1、Designation: C1556 11Standard Test Method forDetermining the Apparent Chloride Diffusion Coefficient ofCementitious Mixtures by Bulk Diffusion1This standard is issued under the fixed designation C1556; the number immediately following the designation indicates the year oforiginal adoption or, in the
2、 case of revision, 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 laboratory determination ofthe apparent chloride diffusion
3、 coefficient for hardened cemen-titious mixtures.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibili
4、ty 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:2C31/C31M Practice for Making and Curing Concrete TestSpecimens in the FieldC42/C42M Test Method for
5、 Obtaining and Testing DrilledCores and Sawed Beams of ConcreteC125 Terminology Relating to Concrete and Concrete Ag-gregatesC192/C192M Practice for Making and Curing ConcreteTest Specimens in the LaboratoryC670 Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction Ma
6、terialsC1152/C1152M Test Method for Acid-Soluble Chloride inMortar and ConcreteC1202 Test Method for Electrical Indication of ConcretesAbility to Resist Chloride Ion Penetration2.2 NORDTEST Standards:NT BUILD 443, Approved 1995-11, Concrete, Hardened:Accelerated Chloride Penetration (in English)33.
7、Terminology3.1 Definitions:3.1.1 For definitions of terms used in this test method, referto Terminology C125.3.2 Definitions of Terms Specific to This Standard:3.2.1 apparent chloride diffusion coeffcient, Da, na chlo-ride transport parameter calculated from acid-soluble chlorideprofile data obtaine
8、d from saturated specimens exposed tochloride solutions, without correction for chloride binding, thatprovides an indication of the ease of chloride penetration intocementitious mixtures.3.2.2 chloride binding, vthe chemical process by whichchloride ion is removed from solution and incorporated into
9、cementitious binder hydration products.3.2.2.1 DiscussionChloride binding is primarily associ-ated with hydration products formed by the aluminate phase ofcement and mixtures containing ground granulated blast fur-nace slag.3.2.3 chloride penetration, vthe ingress of chloride ionsdue to exposure to
10、external sources.3.2.4 exposure liquid, nthe sodium chloride solution inwhich test specimens are stored prior to obtaining a chlorideprofile.3.2.5 exposure time, nthe time that the test specimen isstored in the solution containing chloride ion.3.2.6 initial chloride-ion content, Ci, nthe ratio of th
11、emass of chloride ion to the mass of concrete for a test specimenthat has not been exposed to external chloride sources.3.2.7 profile grinding, vthe process of grinding off andcollecting a powder sample in thin successive layers from a testspecimen using a dry process.3.2.8 surface chloride content,
12、 Cs, nthe theoretical ratioof the mass of chloride ion to the mass of concrete at theinterface between the exposure liquid and the test specimen.4. Summary of Test Method4.1 Obtain a representative sample of the cementitiousmixture prior to exposure to chloride ion. Separate each sample1This test me
13、thod 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 Oct. 15, 2011. Published November 2011. Originallyapproved in 2003. Last previous editi
14、on approved in 2004 as C155604. DOI:10.1520/C1556-11.2For 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.3Publish
15、ed by NORDTEST, P.O. Box 116 FIN-02151 ESPOO Finland, Project1154-94, e-mail: nordtest vtt.fi, website: http:/www.vtt.fi/nordtest1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, Unit
16、ed States.into a test specimen and an initial chloride-ion content speci-men. Crush the initial chloride-ion content specimen anddetermine the initial acid-soluble chloride-ion content. Seal allsides of the test specimen, except the finished surface, with asuitable barrier coating. Saturate the seal
17、ed specimen in acalcium hydroxide solution, rinse with tap water, and thenplace in a sodium chloride solution. After a specified exposuretime, the test specimen is removed from the sodium chloridesolution and thin layers are ground off parallel to the exposedface of the specimen. The acid-soluble ch
18、loride content of eachlayer is determined. The apparent chloride diffusion coefficientand the projected surface chloride-ion concentration are thencalculated using the initial chloride-ion content, and at least sixrelated values for chloride-ion content and depth below theexposed surface.5. Signific
19、ance and Use5.1 This test method is applicable to cementitious mixturesthat have not been exposed to external chloride ions, other thanthe negligible quantity of chloride ion exposure from samplepreparation using potable water, prior to the test.5.2 The calculation procedure described in this test m
20、ethodis applicable only to laboratory test specimens exposed to asodium chloride solution as described in this test method. Thiscalculation procedure is not applicable to specimens exposed tochloride ions during cyclic wetting and drying.NOTE 1The diffusion of ionic species in concrete occurs within
21、 thefluid-filled pores, cracks and void spaces. The concentration and valenceof other ionic species in the pore fluid also influence the rate of chloridediffusion, and therefore, the apparent diffusion coefficient as determinedby this test procedure.5.3 In most cases, the value of the apparent chlor
22、idediffusion coefficient for cementitious mixtures changes overtime (See Note 2). Therefore, apparent diffusion coefficientsobtained at early ages may not be representative of perfor-mance in service.NOTE 2The rate of change of the apparent diffusion coefficient forcementitious mixtures containing p
23、ozzolans or blast-furnace slag istypically different than that for mixtures containing only portland cement.5.4 The apparent chloride diffusion coefficient is used inFicks second law of diffusion to estimate chloride penetrationinto cementitious mixtures that are in a saturated condition.5.5 The app
24、arent chloride diffusion coefficient is commonlyused in chloride ingress models based on Ficks second law ofdiffusion. The apparent diffusion coefficient determined by thismethod includes bound chloride, so proper use of the apparentchloride diffusion coefficient to predict chloride ingress re-quire
25、s consideration of chloride binding.5.6 The resistance to chloride penetration is affected by suchfactors as the environment, finishing, mixture composition,workmanship, curing, and age.6. Apparatus6.1 Balance, accurate to at least 60.01 g.6.2 Thermometer, accurate to at least 61.0 C.6.3 Controlled
26、Temperature Laboratory or Chamber. Thelaboratory or chamber shall maintain the temperature of awater bath at 23 6 2 C.6.4 Plastic Container, with tight-fitting lid. Select a con-tainer size in accordance with provisions in 9.1.2.6.5 Equipment for grinding off and collecting powder fromconcrete, mort
27、ar, or grout specimens in layers of approximately2 mm thickness. Refer to Figs. 1 and 2 for examples ofsatisfactory equipment (See Note 3).NOTE 3A lathe or milling machine equipped with a short-barrelcarbide-tipped, or diamond-tipped, core drill bit has been found satisfac-tory for profile grinding.
28、6.6 Resealable Polyethylene Bags, 200- to 300-mm wide by250- to 300-mm long, and sheet thickness not less than 0.1mm.6.7 Equipment for crushing concrete, mortar or grout. Suit-able equipment is described in Test Method C1152/C1152M.6.8 Equipment for chloride analysis as described in TestMethod C1152
29、/C1152M.6.9 Slide Caliper, accurate to at least 6 0.1 mm.7. Reagents and Materials7.1 Distilled or De-ionized Water.7.2 Calcium Hydroxide Ca(OH)2, technical grade.7.3 Calcium Hydroxide Solution, saturated, (approx. 3 g/L).7.4 Sodium Chloride NaCl, technical grade.7.5 Exposure LiquidAn aqueous NaCl s
30、olution preparedwith a concentration of 165 6 1 g NaCl per L of solution.7.6 Two-component Polyurethane or Epoxy-resin BasedPaint, capable of forming a barrier membrane that is resistantto chloride ion diffusion.8. Test Specimens8.1 Drilled cores, molded cylinders, or molded cubes areacceptable test
31、 specimens. One sample consists of at least twotest specimens representative of the cementitious mixtureunder test (See Note 4). Specimens must be free of defects suchas voids or cracks visible to the unaided eye (See Note 5). Theminimum dimension across the finished surface of each testspecimen mus
32、t be at least 75 mm, but not less than three timesthe nominal maximum aggregate particle size. The specimendepth must be at least 75 mm.NOTE 4The material between the exposed surface and the outermostlayer of reinforcement is often of interest because it is here that theprotection against chloride p
33、enetration is needed. Furthermore, the qualityof the material in this particular area can deviate from that in the rest ofthe system, as this region is often affected by construction practices.NOTE 5Specimens with voids deeper than the profile layer thicknesscan increase the apparent rate of chlorid
34、e penetration, and increases testvariability.8.2 Unless otherwise specified, provide 28 days of labora-tory standard moist curing in accordance with Practice C31/C31M or C192/C192M prior to sample preparation for immer-sion in the exposure liquid.8.2.1 Describe any variance from standard curing prac
35、ticein the report.8.3 For drilled cores obtained according to Test MethodC42/C42M, prepare the test specimen by cutting off theoutermost 75 mm of the core. The test specimen thus obtainedhas one face that is the original finished surface, and the otherface that is a sawn surface as shown in Fig. 3.C
36、1556 1128.4 For specimens prepared in accordance with PracticeC31/C31M or C192/C192M, the test specimen is prepared bycutting parallel to the finished surface. The top 75 mm is usedas the test specimen (see Fig. 3).8.5 From the remainder of the drilled core, or moldedspecimen, cut a slice that is at
37、 least 20-mm thick. Use this sliceto determine the initial chloride-ion content, Ci.8.6 Rinse the specimens with tap water immediately aftercutting. Scrub the surface with a stiff nylon brush, and rinseagain. Prior to sealing specimen surfaces, air dry until nomoisture can be removed from the surfac
38、e with a dry papertowel (See Note 6).8.6.1 Exposure specimens must be surface-dry but inter-nally moist prior to sealing. This condition is satisfied byFIG. 1 Profile Grinding Using a Milling MachineFIG. 2 Profile Grinding Using a LatheC1556 113standard moist-cured specimens allowed to air dry for n
39、o morethan 24 h in laboratory air maintained at 23 6 2 C and 50 63 % RH.NOTE 6Specimens cured in a saturated calcium hydroxide water bathare normally covered by residual lime particles. If this residue is notremoved and test specimens are allowed to temporarily dry in air, acalcium carbonate layer c
40、an form on the surface of the specimen. Thiscarbonate layer may interfere with the test result, which is why cleansingand rinsing with tap water after cutting or removal from the saturatedcalcium hydroxide water bath is required.8.7 Seal all sides of the exposure specimen except for thefinished surf
41、ace following the procedure described in TestMethod C1202.8.8 Determine the initial mass of the test specimen when thecoating has hardened.8.9 Immerse the test specimen in the saturated calciumhydroxide water bath at 23 6 2C in a tightly closed plasticcontainer. The container must be filled to the t
42、op to preventcarbonation. After 24 h of immersion, remove the specimen,blot the surface dry with a paper towel, and determine the massof the specimen in the surface-dry condition.8.10 The test specimen is immersed in a saturated calciumhydroxide water bath until the mass does not change by morethan
43、0.1 % in 24 h (See Note 7). An acceptable alternativeprocedure is to vacuum saturate the specimens with saturatedcalcium hydroxide solution using a vacuum chamber similar tothe system described in Test Method C1202.NOTE 7Typically, the mass of moist-cured specimens stabilizeswithin 48 h.9. Procedure
44、9.1 Exposure:9.1.1 Remove the saturated test specimen from the calciumhydroxide water bath, immediately rinse the specimen surfacewith tap water, place the specimen in the exposure container,fill the container with the exposure liquid, and then seal thecontainer. Place the container in a temperature
45、-controlledchamber or room maintained at 23 6 2C. Record the start dateand start time to the nearest hour.9.1.2 It is permitted to place multiple specimens in a singlecontainer as long as the specimens are placed in the containersuch that the entire exposure surface is unobstructed. Maintainthe expo
46、sed surface area to exposure liquid volume ratio withinthe range of 50 6 30 cm2/L (See Note 8).NOTE 8The volume of exposure liquid required for nominal 100-mmdiameter cylinder or core exposure specimens is approximately one literper specimen.9.1.3 The specimens must remain in the exposure liquid for
47、at least 35 days (See Note 9).NOTE 9The exposure time should be extended for mixtures such asthose that are more mature, were made with low w/cm, or high-performance mixtures containing supplementary cementitious materials.9.1.4 If evaporation of water from the exposure liquid or acontainer leak all
48、ows the specimen surface to dry during theexposure time, the test is not valid (See Note 10).NOTE 10It is suggested to monitor the mass of the sealed container ifevaporation of water from the exposure solution is expected.9.1.5 Record the exposure time to the nearest hour.9.2 Profile Grinding:9.2.1
49、Remove the test specimen from the exposure liquid,rinse with tap water, and dry for at least 24 h in laboratory airmaintained at 23 6 2C and 50 6 3 % RH.9.2.2 When grinding is to be performed longer than 48 hafter removal from the exposure solution, store the specimensin watertight resealable polyethylene bags until time of grind-ing. When grinding is to be performed longer than 7 days afterremoval from the exposure solution, store the bagged speci-mens in a freezer maintained at -15 C (65 C) until time ofgrinding.9.2.3 Obtain the powder sampl
