ASTM G109-1999a(2005) Standard Test Method for Determining the Effects of Chemical Admixtures on the Corrosion of Embedded Steel Reinforcement in Concrete Exposed to Chloride Envir.pdf

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1、Designation: G 109 99a (Reapproved 2005)Standard Test Method forDetermining the Effects of Chemical Admixtures on theCorrosion of Embedded Steel Reinforcement in ConcreteExposed to Chloride Environments1This standard is issued under the fixed designation G 109; the number immediately following the d

2、esignation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers a

3、procedure for determining theeffects of chemical admixtures on the corrosion of metals inconcrete. This test method can be used to evaluate materialsintended to inhibit chloride-induced corrosion of steel inconcrete. It can also be used to evaluate the corrosivity ofadmixtures in a chloride environm

4、ent.1.2 The values stated in SI units are to be regarded as thestandard. The inch-pound units in parentheses are provided forinformation only.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard

5、 to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2A 615/A 615M Specification for Deformed and PlainBillet-Steel Bars for Concrete ReinforcementC33 Specification for Concrete Aggreg

6、atesC 143/C 143M Test Method for Slump of Hydraulic Ce-ment ConcreteC 150 Specification for Portland CementC 173/C 173M Test Method for Air Content of FreshlyMixed Concrete by the Volumetric MethodC 192/C 192M Practice for Making and Curing ConcreteTest Specimens in the LaboratoryC 231 Test Method f

7、or Air Content of Freshly MixedConcrete by the Pressure MethodC511 Specification for Mixing Rooms, Moist Cabinets,Moist Rooms, and Water Storage Tanks Used in theTesting of Hydraulic Cements and ConcretesC 876 Test Method for Half-Cell Potentials of UncoatedReinforcing Steel in ConcreteC 881/C 881M

8、Specification for Epoxy-Resin-Base Bond-ing Systems for ConcreteC 1152/C 1152M Test Method for Acid-Soluble Chloridein Mortar and ConcreteD 448 Classification for Sizes of Aggregate for Road andBridge ConstructionD 632 Specification for Sodium ChlorideE 177 Practice for Use of the Terms Precision an

9、d Bias inASTM Test MethodsE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodG3 Practice for ConventionsApplicable to ElectrochemicalMeasurements in Corrosion TestingG15 Terminology Relating to Corrosion and CorrosionTestingG33 Practice for Recording Dat

10、a from Atmospheric Cor-rosion Tests of Metallic-Coated Steel SpecimensG46 Guide for Examination and Evaluation of PittingCorrosion2.2 NACE Standards:SSPC SP 5 (NACE No. 1) White Metal Blast Cleaning33. Significance and Use3.1 This test method provides a reliable means for predict-ing the inhibiting

11、or corrosive properties of admixtures to beused in concrete.3.2 This test method is useful for development studies ofcorrosion inhibitors to be used in concrete.3.3 This test method has been used elsewhere with goodagreement between corrosion as measured by this test methodand corrosion damage on th

12、e embedded steel (1, 2, 3, 4).4Thistest method might not properly rank the performance ofdifferent corrosion inhibitors, especially at concrete coversover the steel less than 40 mm (1.5 in.) or water-to-cementratios above 0.45. The concrete mixture proportions and cover1This test method is under the

13、 jurisdiction of ASTM Committee G01 onCorrosion, Deterioration, and Degradation of Materials and is the direct responsi-bility of Subcommittee G01.14 on Metals in Construction Materials.Current edition approved May 1, 2005. Published May 2005. Originallyapproved in 1992. Last previous edition approv

14、ed in 1999 as G 109 99ae1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Society for Protect

15、ive Coatings (SSPC), 40 24th St., 6th Floor,Pittsburgh, PA 15222-4656.4The boldfaced numbers in parentheses refer to the list of references at the endof this test method.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.over the steel

16、are chosen to accelerate chloride ingress. Someinhibitors might have an effect on this process, which couldlead to results that would differ from what would be expectedin actual use (5).4. Apparatus4.1 The apparatus required for the evaluation of corrosioninhibitors includes a high impedance voltmet

17、er (at least oneMohm) capable of measuring to 0.01 mV, a 100-ohm (65%)resistor.5. Reagents and Materials5.1 Cement, that conforms to Type I or Type II of Specifi-cation C 150. Coarse aggregate shall conform to SpecificationC33and Classification D 448, with nominal maximum sizebetween 9.5 and 19 mm (

18、38 and34 in.).NOTE 1Preferred maximum size aggregate is 12.5 mm (0.5 in.).5.2 Steel Reinforcement Bars, deformed, meeting the re-quirement of Specification A 615/A 615M; with a diameterbetween 10 mm (0.4 in.) and 16 mm (0.6 in.), and a length of360 mm (14 in.), drilled and tapped at one end to be fi

19、tted withcoarse-thread stainless steel and nuts, as described in 5.3 and5.4. These bars shall be used to manufacture the test specimens,as described in Section 6.NOTE 2Interlaboratory test program and statistical data in Section 11are based upon 13-mm (0.5-in.) steel bars, 12.5-mm maximum sizeaggreg

20、ate, and 19-mm (0.75-in.) and 25-mm (1 in.) cover5.3 316 Stainless Steel Screws, with diameter smaller thanbar diameter (coarse thread in diameter shall be produced for backgroundchloride analysis.NOTE 6A larger number of replicates is preferred.6.9 Apply a wood float finish after consolidation. Aft

21、erremoval from the forms, cure the specimens for 28 days in amoist room in accordance with Test Method C 192/C 192Mand Specification C511.6.10 Upon removal from the moist room, hand wire brushthe specimens on the concrete top surface (wood floatedsurface). Allow the specimens to dry for two weeks in

22、 a 50 %relative humidity (RH) environment before sealing the fourvertical sides with an epoxy sealer, as described in 5.11,inaccordance with the manufacturers recommendation. Place aplastic dam with dimensions, as described in 5.12,onthespecimen, as shown in Fig. 1, and about 13 mm (0.5 in.) fromeac

23、h side so that it does not extend over the taped sections ofthe bars (see Fig. 2). Use a silicone caulk to seal the dam fromthe outside, and apply epoxy sealer to the top surface outside ofthe dam.NOTE 7Allowing the specimens to dry before applying the concreteepoxy will make the initial exposure to

24、 chloride more severe, and moreclosely follow the interlaboratory test program conditions.6.11 Attach wires and resistors.7. Procedure7.1 Support each test specimen on two nonelectricallyconducting supports at least 13-mm (0.5-in.) thick, thus allow-ing air flow under most of the specimen. Start the

25、 test onemonth after the samples are removed from the 100 % RHatmosphere (moist room). Pond the specimens for two weeks at23 6 3C (73 6 5F) with the salt solution, as described in5.10. The volume of this solution is approximately 400 mL ata depth of 40 mm (1.5 in.). Use a plastic loose fitting cover

26、 tominimize evaporation. Maintain a relative humidity around thespecimens of 50 6 5 %. After two weeks, vacuum off thesolution and allow the samples to dry for two weeks. Repeatthis cycle.7.2 Measure the voltage across the resistor at the beginningof the second week of ponding using the voltmeter de

27、fined in4.1. Calculate the current, Ij, from the measured voltage acrossthe 100-ohm resistor, Vj, measured in volts (see Note 8) as:Ij5 Vj/100NOTE 8With the common terminal on the bottom bar, negativevoltages correspond to positive galvanic current (that is, the top bar is theanode).7.3 At the same

28、time, measure the corrosion potential of thebars against a reference electrode that is placed in the damcontaining the salt solution (see Practice G3and Test MethodC 876). Connect the voltmeter between the reference electrode(ground or common terminal) and the bars.8. Period of Testing8.1 Monitor th

29、e current as a function of time once everyfour weeks, as described in 7.2, until the average integratedmacrocell current of the control specimens is 150 C or greater,NOTEAll measurements in in. (25.4 mm = 1 in.).FIG. 1 Concrete BeamNOTEAll measurements in in. (not to scale) (25.4 mm = 1 in.).FIG. 2

30、Concrete Beam (Side View)G 109 99a (2005)3as determined in 10.1.8, and at least half the samples showintegrated macrocell currents equal to or greater than 150 C(see Note 9).NOTE 9The value of 150 C is consistent with a macrocell current of10 A over six months. The value of 10 A was measured by alll

31、aboratories on all specimens showing corrosion (controls and sampleswith calcium chloride at 19-mm (34-in.) cover). This degree of integratedmacrocell current is sufficient to ensure the presence of sufficientcorrosion for visual evaluation.8.2 In those cases where the admixtures being tested arecor

32、rosive, end the test three full cycles after an averageintegrated macrocell current of 75 C is observed and theintegrated macrocell current of at least half the specimensbeing tested is equal or greater than 75 C.9. Examination of Embedded Bars9.1 At the conclusion of testing, break the specimens an

33、dexamine the reinforcement bars for extent of corrosion, mea-sure the corroded area, and record the percentage of corrodedarea recorded, as described in Practice G33.NOTE 10Photograph the bars at the end of the test to provide a recordof the corrosion damage.9.2 Determine the acid soluble chloride c

34、ontent at the depthcorresponding to the cover over the top-reinforcing bar, usingTest Method C 1152/C 1152M.9.3 Determine the acid soluble chloride content in thespecimen produced for background chloride analysis, usingTest Method C 1152/C 1152M. This value is to be subtractedfrom the acid soluble c

35、hloride, as determined in 9.2, to providea corrected acid soluble chloride content reflecting ingressedchloride.10. Report10.1 Report the following information:10.1.1 Full details of the concrete proportions, air content,and slump of the concrete used in the control and testspecimens,10.1.2 A plot o

36、f the corrosion current and potential for eachconcrete specimen versus time,10.1.3 A plot of the average integrated current for eachcondition of concrete versus time,10.1.4 Time to failure, as considered to be the time for theaverage macrocell current to reach 10 A and at least half thesamples showi

37、ng a current greater than 10 A,10.1.5 Results of the visual inspection of each bar. Thereport shall include the percentage of original exposed steelsurface corroded and optionally the number and depths ofcorrosion pits where present, as described in Practice G46,10.1.6 Photographs of the bars at the

38、 end of the test(optional), and10.1.7 Chloride content at the top reinforcing bar depthfrom the surface. This value is the corrected total chloridecontent, as corrected 9.3.10.1.8 The ratio of total integrated current of the testspecimen to that of the control and time the test ended. Thetotal integ

39、rated current is:TCj5 TCj211 tj2 tj21! 3 ij1 ij21!/2where:TC = total corrosion (coulombs),tj= time (seconds) at which measurement of the macro-cell current is carried out, andij= macrocell current (amps) at time, tj.A sample calculation is given in Appendix X1.11. Precision and Bias911.1 Information

40、 on the precision of the results obtained bythis test method was derived from an interlaboratory test withtwo to three specimens per laboratory. Eleven laboratoriesparticipated in the study. The repeatability and reproducibilityof the test results were dependent on the magnitude of the meanmacrocell

41、 current.11.2 Precision is as follows:11.2.1 95 % Repeatability Limit (Within Laboratory)Thewithin-laboratory precision of the average macrocell current(for each laboratory), as expressed by the repeatability limit, r,is given by the following relation:log r 5 0.931 log Iavg1 0.441 (1)11.2.2 95 % Re

42、producibility Limit (BetweenLaboratories)The between-laboratory precision of the aver-age macrocell current (for all laboratories), as expressed by thereproducibility, R, is given by the following relation:log R 5 0.833 log Iavg1 0.624 (2)11.2.3 The repeatability and reproducibility limits of theave

43、rage macrocell current were calculated in accordance withPractice E 177. The respective standard deviations of thevariation among test results can be obtained by dividing by 2.8the values of r and R calculated using (Eq 1) and (Eq 2). Thefollowing equations were then obtained:log Sr5 0.931 log Iavg2

44、 0.006 (3)log SR5 0.833 log Iavg1 0.177 (4)11.2.4 The data used for compiling the test method preci-sion, together with the statistical parameters as defined inPractice E 691, are given in the research report.9The graphicalrepresentations of the repeatability and reproducibility limitsare given in F

45、igs. 3 and 4.11.2.5 The time to failure has been analyzed using PracticeE 691. This analysis is given in the research report.911.2.6 The maximum end of the 95 % confidence intervalfor time to failure for control specimens with 19-mm (0.75-in.)concrete cover is six months for both intralaboratory and

46、interlaboratory tests. The maximum ends of the 95 % confi-dence intervals are two and six months for intra- and interlabo-ratory tests respectively for specimens containing calciumchloride.11.2.7 The complete data for percent area corroded is givenin the research report that has been filed with ASTM

47、 Head-quarters.9In all cases where there was corrosion, the macrocellcurrent was greater than 9 A. However, not enough laborato-ries reported percent area corroded to carry out a statisticalanalysis following Practice E 691.9Supporting data have been filed at ASTM International Headquarters and mayb

48、e obtained by requesting Research Report RR: G011009.G 109 99a (2005)411.3 BiasThe procedure given in this test method has nobias because the effects of chemical admixtures on the corro-sion of embedded steel of reinforcement are defined only interms of this test method.12. Keywords12.1 admixtures;

49、concrete; corrosion; corrosivity; inhibitor;reinforcing steelAPPENDIX(Nonmandatory Information)X1. TOTAL CORROSION CALCULATIONX1.1 Total Corrosion Calculation:TCj5 TCj211 tj2 tj21! * ij1 ij 21!/2 (X1.1)X1.1.1 Assume the following readings were obtained over a90 day period of time:Days 0 30 60 90imac(A) 202735X1.1.2 At the end of the first 30 day period the totalcorrosion is:TC15 0 1 30 2 0! * 86400 * 20 1 0 !/2*1026#525.92 C(X1.2)X1.1.3 At the end of the 60 day period:TC25 25.92 1 60 2 30! * 86400 * 20 1 27!/2*1026#586.83 C(X1.3)X1.1.4 At the e