Standard Practice for Evaluating Adhesion of Installed Weatherproofing Sealant Joints

Importancia y uso:

4.1 Many parameters contribute to the overall performance of a sealant application. Some of the most significant parameters are sealant bead size and configuration, joint movement, quality of workmanship, the quality of the adhesive bond, and the quality of the sealant material.

4.2 A sealant usually fails to perform as a weatherseal when it experiences cohesive or adhesive failure.

4.3 If a sealant bead fails, an evaluation of the total joint movement may be needed to determine if the joint sealant was strained beyond its intended design, or if the sealant failed within the design parameters.

4.4 If a sealant bead fails adhesively, there is no straightforward procedure for determining the cause. The adhesive failure may be due to workmanship, the specific surface preparation 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 a sealant bead, an understanding of the quality of the adhesive bond is instrumental in any evaluation of sealant performance. It is critical that the evaluation procedures used truly evaluate the quality of the adhesive bond and do not simply take advantage of the tear resistance of the sealant.

4.6 This method does not evaluate the performance of a sealant bead as a weatherseal. It only evaluates the characteristics of the adhesive bond relative to the cohesive strength of the sealant in a particular installation. Since any failures that result from use of these procedures are intentionally induced, they do not necessarily mean that the sealant bead will not perform as a weatherseal.

4.7 The results of these methods are most useful in identifying sealant beads with poor adhesion. The continuous inspection procedure is also useful in the identification of places of poor joint configuration. Obvious cohesive failures are also identified. The results of these methods can be used to assess the likely performance of the sealant bead and to compare the adhesion of different substrate preparations and sealant materials.

4.8 The non-destructive methods are most effective while the sealant is in a state of extension due to mild or low temperatures. They are least effective during high temperature when the sealant is in a compressed condition.

Subcomité:

C24.30

Referida por:

C1722-23, C1394-20, C1401-23, C1193-25

Volúmen:

04.07

Número ICS:

83.060 (Rubber)

Palabras clave:

adhesive failure; cohesive failure; field adhesion; flap; probing tool; tail;