A more extensive use of wood can reduce the environmental and climatic impact of the building industry. However, flammability limits the application of wood in multi-story and high rise timber buildings. Struvite mineralization has been shown to be a green solution for fire-resistant timber, but the influence of struvite minerals on the mechanical and gluing properties of wood as well as the combustion behavior have not been studied yet. In this work, we investigate the mechanical properties of mineralized wood by compression, bending, and tension tests as well as the gluing properties by tensile shear tests. Evolved gas analysis using GC/MSD system is applied to determine the thermal decomposition behavior of the mineralized wood, and Double shot analysis reveals volatile components of mineralized wood during the thermal decomposition process. The results show that the struvite mineralization treatment is a bulk modification technique that improves the fire resistance of wood. The mineralization can significantly influence the thermal decomposition behavior of wood, which results in an enhanced char formation. This char layer is a fire barrier that slows down the heat and oxygen penetration. The heat penetration rate of wood panels fabricated with mineralized wood is 0.6 mm/min during the cone calorimeter test, which is half of that of the wood panels fabricated with native wood. Transverse strength and stiffness under compression were improved, whereas mechanical loading in the longitudinal direction revealed similar or slightly decreased strength and stiffness. The mineralization had a minor impact on the gluing properties of solid wood. Wood mineralization by struvite may enable the more extensive use of wood in the construction sector as a substitute to less eco-friendly building materials.

Concrete construction harms our environment, making it urgent to develop new methods for building with less materials. Structurally efficient shapes are, however, often expensive to produce, because they require non-standard formworks, thus, standard structures, which use more material than is often needed, remain cheaper. Digital fabrication has the potential to change this paradigm. One method is Digital Casting Systems (DCS), where the hydration of self-compacting concrete is controlled on the fly during production, shortening the required setting time and reducing hydrostatic pressure on the formwork to a minimum. This enables a productivity increase for standard concrete production. More importantly, though, it enables a rethinking of formworks, as the process requires only cheap thin formworks, thus, unlocking the possibility to produce optimised structural members with less bulk material and lower environmental cost. While DCS has already proven effective in building structural members, this process faces the challenge of moving into industry. This paper covers the next steps in doing so. First, we present the benchmark and expectations set by the industry. Second, we consider how we comply with these requirements and convert our fast-setting self-compacting mortar mix into a coarser one. Third, we present the next generation of our digital processing system, which moves closer to the industrial requirements in terms of size and the control system. Finally, two prototypes demonstrate how DSC: (a) increases standard bulk production by 50% and (b) can be cast into ultra-thin formworks. We discuss the results and the short-term industrial concerns for efficiency and robustness, which must be addressed for such a system to be fully implemented in industry.

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