Advancing Underwater Construction with 3D Printing: A Two-Stage Approach

Underwater concreting presents a unique challenge, requiring advanced materials and construction methods to endure harsh submerged environments. Traditional techniques often encounter difficulties in adapting to the dynamic underwater conditions. In contrast, 3D concrete printing (3DCP) offers a revolutionary alternative, enabling automated, precise, and highly customizable fabrication of resilient underwater structures. This study introduces a two-stage cementitious 3D printing system that dynamically adjusts accelerator dosages at the nozzle, optimizing printability in submerged conditions. Evaluations in both air and underwater settings reveal that real-time dosage control effectively addresses critical challenges, overcoming the limitations of pre-mixed underwater admixtures (reduced flowability and compromised strength) while adapting to environmental changes. These findings underscore the transformative potential of two-stage 3DCP, advancing both innovation and sustainability in underwater construction by offering unprecedented control over material properties. This approach lays the foundation for more efficient, durable, and environmentally friendly solutions in the evolving field of 3DCP.