Lightweight wood-based concrete "WooCon" – Institute of Construction and Environmental Technology

Cement-bonded wood products are applied since more than 100 years in construction, although almost exclusively for non-structural purposes and as prefabricated panels. If such lightweight wood-based concrete materials would be pourable, new conceptual designs for alternative and innovative slab and wall elements are possible, where the cement-bonded wood also contributes to structural performance, and which are provided with an integral acoustic insulation and fire protection, and are largely based on renewable resources.

In a project of the National Research Program 66 “Resource Wood” (2012–18) of the Swiss National Science Foundation, first recipes for pourable, possibly self-compacting lightweight wood-based concrete (WooCon) were developed, considering easily available, preferably untreated and economically advantageous basic materials. To assess suitability as structural materials, their mechanical properties were determined and engineering material laws were developed. Additionally, further potential WooCon performances – relevant for construction – such as thermal insulation and storage capacity, contribution to acoustic insulation, and fire protection properties were evaluated. In view of thermal recycling, combustion energy and fumes composition as well as reuse options for combustion ashes were analyzed as well. These results were considered in conceptual designs for slab and wall elements, of which the structural behavior up to rupture and under long-term loads was evaluated in full-scale tests, being also analytically retraced. Thanks to these results, the applicability of such construction elements in residential, school and office buildings could be proven and remaining challenges could be identified. Further improvements of construction-relevant WooCon properties are currently developed, being also open to potential developments.

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