The process involves the extrusion of ready mixed concrete using an industrial robotic arm programmed to follow a linear fabrication tool path. The concrete is pumped to the robot and deposited through a customized tool head that extrudes to a 1cm resolution. This is done at multiple layers, each time depositing granular support material around the extruded concrete. In order to enhance the results a binder was incorporated into the extrusion process which was used to harden certain parts of the granular support to produce a multi material piece. The finalized 3D printing process therefore combines a dual material nozzle of concrete and binder which connects to an industrial robot and print both materials in the same routine.
3D PRINTING CONCRETE
A fabrication method was developed that combines two already existing concrete 3D printing methods: the extrusion printing method, and the powder printing method. This combination of techniques has given rise to a form of supported extrusion, whereby the concrete is extruded layer-by-layer over a bed of granular support material. Due to the support, the resulting extruded concrete is of a much higher resolution with large overhangs. The supported extrusion method has therefore presented the opportunity to design forms that are more varied and more volumetric, as opposed to the very straight vertical forms so far achieved in 3D concrete practice.