Compressive Strength and Dimensional Accuracy of Portland Cement Mortar Made Using Powder-Based 3D Printing for Construction Applications

An innovative methodology has recently been developed by the authors of this study for geopolymer formulations for the requirements and demands of commercially available powder-based 3D printers. In this study, the formulation is extended to conventional Portland cement to expand the scope of printable materials that can be used in the commercially available powder-based 3D printers for construction applications. A Portland cement-based powder composed of Portland cement, amorphous calcium aluminate and fine silica sand was developed for powder-based 3D printing process. Effects of different printing parameters including binder saturation level (100%, 135% and 170%) and shell to core ratio (1:1 and 1:2) on dimensional accuracy and compressive strength of the green specimens have been investigated. A compressive strength of up to 8.4 MPa was achieved for the ‘green’ 3D printed samples before any post-processing process. The results indicated that the increase in the binder saturation level and the change in the Shell/Core ratio from 1:1 to 1:2 significantly increased the compressive strength, but considerably reduced the linear dimensional accuracy of the green samples. The compressive strength and linear dimensional accuracy of the green samples exhibited an anisotropic behavior, depending on the testing direction.