In-process reinforcement method for 3D-printed concrete layers

State-of-the-art methods for reinforcement of 3D printed concrete layers require manual intervention, cause poor bonding between concrete and reinforcement, or result in a disrupted concrete flow. This paper presents an automated reinforcement method. A printhead bifurcates the incoming concrete flow and merges the two streams near a tapered outlet, while a fiber mesh is fed from an integrated spool and embedded within the printed layer. Mesh reinforced concrete was printed along linear and curved paths. A greater path radius helped reduce out-of-plane distortion in the mesh (and concrete) along curvilinear paths. Compaction due to tapering in the printhead reduced amount of voids near mesh, and increased green strength and mesh pull-out force in the fresh state. Cubes extracted from printed beams exhibited strength comparable to mould-cast specimens. The presence of fiber mesh substantially enhanced the deformability of printed beams. • Developed a printhead to automatically reinforce concrete layers during printing. • Tapered end of printhead allowed effective integration of mesh within printer layers. • Intra-layer mesh reinforcement led to substantial increase in green strength. • Mesh reinforcement led to significant increase in the deformability of printed beams.