Ancient Roman concrete longevity offers mixed sustainability benefits

Ancient Roman concrete longevity offers mixed sustainability benefits
by Clarence Oxford
Los Angeles CA (SPX) Aug 01, 2025

Ancient Roman concrete, famed for its durability across centuries, may offer partial sustainability advantages over modern concrete, according to a new study published July 25 in iScience. Researchers from Universidad del Norte and U.S. institutions found that although Roman concrete uses comparable energy and emits similar CO2 during production, its resilience could reduce long-term environmental impacts.

"Studying Roman concrete can teach us how to use materials in a way that can maximize the longevity of our structures, because sustainability goes hand-by-hand with durability," said study author Daniela Martinez, an engineer at Universidad del Norte.

Concrete production currently accounts for about 8% of global man-made CO2 emissions and 3% of total energy demand. Motivated by suggestions that Roman concrete could be more eco-friendly, the research team conducted detailed sustainability modeling, comparing raw materials, energy inputs, and pollutant outputs between ancient and modern formulations.

Both types rely on limestone, which releases CO2 when heated. However, Roman concrete also includes local rock, recycled rubble, and pozzolan-volcanic ash that enhances durability. The team modeled several historical recipes and production techniques, factoring in different energy sources such as fossil fuels, biomass, and renewables.

Despite expectations, results showed that Roman concrete emits CO2 in amounts similar to or greater than modern concrete per unit volume. "Contrary to our initial expectations, adopting Roman formulations with current technology may not yield substantial reductions in emissions or energy demand," Martinez explained. She added that alternative fuels for modern kilns might offer greater decarbonization benefits.

Still, Roman concrete production consistently yielded fewer harmful air pollutants like nitrogen and sulfur oxides-up to 98% less depending on the energy source-offering a significant public health advantage.

The authors emphasized that longevity may be the most critical factor in concrete sustainability. Roman concrete's robustness, especially in high-wear structures like roads, could reduce repair and replacement needs. "When we take concrete's service life into consideration, that's when we start seeing benefits," Martinez said.

Sabbie Miller of UC Davis added, "In cases where prolonging the use of concrete can reduce the need to manufacture new materials, more durable concrete has the potential to reduce environmental impact."

However, Paulo Monteiro of UC Berkeley cautioned that Roman and modern concretes differ fundamentally, especially since modern versions incorporate steel reinforcement, which is vulnerable to corrosion. "Corrosion of steel reinforcement is the main cause of concrete deterioration, so comparisons should be made with great care," he noted.

Looking ahead, the team plans to develop deeper assessments to compare lifespan and performance of both concrete types in various use cases. "There's a lot of lessons that we can draw from the Romans," Martinez said. "If we can incorporate their strategies with our modern innovative ideas, we can create a more sustainable built environment."

Research Report:How sustainable was Ancient Roman concrete