Micro-cable reinforced geopolymer composite for extrusion-based 3D printing

Geopolymer has been applied to accommodate the rapid development of 3D printing in civil engineering practices and contributed this technique to reach its maximum eco-friendly potentials by eliminating the use of Portland cement. However, inherent problems with 3D printing concrete lie in the low tensile strength and poor ductility due to non-reinforcement, which greatly limit the application of 3D printing materials and structures. Hence, this study experimentally explores the feasibility of directly entraining a continuous micro steel cable (1.2 mm) during filaments (12 mm) deposition process, forming a reinforced geopolymer composite material. Three different printing path configurations are deigned to verify the applicability of micro-cable reinforced geopolymer composite for extrusion-based 3D printing. Flexural bending capacities of the proposed composite is measured and evaluated through four-point bending test. The results prove the well bonding and coordination of the micro-cable and geopolymer. Significant improvement of mechanical strength, toughness and post-cracking deformation of geopolymer composite are demonstrated.