Permanent Hydrothermal Exposure on Load-bearing Adhesives in Glass Constructions
The German research team FABIG develops a bioenergy building skin including modules of glass which contain a liquid medium processing biomass. Inside the facade modules, load-bearing adhesives were applied that are subject to permanent water exposure. Water is known as a major hazard for adhesives because water molecules diffuse into the adhesive polymer matrix and into the interface between adhesive and substrate. As a result, material characteristics as well as the adhesion properties may change significantly. Additionally, the adhesive is exposed to conventional aging in building skin as the temperature ranges between -20°C and +80°C. This paper focuses on the effect of water on load-bearing adhesives in a bioenergy facade. It evaluates potential adhesives for permanent hydrothermal application. The paper introduces water as a key aging medium. Furthermore, it describes the construction of an innovative flat plate photobioreactor as an example for load-bearing adhesives under permanent hydrothermal treatment. The conditions inside the photobioreactor, which lead to particular mechanical, physical and chemical loads for constructive elements in comparison with conventional facade systems are presented. The main part describes the results of experimental tensile tests on the adhesive short-term behavior considering temperature conditioning and chemical treatment with substances emerging from bio-processing like storing in acid, base and hydrogen peroxide solution. The paper concludes with an outlook on future research work of the team including ARUP Deutschland GmbH (Berlin, Germany), ADCO Technik GmbH (Rostock, Germany), SSC GmbH (Hamburg, Germany) and Technische Universität Dresden (Dresden, Germany).