Prototypical Realization of Fully Automated 3D-Printing of Reinforced Concrete Using AMoRC Method

This paper presents the prototypical implementation of a novel 3D printing process for reinforced concrete structures called Additive Manufacturing of Reinforced Concrete (AMoRC), by showcasing the production of a half-meter-high S-shaped reinforced concrete wall within the laboratories at Institute of Structural Concrete at RWTH Aachen using two robotic systems. The process consists of a continuous concrete extrusion process and an intermittent arc stud welding process, both carried out by a robotic arm respectively. To avoid collision in the first step, the entire printing process is carried out by the robot for concrete printing and the robot for reinforcement welding in alternation, whereby iterative steps are required to create the entire reinforced concrete demonstrator. Segmented rebars of limited length were welded into a spatial reinforcement mesh and then enclosed by the 3D-printed concrete using an innovative fork-shaped printing head with two nozzles, spaced at an adjustable distance to accommodate varying reinforcement diameters. A specialized clamping mechanism was developed for the welding pistol in the welding process at the Welding and Joining Institute at RWTH. The pursuit of fully automated 3D-printing of reinforced concrete involves the following core technical procedures: (1) 3D concrete printing (3DCP) with programmed robot paths, (2) robotic charging of reinforcement studs, (3) robotic welding of the vertical reinforcement, (4) robotic laying of the longitudinal reinforcement, (5) robotic welding of the longitudinal reinforcement.