Wood-concrete hybrid components optimally combine the specific material properties of wood and concrete. With its low weight and high tensile strength, wood is perfectly suited for lightweight construction. The combination with concrete improves the load-bearing capacity, fire resistance and sound insulation, whilst simultaneously enabling a slender component design.

In the current “SafeTeCC” research project, researchers at the Fraunhofer WKI are, in collaboration with two research partners and great support from the industry, developing processes and technologies for the rapid and simple production of high-quality wood-concrete composite elements using an innovative rapid-bonding technique. The novel joining technique is intended to improve the structural properties, cost-effectiveness and recyclability of wood-concrete composite elements and, as a result, to contribute towards an increased application of renewable raw materials in solid construction. The researchers are thereby also taking into account the utilization of hardwood as a regionally available raw-material source.

“We are developing a standardized procedure for the production of long-term resistant WCC components under practical conditions. In addition to the hot-bonding technique, we are testing and analyzing alternative bonding technologies for the joining of wood and smooth-surfaced precast concrete components. This is being conducted in collaboration with our project partners from the Technische Universität Braunschweig and the University of Kassel. During the research work, a practical application for factory and construction-site production of the components is also being taken into account,” reported Malte Mérono, Project Manager at the Fraunhofer WKI.

The research results will be summarized in a practical guide that presents the specific implementation steps and relevant criteria in a user-friendly format. This guide is intended to serve as a planning basis and to facilitate the efficient production of WCC elements by, in particular, small and medium-sized enterprises (SMEs).

The development devised by Malte Mérono and his partners has already passed the practical test. In collaboration with fischerwerke GmbH & Co. KG, a bonded WCC element has been successfully installed as a suspended ceiling in a multi-story construction project. The company is now seeking building-authority approval for the suspended ceiling. “With the approval of the bonded suspended ceiling, we will take a big step forward towards our goal of being able to utilize wood in multi-story building construction. This is an important contribution towards an ecological revolution in the construction industry, which is dominated by reinforced concrete,” said Malte Mérono.

The topic of bonded wood-concrete composite elements is being met with great demand within the industry as a whole. Construction companies, engineering offices, adhesive manufacturers and architects are interested in this construction method. “We are experiencing high demand, both in Germany and from abroad; firstly, for testing by our “Structural Bonding” testing body and, secondly, for industry qualification in the field of “Proof of suitability for the execution of bonding work for the production of load-bearing timber components and glued laminated timber”, colloquially known as “glue approvals”. Detailed questions and new bonding methods in the WCC area are, however, constantly being developed and submitted to us. The industry is pushing this type of construction very strongly,” reported Harald Schwab, Head of Department at the Fraunhofer WKI.