Computational optimized biomimetic structural design is a highly advanced field [21], pathing the way to create more sustainable and resource conscious constructions. However, the mostly biomorphic and freely shaped structural designs (Figure 4 - a) have a large draw-back in conventional manufacturing due to intensive use of non-standard molding and manufacturing shapes. Recent advancements in additive manufacturing (AM) [22] show possibilities in computer numerical controlled production without formwork and little waste material. The most advanced technology in constructional AM is 3D-printing of concrete using cementitious composites as a filament for construction. Judging the State-of-Art, designs manufactured by using this technology show a high potential for reaching construction-site-readiness in near future. Using cementitious filament allows relying on proven properties regarding performance as building material, but implies as well disadvantages such as lack of tensional strength, long setting times and environmental impact.
Novel construction methods and the associated material choices are the link between optimized structural designs, resource consumption feeding into the impact on the global climate (Figure 1). The aim of ‘Climate&Structures’ is to advance construction methods using materials, that enable the realization of the complex and optimized geometries presented in Section 3.
Additive manufacturing
The group explores possibilities of applying and advancing layered, extrusion-based constructional 3D-printing. The up to date, rather limited free form construction techniques, show difficulties in printing overhanging geometries needed for the realization of structures as shown in Figure 4. Climate&Structures focuses on the advancement of the filament’s performance in terms of hardening characteristics, early age material strength, printed induced dead load and increasing tensional strengths by attempting and introducing novel choices of extruded materials [23].
Use of secondary resources
Filaments for constructional 3D-printing can be taken from secondary resources of local industry branches as attempted before (e.g. in Guan [24]). These could deliver solutions to waste problems and increase reuse possibilities of secondary resources in constructions through modern construction technologies.
Figure 6: (a), (b) Concrete composite samples with biologically based binding materials, envisaged as filament for constructional 3D-printing. Image: [23].
Local resourcing from waste products reducing or even avoiding long transportation ways and production infrastructures is thereby one of the group’s core ideas. The approach aims on the use of basic biological secondary materials connected with the food industry. The reuse of these materials could decrease emission and waste products due to lower production temperatures and recycle/reuse possibilities [23], falling in line with the EU’s bioeconomic strategy [25]. Current research shows that use of secondary materials from food industry (biologically gels) as bio-based binding material for concrete (Figure 6) has a high potential for advanced applicability as filament in constructional 3D-printing [23].
Ecology: Structures, Part of a living System
Ecology, a science evolving from biology, describes the interrelation of organisms with their biotic and abiotic environment [26]. The investigated body within an ecological unit is thereby the ecosystem and includes the interaction of its biological, physical and chemical components [27]. This relation exists and is subjected to investigation at different scales: from Petri-dish bacteria cultures to our planetary biosphere [28]. On the example of the largest anthropogenic affected ecosystem, humans affect their environment by changing available resources in their physical, chemical and biological state [27]. In the same way, humans in turn are affected by other living components of the ecosystem and by the availability of non-living resources and physical states in nature. An ecosystem is often misunderstood as a community, limited to a field in ecology describing the interrelation of living biotic components (plants animals, microbes, etc.). By the definitions introduced above, a full view of an ecosystem includes as well numerous abiotic factors like climate, soil, and general energy and material consumption [26],[29].
In fields, such as ecological economics [30], ecological agriculture, or ecological building [26], the objective is to adopt the respective human systems (economics, industry, etc.) to be co-existent in symbiosis [31] (or mutualism [32]) with their environment. Consequently, these disciplines are a subsystem of the human organism within the ecosystem [30] of our own biosphere. The term ‘ecological building’ describes this role for the field of Civil Engineering and is explained in Daniels [26]. Focusing on a specific part of this field, the paper describes the interrelation of the load carrying structure (design and construction) as a subsystem of the human organism, with the climate as its abiotic environment. Conceptual relations are laid out by mapping interdependencies between climate and structures. Furthermore, strategies and methodologies are presented to understand, quantify and influence the ecological processes and are presented as part of the core disciplines of the research group ‘Climate&Structures’ at DTU Civil Engineering.