carbon steel C1215 should be
Corrosion of Metals in Concrete, Mortar, or Cement.
used.
Current edition approved July 1, 2004. Published July 2004.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
NOTE 1—If specimen forms are used other than those called for by this
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
test method, for example flat sheet specimens, care should be taken not to
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. introduce crevices which can lead to erroneous results.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
G180–04
NOTE 4—An example of a polarization resistance curve is given in the
5.6 Auxiliary Electrodes:
Appendix as Fig. X1.4.
5.6.1 Two graphite rods or platinized-niobium or platinum
mesh.
8. Interpretation of Results
5.7 Reference Electrodes:
8.1 An admixture is behaving as a corrosion inhibitor in this
5.7.1 Asaturated calomel electrode with a controlled rate of
test method if the average log (1/R ) value is 1.0 or less than
10 p
leakage (about 3 µL/h) is recommended.
that of the chloride only average.
6. Reagents and Materials 8.2 If the admixture does not reduce average 1/R by an
p
order of magnitude another test method is needed to determine
6.1 Type I/II cement (C3A content between 6 and 10 %),
if it is an inhibitor.
according to Specification C 150.
8.3 An admixture that increases average 1/R by an order of
6.2 Filter paper with 1.1 µm retention. p
magnitude over a slurry without chloride or inhibitor is
6.3 Teflon stir bars.
corrosive.
6.4 Carbon steel C1215 samples.
6.5 Sodium chloride, reagent grade, according to Specifica-
NOTE 5—The change in log (1/R ) by 1.0 is an order of magnitude
10 p
tion D 632.
change in 1/R . Log values are useful in comparing corrosion rates since
p
6.6 Calcium hydroxide, reagent grade. rates from different specimens or conditions can differ by orders of
magnitude making a linear scale less useful.
6.7 Admixtures to be tested.
6.8 Carbon dioxide free compressed air.
9. Report
7. Experimental Procedure
9.1 Report the following information:
9.1.1 Value of the open circuit potential (OCP) versus SCE,
7.1 Prepare a cement slurry consisting of 1000 g of water
and
and 200 g cement. Mix thoroughly, stir for 60 min and filter.
9.1.2 Corrosion rate given by 1/R in µS/cm .
p
NOTE 2—Anadmixtureshouldbeaddedataquantityconsistentwithits
addition rate in concrete. 35 to 965 mL of water is equivalent to 5 L/m
10. Precision and Bias
in concrete. If other dosages are desired, proportion them based on this
10.1 Based on the pooled estimates of precision, the follow-
ratio.
ing statement of precision and bias can be made:
7.2 Filter,andadd4g/Lcalciumhydroxideandstirafurther
10.1.1 Interlaboratory Test Program—An interlaboratory
30 min.
studyofaporesolutiontestforcorrosioninhibitingadmixtures
7.3 Setup a standard electrochemical cell according to Test
for steel reinforcement in concrete was conducted in 2001.
Method G 5 and fill it with 900 mL of filtered slurry solution.
Each of six laboratories tested two randomly drawn samples of
Purge the cell with carbon dioxide free air.Air flow rate should
each of four materials (two sodium chloride solutions, 0.5M
be at least 300 cc/min.
and 1.0M, each with and without 35 mL/L of a solution
7.4 Degrease the metal sample by cleaning ultrasonically in
containing 30 % calcium nitrite). Practice E 691 was followed
hexanefor2min.Ifanultrasonicbathisnotavailable,soakthe
for the design and analysis of the study.
samples in hexane and wipe dry. Make sure the sample is
10.1.2 Single-Operator Precision—The single operator
thoroughly dried before mount
...
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