Case Study on Comparison of Joint Sealant Adhesive Properties Tested in Laboratory and <i>In Situ</i>

Abstract

The main objective of this case study is to compare whether standardized test methods are able reliably prognosticate the performance of joint sealants and adhesives after installation in a construction. The authors of presented study believe that existing testing procedures intended for testing of bonded and sealed joints do not fully reflect the weather changes exterior surfaces have to withstand. Based on previous experiences a unique geometry of testing sample was used for this purpose allowing the testing of a so-called real joint. A group of test samples was subjected to two normalized test procedures that may influence the resulting behavior of the joint in the exterior. The second group of test samples was exposed to the external environment for a particular period. The obtained results of tests show that the standardized methods are able to simulate an outdoor environment, however, only to a certain level. Unfortunately, these methods do not consider the possibility that the sealed or bonded joint might be damaged already during the application itself. While laboratory environment is clean and often dust free, it is not possible to ensure the same conditions in situ. Moreover, in some cases it was monitored that some of the selected sealants tested in an external environment aged rapidly compared to the ones cured and stored in the laboratory. In some cases, the difference between monitored failure modes for indoor and outdoor environment was substantial. The predominant type of sealant failure observed in-situ was adhesive while mainly cohesive failure was monitored in laboratory.