Underwater 3D printing of cement-based mortar

Nowadays, the development of renewable marine energies and needs for coastal protection to face global warming issues goes simultaneously with the fast development of digitally based construction methods such as concrete 3D printing. This creates the conditions to change the coastal and off-shore construction methods. Therefore in this study, we assess the possibility to design an underwater 3D printing materials. This possibility needs to develop cement-based materials that are simultaneously printable (pumpability, fast structuring) and also resistant to water washing out. After a mix design protocol that complies with the rheological requirements of the concrete and its water anti-washout properties (through permeability measurements), 3D printed samples has been fabricated in air and underwater. Then, the compressive strength of hardened printed mortar has been measured in order to validate the concept of the process. (C) 2019 Elsevier Ltd. All rights reserved.