Some Roman Concrete Gets Stronger Over Time

The tomb of Caecilia Metella is a landmark on the Via Appia Antica. the Appian Way. It has stood for over 2,000 years. The mortar in its construction has actually become stronger over time. It's secret is minerals from a nearby pyroclastic flow. As water saturates the mortar, unique chemical reactions create stronger bonds and the aggregate works to stop microfracture from propagating.

Jackson and her colleagues are working to replicate some of the Romans' successes in modern concretes, specifically in a U.S. Department of Energy ARPA-e project to encourage similar beneficially reactive aggregates in concretes that use engineered cellular magmatics in place of the tephra of the ancient Roman structures. The objective, according to ARPA-e, is that a Roman-like concrete could reduce the energy emissions of concrete production and installation by 85% and improve the 50-year lifespan of modern marine concretes four-fold.

"Focusing on designing modern concretes with constantly reinforcing interfacial zones might provide us with yet another strategy to improve the durability of modern construction materials," Masic says. "Doing this through the integration of time-proven 'Roman wisdom' provides a sustainable strategy that could improve the longevity of our modern solutions by orders of magnitude."