The article at hand presents an approach for analyzing the 3D Concrete Printing (3DCP) by means of the Discrete Element Method (DEM). An advanced user-defined simulation material model for fresh printable concrete has been developed to simulate extrusion, discharge and deposition. In addition, a calibration procedure is shown to find a fitting parameter set for the material model parameters based on experimental data. The calibration of the latter is an iterative adaption process, leading to a realistic representation of real printable concrete. Finally, an extrusion-based 3DCP process is exemplary simulated to show the potential of the simulation method for process analyses and to verify the applicability of the model. The developed simulation tool enables a better understanding of the extrusion process during 3DCP and a profound analysis of the material flow within the extruder. Based on this information, improvements in the machine layout and the process parameter settings can be identified, allowing for further printing process optimizations.