ASTM_C_1756_-_14.pdf

Designation:C175614Standard Guide forComparing Sealant Behavior to Reference Photographs1This 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 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 sealantbehavior terms that have been defined by Committee C24.1.2 When available,photographs that better illustrate theseterms,or that illustrate additional terms defined by CommitteeC24,will be included in future editions of this standard.Photographs for consideration may be submitted to the com-mittee using the form in Appendix X1.1.3 The committee with jurisdiction over this standard is notaware of any comparable standards published by other orga-nizations.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 of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2C717 Terminology of Building Seals and Sealants3.Terminology3.1 The terms used in this guide are defined in TerminologyC717.4.Significance and Use4.1 This guide is intended to be used in evaluating sealantconditions that occur in service,along with other diagnostictechniques in failure analysis.These standard reference photo-graphs have been selected and approved through ASTMsconsensus balloting process to illustrate terms defined byCommittee C24.4.2 Not all of the terms illustrated here are failures,andthere are other failure mechanisms that affect sealants that arenot discussed in this guide.This guide is intended to be one ofa number of sources of information used in the evaluation ofsealant behavior.5.Reference Photographs5.1 Figs.1-9 present a standard reference photograph foreach of the terms defined in Terminology C717,reprinted withtheir definitions.6.Keywords6.1 adhesion failure;chalking;cohesion failure;crazed;dirtpick-up;elastomeric joint sealant;fluid migration;reversion;rundown;sag1This guide is under the jurisdiction ofASTM Committee C24 on Building Sealsand Sealants and is the direct responsibility of Subcommittee C24.10onSpecifications,Guides and Practices.Current edition approved Jan.1,2014.Published January 2014.Originallyapproved in 2011.Last previous edition approved in 2011 as C1756-11.DOI:10.1520/C1756-14.2For 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 International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 adhesion failure,nin building construction,failure of the bond between asealant and a substrate.DiscussionThis definition pertains to interfacial adhesion failure,a lack ofbond at the interface between the materials.Interphasal adhesion failure,withinthe sealant or substrate near the interface,is less common and may appear to beinerfacial without the use of magnification.FIG.1 Adhesion Failurechalking,vin building construction,formation of a powder on the surface of asealant that is caused by the disintegration of the polymer or binding medium dueto weathering.FIG.2 Chalkingcohesive failure,nin building construction,failure characterized by rupturewithin the sealant.FIG.3 Cohesive Failurecrazed,adjin building construction,having a random network of cracks in asealant surface which do not penetrate through the body of the material.FIG.4 CrazedC1756 142 dirt 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 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 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 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 movementof contaminants incl