Portuguese 
English 
Spanish 
6 min of reading 
0 comments 
Technology developed by Cornell researchers uses robots, special concrete, and marine sediment to test a new way of building and repairing submerged structures in areas where conventional works require complex operations.
Researchers at Cornell University in the United States have developed an experimental method to 3D print concrete underwater using robots and a mixture made primarily with seabed sediment.
The proposal, according to the Cornell Chronicle, is to allow maritime structures to be built or repaired directly on-site, with less reliance on prefabricated parts, divers, and large transportation operations.
The research was presented by the university on January 28, 2026, and is part of a project funded by DARPA, a research agency linked to the United States Department of Defense.
-
Owner of ChatGPT enters the stock market queue and could be worth $1 trillion, while Anthropic and SpaceX accelerate their own plans in a race that promises to test if the market is still willing to bet heavily on artificial intelligence.
-
Chinese drone BZK-005 receives new technology capable of locating radars, mapping communications, identifying radio frequency emitters, and conducting electronic intelligence missions in strategic areas near Japan, Taiwan, and the Western Pacific.
-
Slimming pen still unapproved becomes a global topic after study indicates weight loss similar to bariatric surgery, while clandestine versions of retatrutide appear at the border.
-
Brazilian dengue vaccine from Butantan temporarily suspended after two suspicious deaths, putting Anvisa and the Ministry of Health on national alert
The work is part of the Trenton program, created to test underwater 3D printing with concrete technologies in military and civilian applications.
The technology is still in the development phase and does not represent a ready solution for commercial use or large-scale works.
The tests described by the university were conducted in a controlled environment, focusing on evaluating whether robots can deposit concrete at the bottom of the water without the material dispersing before forming a stable structure.
Instead of transporting large volumes of supplies by vessels, the technique seeks to utilize materials already available in the submerged environment.
The mixture developed by the team uses marine sediment as the main ingredient and a reduced amount of cement, a requirement defined by DARPA to reduce the logistical complexity of the process.
The team is led by Sriramya Nair, assistant professor of civil and environmental engineering at the David A. Duffield College of Engineering, Cornell.
According to the university, the group was already working with an industrial robot weighing about 6,000 pounds, equivalent to approximately 2.7 tons, used in 3D printing projects of large concrete structures on land, when they decided to adapt the technology to the submerged environment.
How 3D printing of concrete underwater works
3D printing applied to civil construction works by layer deposition.
Instead of molding the concrete in traditional forms, a machine releases the material following a programmed path, until forming walls, arches, or other structural elements.
Underwater, this process faces a specific technical limitation.
The water interferes with the deposition, alters the behavior of the mixture, and can disperse cement particles before they bond with the rest of the material.
This phenomenon is known as “washout,” or cement washing, and can compromise the structure’s strength.
To tackle this problem, the Cornell team adjusted the formulation until they found a balance between viscosity and pumpability.
In practical terms, the concrete needs to be thick enough not to disintegrate in water, but it also must maintain fluidity to pass through the tubes and exit the robotic printer’s nozzle.
Nair explained to the Cornell Chronicle that the addition of anti-washout chemical agents increases the mixture’s viscosity and can hinder pumping.
“When you add these chemicals, your mixture becomes really viscous, and you can’t pump it,” stated the researcher.
At the same time, the material needs to maintain its shape as it exits the nozzle and adhere correctly to the previous layers.
This step is one of the project’s foundations because 3D printing depends on the continuity between layers.
If the concrete loses shape, spreads, or does not fix to the desired point, the structure no longer follows the design planned by the robotic system.
Why use seabed sediment in concrete
The use of marine sediment is one of the central features of the project.
In conventional submerged constructions, materials need to be transported to the site by ships or support equipment, which increases logistical operations and may require additional steps for site preparation.
The DARPA requirement was that the concrete primarily consists of material collected from the submerged environment itself, with a smaller amount of additional cement.
According to Cornell, this condition was set to reduce dependence on the transportation of supplies and to evaluate whether materials available on the seabed can be incorporated into construction.
The sediment, however, does not behave the same way as the sand used in conventional constructions.
It can have very fine particles, variable composition, and different behavior depending on the collection region.
When moved, it can also make the water cloudy and hinder the monitoring of the printing.
According to Nair, the proposal differs from traditional methods because it uses the marine sediment itself as the base of the mixture.
“No one does this now. No one takes seabed sediment and prints with it,” said the researcher, in a statement published by Cornell.
The formulation also needs to consider the impact of the environment on the material.
Current, turbidity, sediment texture variation, and hardening time are factors that can interfere with deposition and, therefore, need to be controlled before any use outside the laboratory.
Underwater robots need to operate with low visibility
In addition to the concrete mix, researchers also needed to develop ways to monitor the printing.
In a laboratory tank, it is possible to observe if the layers are aligned, if the arch maintains its shape, and if the material is being deposited according to the planned path.
In the ocean, this visual monitoring can be limited.
The movement of sediment tends to make the water murky and can prevent cameras from clearly recording the deposition point.
Nils Napp, assistant professor of electrical and computer engineering at Cornell and a member of the project, stated that the team did not know how much turbidity there would be in the process.
In some conditions, visibility can drop significantly.
For this reason, the group is working on sensor systems capable of monitoring the printing in real-time.
The goal is to allow the robot to adjust the deposition path according to environmental conditions, without relying solely on direct visual observation.
This control is necessary because the position of each layer influences the final result of the structure.
If the material is placed outside the planned path, the piece may lose alignment, present flaws, or deviate from the specifications determined by the project.
Trenton Program tests underwater construction with 3D printed concrete
The project is part of the Trenton program by DARPA, created to demonstrate the feasibility of 3D printing concrete in a submerged environment.
The program’s official page states that the technology can support military and civilian applications, including coastal infrastructure reinforcement, bridge repair, and other underwater structures.
The agency reports that 3D concrete printing has already shown applications on land, such as design flexibility and reduction in material use, but there are still no equivalent systems applied to the underwater environment on a practical scale.
The program seeks to adapt existing equipment, develop suitable formulations, and test the fabrication of small concrete structures in the laboratory.
The Cornell team received a grant of US$ 1.4 million in May 2025, with a duration of one year and conditional on meeting technical goals.
According to the university, five other groups were also participating in the challenge promoted by DARPA.
In September 2025, the team demonstrated to agency representatives that they were close to achieving the high sediment content target required in the program.
The next stage involved a technical competition in March 2026, in which the teams were to print a submerged arch according to specifications established by DARPA.
Where underwater 3D printing could be applied
If it advances to real environment tests and overcomes the planned technical stages, underwater 3D printing could be applied in maritime infrastructure construction and repairs.
Among the possibilities mentioned by DARPA and Cornell are bridges, coastal structures, submerged elements, and components related to operations in maritime areas.
Currently, many interventions of this type require heavy equipment, material transportation, planning of work windows, and specialized teams.
Robotic systems capable of depositing concrete directly on-site could alter part of this process, especially in localized repairs or in structures adapted to the seabed terrain.
The environmental dimension of the technology still depends on real-scale evaluation.
The use of local sediment can reduce material transportation, but the collection, seabed movement, and mixture composition need to be analyzed to measure effects on submerged ecosystems.
So far, the progress reported by Cornell is concentrated on the proof of concept.
The team claims to have developed a mixture compatible with submerged printing, tested deposition in tanks, and worked on sensors to operate in low visibility conditions.
Application outside the laboratory still depends on new tests, including operation in environments with currents, pressure, sediment variation, and remote control in real areas.
Be the first to react!