1、Designation: C1248 18Standard 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 last revision. A num
2、ber 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 aporous substrate (suc
3、h 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 stated in SI units ar
4、e 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 concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health, and enviro
5、nmental practices and deter-mine the applicability 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.1.5 This international standard was developed in accor-dance with internationally
6、 recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2C717 Terminolog
7、y of Building Seals and 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 Lab
8、oratory Light SourcesG154 Practice for Operating Fluorescent Ultraviolet (UV)Lamp Apparatus for 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 defin
9、itionsof terms used in this test method.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 unde
10、rcompression for up to 28 days; (b) 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 allow
11、s for additional exposure be-yond the 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 descri
12、bed in the three conditionsnamed in 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 substra
13、te.5. Significance and Use5.1 Staining 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 ne
14、cessarily predict that the testedsealants will not stain or discolor porous substrates over longerperiods of time.1This test method is under the jurisdiction ofASTM Committee C24 on BuildingSeals and Sealants and is the direct responsibility of Subcommittee C24.40 onWeathering.Current edition approv
15、ed June 1, 2018. Published June 2018. Originallyapproved in 1993. Last previous edition approved in 2012 as C1248-08(2012). DOI:10.1520/C1248-18.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards
16、volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on s
17、tandardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.16. Apparatus6.1 Forced-Draft Oven.6.2 Exposure Apparatus:6.2.1 Fluorescent UV/condens
18、ation apparatus that conformsto the requirements in Practices G151 and G154 with UVA-340type lamps.6.2.2 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
19、 25 by 25 by 75 mm (1 by 1 by 3 in.).A total of 24 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 st
20、atement is based on Vermont whitemarble and Bethel 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 Tes
21、t Specimens:7.3.1 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 standardconditions, mix thoroughly for 5 min at least 250 g of basecompound with the appropriate amount of curing agent.
22、 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 adhesive tape, rubber bands, or clamps to hold thetest specimen together before and after filling it with th
23、esealant. 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 onthe finished surface. Remove the tape immediately followingfilling of the specimen joint cavity.7.3.2 Single-Co
24、mponent SealantsPrepare the specimensas described in 7.3.1 except that no mixing is required.Condition the sealed cartridge or bulk container at standardconditions for at least 24 h before use.8. Conditioning8.1 Cure specimens for 21 days at standard conditions.Separate the TFE-fluorocarbon spacers
25、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-component sealants provided they meetthe following requirements: the curing period shall extend for 21 days; andt
26、he 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 beingtested.9.2 Store four compressed specimens at standard condi-tions. Remove two after 14 days and two after
27、 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 compressed specimens at the end of each extendedperiod.9.3 Place four compressed specimens in an oven at 706 2C(158 6
28、 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) for each extended period, andremove those two compressed specimens at the end of eachextended period.9.4 Exp
29、ose 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 of differences in type of light source andtest conditions, test results may differ with the type ofapparatus
30、 used. Consult Practices G154 and G155 for differ-ences in the spectral power distributions of the exposureFIG. 1 Stain Test SpecimenC1248 182sources and Practice C1442 for differences in test parameters inthe two types of apparatus specified.9.4.1 If testing beyond the minimum 28 day exposureperiod
31、, 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 Section 7.3 of Practice C1442. Remove two specimensafter 14 days (336 h) an
32、d two after 28 days (672 h).9.4.2.1 If testing beyond the minimum 28 day exposureperiod, similarly remove the two additional test specimensfrom the weathering device, after each extended period haselapsed.9.4.3 Procedure for Xenon-Arc ApparatusOperate the de-vice in accordance with the procedure in
33、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 specimensafter 28 days (1234 kJ/(m2 nm) at 340 nm). See Annex A1 inC1442 for determining the exposure time required to provid
34、ethe 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 period has elapsed, from the Xenon-ArcApparatus. When operated at the preferred irradiance level of0.51 W/(m2 nm) a
35、t 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 pieces on eachspecimen) to determine if the surface appearance has changedin any way. Measure the width of any stain in
36、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 specimen.9.6 Break the substrates into two pieces along the 25 mmaxis (the final pieces will be approximately 40 by 2
37、5 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 measurements tothe nearest 0.5 mm.10. Report10.1 Report the following information:10.1.1 Name of sealant, type of se
38、alant, 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 level andexposure cycle with test parameters.10.1.4.1 Report the total length (days) of exposure.10.1.5 Description of
39、 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 Description of, and reasons for any variations fromthe test procedure,10.1.7 Statement describing curing conditions if o
40、ther 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 for six test parameters tested by fourlaboratories are listed in Table 1. In future use of this testmethod, the diffe
41、rence 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)The reproducibility (betweengiven laboratories) intervals for six test parameters tested byfour laboratories are list
42、ed 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 Table 1 only about 5 % of the time.11.3 Both UVA and UVB type bulbs were evaluated in theround robin testing. Neglig
43、ible 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 natural ultraviolet.12. Keywords12.1 joint sealants; porous substrates; sealants; staining;ultraviolet exposureFIG. 2
44、 Staining Test Report FormC1248 183ASTM 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 risk
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49、978) 646-2600; http:/ 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 6.69Granite 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 184
