3D-3B - 3D concrete printing and reinforcement for low-emission bending stressed bearing structures in building construction

3D extrusion processes with cement-based mortar materials are the starting point for the present application. This technology currently offers the possibility of producing unreinforced components very precisely and automatically at high speeds with low material input. This is the first time in the history of concrete and reinforced concrete construction that the construction of a costly formwork, which is essential, is no longer necessary. Due to this characteristic of a formwork printer, the aim is to combine the technology with the standard processes used in building construction in order to make greater use of the potential for reducing concrete cubature and thereby lower CO2 equivalents for load-bearing structures in building construction. A major limitation here is the lack of standardised requirements for the design of unreinforced and reinforced printed concrete materials and the components manufactured using them. This means that the technology is far from being integrated into standard BIM-compatible planning and design processes. The application of 3D printed components as voids in the construction process leads to increased geometric complexity, which in turn increases the demands on the construction site processes. For example, the installation and placement of the 3D printed concrete components and the steel reinforcement for the cast-in-place concrete. The aim of the project is (i) to establish a basis for numerical simulations of unreinforced and reinforced 3D printed concrete components by means of systematic development of test set-ups and test series. A further objective (ii) is the development of mass-relevant, predominantly flexurally stressed elements and therefore reinforced applications for building construction. Here, the focus is on ultralight façade panels with reinforcement integrated into the printing process and on panel- and slab-like structural elements such as ribbed ceilings that use lost formwork and 3D printed void bodies for mass reduction. Here, the focus is on issues of complementary steel reinforcement and construction logistics. After completion of the project, (i) data and methods for the characterisation of 3D printed concrete components will be available, which will enable numerical simulation in the design and planning phase and can also provide the basis for future production monitoring. The project clarifies and evaluates (ii) on the basis of selected application examples the potentials of 3D printed concrete components for the reduction of concrete cubature and the associated CO2 equivalents in building construction. (iii) Construction processes and construction logistics (placement of 3D printed concrete components and steel reinforcement for in-situ concrete) are developed, tested and evaluated for BIM-compatible processes.