A bold plan to 3D print artificial coral reef

Inspired by the remarkable durability of ancient Roman construction materials in seawater, a University of Texas at Arlington civil engineering researcher is attempting to duplicate Roman concrete by developing 3D-printed materials to restore damaged or dying coral reefs.

Warda Ashraf, associate professor in the Department of Civil Engineering, will lead a multidisciplinary team, funded by a $2 million National Science Foundation (NSF) grant, that aims to build 3D-printed artificial reefs. The team’s project is titled “Carbon Sequestration and Coastal Resilience Through 3D Printed Reefs” and is part of the NSF’s Emerging Frontiers in Research and Innovation program.

“In the past few decades, artificial reefs made from concrete, old tires and old ships were used. But those just don’t work well because seawater disintegrates those materials, and many of them cause additional environmental pollution,” Ashraf said. “We can replicate Roman concrete, which lasts longer and is better for the environment.

“We will modify the concrete recipe to store carbon and offer a novel pathway to permanently sequester thousand tons of carbon under the ocean in addition to providing coastal resilience and supporting marine habitat.”

Ashraf said the team already has installed small cylinders and cubes of the recreated Roman concrete in Baffin Bay, just south of Corpus Christi, in the Gulf of Mexico. Marine organisms love it, she said.

“We’ve already done some testing there,” Ashraf said. “Barnacles that have attached themselves to the new reef really grab hold of it. The materials also got 40% to 50% stronger in seawater within five months.”

The project is critical because climate change has already damaged nearly 40% of the reefs and their dependent ecosystems, according to the National Oceanic and Atmospheric Administration Fisheries and The World Counts. Some experts anticipate coral reefs to be extinct by the end of this century. Coral reefs play a vital role in separating carbon dioxide from the atmosphere and in protecting coastal areas from extreme events, such as hurricanes and flooding.

Ashraf is the principal investigator on the multi-disciplinary team, which also includes Laura Mydlarz, UT Arlington biology professor, and Adnan Rajib, UT Arlington civil engineering assistant professor.

Mydlarz is an expert on coral reefs and will study if the artificial reef material can co-exist with natural reefs and how new coral reacts and grows with the artificial reef. Rajib’s expertise is in nature-based climate solutions. He will develop a coastal hydrodynamic model to determine the size of the artificial reefs and how they will reduce sea level rise and coastal flood impacts. Researchers from the University of Texas at Dallas and Texas A&M University-College Station also will participate in the project.

Ashraf previously has received two Defense Advanced Research Projects Agency (DARPA) awards totaling about $740,000 to work on durable marine concrete. In 2020, she received a DARPA Young Faculty Award that supported the development of a cementitious material mimicking Roman concrete. She also received the DARPA Directors Award in 2022 for testing the performance of those materials in a field environment.

Melanie Sattler, chair and Dr. Syed Qasim Professor in the Department of Civil Engineering, said Ashraf’s work is an exceptional example of reaching across the campus for a project that could save natural resources.

“Her work is astounding,” Sattler said. “This artificial reef holds so much promise for the entire world.”