Bonding performance of 3D printing concrete with self-locking interfaces exposed to compression–shear and compression–splitting stresses

Abstract Currently, applying 3D concrete printing to compressed structural systems with low tensile/shear stresses is a feasible and alternative route to promote this advanced technology into engineering practice because of the lack of an effective structural reinforcing method. Modular manufacturing of segmental components and fabricated construction of large-scale structures are promising for overcoming the limitations of the working dimensions of 3D printers. In this study, four different interlocking configurations are designed with "I," "V," "π," and "s"-shaped forms. Moreover, three cementitious composites―cement-, epoxy-, and phosphate-based composites―are prepared, aiming at optimizing the mechanical integrity and capacity of prefabricated structures with mechanical bite and adhesive forces. The effects of the interlocking forms on the interfacial connection strength at the joints are investigated and evaluated by compression–tensile and compression–shear tests. The results provide experimental data and references for constructing large-scale concrete arch structures by the modular assembly of 3D-printed segments.