Performance of 3D printed columns using self-sensing cementitious composites

Self-sensing cementitious composites can be used as an economical method of structural health monitoring. This is achieved by using the piezoresistivity effect to assist in the detection of defects and enabling repairs to be conducted early which can therefore avoid structural failures. This study uses an established self-sensing cementitious composite mix to 3D print column to examine its structural performance and sensing capabilities in components of large-scale concrete structures. An extrusion-based 3D printer was used to print hollow square column segments. These segments were then joined and filled with steel rebar reinforcement and cast concrete. Another column was created using mould cast concrete for comparison. The specimens were tested under static axial compression to determine their compressive properties, electrical resistivity and piezoresistivity response. The results showed that the 3D printed column performance can be monitored using the self-sensing composite until the printed shell cracks. The 3D printed column did show superior electrical properties with a lower electrical resistance of 274.2 Ω.cm. These results indicate that a different manufacturing approach to creating a 3D printed column should utilise the advantages of 3D printing for use in self-sensing concrete structures.