Impact of Concrete Interfaces on the Mechanical Performance of 3D Printed Concrete Structures

Abstract

This study primarily aims to investigate the influence of concrete interface properties on the anisotropic behavior of three-dimensional (3D) printed concrete (3DPC). A numerical model employing the traction-separation law was developed to capture the detailed behavior of concrete interfaces in 3DPC. To simulate the interfaces, zero-thickness cohesive elements were implemented. Experimental results indicate that horizontal shear deformation at the interfaces between printed layers reduces the compressive strength of 3D printed specimens. Additionally, the flexural strength of the 3D printed sample is mainly influenced by the tensile strength at the midspan. Specimens loaded in the Y- and Z-directions show relatively lower compressive strength but significantly higher flexural strength. Numerical analysis reveals that the number of interlayers and interstrips and shear properties contribute to changes in anisotropy when specimens are subjected to compression and flexure. Recommendations and influencing factors for improving the simulation modeling of 3DPC with anisotropic behavior have been proposed for future studies.