1、Designation: C 1248 06Standard Test Method forStaining of Porous Substrate by Joint Sealants1This standard is issued under the fixed designation C 1248; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A n
2、umber 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 four types of laboratory tests todetermine if a joint sealant has a probability of staining aporous substrate (
3、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 stated in SI units
4、 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 and health pract
5、ices 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:2C 717 Terminology of Building Seals and SealantsC 1
6、442 Practice for Conducting Tests on Sealants UsingArtificial Weathering ApparatusG113 Terminology Relating to Natural and ArtificialWeathering Tests of Nonmetallic MaterialsG 151 Practice for Exposing Nonmetallic Materials in Ac-celerated Test Devices that Use Laboratory Light SourcesG 154 Practice
7、 for Operating Fluorescent Light Apparatusfor UV Exposure of Nonmetallic MaterialsG 155 Practice for Operating Xenon Arc Light Apparatusfor Exposure of Non-Metallic Materials3. Terminology3.1 Definitions:3.1.1 Refer to Terminology C 717 and G113for definitionsof terms used in this test method.4. Sum
8、mary 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) four of th
9、e 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.4.2 The effects of the test are evaluated by visual inspectionfor changes
10、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 Staining of building materials is an aesthetically unde-sirable occurrence. This tes
11、t 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 testedsealants will not stain or discolor porous substrates over longerperiods of time.
12、6. Apparatus6.1 Forced-Draft Oven.6.2 Exposure Apparatus:6.2.1 Fluorescent UV/condensation apparatus that conformsto the requirements in Practices G 151 and G 154 with UVA-340 type lamps.6.2.2 Xenon-Arc apparatus that conforms to the require-ments in Practices G 151 and G 155 with daylight type filt
13、ers.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 approved Jan. 1, 2006. Published February 2006. Originallyapproved in 1993. Last previous edition approved in 2004 a
14、s C 1248-04.2For 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.1Copyright ASTM International, 100 Barr Harbor Dr
15、ive, PO Box C700, West Conshohocken, PA 19428-2959, United States.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 substrates are required to make the twelve testspecimens.NOTE 1The precision and bias statement i
16、s based on Vermont whitemarble and Bethel white granite substrates.7.2 PrimersWhen a primer is recommended by the seal-ant manufacturer, apply the primer to one substrate block ofeach test specimen. Apply the primer where the sealant will bein contact with the substrate.7.3 Preparation of Test Speci
17、mens:7.3.1 Standard conditions of temperature 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 unop
18、ened 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. 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 appropri
19、ate spacers to form the proper sizebead. Use 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 su
20、bstrates to prevent sealant from curing onthe 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 st
21、andardconditions for at least 24 h before use.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 stan
22、dardconditions for the curing of single-component 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
23、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 28 days.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.9.4 Expose four compre
24、ssed 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 used. Consult
25、Practices G 154 and G 155 for differ-ences in the spectral power distributions of the exposuresources and Practice C 1442 for differences in test parametersin the two types of apparatus specified.9.4.1 Procedure for Fluorescent UV/CondensationApparatusOperate the device in accordance with the proce-
26、dure in Section 7.3 of Practice C 1442. Remove two specimensafter 14 days (336 h) and two after 28 days (672 h).9.4.2 Procedure for Xenon-Arc ApparatusOperate thedevice in accordance with the procedure in Section 7.2 ofPractice C 1442. When operated at the preferred irradiancelevel of 0.51 W/(m2 nm)
27、 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 inC 1442 for determining the exposure time required to providethe same radiant exposure at other irradiance levels.9.5 Allow specimens to cool at standard
28、 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 at least threeplaces. Record the average of the measurements to the nearest0.5 mm. If primer was used, record th
29、e 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 25 by 25 mmin size). If there was a surface stain, break the substrates at theFIG. 1 Stain Test SpecimenC1248062p
30、oint 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 sealant, rated movementcapability and identifying batch number,10.1.2 Substrates
31、 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.10.1.5 Description of test effects observed, such as changein finished surface appearance, discoloration into the substrate,or other characteristics; a
32、verage 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 other thanat standard conditions, and10.1.8 Record data on report form (see Fig. 2).11. Precision and Bias11.1 Repeatability (Ir)Th
33、e repeatability (within a givenlaboratory) intervals for 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
34、 only about 5 % of the time.11.2 Reproducibility (IR)The 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
35、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. Negligible difference was found betweenthese two types of bulbs during this short exposure period.However, UVA bulbs are the recommended
36、 light sourceinasmuch as they more closely represent natural ultraviolet.12. Keywords12.1 joint sealants; porous substrates; sealants; staining;ultraviolet exposureFIG. 2 Staining Test Report FormC1248063ASTM International takes no position respecting the validity of any patent rights asserted in co
37、nnection 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 riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the respo
38、nsible technical committee and must be reviewed 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
39、 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 your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International,
40、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 contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM
41、 website(www.astm.org).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 6.69Granite 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 4.57C1248064
