1、Designation: C1248 08 (Reapproved 2012)Standard Test Method forStaining of Porous Substrate by Joint Sealants1This standard is issued under the fixed designation C1248; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of la
2、st revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers four types of laboratory tests todetermine if a joint sealant has a probability of staining apor
3、ous substrate (such as marble, limestone, sandstone, andgranite). The tests are on compressed samples and include (1)storage under standard laboratory conditions, (2) storage in anoven, and (3) exposure in a fluorescent UV/condensationdevice, and (4) exposure in a xenon arc device.1.2 The values sta
4、ted in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety problems, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety a
5、nd health practices and determine the applica-bility of regulatory limitations prior to use.1.4 The committee with jurisdiction over this standard is notaware of any comparable standards published by other orga-nizations.2. Referenced Documents2.1 ASTM Standards:2C717 Terminology of Building Seals a
6、nd SealantsC1442 Practice for Conducting Tests on Sealants UsingArtificial Weathering ApparatusG113 Terminology Relating to Natural and Artificial Weath-ering Tests of Nonmetallic MaterialsG151 Practice for Exposing Nonmetallic Materials in Accel-erated Test Devices that Use Laboratory Light Sources
7、G154 Practice for Operating Fluorescent LightApparatus forUV Exposure of Nonmetallic MaterialsG155 Practice for Operating Xenon Arc Light Apparatus forExposure of Non-Metallic Materials3. Terminology3.1 Definitions:3.1.1 Refer to Terminology C717 and G113 for definitionsof terms used in this test me
8、thod.4. Summary of Test Method4.1 In this test method standard joint specimens are com-pressed and clamped at the manufacturers rated movementcapability and subjected to the following treatments; (a) four ofthe specimens are stored at standard conditions while undercompression for up to 28 days; (b)
9、 four of the specimens areexposed in an oven while under compression for up to 28 days;(c) four of the specimens are exposed either in a fluorescentUV/condensation device or in a xenon arc device while undercompression for up to 28 days.4.1.1 This test method allows for additional exposure be-yond t
10、he minimum 28 day exposure period as described in 4.1.If it is desired to extend the exposure period beyond 28 days,prepare an additional six specimens for each extended expo-sure period. Of these six specimens prepared, two specimenseach should be stored as described in the three conditionsnamed in
11、 4.1.4.2 The effects of the test are evaluated by visual inspectionfor changes in surface appearance and average measurementsof any stain depth and stain width.4.3 This test method is applicable to any type of elastomericjoint sealant and any type of porous substrate.5. Significance and Use5.1 Stain
12、ing of building materials is an aesthetically unde-sirable occurrence. This test method evaluates the likelihood ofa sealant causing an early stain on a porous substrate due toexudation of materials from the sealant. Since this is anaccelerated test, it does not necessarily predict that the testedse
13、alants will not stain or discolor porous substrates over longerperiods of time.6. Apparatus6.1 Forced-Draft Oven.6.2 Exposure Apparatus:6.2.1 Fluorescent UV/condensation apparatus that conformsto the requirements in Practices G151 and G154 with UVA-340type lamps.1This test method is under the jurisd
14、iction ofASTM Committee C24 on BuildingSeals and Sealants and is the direct responsibility of Subcommittee C24.40 onWeathering.Current edition approved Dec. 1, 2012. Published December 2012. Originallyapproved in 1993. Last previous edition approved in 2008 as C1248-08. DOI:10.1520/C1248-08R12.2For
15、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.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700,
16、West Conshohocken, PA 19428-2959. United States16.2.2 Xenon-Arc apparatus that conforms to the require-ments in Practices G151 and G155 with daylight type filters.6.3 TFE-Fluorocarbon Spacers.6.4 Masking Tape.7. Test Specimens7.1 Substrates shall be 25 by 25 by 75 mm (1 by 1 by 3 in.).A total of 24
17、substrates are required to make the twelve testspecimens.7.1.1 If testing beyond the minimum 28 day exposureperiod, prepare an additional twelve substrates to make the sixadditional test specimens as required in 4.1.1.NOTE 1The precision and bias statement is based on Vermont whitemarble and Bethel
18、white granite substrates.7.2 PrimersWhen a primer is recommended by the sealantmanufacturer, apply the primer to one substrate block of eachtest specimen. Apply the primer where the sealant will be incontact with the substrate.7.3 Preparation of Test Specimens:7.3.1 Standard conditions of temperatur
19、e and relative hu-midity used throughout this test method are defined as 23 62C (73.4 6 3.6F) and 50 6 5 %, respectively.7.3.2 Multi-Component SealantsPrepare twelve testspecimens for each substrate that is to be used in the test. Aftermaintaining the unopened sample for at least 24 h at standardcon
20、ditions, mix thoroughly for 5 min at least 250 g of basecompound with the appropriate amount of curing agent. Applya bead of sealant 13 by 13 by 50 mm (12 by12 by 2 in.)between parallel 25 by 75 mm (1 by 3 in.) faces of substrates(see Fig. 1). Use appropriate spacers to form the proper sizebead. Use
21、 adhesive tape, rubber bands, or clamps to hold thetest specimen together before and after filling it with thesealant. In the case of a self leveling sealant, use masking orother suitable tape to retain the sealant. Use masking tape onthe top surface of substrates to prevent sealant from curing onth
22、e finished surface. Remove the tape immediately followingfilling of the specimen joint cavity.7.3.3 Single-Component SealantsPrepare the specimensas described in 7.3.2 except that no mixing is required.Condition the sealed cartridge or bulk container at standardconditions for at least 24 h before us
23、e.8. Conditioning8.1 Cure specimens for 21 days at standard conditions.Separate the TFE-fluorocarbon spacers from the sealant assoon as practical during the curing period without damagingthe sealant.NOTE 2The producer may request conditions other than standardconditions for the curing of single-comp
24、onent sealants provided they meetthe following requirements: the curing period shall extend for 21 days; andthe temperature during the curing period shall not exceed 50C (122F).9. Procedure9.1 Compress all test specimens and clamp them at themanufacturers rated movement capability for the sealant be
25、ingtested.9.2 Store four compressed specimens at standard condi-tions. Remove two after 14 days and two after 28 days.9.2.1 If testing beyond the minimum 28 day exposureperiod, prepare an additional two compressed specimens atstandard conditions for each extended period, and removethose two compress
26、ed specimens at the end of each extendedperiod.9.3 Place four compressed specimens in an oven at 706 2C(158 6 3.6F). Remove two after 14 days and two after 28days.9.3.1 If testing beyond the minimum 28 day exposureperiod, place an additional two compressed specimens in anoven at 70 6 2C (158 6 3.6F)
27、 for each extended period, andremove those two compressed specimens at the end of eachextended period.9.4 Expose four compressed samples in one of the labora-tory accelerated exposure devices listed below. Choice of typeof apparatus shall be by mutual agreement among the inter-ested parties. Because
28、 of differences in type of light source andtest conditions, test results may differ with the type ofapparatus used. Consult Practices G154 and G155 for differ-ences in the spectral power distributions of the exposuresources and Practice C1442 for differences in test parameters inthe two types of app
29、aratus specified.9.4.1 If testing beyond the minimum 28 day exposureperiod, similarly expose two additional compressed samples inthe devices as described in 9.4, for each extended period.9.4.2 Procedure for Fluorescent UV/CondensationApparatusOperate the device in accordance with the proce-dure in S
30、ection 7.3 of Practice C1442. Remove two specimensafter 14 days (336 h) and two after 28 days (672 h).FIG. 1 Stain Test SpecimenC1248 08 (2012)29.4.2.1 If testing beyond the minimum 28 day exposureperiod, similarly remove the two additional test specimensfrom the weathering device, after each extend
31、ed period haselapsed.9.4.3 Procedure for Xenon-Arc ApparatusOperate the de-vice in accordance with the procedure in Section 7.2 ofPractice C1442. When operated at the preferred irradiancelevel of 0.51 W/(m2 nm) at 340 nm, remove two specimensafter 14 days (617 kJ/(m2 nm) at 340 nm) and two specimens
32、after 28 days (1234 kJ/(m2 nm) at 340 nm). See Annex A1 inC1442 for determining the exposure time required to providethe same radiant exposure at other irradiance levels.9.4.3.1 If testing beyond the minimum 28 day exposureperiod, similarly remove the two additional test specimensafter each extended
33、 period has elapsed, from the Xenon-ArcApparatus. When operated at the preferred irradiance level of0.51 W/(m2 nm) at 340 nm, the exposure is 44.07 kJ/(m2 nm)at 340 nm, per day of exposure.9.5 Allow specimens to cool at standard conditions for oneday. Examine the surface of the substrates (both piec
34、es on eachspecimen) to determine if the surface appearance has changedin any way. Measure the width of any stain in at least threeplaces. Record the average of the measurements to the nearest0.5 mm. If primer was used, record the stain width separatelyfor the primed and unprimed substrates on each s
35、pecimen.9.6 Break the substrates into two pieces along the 25 mmaxis (the final pieces will be approximately 40 by 25 by 25 mmin size). If there was a surface stain, break the substrates at thepoint of maximum surface stain. Measure the stain depth in atleast three places. Record the average of the
36、measurements tothe nearest 0.5 mm.10. Report10.1 Report the following information:10.1.1 Name of sealant, type of sealant, rated movementcapability and identifying batch number,10.1.2 Substrates used,10.1.3 Name and description of primers used, if any,10.1.4 Type of exposure apparatus, irradiance le
37、vel andexposure cycle with test parameters.10.1.4.1 Report the total length (days) of exposure.10.1.5 Description of test effects observed, such as changein finished surface appearance, discoloration into the substrate,or other characteristics; average measurement of stain widthand depth,10.1.6 Desc
38、ription of, and reasons for any variations fromthe test procedure,10.1.7 Statement describing curing conditions if other thanat standard conditions, and10.1.8 Record data on report form (see Fig. 2).11. Precision and Bias11.1 Repeatability (Ir)The repeatability (within a givenlaboratory) intervals f
39、or six test parameters tested by fourlaboratories are listed in Table 1. In future use of this testmethod, the difference between two test results obtained in thesame laboratory on the same material will be expected toexceed the values in Table 1 only about 5 % of the time.11.2 Reproducibility (IR)T
40、he reproducibility (betweengiven laboratories) intervals for six test parameters tested byfour laboratories are listed in Table 1. In future use of this testmethod, the difference between two test results obtained indifferent laboratories on the same material will be expected toexceed the values in
41、Table 1 only about 5 % of the time.11.3 Both UVA and UVB type bulbs were evaluated in theround robin testing. Negligible difference was found betweenthese two types of bulbs during this short exposure period.However, UVA bulbs are the recommended light sourceinasmuch as they more closely represent n
42、atural ultraviolet.12. Keywords12.1 joint sealants; porous substrates; sealants; staining;ultraviolet exposureFIG. 2 Staining Test Report FormC1248 08 (2012)3ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standa
43、rd. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof 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 reviewe
44、d every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible
45、technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake 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 Consh
46、ohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by 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). Permission rights to p
47、hotocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).TABLE 1 Repeatability (Ir) and Reproducibility (IR)MaterialDepth of Stain (mm) Width of Stain (mm)Ir IR Ir IRPolyurethaneMarble 0.68 1.14 0.72 1.10Granite 1.02 2.29 1.25 3.56SiliconeMarble 2.72 10.35 3.14 6.69G
48、ranite 1.38 13.46 2.69 5.93PolysulfideMarble 2.74 12.73 1.42 3.62Granite 1.48 13.33 1.08 1.73LatexMarble 1.27 2.03 0.51 1.02Granite 1.02 2.03 0.76 1.78Styrene Block CopolymerMarble 0.51 1.52 0.25 0.76Granite 0.51 1.02 0.25 0.51Oil BaseMarble 5.08 6.10 4.83 7.11Granite 2.54 3.05 3.81 4.57C1248 08 (2012)4
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