Adhesion and Cohesion Testing of Joint Sealants after Artificial Weathering - New Test Method

The use of construction sealants is an important area not just of the building construction. Each building requires a careful processing of all details and façades are no exception. From today's point of view we may note that sealing of façade joints and different types of cracks, fissures or gaps is nothing unusual and, therefore, it is astonishing that there still occur defects that often cause a significant decrease of the durability of the structures and sealed structures. This paper deals with testing of a selected group of construction sealants at a so-called 'real joint'. The real joint is a term defining a set of testing samples when the testing body contains a sealant applied in a manner corresponding to its real application. Cement bonded particleboard board was representing the façade cladding in this research since during the sealing there often occur complications with adhesion of sealants. For the presented experiment the existing testing methods that are used for verification of adhesion of cladding materials were studied and modified. According to the opinion of the authors those modified methods simulate well the parameters of the external environment and thus also the negative influences that may have a significant impact on the sealed joint in practice. The measured results prove that in the application of the sealants it is very important to follow the technology discipline and namely it is necessary upfront to verify whether the chosen materials are compatible. In most tested cases, diversion from the above-given steps resulted in failure of the sealed joint.