Crack Width Investigation of Reinforced Concrete Beam with 3D Concrete Printed Formwork Using Modified Parameters (2025-08)¶

Three-dimensional permanent formwork (3DPF) represents an innovative technology in the construction industry, providing a digital manufacturing alternative to conventional formwork. Despite the advantages of 3DPF, a dedicated design code for predicting the crack width of 3DPF beam members under service conditions does not currently exist. This study examines the flexural cracking behavior and crack width investigation of reinforced concrete (RC) beams incorporating 3DPF by adapting the empirical equation parameters specified in Eurocode 2. Given that the interfaces between printed layers render the standard Eurocode 2 equation for maximum crack spacing inapplicable to 3DPF members, observed experimental values were used in the calculations. The research involved designing and testing two 3D-printed beam specimens alongside one conventional RC beam under four-point bending loads. An empirical equation for crack width calculation, integrating an equivalent material property for the printed material, is proposed to enhance the accuracy of 3DPF crack width predictions. The experimental results were strongly consistent with analytical predictions, thus highlighting the potential of the proposed methodology as a reliable approach for controlling cracking in 3DPF beam members.