Experimental and numerical investigation of 3D-printed mortar walls under uniform axial compression

Abstract

This study aims to investigate and trace the behavior of 3D-printed load-bearing walls under uniform axial compression load. The manufacturing procedure of 3D-printed structures is unique as they are printed layer by layer where the interface between layers is usually a weak plane for 3D-printed structures. This weak plane also causes the printed mortar to behave as an orthotropic material. To analyze and trace the behavior of 3D-printed structures, the basic mechanical properties of the 3D-printed mortar as well as the interface strength between printed layers are investigated in this study. In addition, a series of load tests on 3D-printed load-bearing walls were performed to investigate the behavior of this kind of printed structure under uniform axial compression load. There are three different printing wall patterns tested in this study, plain, diamond, and carp walls. Both diamond and carp walls failed by buckling of the printed mortar. However, with a better load transfer path of the diamond wall, the diamond wall showed a more ductile response compared to the carp wall. The diamond wall requires less printing time and less mortar consumption, but it shows a higher load at first crack, higher load-carrying capacity, and more ductile response compared to the other two walls, depicting its better overall performance as a load-bearing wall. This research also proposes an FE model which considers the interface strength of the 3D-printed layers. The proposed model can be used to predict the load–displacement, stress–strain distribution, load transfer path as well as failure pattern of the tested 3D-printed walls with satisfactory accuracy. The model can also capture well a complex geometrical non-linearity of the printed wall observed through buckling of the tested walls.