Universität Stuttgart
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Item Open Access A method for 3D printing bio-cemented spatial structures using sand and urease active calcium carbonate powder(2020) Nething, Christoph; Smirnova, Maya; Gröning, Janosch A. D.; Haase, Walter; Stolz, Andreas; Sobek, WernerThe substitution of Portland cement with microbially based bio-cement for the production of construction materials is an emerging sustainable technology. Bio-cemented building components such as bricks have been fabricated in molds, where bacteria-containing aggregates solidify when treated with a cementation solution. Thisrestricts component size due to the limitedfluid penetration depth and narrows options for component customization. The use of additive manufacturing technologies has the potential to overcome those limitations and toexpand the range of bio-cement applications. In the present work an automated process for the production ofspatial structures has been developed, in which sand and urease active calcium carbonate powder were selectively deposited within a print volumeand treatedwith a cementation solution.This method provided conditionsfor calcite precipitation in the powder-containing areas, whereas areas of pure sand served as removable supportstructure allowing improvedfluid exchange. The 3D printed structure was geometrically stable and had sharplydefined boundaries. Compressive strength tests on cylindricalspecimens showed thatthe used powder-sandmixwas suitable for the production of high-strength bio-cemented material. The present work demonstrates an application of bio-cement in an additive manufacturing process, that can potentially be used to produce resourceefficient sustainable building components.Item Open Access Integration of LCA in the planning phases of adaptive buildings(2019) Schlegl, Friederike; Honold, Clemens; Leistner, Sophia; Albrecht, Stefan; Roth, Daniel; Haase, Walter; Leistner, Philip; Binz, Hansgeorg; Sobek, WernerThe high consumption of resources in the building industry requires a significant reduction of material in buildings and consequently a reduction of emissions over all phases of the life cycle. This is the aim of the Collaborative Research Centre 1244 Adaptive Skins and Structures for the Built Environment of Tomorrow, funded by the German Research Foundation (DFG), which addresses research on the development and integration of adaptive systems in building structures and skins. New approaches in building planning are required for the implementation of adaptive buildings. Therefore, a multidisciplinary team from various fields such as architecture, civil and mechanical engineering, and system dynamics is necessary. The environmental impacts of the whole life cycle have to be considered for an integral planning process for adaptive buildings right from the beginning. For the integration of the Life Cycle Assessment (LCA), four temporal and content-related interfaces were identified in the planning process. Inputs and outputs of the LCA were defined for the relevant planning stages in order to enable the greatest possible benefit for the planners and to minimize the environmental impacts as far as possible. The result of the research work is a methodology that can be used in the future to reduce life cycle-related environmental impacts in the planning process of adaptive buildings (ReAdapt).