1、Designation: C1246 17Standard Test Method forEffects of Heat Aging on Weight Loss, Cracking, andChalking of Elastomeric Sealants After Cure1This standard is issued under the fixed designation C1246; the number immediately following the designation indicates the year oforiginal adoption or, in the ca
2、se 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. Scope1.1 This test method covers a laboratory procedure fordetermining the effects of heat aging on
3、 weight loss, crackingand chalking of elastomeric joint sealants (single and multi-component) for use in building construction.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.3 The committee having jurisdiction for this s
4、pecificationis not aware of any similar ISO standard.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 o
5、f regulatory limitations prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World T
6、rade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2C717 Terminology of Building Seals and SealantsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Terminology3.1 DefinitionsDefinitions of the follo
7、wing terms arefound in Terminology C717: cure, elastomeric, joint, sealant,self-leveling sealant, standard conditions.4. Summary of Test Method4.1 Sealant is spread on three aluminum panels and the netweight of sealant on each panel is determined. After the threesealant specimens are allowed to cure
8、 for 28 days at standardconditions, two specimens are then heat-aged for 21 days in aforced-draft oven maintained at 706 2C (158 6 3.6F). Thepercentage weight lost during the heat aging period is thendetermined and examination is made for presence of cracks andchalking.5. Significance and Use5.1 Wei
9、ght loss from a sealant after application in a buildingjoint can be detrimental to long term sealant durability. Asealants service life will be shortened if it containscomponents, critical to its durability, that are volatilized byhigh environmental temperatures. Also, development of cracksand chalk
10、ing lessens a sealants service life.5.2 The test described herein measures weight loss,cracking, and chalking. The amount of weight lost during theheat aging period and any cracking or chalking helps predictpremature sealant failure. However, a sealant developing nocracks or chalking, or low weight
11、loss in this test, does notnecessarily ensure good durability.6. Apparatus6.1 Forced-Draft Oven, controlled at 70 6 2C (158 63.6F).6.2 Balance, sensitive to 0.01 g.6.3 Rectangular Brass or TFE-Fluorocarbon Frame, withinside dimensions 130 by 40 by 3.2 mm (5 by 112 by18 in.).6.4 Aluminum Panels, thre
12、e, each 152 by 80 by 0.6 to 1.6mm (24 to 16 gage) (6 by 3 by 0.024 to 0.0625 in.).6.5 Straight Edge, metal or plastic, about 152 mm (6 in.)long.6.6 Thin Knife Blade.6.7 Spatula, steel, about 152 mm (6 in.) long.7. Procedure7.1 Unless otherwise specified by those authorizing the test,standard conditi
13、ons shall be used.1This test method is under the jurisdiction ofASTM Committee C24 on BuildingSeals and Sealants and is the direct responsibility of C24.20 on General TestMethods.Current edition approved June 1, 2017. Published June 2017. Originallyapproved in 1993. Last previous edition approved in
14、 2012 as C1246 00(2012).DOI: 10.1520/C1246-17.2For 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.Copyright ASTM
15、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 standardization established in the Decision on Principles for theDevelopment of International Standa
16、rds, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1Mon Apr 30 06 7.2 Test of Multicomponent Sealants:7.2.1 Condition at least 400 g of base compound andappropriate amount of curing agent in closed containers for atleast 24 h at standar
17、d conditions; then mix thoroughly togetherfor five min.7.2.2 Weigh each of the three aluminum panels to thenearest 0.01 g.7.2.3 Center the brass frame on an aluminum panel. Fill theframe with the mixed compound and strike it off flat with thestraightedge. Run a thin-bladed knife along the inside of
18、theframe to separate it from the sealant and immediately lift theframe from the sealant (Note 1). Prepare two more specimensthe same way.NOTE 1In the case of self-leveling sealants, do not lift the brass frameuntil the sealant is sufficiently set that it will retain its rectangular shape.7.2.4 Cure
19、the three specimens for 28 days at standardconditions.7.2.5 At the end of the 28 day cure period weigh eachspecimen to the nearest 0.01 g.7.2.6 Place two of the three specimens in the forced-draftoven at 706 2C (158 6 3.6F) for 21 days, leaving the third(control) specimen at standard conditions for
20、the same period.7.2.7 At the end of the 21 day heat-aging period, remove thespecimens from the oven and allow them to cool for1hatstandard conditions. Then weigh each specimen to the nearest0.01 g and calculate the percent weight loss during heat agingas follows:% WLha5W22 W3!/W22 W1! 3100 (1)where:
21、WLha= weight loss from cured sealant during heat aging,W1= weight of aluminum panel,W2= weight of panel and sealant after the 28 day cureperiod described in 7.2.4, andW3= weight of panel and sealant after 21 day heat-agingperiod described in 7.2.6.7.3 Test of Single-Component Sealants:7.3.1 Follow t
22、he same procedure as specified in 7.2.1 7.2.7, eliminating curing agent and the mixing necessary formulticomponent sealants.8. Report8.1 Report the following information for each sealant tested:8.1.1 Identification of the sealant tested.8.1.2 Description of the type of sealant, such as single ormult
23、icomponent, nonsag or self-leveling, color, etc.8.1.3 The percent weight losses during heat aging, % WLha,of the two heat aged specimens tested.8.1.4 Presence of cracking and chalking as compared withthe control specimen. Fig. 1 includes examples of crackingobtainable in this test. Number 0 represen
24、ts no cracking.8.1.5 Variation, if any, from the specified test procedure.9. Precision and Bias39.1 PrecisionThe precision information given below isbased on an interlaboratory study conducted in 1992 inaccordance with Practice E691, in which four sealants weretested in each of four laboratories, wi
25、th each laboratoryobtaining two test results on each sealant. Each of the two testresults was obtained on different days and is the average of twotest determinations.9.1.1 Repeatability:9.1.1.1 Weight LossIn future use of this test method, thedifference between two test results obtained in the samel
26、aboratory on the same material will be expected to exceed0.658 % only about five percent of the time.9.1.1.2 Cracking or ChalkingNone of the sealants testedshowed any cracking or chalking. Therefore, no repeatabilitywith respect to cracking or chalking has been established.9.1.2 Reproducibility:9.1.
27、2.1 Weight LossIn the future use of this test method,the difference between two test results obtained in differentlaboratories on the same material will be expected to exceed1.562 % only about five percent of the time.9.1.2.2 Cracking or ChalkingNone of the sealants testedshowed any cracking or chal
28、king. Therefore, no reproducibilitywith repect to cracking and chalking has been established.9.2 BiasSince there is no accepted reference material fordetermining the bias for this test method for the effects of heataging during cure on weight loss, cracking, and chalking, biashas not been determined
29、.10. Keywords10.1 durability; sealant; weight loss3Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:C24-1045.C1246 172Mon Apr 30 06 ASTM International takes no position respecting the validity of any patent rights asserted in conn
30、ection 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 respons
31、ible 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 c
32、onsideration 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, 10
33、0 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 website(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 1Number 0 represents no cracking.FIG. 1 Examples of Cracking Obtainable in This TestC1246 173Mon Apr 30 06
