Additive manufacturing (AM) has the potential to revolutionize the construction industry in a way where material, geometric complexity, building sustainability and design freedom can be interwoven [1]. Cementitious materials AM can reduce the structural environmental impact by one third (Wangler et al., 2016 [2]) along with the tailored material and mechanical properties. Binder jetting (BJT) is a powder-based AM method that enables the production of complex components for a wide range of applications. The pre densification interaction of binder and powder is vital among various parameters that can affect the BJT performance. In this study, the BJT process is studied for the binder interaction with the powder bed of Ordinary Portland Cement (OPC). The effects of capillary forces or action, viscosity, gravity and inertia are described via computational fluid dynamics (CFD) modelling of the system. The effect of the droplet-size is thoroughly analyzed. Two different droplet sizes are considered 0.3 mm and 0.5 mm. Through the application of particle flowlines, the uniformity of binder distribution over the powder bed is scrutinized. This research introduces an enhanced and more accurate discrete element method (DEM) representation of the powder bed coupled with CFD analysis, providing a comprehensive understanding of binder droplet spreading and penetration dynamics within the powder bed. The significance of splashing, influenced by the size of the binder droplet, is identified as a critical parameter. The findings contribute to advancing the understanding of binder jetting processes in construction material applications, offering valuable insights for optimizing the printing parameters to achieve superior part quality.