The Influence of the Cross-Sectional Geometry on Stress Concentration in 3D Printed Concrete Elements (2025-06)¶

This study investigates the influence of path geometry on stress concentration at notches located at layer interfaces in 3D Concrete Printing (3DCP) elements. Concrete specimens with circular and trapezoidal paths as well as the reference specimens without defined paths, were cast to ensure precise geometry. It is important to note that specimens were intentionally cast rather than printed. It was done to overcome challenges related to dimensional and curvature variability inherent in 3D printing processes caused by concrete rheology. The primary objective of this approach was to validate the experimental methodology against Finite Element Method (FEM) analysis. In this case using FEM would have been impractical with printed specimens due to uncontrolled geometrical variability. The experimental results obtained from cast specimens were compared with numerical FEM analyses and measurements using Digital Image Correlation (DIC). The findings indicated that circular paths resulted in the highest stress concentrations. The strong agreement between FEM and DIC results confirmed the reliability of both methods in stress concentration assessment for concrete structures. The next discussed point was that the geometry proposed and verified through these tests provided an effective standard for future mechanical strength evaluations of 3DCP elements. The outcomes of the conducted research highlighted the necessity of developing the new designed guidelines for 3DCP elements, aiming to optimize structural performance considering path geometry.