1、Designation: C1756 17C1756 17aStandard Guide forComparing Seal or Sealant Behavior to ReferencePhotographs1This standard is issued under the fixed designation C1756; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、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 guide provides photographs that illustrate sealant behavior terms that have been defined by seal and sealant behaviorc
3、onsistent with the scope and areas of interest of Committee C24.1.2 When available, photographs that better illustrate these terms, or that illustrate additional terms defined by Committee C24,will be included in future editions of this standard. Photographs for consideration may be submitted to the
4、 committee using theform in Appendix X1.1.3 The committee with jurisdiction over this standard is not aware of any comparable standards published by otherorganizations.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityo
5、f the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability ofregulatory limitations prior to use.1.5 This international standard was developed in accordance with internationally recognized principles on standardizationestablished
6、in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2C717 Terminology of Building Seals and Sealants3. Terminology3.1 The t
7、erms used in this guide are defined in Terminology C717.4. Significance and Use4.1 This guide is intended to be used in evaluating sealant conditions that occur in service, along with other diagnostictechniques in failure analysis. These standard reference photographs have been selected and approved
8、 throughASTMs consensusballoting process to illustrate terms defined by Committee C24.4.2 Not all of the terms illustrated here are failures, and there are other failure mechanisms that affect sealants that are notdiscussed in this guide. This guide is intended to be one of a number of sources of in
9、formation used in the evaluation of sealantbehavior.5. Reference Photographs5.1 Figs. 1-9 present a standard reference photograph for each of the terms defined in Terminology C717, reprinted with theirdefinitions.1 This guide is under the jurisdiction of ASTM Committee C24 on Building Seals and Seal
10、ants and is the direct responsibility of Subcommittee C24.10 onSpecifications,Guides and Practices.Current edition approved Sept. 1, 2017Nov. 1, 2017. Published September 2017November 2017. Originally approved in 2011. Last previous edition approved in 20142017as C1756-14.-17. DOI: 10.1520/C1756-17.
11、10.1520/C1756-17A.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.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 i
12、s intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit 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
13、 current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16. Keywords6.1 adhesion failure; chalking; cohesion failure; crazed; dirt pick-up; elastome
14、ric joint sealant; fluid migration; reversion;rundown; sagadhesion failure, nin building construction, failure of the bond between a sealant and a substrate.DiscussionThis definition pertains to interfacial adhesion failure, a lack of bond at the interface between the materials. Interphasal adhesion
15、 failure, within the sealantor substrate near the interface, is less common and may appear to be interfacial without the use of magnification.FIG. 1 Adhesion Failurechalking, vin building construction, formation of a powder on the surface of a sealant that is caused by the disintegration of the poly
16、mer or binding medium due toweathering.FIG. 2 Chalkingcohesive failure, nin building construction, failure characterized by rupture within the sealant.FIG. 3 Cohesive FailureC1756 17a2crazed, adjin building construction, having a random network of cracks in asealant surface which do not penetrate th
17、rough the body of the material.FIG. 4 Crazeddirt pick-up, nin building construction, soiling caused by a foreign materialother than micro-organism growth that is deposited on, adhered to, or embeddedinto a sealant.FIG. 5 Dirt Pick-upfluid migration, nin building construction, accumulation of a fluid
18、 from a sealanton or in an adjacent material.FIG. 6 Fluid Migrationreversion, nin building construction in joint sealing, a loss of elastomericproperties and a decrease in durometer hardness of a seal or cured sealantfollowing environmental exposure.DiscussionSoftening and the ability to permanently
19、 reshape a seal or sealantusually characterizes reversion. Depending on a specific seal or sealantformulation, high heat, ultraviolet radiation, or moisture (as a liquid or vapor) maycause reversion acting either alone or in combination. The seal and sealantindustry is not in agreement on reversion
20、causes.FIG. 7 Reversionrundown, nin building construction, discoloration of a buildings surfaces bymovement of a contaminant due to natural forces.DiscussionNatural forces include wind, snow-melt, rain movement by surfacetension, gravity, capillary action, kinetic energy, and air currents.Typical mo
21、vementof contaminants includes fluid migration and blooming from a sealant, deposit ofatmospheric pollutants, and chemical staining.FIG. 8 RundownC1756 17a3APPENDIXX1. TRANSMITTAL FORM SEALANT FAILURE PHOTO(S) FOR C1756INTRODUCTIONPlease submit photographs of sealant failures with this transmittal f
22、rom by email to thesubcommittee C24.10 on Specifications, Guides and Practices, chairperson. Current email addressesare available on the roster on ASTMs web site.X1.1 PhotographsX1.1.1 Submit JPEG or TIFF files with resolution of at least 1200 960 pixels, grayscale. (Selected photos will be converte
23、d toTIFFs for publication.)X1.1.2 Do not show brand names or other identifiable proprietary information in the photos (or state them on the form).X1.1.3 Photographs of sealant failures in service are preferred to laboratory or mock-up conditions. However, staged or laboratoryphotographs will be cons
24、idered.X1.1.4 The person submitting these photos represents to ASTM that, to the best of his/her knowledge, information, and belief,there is not copyright or other limitation on ASTMs use of these photos, and he/she acknowledges that ASTM maintains theexclusive right to publish these phtotos.sagnin
25、building construction, the gravity-induced downward flow of asealant or glazing compund, resulting in an uneven thickness, when applied on avertical surface.FIG. 9 SagC1756 17a4X1.2 Transmittal FormX1.2.1 Complete as much of this form as possible (leave blanks if necessary), and submit it as an atta
26、chment to the same emailmessage with the photos.X1.2.2 Submit completed from in TIFF or PDF format.X1.2.3 Multiple photographs may be submitted with the same transmittal form so long as they relate to the same condition; forexample, multiple views of the same detail will allow the subcommittee to un
27、derstand the condition and select the bestrepresentation.Condition illustrated (i.e., adhesion failure): _Generic sealant chemistry, if known (i.e., 2-part urethane): _Substrates (i.e., brick masonry and anodized aluminum): _Approximate date sealant was installed, if known: _Data photo taken: _Locat
28、ion (city, state): _Weather exposure (i.e., north face under roof eave): _Observations and comments to be considered by subcommittee: _Form completed and photo(s) submitted by (printed name): _Submitted on (date): _ASTM International takes no position respecting the validity of any patent rights ass
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