1、Designation:C155611 Designation: C1556 11aStandard 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 oforigina
2、l adoption or, in the 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 of the appar
3、ent chloride diffusion coefficient for hardened cementitiousmixtures.1.2 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
4、. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C31/C31M Practice for Making and Curing Concrete Test Specimens in the FieldC42
5、/C42M Test Method for Obtaining and Testing Drilled Cores and Sawed Beams of ConcreteC125 Terminology Relating to Concrete and Concrete AggregatesC192/C192M Practice for Making and Curing Concrete Test Specimens in the LaboratoryC670 Practice for Preparing Precision and Bias Statements for Test Meth
6、ods for Construction MaterialsC1152/C1152M Test Method for Acid-Soluble Chloride in Mortar and ConcreteC1202 Test Method for Electrical Indication of Concretes Ability to Resist Chloride Ion Penetration2.2 NORDTEST Standards:NT BUILD 443, Approved 1995-11, Concrete, Hardened: Accelerated Chloride Pe
7、netration (in English)33. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this test method, refer to Terminology C125.3.2 Definitions of Terms Specific to This Standard:3.2.1 apparent chloride diffusion coeffcient, Da, na chloride transport parameter calculated from acid-soluble ch
8、loride profiledata obtained from saturated specimens exposed to chloride solutions, without correction for chloride binding, that provides anindication of the ease of chloride penetration into cementitious mixtures.3.2.2 chloride binding, vthe chemical process by which chloride ion is removed from s
9、olution and incorporated intocementitious binder hydration products.3.2.2.1 DiscussionChloride binding is primarily associated with hydration products formed by the aluminate phase of cementand mixtures containing ground granulated blast furnace slag.3.2.3 chloride penetration, vthe ingress of chlor
10、ide ions due to exposure to external sources.3.2.4 exposure liquid, nthe sodium chloride solution in which test specimens are stored prior to obtaining a chloride profile.3.2.5 exposure time, nthe time that the test specimen is stored in the solution containing chloride ion.3.2.6 initial chloride-io
11、n content, Ci, nthe ratio of the mass of chloride ion to the mass of concrete for a test specimen thathas not been exposed to external chloride sources.3.2.7 profile grinding, vthe process of grinding off and collecting a powder sample in thin successive layers from a testspecimen using a dry proces
12、s.1This test method is under the jurisdiction of ASTM Committee C09 on Concrete and Concrete Aggregates and is the direct responsibility of Subcommittee C09.66 onConcretes Resistance to Fluid Penetration.Current edition approved Oct.Dec. 15, 2011. Published November 2011.January 2012. Originally app
13、roved in 2003. Last previous edition approved in 20042011 asC155604.C155611. DOI: 10.1520/C1556-11a.2For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards D
14、ocument Summary page on the ASTM website.3Published by NORDTEST, P.O. Box 116 FIN-02151 ESPOO Finland, Project 1154-94, e-mail: nordtest vtt.fi, website: http:/www.vtt.fi/nordtest1This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what
15、 changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the
16、official document.*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, United States.3.2.8 surface chloride content, Cs, nthe theoretical ratio of the mass of chloride ion to the mass of
17、concrete at the interfacebetween the exposure liquid and the test specimen.4. Summary of Test Method4.1 Obtain a representative sample of the cementitious mixture prior to exposure to chloride ion. Separate each sample into atest specimen and an initial chloride-ion content specimen. Crush the initi
18、al chloride-ion content specimen and determine the initialacid-soluble chloride-ion content. Seal all sides of the test specimen, except the finished surface, with a suitable barrier coating.Saturate the sealed specimen in a calcium hydroxide solution, rinse with tap water, and then place in a sodiu
19、m chloride solution.After a specified exposure time, the test specimen is removed from the sodium chloride solution and thin layers are ground offparallel to the exposed face of the specimen. The acid-soluble chloride content of each layer is determined. The apparent chloridediffusion coefficient an
20、d the projected surface chloride-ion concentration are then calculated using the initial chloride-ion content,and at least six related values for chloride-ion content and depth below the exposed surface.5. Significance and Use5.1 This test method is applicable to cementitious mixtures that have not
21、been exposed to external chloride ions, other than thenegligible quantity of chloride ion exposure from sample preparation using potable water, prior to the test.5.2 The calculation procedure described in this test method is applicable only to laboratory test specimens exposed to a sodiumchloride so
22、lution as described in this test method. This calculation procedure is not applicable to specimens exposed to chlorideions during cyclic wetting and drying.NOTE 1The diffusion of ionic species in concrete occurs within the fluid-filled pores, cracks and void spaces. The concentration and valence of
23、otherionic species in the pore fluid also influence the rate of chloride diffusion, and therefore, the apparent diffusion coefficient as determined by this testprocedure.5.3 In most cases, the value of the apparent chloride diffusion coefficient for cementitious mixtures changes over time (See Note2
24、). Therefore, apparent diffusion coefficients obtained at early ages may not be representative of performance in service.NOTE 2The rate of change of the apparent diffusion coefficient for cementitious mixtures containing pozzolans or blast-furnace slag is typicallydifferent than that for mixtures co
25、ntaining only portland cement.5.4 The apparent chloride diffusion coefficient is used in Ficks second law of diffusion to estimate chloride penetration intocementitious mixtures that are in a saturated condition.5.5 The apparent chloride diffusion coefficient is commonly used in chloride ingress mod
26、els based on Ficks second law ofdiffusion. The apparent diffusion coefficient determined by this method includes bound chloride, so proper use of the apparentchloride diffusion coefficient to predict chloride ingress requires consideration of chloride binding.5.6 The resistance to chloride penetrati
27、on is affected by such factors 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 Temperature Laboratory or Chamber. The laboratory or chamber shall maintain
28、 the temperature of a water bathat 23 6 2 C.6.4 Plastic Container, with tight-fitting lid. Select a container size in accordance with provisions in 9.1.2.6.5 Equipment for grinding off and collecting powder from concrete, mortar, or grout specimens in layers of approximately 2mm thickness. Refer to
29、Figs. 1 and 2 for examples of satisfactory equipment (See Note 3).NOTE 3A lathe or milling machine equipped with a short-barrel carbide-tipped, or diamond-tipped, core drill bit has been found satisfactory forprofile grinding.6.6 Resealable Polyethylene Bags, 200- to 300-mm wide by 250- to 300-mm lo
30、ng, and sheet thickness not less than 0.1 mm.6.7 Equipment for crushing concrete, mortar or grout. Suitable equipment is described in Test Method C1152/C1152M.6.8 Equipment for chloride analysis as described in Test Method C1152/C1152M.6.9 Slide Caliper, accurate to at least 6 0.1 mm.7. Reagents and
31、 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 solution prepared with a concentration of 165 6 1 g NaCl per L of soluti
32、on.7.6 Two-component Polyurethane or Epoxy-resin Based Paint, capable of forming a barrier membrane that is resistant tochloride ion diffusion.C1556 11a28. Test Specimens8.1 Drilled cores, molded cylinders, or molded cubes are acceptable test specimens. One sample consists of at least two testspecim
33、ens representative of the cementitious mixture under test (See Note 4). Specimens must be free of defects such as voids orcracks visible to the unaided eye (See Note 5). The minimum dimension across the finished surface of each test specimen mustbe at least 75 mm, but not less than three times the n
34、ominal maximum aggregate particle size. The specimen depth must be at least75 mm.FIG. 1 Profile Grinding Using a Milling MachineFIG. 2 Profile Grinding Using a LatheC1556 11a3NOTE 4The material between the exposed surface and the outermost layer of reinforcement is often of interest because it is he
35、re that the protectionagainst chloride penetration is needed. Furthermore, the quality of the material in this particular area can deviate from that in the rest of the system, asthis region is often affected by construction practices.NOTE 5Specimens with voids deeper than the profile layer thickness
36、 can increase the apparent rate of chloride penetration, and increases testvariability.8.2 Unless otherwise specified, provide 28 days of laboratory standard moist curing in accordance with Practice C31/C31M orC192/C192M prior to sample preparation for immersion in the exposure liquid.8.2.1 Describe
37、 any variance from standard curing practice in the report.8.3 For drilled cores obtained according to Test Method C42/C42M, prepare the test specimen by cutting off the outermost 75mm of the core. The test specimen thus obtained has one face that is the original finished surface, and the other face
38、that is a sawnsurface as shown in Fig. 3.8.4 For specimens prepared in accordance with Practice C31/C31M or C192/C192M, the test specimen is prepared by cuttingparallel to the finished surface. The top 75 mm is used as the test specimen (see Fig. 3).8.5 From the remainder of the drilled core, or mol
39、ded specimen, cut a slice that is at least 20-mm thick. Use this slice todetermine the initial chloride-ion content, Cieither by crushing the entire slice or by grinding off a layer at least 2-mm thick.Alternately, if the profile from the diffusion test specimen is ground deep enough such that the l
40、ast 2 successive layers taken havechloride contents within 0.01 % by mass of concrete of each other, it is permitted to extrapolate the best-fit equation of the chlorideprofile to obtain the initial chloride-ion content, Ci.8.6 Rinse the specimens with tap water immediately after cutting. Scrub the
41、surface with a stiff nylon brush, and rinse again.Prior to sealing specimen surfaces, air dry until no moisture can be removed from the surface with a dry paper towel (See Note6).8.6.1 Exposure specimens must be surface-dry but internally moist prior to sealing. This condition is satisfied by standa
42、rdmoist-cured specimens allowed to air dry for no more than 24 h in laboratory air maintained at 23 6 2 C and 50 6 3 % RH.NOTE 6Specimens cured in a saturated calcium hydroxide water bath are normally covered by residual lime particles. If this residue is not removedand test specimens are allowed to
43、 temporarily dry in air, a calcium carbonate layer can form on the surface of the specimen. This carbonate layer mayinterfere with the test result, which is why cleansing and rinsing with tap water after cutting or removal from the saturated calcium hydroxide water bathis required.8.7 Seal all sides
44、 of the exposure specimen except for the finished surface following the procedure described in Test MethodC1202.8.8 Determine the initial mass of the test specimen when the coating has hardened.8.9 Immerse the test specimen in the saturated calcium hydroxide water bath at 23 6 2C in a tightly closed
45、 plastic container.The container must be filled to the top to prevent carbonation. After 24 h of immersion, remove the specimen, blot the surface drywith a paper towel, and determine the mass of the specimen in the surface-dry condition.8.10 The test specimen is immersed in a saturated calcium hydro
46、xide water bath until the mass does not change by more than0.1 % in 24 h (See Note 7). An acceptable alternative procedure is to vacuum saturate the specimens with saturated calciumhydroxide solution using a vacuum chamber similar to the system described in Test Method C1202.NOTE 7Typically, the mas
47、s of moist-cured specimens stabilizes within 48 h.9. Procedure9.1 Exposure:9.1.1 Remove the saturated test specimen from the calcium hydroxide water bath, immediately rinse the specimen surface withtap water, place the specimen in the exposure container, fill the container with the exposure liquid,
48、and then seal the container. Placethe container in a temperature-controlled chamber or room maintained at 23 6 2C. Record the start date and start time to thenearest hour.FIG. 3 Sketch of Specimens Obtained from a Typical SampleC1556 11a49.1.2 It is permitted to place multiple specimens in a single
49、container as long as the specimens are placed in the container suchthat the entire exposure surface is unobstructed. Maintain the exposed surface area to exposure liquid volume ratio within the rangeof 50 6 30 cm2/L (See Note 8).NOTE 8The volume of exposure liquid required for nominal 100-mm diameter cylinder or core exposure specimens is approximately one liter perspecimen.9.1.3 The specimens must remain in the exposure liquid for at least 35 days (See Note 9).NOTE 9The exposure time should be extended for mixtures such as those that are more
