Compressive performance and damage mechanism of concrete short columns confined by steel wires reinforced 3DPM

The incorporation of steel reinforcement in cast concrete can effectively enhance the ductility and strength of the concrete. In this paper, the steel wires reinforced 3D printed mortar (3DPM) was utilized as the external restraint for two series of short concrete columns (S-series: square section, C-series: circular section). Three different wire diameters (fine, medium, and thick) were considered as experimental variables. The experimental results indicate that the specimens reinforced with medium steel wires in both series exhibited strengths comparable to or superior to those of the unreinforced specimens. In terms of crack control, the specimens with the appropriate reinforcement ratio exhibited excellent performance, showing the smallest crack widths for both C-M and S-M specimens. It is found that in both S and C series that an appropriate reinforcement ratio positively influences the load-bearing capacity of the restrained columns. Furthermore, a calculated model for the uniaxial compression model of ECC confined concrete was proposed. The findings reveal that the calculated model is conservative and effective in predicting the compressive strength of the short column, with the exception of the C-F specimen.