ASTM C1202-2008 Standard Test Method for Electrical Indication of Concretes Ability to Resist Chloride Ion Penetration.pdf

1、Designation: C 1202 08Standard Test Method forElectrical Indication of Concretes Ability to Resist ChlorideIon Penetration1This standard is issued under the fixed designation C 1202; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,

2、the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the determination of the elec-trical conductance of concrete to provide a rapid i

3、ndication ofits resistance to the penetration of chloride ions. This testmethod is applicable to types of concrete where correlationshave been established between this test procedure and long-term chloride ponding procedures such as those described inAASHTO T 259. Examples of such correlations are d

4、iscussedin Refs 1-5.21.2 The values stated in inch-pound units are to be regardedas the standard, except where SI units are given first followedby inch-pound units in parentheses. The values given inparentheses are for information only.1.3 This standard does not purport to address all of thesafety c

5、oncerns, if any, associated with its use. It is theresponsibility of the user of this standard 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:3C 42/C 42M Test Method for Obtaining

6、 and Testing DrilledCores and Sawed Beams of ConcreteC 192/C 192M Practice for Making and Curing ConcreteTest Specimens in the LaboratoryC 670 Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction Materials2.2 AASHTO Standard:T 259 Method of Test for Resistance of Con

7、crete to Chlo-ride Ion Penetration43. Summary of Test Method3.1 This test method consists of monitoring the amount ofelectrical current passed through 2-in. (51-mm) thick slices of4-in. (102-mm) nominal diameter cores or cylinders during a6-h period. A potential difference of 60 V dc is maintainedac

8、ross the ends of the specimen, one of which is immersed ina sodium chloride solution, the other in a sodium hydroxidesolution. The total charge passed, in coulombs, has been foundto be related to the resistance of the specimen to chloride ionpenetration.4. Significance and Use4.1 This test method co

9、vers the laboratory evaluation of theelectrical conductance of concrete samples to provide a rapidindication of their resistance to chloride ion penetration. Inmost cases the electrical conductance results have shown goodcorrelation with chloride ponding tests, such as AASHTOT 259, on companion slab

10、s cast from the same concretemixtures (Refs 1-5).4.2 This test method is suitable for evaluation of materialsand material proportions for design purposes and research anddevelopment.4.3 Sample age has significant effects on the test results,depending on the type of concrete and the curing procedure.

11、Most concretes, if properly cured, become progressively andsignificantly less permeable with time.4.4 This test method was developed originally for evalua-tions of alternative materials, but in practice its use has evolvedto applications such as quality control and acceptance testing.In such cases i

12、t is imperative that the curing procedures and theage at time of testing be clearly defined.4.5 Table 1 provides a qualitative relationship between theresults of this test and the chloride ion penetrability ofconcrete.4.6 Care should be taken in interpreting results of this testwhen it is used on su

13、rface-treated concretes, for example,concretes treated with penetrating sealers. The results from thistest on some such concretes indicate low resistance to chlorideion penetration, while 90-day chloride ponding tests on com-panion slabs show a higher resistance.1This test method is under the jurisd

14、iction of ASTM Committee C09 onConcrete and Concrete Aggregates and is the direct responsibility of SubcommitteeC09.66 on Concretes Resistance to Fluid Penetration.Current edition approved Dec. 15, 2008. Published January 2009. Originallyapproved in 1991. Last previous edition approved in 2007 as C

15、1202 07.2The boldface numbers in parentheses refer to the list of references at the end ofthis standard.3For 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 standard

16、s Document Summary page onthe ASTM website.4Methods of Sampling and Testing, 1986, American Association of StateHighway and Transportation Officials, 444 N. Capitol St., NW, Washington, DC20001.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr

17、Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.7 The details of the test method apply to 4-in. (102-mm)nominal diameter specimens. This includes specimens withactual diameters ranging from 3.75 in. (95 mm) to 4.0 in. (102mm). Other specimen diameters may be tested with

18、appropriatechanges in the applied voltage cell design (see 7.5 and Fig. 1).4.7.1 For specimen diameters other than 3.75 in. (95 mm),the test result value for total charge passed must be adjustedfollowing the procedure in 11.2. For specimens with diametersless than 3.75 in. (95 mm), particular care m

19、ust be taken incoating and mounting the specimens to ensure that the con-ductive solutions are able to contact the entire end areas duringthe test.5. Interferences5.1 This test method can produce misleading results whencalcium nitrite has been admixed into a concrete. The resultsfrom this test on so

20、me such concretes indicate higher coulombvalues, that is, lower resistance to chloride ion penetration,than from tests on identical concrete mixtures (controls)without calcium nitrite. However, long-term chloride pondingtests indicate the concretes with calcium nitrite were at least asresistant to c

21、hloride ion penetration as the control mixtures.NOTE 1Other admixtures might affect results of this test similarly.Long term ponding tests are recommended if an admixture effect issuspected.5.2 Since the test results are a function of the electricalresistance of the specimen, the presence of reinfor

22、cing steel orother embedded electrically conductive materials may have asignificant effect. The test is not valid for specimens containingreinforcing steel positioned longitudinally, that is, providing acontinuous electrical path between the two ends of the speci-men.TABLE 1 Chloride Ion Penetrabili

23、ty Based on Charge Passed (1)Charge Passed (coulombs) Chloride Ion Penetrability4,000 High2,0004,000 Moderate1,0002,000 Low1001,000 Very Low100 NegligibleFIG. 1 Applied Voltage Cell (construction drawing)C12020826. Apparatus6.1 Vacuum Saturation Apparatus (see Fig. 2 for example):6.1.1 Separatory Fu

24、nnel, or other sealable, bottom-drainingcontainer with a minimum capacity of 500 mL.6.1.2 Beaker (1000 mL or larger) or other containerCapable of holding concrete specimen(s) and water and offitting into vacuum desiccator (see 6.1.3).6.1.3 Vacuum Desiccator250-mm (9.8-in.) inside diam-eter or larger

25、. Desiccator must allow two hose connectionsthrough a rubber stopper and sleeve or through a rubber stopperonly. Each connection must be equipped with a stopcock.6.1.4 Vacuum Pump or AspiratorCapable of maintaininga pressure of less than 50 mm Hg (6650 Pa) in desiccator.NOTE 2Since vacuum will be dr

26、awn over water, a vacuum pumpshould be protected with a water trap, or pump oil should be changed aftereach operation.6.1.5 Vacuum Gage or ManometerAccurate to 6 5mmHg (6 665 Pa) over range 0100 mm Hg (013300 Pa)pressure.6.2 Coating Apparatus and Materials:6.2.1 CoatingRapid setting, electrically no

27、nconductive,capable of sealing side surface of concrete cores.6.2.2 Balance or Scale, Paper Cups, Wooden Spatulas, andDisposable BrushesFor mixing and applying coating.6.3 Specimen Sizing Equipment (not required if samples arecast to final specimen size).6.3.1 Movable Bed Water-Cooled Diamond Saw or

28、 SiliconCarbide Saw.7. Reagents, Materials, and Test Cell7.1 Specimen-Cell SealantCapable of sealing concrete topoly (methyl methacrylate), for example, Plexiglas, againstwater and dilute sodium hydroxide and sodium chloridesolutions at temperatures up to 200 F (90 C); examplesinclude RTV silicone r

29、ubbers, silicone rubber caulkings, othersynthetic rubber sealants, silicone greases, and rubber gaskets.7.2 Sodium Chloride Solution3.0 % by mass (reagentgrade) in distilled water.7.3 Sodium Hydroxide Solution0.3 N (reagent grade) indistilled water.7.3.1 WarningBefore using NaOH, review: (1) the saf

30、etyprecautions for using NaOH; (2) first aid for burns; and (3) theemergency response to spills, as described in the manufactur-ers Material Safety Data Sheet or other reliable safety litera-ture. NaOH can cause very severe burns and injury to unpro-tected skin and eyes. Suitable personal protective

31、 equipmentshould always be used. These should include full-face shields,rubber aprons, and gloves impervious to NaOH. Gloves shouldbe checked periodically for pin holes.7.4 Filter PapersNo. 2, 90-mm (3.5-in.) diameter (notrequired if rubber gasket is used for sealant (see 7.1)orifsealant can be appl

32、ied without overflowing from shim ontomesh).7.5 Applied Voltage Cell (see Fig. 1 and Fig. 3)Twosymmetric poly (methyl methacrylate) chambers, each contain-ing electrically conductive mesh and external connectors. Onedesign in common use is shown in Fig. 1 and Fig. 3. However,other designs are accept

33、able, provided that overall dimensions(including dimensions of the fluid reservoir) are the same asshown in Fig. 1 and width of the screen and shims are asshown.7.6 Temperature Measuring Device (optional)30to250F (0 to 120 C) range.7.7 Voltage Application and Data Readout ApparatusCapable of holding

34、 60 6 0.1 V dc across applied voltage cellover entire range of currents and of displaying voltage accurateto 6 0.1 V and current to 6 1 mA. Apparatus listed in7.7.1-7.7.5 is a possible system meeting this requirement.7.7.1 VoltmeterDigital (DVM), 3 digit, minimum 099.9V range, rated accuracy 6 0.1 %

35、.7.7.2 VoltmeterDigital (DVM), 412 digit, 0200 mVrange, rated accuracy 6 0.1 %.7.7.3 Shunt Resistor100 mV, 10A rating, tolerance6 0.1 %. Alternatively, a 0.01 V resistor, tolerance 6 0.1 %,may be used, but care must be taken to establish very lowresistance connections.7.7.4 Constant Voltage Power Su

36、pply 080 V dc, 02 A,capable of holding voltage constant at 60 6 0.1 V over entirerange of currents.7.7.5 CableTwo conductor, No. 14 (1.6 mm), insulated,600 V.FIG. 2 Vacuum Saturation Apparatus FIG. 3 Applied Voltage Cell-Face ViewC12020838. Test Specimens8.1 Sample preparation and selection depends

37、on the pur-pose of the test. For evaluation of materials or their propor-tions, samples may be (a) cores from test slabs or from largediameter cylinders or (b) 4-in. (102-mm) diameter cast cylin-ders. For evaluation of structures, samples may be (a) coresfrom the structure or (b) 4-in. (102-mm) diam

38、eter cylinderscast and cured at the field site. Coring shall be done with adrilling rig equipped with a 4-in. (102-mm) diameter diamond-dressed core bit. Select and core samples following proceduresin Test Method C 42/C 42M. Cylinders cast in the laboratoryshall be prepared following procedures in P

39、ractice C 192/C 192M. When cylinders are cast in the field to evaluate astructure, care must be taken that the cylinders receive thesame treatment as the structure, for example, similar degree ofconsolidation, curing, and temperature history during curing.NOTE 3The maximum allowable aggregate size h

40、as not been estab-lished for this test. Users have indicated that test repeatability issatisfactory on specimens from the same concrete batch for aggregates upto 25.0 mm (1 in.) nominal maximum size.8.2 Transport the cores or field-cured cylinders to thelaboratory in sealed (tied) plastic bags. If s

41、pecimens must beshipped, they should be packed so as to be properly protectedfrom freezing and from damage in transit or storage.8.3 Using the water-cooled diamond saw or silicon carbidesaw, cut a 2 618 in. (51 6 3 mm) slice from the top of the coreor cylinder, with the cut parallel to the top of th

42、e core. Thisslice will be the test specimen. Use a belt sander to remove anyburrs on the end of the specimen.8.4 Special processing is necessary for core samples wherethe surface has been modified, for example, by texturing or byapplying curing compounds, sealers, or other surface treat-ments, and w

43、here the intent of the test is not to include theeffect of the modifications. In those cases, the modified portionof the core shall be removed and the adjacent 2 618 in. (51 63 mm) slice shall be used for the test.9. Conditioning9.1 Vigorously boil a litre or more of tapwater in a largesealable cont

44、ainer. Remove container from heat, cap tightly,and allow water to cool to ambient temperature.9.2 Allow specimen prepared in Section 8 to surface dry inair for at least 1 h. Prepare approximately12 oz (10 g) of rapidsetting coating and brush onto the side surface of specimen.Place the sample on a su

45、itable support while coating to ensurecomplete coating of sides. Allow coating to cure according tothe manufacturers instructions.9.3 The coating should be allowed to cure until it is nolonger sticky to the touch. Fill any apparent holes in the coatingand allow additional curing time, as necessary.

46、Place specimenin beaker or other container (see 6.1.2), then place container invacuum desiccator. Alternatively, place specimen directly invacuum desiccator. Both end faces of specimen must beexposed. Seal desiccator and start vacuum pump or aspirator.Pressure should decrease to less than 50 mm Hg (

47、6650 Pa)within a few minutes. Maintain vacuum for 3 h.9.4 Fill separatory funnel or other container (see 6.1.1) withthe de-aerated water prepared in 9.1. With vacuum pump stillrunning, open water stopcock and drain sufficient water intobeaker or container to cover specimen (do not allow air to enter

48、desiccator through this stopcock).9.5 Close water stopcock and allow vacuum pump to run forone additional hour.9.6 Close vacuum line stopcock, then turn off pump.(Change pump oil if a water trap is not being used.) Turnvacuum line stopcock to allow air to re-enter desiccator.9.7 Soak specimen under

49、water (the water used in steps9.4-9.6) in the beaker for 18 6 2h.10. Procedure10.1 Remove specimen from water, blot off excess water,and transfer specimen to a sealed can or other container whichwill maintain the specimen in 95 % or higher relative humidity.10.2 Specimen mounting (all sealants other than rubbergaskets; use 10.2.2 or 10.2.3, as appropriate):10.2.1 If using two-part specimen-cell sealant, prepare ap-proximately 0.7 to 1.4 oz (20 to 40 g).10.2.2 Low Viscosity Specimen-Cell SealantIf filter paperis necessary, center filter pap