1、Designation: C 1246 00 (Reapproved 2006)Standard Test Method forEffects of Heat Aging on Weight Loss, Cracking, andChalking of Elastomeric Sealants After Cure1This standard is issued under the fixed designation C 1246; the number immediately following the designation indicates the year oforiginal ad
2、option or, in the case of revision, the year of last revision. A number 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 a laboratory procedure fordetermining the eff
3、ects 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 ju
4、risdiction 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
5、 the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C 717 Terminology of Building Seals and SealantsE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Terminology3.1 DefinitionsDefinitions of the follo
6、wing terms arefound in Terminology C 717: 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 stan
7、dardconditions, 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 seal
8、ant after 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 seal
9、ants service 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 tes
10、t, 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, three, each 152 by 8
11、0 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 conditions of temperatu
12、re and 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 toget
13、herfor 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 Nov. 15, 2006. Published January 2007. Originallyapproved in 1993. Last previous edition approved
14、in 2000 as C 1246 00.2For 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
15、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 a thin-bladed knife
16、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 retain its rectangul
17、ar 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(control) specimen at stan
18、dard 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 follows:% WLha5 W22 W3!/W
19、22 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 of Single-Component S
20、ealants: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 the type of sealant
21、, 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 crackingobtainable in this
22、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 E 691, in which four sealants weretested in each
23、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 between two test resu
24、lts 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 been established.9
25、.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 the sealants testeds
26、howed 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, cracking, and chalking, b
27、iashas not been determined.10. Keywords10.1 durability; sealant; weight loss3Supporting data is available from ASTM Headquarters. Request RR:C241045.C 1246 00 (2006)2NOTE 1Number 0 represents no cracking.FIG. 1 Examples of Cracking Obtainable in This TestASTM International takes no position respecti
28、ng 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 infringement of such rights, are entirely their own responsibility.This stand
29、ard 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 standard or for additional standardsand should be addressed to ASTM Internation
30、al 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 views known to the ASTM Committee on Standards, at the address shown below.T
31、his 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).C 1246 00 (2006)3
