A research team at the University of Pennsylvania has unveiled an innovative 3D-printed bridge designed to absorb carbon dioxide and reduce the environmental impact of concrete. Dubbed Diamanti, this project represents a significant advancement in sustainable construction methods by using a novel concrete mixture and a material-saving design that retains strength and durability.
Concrete is the most widely used manmade material globally, yet it contributes approximately 8% of total greenhouse gas emissions. The traditional cement industry has long sought ways to mitigate its environmental footprint through more sustainable mixtures and efficient designs. The Diamanti project combines these approaches, employing a robotic 3D printer to create complex lattice-like structures inspired by natural patterns.
Diamanti’s concrete mixture reportedly absorbs 142% more carbon dioxide than conventional concrete, significantly enhancing carbon capture capabilities. According to Masoud Akbarzadeh, an associate professor of architecture at the University of Pennsylvania and director of the lab overseeing the project, the design utilizes principles derived from the porous structure of bones. Akbarzadeh explains that “nature has learned that you don’t need material everywhere,” emphasizing the importance of structural efficiency.
By mimicking the triply periodic minimal surface (TPMS) structures found in bones, Diamanti’s design increases the surface area of the concrete, boosting its carbon absorption potential by an additional 30%. “The surface area, together with this material property, maximizes the reaction with carbon at the microscopic level,” Akbarzadeh states.
Launched in 2022 with collaboration from Sika Group, a chemical company based in Switzerland, and supported by grants from the U.S. Department of Energy, the project is now preparing to construct its first full-size prototype in France.
Addressing Concrete’s Environmental Challenges
The durability and strength of concrete have made it a preferred material in construction worldwide. Yet, according to the Global Cement and Concrete Association, the cement industry has reduced its carbon emissions by 25% per metric ton since 1990. Despite these efforts, emissions have risen since 2015, attributed to heightened demand, as reported by the International Energy Agency.
Most emissions from concrete arise during the cement production process, which involves heating limestone to temperatures reaching 2,000 degrees Celsius (3,632 degrees Fahrenheit). This energy-intensive process releases significant amounts of carbon dioxide. Various organizations are exploring alternative materials to reduce cement usage, with Japan’s CO2-SUICOM claiming a carbon-negative concrete mix and UK-based Seratech incorporating the CO2-absorbing mineral olivine.
Diamanti’s concrete mixture, formulated by Dr. Shu Yang from the university’s Material Science Department, incorporates diatomaceous earth (DE), a silica-rich material derived from fossilized algae. This innovative ingredient creates channels within the concrete that allow for deeper carbon dioxide penetration, enhancing its absorption capabilities. While DE production was approximately 2.6 million tons in 2023, experts caution that supply chain considerations must be addressed to meet future concrete demands.
Akbarzadeh acknowledges that while DE shows promise, access to the material can be limited. He emphasizes the need for a multifaceted approach to tackle material demands and reduce carbon emissions, stating, “There’s no silver bullet. We need to be doing all the different actions that we can.”
Innovative Design and Future Applications
Before practical implementation, the Diamanti team constructed a prototype bridge to test their design. The bridge features a modular system where each block is printed using a robotic arm and connected via tensile cables. Akbarzadeh notes that this method reduces construction time, material, and energy use by 25% while cutting steel requirements by 80%, further minimizing greenhouse gas emissions.
The team initially created a five-meter-long prototype to validate their concept, followed by a ten-meter version that successfully passed load testing. Akbarzadeh remarked, “It exceeded all our expectations.” Currently, the prototype is showcased at the European Cultural Center in Venice as part of the Venice 2025 Architecture Biennial.
Although the team aimed to construct the first full-scale bridge in Venice, changing regulations prompted them to seek alternative locations. Digital renderings created in partnership with Fortes Vision visualize the bridge over the River Seine in Paris, and in September, they secured approval to proceed with plans in France.
The team is enthusiastic about testing their designs in real-world conditions and intends to monitor and evaluate the structure closely. In addition to bridges, they are exploring other architectural possibilities, including prefabricated floor systems. While Akbarzadeh acknowledges that Diamanti is not a comprehensive solution, he envisions it creating “a whole new world of possibilities” for the future of concrete.
