1、Designation: D 6490 99 (Reapproved 2006)Standard Test Method forWater Vapor Transmission of NonFilm Forming TreatmentsUsed on Cementitious Panels1This standard is issued under the fixed designation D 6490; the number immediately following the designation indicates the year oforiginal adoption or, in
2、 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 the determination of the rate atwhich water vapor passes t
3、hrough non film forming treatments,such as silanes, siloxanes and blends of silanes/siloxanesapplied to cementitious substrates.1.2 This test method covers the use of the wet cup tech-nique, which most closely approaches the exterior conditionsfor use for these materials. Other conditions can be use
4、d ifagreed upon between purchaser and supplier. Agreementshould not be expected between results obtained by differentmethods or test conditions.1.3 The values stated in SI units of measurement aredesignated as the standard. Factors for conversion to inch-pound units are given in 9.2.1.1 and 9.2.2.1.
5、1.4 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 to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced D
6、ocuments2.1 ASTM Standards:2D 823 Practices for Producing Films of Uniform Thicknessof Paint, Varnish, and Related Products on Test PanelsD 1193 Specification for Reagent WaterD 1734 Practice for Making Cementitious Panels for Test-ing CoatingsD 3924 Specification for Environment for Conditioning an
7、dTesting Paint, Varnish, Lacquer, and Related MaterialsE 104 Practice for Maintaining Constant Relative Humidityby Means of Aqueous Solutions3. Summary of Test Method3.1 The treated cementitious substrate is sealed to the openmouth of an assembly containing water with the treated sidefacing the wate
8、r, and the assembly placed in a test chamberwith a controlled atmosphere maintained at 50 6 5 % relativehumidity at 23 6 2C (73.5 6 3.5F). Periodic weighings ofthe assembly are made to determine the rate of water vapormovement through the specimen.4. Significance and Use4.1 One of the factors affect
9、ing the performance providedby a cementitious treatment is how readily water vapor passesthrough it. Hence, the water vapor transmission characteristicsof treatments are important in assessing their performance inpractical use.4.2 The purpose of this test method is to obtain values ofwater vapor tra
10、nsfer through treatments that range in perme-ability from high to low. These values are for use in design,manufacture, and marketing.4.3 Water vapor transmission is not a linear function of filmthickness, temperature or relative humidity.4.4 Values of water vapor transmission rate (WVT) andwater vap
11、or permeance (WVP) can be used in the relativerating of treatments only if the treatments are tested under thesame closely controlled conditions of temperature and relativehumidity.5. Apparatus5.1 Assembly, consisting of a container, typically with anopening of approximately 75 mm (3 in.) by 150 mm
12、(6 in.).The depth of the dish is such that there is a 20 6 5 mm (0.8 60.2 in.) distance between the water surface and the surface of1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials and Applications and is the direct responsibility ofSubcommitt
13、ee D01.47 on Concrete, Stone and Masonry Treatments.Current edition approved June 1, 2006. Published June 2006. Originallyapproved in 1999. Last previous edition approved in 1999 as D 6490 - 99.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at s
14、erviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.the under surface of the test specimen, with a water
15、 depth of atleast 5 mm (0.2 in.). The assembly should be made of anoncorroding material, impermeable to water or water vapor inorder to be found acceptable. The treated cementitious sub-strate can be sealed with wax or sealant to the assembly. If theassembly is made of aluminum, it must be anodized
16、or given aprotective clear coating to prevent corrosion.5.2 Test Chamber, with a controlled temperature and rela-tive humidity as specified in Section 3. Air shall be circulatedthroughout the chamber to maintain uniform conditions at alltest locations.NOTE 1For maintaining constant relative humiditi
17、es other than thosespecified in 3.1, by means of aqueous solutions, refer to proceduresoutlined in Practice E 104.5.3 Analytical Balance, having an adequate capacity for theweight of the test assemblies and a sensitivity of 10 mg (0.0002lb).6. Reagents and Materials6.1 Purity of Water, unless otherw
18、ise indicated, reference towater shall be understood to mean reagent water conforming toType IV of Specification D 1193.6.2 Sealant, such as wax for attaching the coated panel tothe top of the test assembly. It must be highly resistant to thepassage of water vapor. It must not lose weight to, nor ga
19、inweight from the atmosphere in an amount, over the requiredperiod of time, that would affect the test results by more than2 %. It must not affect the vapor pressure in a water-filledassembly.NOTE 2Among acceptable sealants are (1) a 60:40 mixture ofmicrocrystalline wax and refined crystalline paraf
20、in wax, (2) tissueembedding wax, and (3) a 50:50 mixture of beeswax and rosin.7. Test Specimen7.1 Suggested cementitious substrates to be used should be75 by 150 by 15 mm (3 by 6 by916 in.) as outlined in PracticeD 1734. Before use, the substrates should be removed fromstorage in water, dried at 80
21、6 5C (176 6 9F) until a constantweight has been reached. A constant weight shall be assumedwhen the specimen weighed to the nearest 0.1 g loses not morethan 0.1 % in any 4-h period. Allow specimens to cool andstore at standard conditions as outlined in Specification D 3924before use.7.2 Apply treatm
22、ent to one face of the test substrates usingone of the methods described in Practices D 823 or by brushfollowing manufacturers application instructions. The amountof material (spreading rate) applied to the substrate must thenbe calculated and reported.7.3 Air-dry the treated substrate in a horizont
23、al position for7 days in a room preferably maintained at 236 2C (73.5 63.5F) and 50 6 5 % relative humidity as outlined in Specifi-cation D 3924. The drying schedule may be modified asrecommended by manufacturer.8. Procedure8.1 Prepare at least three test assemblies for each testmaterial as follows:
24、8.1.1 Fill the assembly with water to within 20 6 5mm(0.8 6 0.2 in. ) of the treated substrate.8.1.2 Seal the treated substrate to the top edge of theassembly with wax or sealant with the treated face placedfacing the water.8.2 Weigh the test assemblies to 0.1 g. and place them in thetest chamber. R
25、ecord time, temperature, and relative humidity.Unless other conditions are agreed upon between the purchaserand the seller, perform the test(s) in a chamber maintained at 236 2C (73 6 3.5F) and 50 6 5 % relative humidity.8.2.1 In general, the test assemblies should be weighedevery 24 h for a period
26、of time until the weight change per 24h has become consistent. The time that weighings are takenshould be recorded to the precision of approximately 1 % ofthe time span between weighings. Thus, if weighings are madeevery day, a time to the nearest 15 min would be allowed.8.2.2 Treatments expected to
27、 have high WVT ratings, over6.7 metric perms (10 perms), may require weighings morefrequently than once a day.8.3 Return the test assemblies to the test chamber immedi-ately after weighings.9. Calculation9.1 For each material tested, plot the weight changes againstelapsed time. When a straight line
28、adequately fits the plot of atleast four properly spaced points, a nominal steady state existsand the slope of the straight line is the rate of water vaportransmission.9.2 Calculate one or more of the following, depending of thewater vapor transmission characteristics to be determined:9.2.1 Calculat
29、e the water vapor transmission rate, WVT:9.2.1.1 In inch-pound units as follows:WVT 5 G/t!/A 5 grains per square foot per 1 h (1)where:G = weight change, grains (from the straight line),t = time during which G occurred, h,A = test area, square foot, and1 g = 15.43 grains.9.2.1.2 In metric units as f
30、ollows:WVT 5 G/t!/A 5 grams per square metre per 24 h (2)where:G = weight change, grams (from the straight line),t = time during which G occurred, h, andA = test area, square metre.9.2.2 Calculate the permeance, WVP:9.2.2.1 In inch-pound units as follows:WVP 5 WVT/p 5 grains per ft2per 1 h per inch
31、of mercury perms!(3)where:p =S(R1R2),S = inches of mercury (saturation vapor pressure at testtemperature) see Table 1,R1= relative humidity at vapor source, andR2= relative humidity at vapor sink.9.2.2.2 In metric units as follows:D 6490 99 (2006)2WVP 5 WVT/p5 grams per square metre per 24 h permill
32、imetre of mercury, metric perms! (4)where:p = S (R1 R2),S = millimetres of mercury (saturation vapor pressure attest temperature) see Table 1,R1= relative humidity at vapor source, andR2= relative humidity at vapor sink.10. Report10.1 Report the following information:10.1.1 Method of application and
33、 curing procedure used.10.1.2 Spreading rate applied or mean film thickness of thetest specimens for each material.10.1.3 Substrate, if different than specified in SpecificationD 1734.10.1.4 Test temperature and relative humidity in the testchamber.10.1.5 Computed rate of water vapor transmission (W
34、VT),either in inch-pound or in metric units.10.1.6 The computed permeance in terms of both perms andmetric units.11. Precision and Bias11.1 Precision is being developed in Subcommittee D01.47.11.2 Bias is not applicable to this test method.12. Keywords12.1 permeability; permeance; perms; water vapor
35、 per-meance; water vapor transmissionASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the ri
36、skof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of th
37、is standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake
38、 your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by
39、 contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).TABLE 1 Saturation Vapor PressureTemperature PressureF C in. Hg mm Hg72.3 22.4 0.800 20.31672.5 22.5 0.805 20.44072.7 22.6 0.810 20.56572.9 22.7
40、 0.816 20.69073.1 22.8 0.819 20.81573.3 22.9 0.824 20.94173.4 23.0 0.829 21.06873.6 23.1 0.834 21.19673.8 23.2 0.840 21.32474.0 23.3 0.845 21.45374.2 23.4 0.850 21.58374.4 23.5 0.855 21.71474.5 23.6 0.860 21.84599.3 37.4 1.894 48.10299.5 37.5 1.904 48.36499.7 37.6 1.914 48.62799.9 37.7 1.925 48.891100.1 37.8 1.935 49.157100.2 37.9 1.946 49.424100.4 38.0 1.956 49.692100.6 38.1 1.967 49.961100.8 38.2 1.978 50.231101.0 38.3 1.988 50.502101.1 38.4 1.999 50.774101.3 38.5 2.010 51.048101.5 38.6 2.021 51.323D 6490 99 (2006)3
