Researchers at the University of Michigan in the US developed a ‘transformative development’ in concrete 3D printing, with better and more environmentally friendly structures at a lower cost.

Common approaches of 3D concrete printing (3DCP) aim to digitive constryctiona nd reduce concrete consumption. However, the common methods have geometric limitations that restrict applications and uses more concrete than necessary. The most widely used approach on construction sites uses a planer toolpath, parallel to the ground or along a single plane, to guide the 3DCP tool head. The tool head follows this path and extrudes mortar from the printer head, depositing it in horizontal layers. After each layer is deposited, the extruder nozzle is raised by the height of the deposited layer. This process is repeated to create a concrete mould, which is later filled with rebars and concrete.

The new method creates ultra-lightweight, waste free concrete. It reduces weight by 72 per cent compared to conventional, solid concrete of the same size. Called the “Shell Wall”, the new method uses a computational design and robotic 3D printing technology to combine ‘topology optimization’ with 3D concrete printing. Topology optimization is a technique that generates the most efficient distribution of material based on performance criteria, such as strength or weight, for a given set of support.

The team created a computational model that synergizes nonplanar and variable material deposition based on the shape and geometric features of the topology-optimized parts. This allows for efficient use of material by placing it precisely where it’s needed for structural purposes, and eliminates unnecessary overbuilding with excessive amounts of materials.

Photos: University of Michigan