Winding fibre thread for 3D concrete robotic printing

Abstract

3D Concrete Printing (3DCP) is a promising method to increase efficiency and automation in construction yet its adoption hinges on effective reinforcement integration to prevent shrinkage cracking and enhance tensile strength. This study explores a novel inprocess reinforcement strategy for 3DCP that integrates continuous fibres via a winding technique, decoupling fibre placement from mortar extrusion. The approach involves a robotic system equipped with a spinning mechanism to intertwine fibre threads with concrete filaments, aiming to enhance structural integrity and sustainability. Two extrusion path strategies, rectilinear and elliptical helices, were tested using glass and basalt fibres. Results indicate rectilinear paths produce thicker walls with better interlocking although these are 125% longer than elliptical paths. Challenges such as fibre entanglement, synchronization issues, and filament carving by the guiding tube were identified. Modifications, including improved guiding tube placement and real-time control systems, partially mitigated these issues. The findings highlight the feasibility of the method while underscoring the need for further refinements. Future work will focus on system optimization, mechanical testing, and incorporating thicker fibres to validate the approach’s structural and practical advantages.