DARPA wants robots to 3D print concrete underwater to build and repair ports

US Navy sailors repair damaged port walls at Palau during a training event in 2024. Chief Builder Tyler Ault/US Navy DARPA wants to 3D print concrete underwater using seafloor sediment and seawater. The supporting tech could autonomously repair ports, seawalls, cables, and other maritime infrastructure. The military sees underwater construction as a potential advantage in contested logistics. The US military's research arm wants to find ways to 3D print concrete underwater to fix and build…