Additive manufacturing and 3D printing are rapidly developing digital fabrication techniques. After the first steps in printing of metals and plastics have been made, research from various groups around the world is now also focusing on printing in concrete and moving to larger scales. Using this technique it will be possible to create customised concrete designs in one go at low costs and high construction speeds. Additionally, this new technology will provide opportunities to create more efficient structures. Structures can already be optimised in the early stages of the design for weight and structural performance, but the resulting optimised structures are often difficult to manufacture due to their shape. Additive manufacturing can be the key to make this possible without high costs for moulds and labour. This thesis will present a novel methodology to include material and manufacturing constraints of 3D printed concrete in the optimisation process. The study examines the possibility to optimise concrete structures in the design phase. In order to save material and thus create more sustainable and more cost efficient structures, a topology optimisation tool has been created specifically for 3D printed concrete. Traditional topology optimisation methods consider isotropic and linear elastic material and will not necessarily produce realisable and reliable optimised structures. In the algorithm presented constraints of the printing process and material properties from physical testing of this layered material are both considered in the optimisation. By adopting this methodology more realistic and feasible optimal concrete structures can be designed.

Additive manufacturing and 3D printing are rapidly developing digital fabrication techniques (Lu et al. 2015). After the first steps in small scale printing of metals (Frazier 2014) and plastics (Gibson et al. 2014) have been made, research from various groups around the world is now also focusing on large scale printing in concrete (Lim et al. 2012) and making this technology more suitable for the construction scale. The potential of using this technology is that it will be possible to create complex and/or customised concrete designs with the expectation that the costs will be low and the construction speeds will be high. Additionally, this new technology will provide opportunities to create more efficient structures. Structures can already be optimised in the early stages of the design for weight and structural performance, but the resulting optimised structures are often difficult to manufacture due to the resulting geometry of the design. Additive manufacturing can address this issue without high costs for moulds and labour. This paper will present a novel methodology to include material performance and manufacturing constraints of 3D printed concrete in design optimisation processes. The study examines the possibility to optimise concrete structures in the design phase. In order to save material and thus create more sustainable and more cost efficient structures, a topology optimisation method has been created specifically for 3D printed concrete. Traditional topology optimisation methods consider isotropic and linear elastic material and will not necessarily produce realisable and reliable optimised structures. In the algorithm presented constraints of the printing process and material properties from physical testing of this layered material have been considered in the optimisation. By adopting this methodology more realistic and feasible optimal concrete structures can be designed.@en