1、Designation: C1246 00 (Reapproved 2012)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 oforigi
2、nal adoption 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 for determining t
3、he effects of heat aging on weight loss, cracking andchalking of elastomeric joint sealants (single and multicomponent) for use in building construction.1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.3 The committee ha
4、ving jurisdiction for this specification is not aware of any similar ISO standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and d
5、etermine the applicability of regulatorylimitations prior to use.1.5 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendatio
6、ns issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2C717 Terminology of Building Seals and SealantsE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method3. Terminology3.1 Definition
7、sDefinitions of the following terms are found in Terminology C717: cure, elastomeric, joint, sealant,self-leveling sealant.sealant, standard conditions.4. Summary of Test Method4.1 Sealant is spread on three aluminum panels and the net weight of sealant on each panel is determined.After the three se
8、alantspecimens are allowed to cure for 28 days at standard conditions, two specimens are then heat-aged for 21 days in a forced-draftoven maintained at 706 2C (158 6 3.6F). The percentage weight lost during the heat aging period is then determined andexamination is made for presence of cracks and ch
9、alking.5. Significance and Use5.1 Weight loss from a sealant after application in a building joint can be detrimental to long term sealant durability.Asealantsservice life will be shortened if it contains components, critical to its durability, that are volatilized by high environmentaltemperatures.
10、 Also, development of cracks and chalking lessens a sealants service life.5.2 The test described herein measures weight loss, cracking, and chalking. The amount of weight lost during the heat agingperiod and any cracking or chalking helps predict premature sealant failure. However, a sealant develop
11、ing no cracks or chalking,or low weight loss in this test, does not necessarily ensure good durability.1 This test method is under the jurisdiction of ASTM Committee C24 on Building Seals and Sealants and is the direct responsibility of C24.20 on General Test Methods.Current edition approved June 1,
12、 2012June 1, 2017. Published July 2012June 2017. Originally approved in 1993. Last previous edition approved in 20062012 asC1246 00(2006).(2012). DOI: 10.1520/C1246-00R12.10.1520/C1246-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at servicea
13、stm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Beca
14、useit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 B
15、arr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16. Apparatus6.1 Forced-Draft Oven, controlled at 70 6 2C (158 6 3.6F).6.2 Balance, sensitive to 0.01 g.6.3 Rectangular Brass or TFE-Fluorocarbon Frame, with inside dimensions 130 by 40 by 3.2 mm (5 by 112 by 18 in.).6.4 A
16、luminum Panels, three, each 152 by 80 by 0.6 to 1.6 mm (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
17、 test, standard conditions of temperature and relative humidity for thetest shall be 23 6 2C (73 6 3.6F) and 50 6 5 %, respectively.shall be used.7.2 Test of Multicomponent Sealants:7.2.1 Condition at least 400 g of base compound and appropriate amount of curing agent in closed containers for at lea
18、st 24h at standard conditions; then mix thoroughly together for five min.7.2.2 Weigh each of the three aluminum panels to the nearest 0.01 g.7.2.3 Center the brass frame on an aluminum panel. Fill the frame with the mixed compound and strike it off flat with thestraightedge. Run a thin-bladed knife
19、along the inside of the frame to separate it from the sealant and immediately lift the framefrom the sealant (Note 1). Prepare two more specimens the same way.NOTE 1In the case of self-leveling sealants, do not lift the brass frame until the sealant is sufficiently set that it will retain its rectan
20、gular shape.7.2.4 Cure the three specimens for 28 days at standard conditions.7.2.5 At the end of the 28 day cure period weigh each specimen to the nearest 0.01 g.7.2.6 Place two of the three specimens in the forced-draft oven at 7062C (15863.6F) for 21 days, leaving the third (control)specimen at s
21、tandard conditions for the same period.7.2.7 At the end of the 21 day heat-aging period, remove the specimens from the oven and allow them to cool for 1 h at standardconditions. Then weigh each specimen to the nearest 0.01 g and calculate the percent weight loss during heat aging as follows:%WLha5W2
22、2W 3!/W22W1!3100 (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 cure period described in 7.2.4, andW3 = weight of panel and sealant after 21 day heat-aging period described in 7.2.6.7.3 Test of Single-C
23、omponent Sealants:7.3.1 Follow the 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 o
24、f sealant, such as single or multicomponent, 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 with the control specimen. Fig. 1 includes examples of cracking obtain
25、ablein 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 is based on an interlaboratory study conducted in 1992 in accordancewith Practice E691, in which four sealants were te
26、sted in each of four laboratories, with each laboratory obtaining two test resultson each sealant. Each of the two test results was obtained on different days and is the average of two test determinations.9.1.1 Repeatability:3 Supporting data have been filed at ASTM International Headquarters and ma
27、y be obtained by requesting Research Report RR:C24-1045.C1246 1729.1.1.1 Weight LossIn future use of this test method, the difference between two test results obtained in the same laboratoryon the same material will be expected to exceed 0.658 % only about five percent of the time.9.1.1.2 Cracking o
28、r ChalkingNone of the sealants tested showed any cracking or chalking. Therefore, no repeatability withrespect to cracking or chalking has been established.9.1.2 Reproducibility:9.1.2.1 Weight LossIn the future use of this test method, the difference between two test results obtained in differentlab
29、oratories on the same material will be expected to exceed 1.562 % only about five percent of the time.9.1.2.2 Cracking or ChalkingNone of the sealants tested showed any cracking or chalking. Therefore, no reproducibility withrepect to cracking and chalking has been established.9.2 BiasSince there is
30、 no accepted reference material for determining the bias for this test method for the effects of heat agingduring cure on weight loss, cracking, and chalking, bias has not been determined.10. Keywords10.1 durability; sealant; weight lossC1246 173ASTM International takes no position respecting the va
31、lidity of any patent rights asserted in connection with any item mentioned inthis 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 su
32、bject 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 International Headqua
33、rters. 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.This standa
34、rd 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 serv
35、iceastm.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:/ 174NOTE 1Number 0 represents no cracking.C1246 175FIG. 1 Examples of Cracking Obtainable in This TestC1246 176
