ASTM C1521-2008a Standard Practice for Evaluating Adhesion of Installed Weatherproofing Sealant Joints.pdf

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1、Designation: C 1521 08aStandard Practice forEvaluating Adhesion of Installed Weatherproofing SealantJoints1This standard is issued under the fixed designation C 1521; 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 practice describes destructive and nondestructiveprocedures.1.2 The destructive procedure stresses the sealant in suc

3、h away as to cause either cohesive or adhesive failure of thesealant or cohesive failure of the substrate where deficientsubstrate conditions exist. The objective is to characterize theadhesive/cohesive performance of the sealant on the specificsubstrate by applying whatever strain is necessary to e

4、ffectfailure of the sealant bead. It is possible that the strain appliedto the sealant bead may result in the failure of a deficientsubstrate before effecting a failure in the sealant.NOTE 1The destructive procedure requires immediate repair of thesealant bead. Appropriate materials and equipment sh

5、ould be available forthis purpose.NOTE 2Sealant formulations may fail in cohesion or adhesion whenproperly installed, and tested by this method. The sealant manufacturershould be consulted to determine the appropriate guidelines for using thismethod.1.3 The nondestructive procedure places strain on

6、the seal-ant and a stress on the adhesive bond. Though termed nonde-structive, this procedure may result in an adhesive failure of adeficient sealant bead, but should not cause a cohesive failurein the sealant. The results of this procedure should be eitheradhesive failure or no failure.NOTE 3The no

7、ndestructive procedure may require immediate repairof the sealant bead, if failure is experienced. Appropriate materials andequipment should be available for this purpose.1.4 The non-destructive procedure can be used for continu-ous inspection of 100 % of the joint(s) or for any areas wheredeficient

8、 conditions, which are inconsistent with the practicesof Guide C 1193, are suspected.1.5 The committee with jurisdiction over this practice is notaware of any comparable practices published by other organi-zations or committees.1.6 The values stated in inch-pound units are to be regardedas standard.

9、 The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.7 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 standar

10、d 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:2C 717 Terminology of Building Seals and SealantsC 1193 Guide for Use of Joint Sealants3. Terminology3.1 DefinitionsFor definition

11、s of terms used in this rec-ommended procedure, see Terminology C 717.3.2 Definitions of Terms Specific to This Standard:3.2.1 flap, nthe term “flap” as used in this specificationrefers to a portion of an installed sealant bead that has beenpurposely cut along one substrate bond line and across the

12、beadat two locations resulting in a portion of bead adhered alongone substrate bond line.3.2.2 tail, nthe term “tail” as used in this specificationrefers to a portion of an installed sealant bead that has beenpurposely cut along both substrate bond lines and across thebead at one location resulting

13、in a portion of bead unadhered tothe substrates but adhered to the remainder of the sealant bead.4. Significance and Use4.1 Many parameters contribute to the overall performanceof a sealant application. Some of the most significant param-eters are sealant bead size and configuration, joint movement,

14、quality of workmanship, the quality of the adhesive bond, andthe quality of the sealant material.1This practice is under the jurisdiction of ASTM Committee C24 on BuildingSeals and Sealants and is the direct responsibility of Subcommittee C24.30 onAdhesion.Current edition approved July 1, 2008. Publ

15、ished August 2008. Originallyapproved in 2002. Last previous edition approved in 2008 as C 1521 08.2For 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 Doc

16、ument Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.2 A sealant usually fails to perform as a weatherseal whenit experiences cohesive or adhesive failure.4.3 If a sealant bead fails, an evaluation

17、of the total jointmovement may be needed to determine if the joint sealant wasstrained beyond design or if the sealant failed within designparameters.4.4 If a sealant bead fails adhesively, there is no straight-forward procedure for determining the cause. The adhesivefailure may be due to workmanshi

18、p, the specific surfacepreparation used, the specific sealant used, poor “installed”joint design, poor bond chemistry and other causes.4.5 Because of the complex nature of the performance of asealant bead, an understanding of the quality of the adhesivebond is instrumental in any evaluation of seala

19、nt performance.It is critical that the test procedures used truly evaluate thequality of the adhesive bond and do not simply take advantageof the tear resistance of the sealant.4.6 This method does not evaluate the performance of asealant joint as a weatherseal. It only evaluates the character-istic

20、s of the adhesive bond relative to the cohesive strength ofthe sealant in a particular installation. Since any failures thatresult from use of this test method are intentionally induced,they do not necessarily mean that the sealant joint will notperform as a weatherseal.4.7 The results of these meth

21、ods are most useful in identi-fying sealant joints with poor adhesion. The continuous inspec-tion procedure is also useful in the identification of places ofpoor joint configuration. Obvious cohesive failures are alsoidentified. The results of these methods can be used to assessthe likely performanc

22、e of the sealant joint and to compareperformance against other sealant joints.4.8 The nondestructive methods are most effective while thesealant is in a state of extension due to mild or low tempera-tures. They are least effective during high temperature whenthe sealant is in a compressed condition.

23、5. Testing Equipment5.1 Field EquipmentThe following equipment is requiredto perform this practice: rule with132 in. divisions (mm),probing tool, razor knife, knife or other cutting instrument witha pointed 2 in. (50 mm) minimum length blade, sealablesample bags, repair sealant compatible with exist

24、ing sealant,tools for installing sealant, butyl tape, water.5.2 Field Equipment, Nondestructive ContinuousMethodA wheel roller such as a screen roller or a backer rodinsertion roller or a pressure controlled roller.5.3 Provide materials for recording data. These may includemasking tape, marking pen,

25、 note books, shop or architecturaldrawings, a camera or video recorder, or both.6. Summary of Methods6.1 Nondestructive Spot MethodThis method makes useof a blunt dowel shaped tool to impart pressure against thesurface of the sealant bead. Firm pressure is applied to thesurface of the sealant in the

26、 center of the bead and near thebond line. This method evaluates a discrete area of the sealantbead and is repeated numerous times to provide an evaluationof a given length of sealant joint.6.2 Nondestructive Continuous MethodThis methodmakes use of a wheel to impart pressure against the surface oft

27、he sealant bead. The wheel is rolled continuously along thecenter of the sealant bead to provide 100 % inspection of agiven length of sealant joint.6.3 All MethodsData is collected continuously for allmethods. Precise description of location and type of allanomalies is recorded by a method appropria

28、te for the givenevaluation. See Appendix X1.6.4 Destructive MethodThis method is performed bycutting through the sealant bead to provide either a “tail” or a“flap” of sealant that can be pulled by hand, to stress the bondline of the sealant. The width and location of the sealant beadwill determine h

29、ow and to what degree the hand pull methodcan be performed. This method uses described techniques tocause an adhesive failure from the substrate.NOTE 4Narrow joints (less than516 in. or 8 mm wide) do not lendthemselves to destructive field adhesion tests. Usually, some kind of “tail”can be provided

30、to perform an adhesion pull. However, these tests tend toevaluate the cohesive property of the sealant more than the adhesiveproperty.NOTE 5Joints that are less than58 in. or 16 mm wide or that are morethan12 in. (13 mm) deep do not lend themselves to a “flap” style adhesionpull. The “tail” style ad

31、hesion pull should be performed on these joints.7. Procedures7.1 Nondestructive Procedure:7.1.1 Select a probing tool that is at least18 in. (3 mm)narrower than the width of the sealant joint to be evaluated.Fig. 1 provides example dimensions for a probing tool.NOTE 6The probing tool should be blunt

32、 without sharp edges andshaped in such a way that it will not puncture the sealant bead.7.1.2 Technique 1Using the probing tool, depress thecenter of the sealant bead to create an elongation strain on thesealant joint. Record the depth of the depression as a percent-age of the width of the bead. A c

33、ommon percentage used tocreate reasonable strain and reveal poor adhesion is 50 %. Theappropriate percentage varies with each sealant joint and isapproximately proportional to the expected joint movement.The percentage can be correlated with destructive proceduretest results.7.1.3 Technique 2Locatin

34、g the probing tool adjacent tothe sealant/substrate bond line, depress the sealant bead to theextent that (visually) it appears the sealant is about to failFIG. 1 Probing ToolC 1521 08a2cohesively. The sealant bead should be depressed in such a waythat the probing tool does not contact or scrape aga

35、inst thesubstrate, nor slide toward the center of the joint. Thistechnique will effect a peel-type strain on the sealant joint. Thistechnique will produce shear forces close to the bond line andtherefore the results should be prudently interpreted.7.2 Nondestructive Continuous Inspection Procedure:7

36、.2.1 Place masking tape on the exposed surface of thesubstrate adjacent to the sealant to be inspected. Using a rollerof such thickness as to be equal to or less than half of the widthof the joint, apply pressure to the sealant through the roller todevelop a depression in the sealant joint that repr

37、esentsapproximately 50 % deflection of the sealant. Advance theroller along the centerline of the length of the joint, usinguniform pressure. Observe the condition of the sealant forconditions, such as deflection of the sealant that is greater thanor less than expected, adhesive failure, cohesive fa

38、ilure ormechanical damage to the sealant, and mark the location ofthese conditions on the masking tape. It is helpful to usecharacteristic marks such as “A” for adhesion loss, “H” wherethe sealant appears hard, “S” where the sealant appears soft,“C” where a cohesive failure exists, for example, when

39、marking the masking tape. Where extended length of adhesivefailure occurs, the masking tape can be marked to indicate theends of the adhesive failures. The tape can also containmarkings that identify the location and side of the joint atwhich it is located. Upon completion of depressing the sealantw

40、ith the roller, documentation of the locations and types ofconditions can be performed.7.2.2 Determining the Causes of the AnomaliesEachanomaly can be inspected for obvious causes. However, it isgenerally helpful to remove a portion of the sealant and backermaterial for inspection. Sometimes, a more

41、 thorough examina-tion of the anomaly location will be required. The destructiveprocedure described in 7.3 can be used.7.3 Destructive Procedure:7.3.1 The “Tail” Procedure consists of cutting through thesealant, 6 in. (150 mm) along the bond line at both substrates.Cut across the sealant bead to rel

42、ease one end of the “tail” thatis formed (see Fig. 2). Insure that the sealant is cut at thesubstrate and that the sealant bead is free of nicks or jaggededges.7.3.2 Nondestructive Spot ProcedureFor each area to beinspected, perform procedure every 12 in. (300 mm) for first 10linear ft (3 m) of join

43、t. If not test failure loss is observed in thefirst 10 linear ft (3 m) of joint tested, test every 24 in. (600 mm)thereafter.7.3.2.1 Nondestructive Continuous Inspection ProcedureThe quantity and location of the inspection is dependent uponthe purpose of the inspection. In some cases, specific lengt

44、hs ofsealant are inspected as they relate to internal water or airleakage. An entire assembly, be it a window unit, a portion ofthe curtain wall, or a portion of a building facade are inspected.In some cases, such as quality control, 100 % inspection of thesealant can be designated for inspection. F

45、or general assess-ment of the sealant, joint configurations known to be difficult toinstall, as well as changes in the sealant and substrate types, arechosen for inspection.7.3.3 Method A:7.3.3.1 Mark the cut portion of the sealant 1 in. (25 mm)from the adhesive bond.7.3.3.2 Grasp the sealant “tail”

46、 at the mark 1 in. (25 mm)from the adhesive bond.7.3.3.3 Pull tail at an angle of 90 to the substrate toeffectively extend the 1-in. mark to two times the statedmovement capability of the sealant.7.3.3.4 Record the type of failure that occurred and thedistance of the mark from the adhesive bond when

47、 failureoccurred, or the distance recommended by manufacturer with-out causing failure.7.3.4 Method B:7.3.4.1 Mark the cut portion of the sealant 1 in. (25 mm)from the adhesive bond.7.3.4.2 Grasp the sealant tail at the mark 1 in. (25 mm) fromthe adhesive bond.7.3.4.3 Various tests can be performed

48、pulling the tailslowly at an angle of 30, 90 or 150 to the substrate, keepingthe tail in line with the sealant bead as nearly as possible.Monitor the extension to determine the elongation resulting infailure.NOTE 7Techniques using the “tail procedure” that allow evaluationsof sealant adhesion to one

49、 substrate at a time are acceptable.7.3.4.4 If the sealant begins to tear cohesively, stop pullingand readjust the grasp on the tail and begin pulling again. Pullon the tail in whatever direction or manner that best avoidscohesive tearing and encourages adhesive failure.7.3.4.5 Repeat procedure as necessary to evaluate adhesionto both substrates forming the joint.7.3.5 Flap Procedure:7.3.5.1 The “Flap” Procedure consists of cutting through thesealant, 3 in. (76 mm) along the bondline on the substrateopposite to the substrate to be evaluated. Make two cuts