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2019
Conference Paper
Titel
Fast heating adhesive-tape solutions for structural timber-concrete-composite joints
Abstract
In the building industry, different construction materials and processes are well established worldwide. New combinations of different materials like timber-concrete-composites can bring benefits regarding lightweight design, increased prefabrication and faster building progress to increase productivity. By using timber-concrete-composite constructions, several advantages can be achieved in buildings such as weight reduction or an optimized load carrying capacity. Furthermore, the combination improves the reaction to fire as well as the deformation and noise reduction behavior. A new approach regarding the usage of specific adhesive tapes between both, the prefabricated timber and the concrete part allows a fast curing by applying high temperatures in the bondline. The adhesive tape is based on an adhesively coated metallic carrier (Fig. 1).The ends of the tapes are connected to an electric power supply similar to a welding workstation for controlled conductive resistive heating (Fig. 2). The adhesives have to fulfil a number of boundary conditions derived out of the different substrates (timber from beech and spruce, standard to high performing concrete with different surfaces) and should be able to cure at high heating rates by electrical heated thin metal carriers in the bondline. This is a very good precondition for a highly productive joining on the construction site. Additionally, the procedure is less sensitive to cold temperatures than the conventional method. Investigations in the research project started with a screening for most appropriate adhesives in a broad range of polymer chemistry and were followed by a screening for the most suitable concrete surface. After defining the basic material an investigation for a scale up of the new method were carried out by producing specimens with a bondline of 170 cm length and 5 cm width. Furthermore, the short and long-term behavior of bondlines produced with the fast heating adhesive-tape will be defined by two different test matrices via bending strength, block-shear and delamination tests. Therefore, specimens of dimensions up to 600 cm in length will be also produced and tested.
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