1、Designation: C 1202 05Standard 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 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 The numerical results (total charge passed, in coulombs)from this test method must be used with caution, especiall
11、y inapplications such as quality control and acceptance testing. Thequalitative terms in the right-hand column of Table 1 should beused in most cases.4.4 Care should be taken in interpreting results of this testwhen it is used on surface-treated concretes, for example,concretes treated with penetrat
12、ing 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.4.5 The details of the test method apply to 4-in. (102-mm)nominal diameter specimens. This includes speci
13、mens withactual diameters ranging from 3.75 in. (95 mm) to 4.0 in. (1021This test method is under the jurisdiction 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 Jul
14、y 1, 2005. Published August 2005. Originallyapproved in 1991. Last previous edition approved in 1997 as C 1202 97.2The 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 Custo
15、mer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards 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.
16、1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.mm). Other specimen diameters may be tested with appropriatechanges in the applied voltage cell design (see 7.5 and Fig. 1).4.5.1 For specimen diameters other than 3.75 in. (95 mm),the
17、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 must be taken incoating and mounting the specimens to ensure that the con-ductive solutions are able to contact the entire end areas duri
18、ngthe test.4.6 Sample age may have significant effects on the testresults, depending on the type of concrete and the curingprocedure. Most concretes, if properly cured, become progres-sively and significantly less permeable with time.5. Interferences5.1 This test method can produce misleading result
19、s whencalcium nitrite has been admixed into a concrete. The resultsfrom this test on some 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
20、pondingtests indicate the concretes with calcium nitrite were at least asresistant to chloride 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 resu
21、lts are a function of the electricalresistance of the specimen, the presence of reinforcing 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
22、 electrical path between the two ends of the speci-men.6. Apparatus6.1 Vacuum Saturation Apparatus (see Fig. 2 for example):TABLE 1 Chloride Ion Penetrability Based on Charge Passed(1)1Charge Passed (coulombs) Chloride Ion Penetrability4,000 High2,0004,000 Moderate1,0002,000 Low1001,000 Very Low100
23、NegligibleFIG. 1 Applied Voltage Cell (construction drawing)C12020526.1.1 Separatory Funnel, 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 de
24、siccator (see 6.1.3).6.1.3 Vacuum Desiccator250-mm (9.8-in.) inside diam-eter or larger. 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 maintainin
25、ga pressure of less than 50 mm Hg (6650 Pa) in desiccator.NOTE 2Since vacuum will be drawn 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)p
26、ressure.6.2 Coating Apparatus and Materials:6.2.1 CoatingRapid setting, electrically nonconductive,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 i
27、f samples arecast to final specimen size).6.3.1 Movable Bed Water-Cooled Diamond Saw or 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 sodi
28、um chloridesolutions at temperatures up to 200 F (90 C); examplesinclude RTV silicone rubbers, 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
29、N (reagent grade) indistilled water.7.3.1 WarningBefore using NaOH, review: (1) the safetyprecautions 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 v
30、ery severe burns and injury to unpro-tected skin and eyes. Suitable personal protective 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.) diam
31、eter (notrequired if rubber gasket is used for sealant (see 7.1)orifsealant can be applied 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.
32、Onedesign in common use is shown in Fig. 1 and Fig. 3. However,other designs are acceptable, 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
33、(0 to 120 C) range.7.7 Voltage Application and Data Readout ApparatusCapable of holding 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 requirem
34、ent.7.7.1 VoltmeterDigital (DVM), 3 digit, minimum 099.9V range, rated accuracy 6 0.1 %.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 mu
35、st be taken to establish very lowresistance connections.7.7.4 Constant Voltage Power Supply 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.8. Test Specimens8.1 Sample preparation and selection d
36、epends 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 largeFIG. 2 Vacuum Saturation ApparatusFIG. 3 Applied Voltage Cell-Face ViewC1202053diameter cylinders or (b) 4-in. (102-mm) diameter cast cylin-ders. For evaluatio
37、n of structures, samples may be (a) coresfrom the structure or (b) 4-in. (102-mm) diameter 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
38、 42/C 42M. Cylinders cast in the laboratoryshall be prepared following procedures in Practice 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, curi
39、ng, and temperature history during curing.NOTE 3The maximum allowable aggregate size has 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 t
40、he cores or field-cured cylinders to thelaboratory in sealed (tied) plastic bags. If specimens 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
41、 mm) slice from the top of the coreor cylinder, with the cut parallel to the top of the 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
42、texturing or byapplying curing compounds, sealers, or other surface treat-ments, and where 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.
43、9. Conditioning9.1 Vigorously boil a litre or more of tapwater in a largesealable container. 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 rap
44、idsetting coating and brush onto the side surface of specimen.Place the sample on a suitable 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.
45、Fill any apparent holes in the coatingand allow additional curing time, as necessary. 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 desiccat
46、or and start vacuum pump or aspirator.Pressure should decrease to less than 50 mm Hg (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
47、 sufficient water intobeaker or container to cover specimen (do not allow air to enterdesiccator 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.)
48、 Turnvacuum line stopcock to allow air to re-enter desiccator.9.7 Soak specimen under 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 s
49、pecimen 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 paper over one screen of the appliedvoltage cell. Trowel sealant over brass shims adjacent toapplied voltage cell body. Carefully remove filter paper. Pressspecimen onto screen; remove or smooth excess sealant whichhas
