1、Designation: C1246 00 (Reapproved 2012)Standard 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 adop
2、tion or, in the case 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 effect
3、s of heat aging on 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 juris
4、diction for this specificationis 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 th
5、e applica-bility of regulatory limitations prior to use.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 following
6、terms arefound in Terminology C717: cure, elastomeric, joint, sealant,self-leveling sealant.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 for 28 days at standardco
7、nditions, 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 Weight loss from a sealant af
8、ter application in a buildingjoint can be detrimental to long term sealant durability. Asealants service life will be shortened if it contains compo-nents, critical to its durability, that are volatilized by highenvironmental temperatures. Also, development of cracks andchalking lessens a sealants s
9、ervice life.5.2 The test described herein measures weight loss, crack-ing, and chalking. The amount of weight lost during the heataging period and any cracking or chalking helps predictpremature sealant failure. However, a sealant developing nocracks or chalking, or low weight loss in this test, doe
10、s 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, three, each 152 by 80 by 0
11、.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 conditions of temperature and
12、 relative humidity forthe test shall be 23 6 2C (73 6 3.6F) and 50 6 5%,respectively.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 standard conditions; then mix thoroughly togetherfor
13、 five min.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, 2012. Published July 2012. Originally approvedin 1993. Last previous edition approved in 2006 as
14、 C1246 00(2006). DOI:10.1520/C1246-00R12.2For 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 Inte
15、rnational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.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
16、a thin-bladed knife along the inside of 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
17、retain its rectangular shape.7.2.4 Cure 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(contr
18、ol) specimen at standard conditions for 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 follo
19、ws:% WLha5 W22 W3!/W22 W1! 3 100 (1)where: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 o
20、f Single-Component Sealants:7.3.1 Follow the same procedure as specified in 7.2.1-7.2.7,eliminating curing agent and the mixing necessary for multi-component 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
21、 the type of sealant, such as single ormulticomponent, 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 crackin
22、gobtainable in this test. Number 0 represents 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
23、weretested in each of four laboratories, with 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 Loss In future use of this test method, thedifference be
24、tween two test results obtained in the samelaboratory 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
25、 been established.9.1.2 Reproducibility:9.1.2.1 Weight Loss In 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 t
26、he sealants testedshowed any cracking or chalking. 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, cracki
27、ng, and chalking, biashas not been determined.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 00 (2012)2NOTE 1Number 0 represents no cracking.FIG. 1 Examples of Cra
28、cking Obtainable in This TestASTM 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 riskof inf
29、ringement 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 this stand
30、ard 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 your vi
31、ews 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 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 ASTM website (www.astm.org/COPYRIGHT/).C1246 00 (2012)3
