As a hygroscopic material, wood interacts with moisture during both the building phase and subsequent use, especially when unintended water leakages like broken pipes or weather events occur in building installations. If high moisture levels are not detected, prolonged exposure can lead to structural damage and decay. Therefore, it is essential to monitor moisture in built-in wood to ensure the durability and safety of wooden structures. However, current monitoring practices predominantly rely on very local sensors, are mainly destructive and limited by high costs and technology constraints.
This research aims to address this gap by enabling spatial monitoring using adhesive bondlines as in-situ electrodes of entire engineered wood products. Specifically, this study investigates different configurations of cross-laminated timber with electrically conductive adhesives, which could detect changes in moisture via electrical measurements. Previous investigations for adhesive selection showed that a combination of carbon black and graphene nanoplatelets as electrically conductive fillers improved the electrical properties at low filler content. The electrical properties of the different configurations, depending on moisture levels ranging from standard climate to full water immersion, were measured using impedance spectroscopy.
By proper sensor design, those functionalised engineered wood products can contribute to safe wooden buildings and prolong the lifetime of wood products and structures by ensuring continuous moisture monitoring in a non-destructive and efficient manner.
Keywords: electrically conductive adhesive, engineered wood, wood moisture, moisture monitoring, impedance spectroscopy
Authors
Sarah Suarez
BOKU University, Institute of Wood Technology and Renewable Materials, Austria
Maja Vasiljevic
BOKU University, Institute of Physics and Materials Science, Austria
Johannes Konnerth
Wood K plus – Competence Centre for Wood Composites and Wood Chemistry, Austria
Martin Riegle
BOKU University, Institute of Wood Technology and Renewable Materials, Austria
Anita Tran
BOKU University, Institute of Wood Technology and Renewable Materials, Austria
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