Bond shear performances and constitutive model of interfaces between vertical and horizontal filaments of 3D printed concrete

Abstract

To determine the bond shear performance and shear load-deformation curve of the interfaces between vertical and horizontal filaments of 3D printed concrete (3DPC), a double-shear test was conducted. An advanced XCT scanning technique was used to detect the distribution of defects and porosity in the matrix and interfaces. Based on the elastic brittle damage theory, shear constitutive models of interfaces between layers, strips, and matrices were proposed. Note that the shear strengths between the layers and the strips are 5.16 MPa and 4.84 MPa, accounting for 85.7% and 80.3% of the matrix shear strength, respectively. The porosity of the matrix, interface between layers, and porosity of the interface between the strips were 2.22%, 3.82%, and 4.09%, respectively, which had a linear relationship with the shear strength. Moreover, the obtained shear constitutive model of the interface can accurately reflect the mechanical response of the interface of the 3DPC under shear stress, which fits well with the test results. This provides a foundation for the theoretical and numerical analysis of 3DPC.