Cornell University researchers are developing technology to 3D print concrete underwater for maritime construction and infrastructure repair. The interdisciplinary team, led by assistant professor Sriramya Nair, received a $1.4 million grant from DARPA in May 2025 to advance the technology within a one-year timeframe.
The project addresses several technical challenges, including preventing washout where cement particles fail to bind during underwater deposition. DARPA requires the concrete to consist primarily of seafloor sediment with minimal cement content to reduce transportation logistics. “Nobody is doing this right now,” Nair said. “Nobody takes seafloor sediment and prints with it.”
The research team has been conducting test prints in laboratory water tanks using a 6,000-pound industrial robot. They successfully demonstrated progress toward DARPA’s high sediment content targets during a September visit by agency officials. The team includes specialists from multiple universities working on material design and fabrication processes.
Since underwater monitoring presents visibility challenges due to sediment turbidity, researchers are developing sensor systems to track printing quality in real time. The project will culminate in a March demonstration where multiple competing teams will 3D print arches underwater. Cornell’s team is one of six groups competing to meet DARPA’s benchmarks for the underwater concrete printing challenge.
Source: news.cornell.edu