(Image: Drilling out a sample of an ancient Roman concrete structure in Portus Cosanus,
Tuscany, in 2003.)
Ancient Roman concrete was more durable than any developed before or since. "It's the most durable building material in human history," Philip Brune, a researcher at DuPont Pioneer who studies the engineering of ancient Roman monuments, told the Washington Post. "And I say that as an engineer not prone to hyperbole."
Indeed, academics study the properties and chemical mixture of the concrete, which was made with volcanic ash found in Italy and is particularly well suited to marine structures. Now some researchers are wondering if the secrets of this ancient building material could help us adapt to a world of rising seas.
As global temperatures rise, sea ice is melting and causing the sea level to rise at a faster rate than during the 1900s. Exactly how much it will rise is dependent on a number of variables, but there is a high likelihood that rising sea levels will force us to reinforce infrastructure around coastal cities. Venice is already sinking.
One of the most direct solutions for a coastal city is to construct a seawall. These structures do not need to hold back the ocean constantly, but rather are built to block the water from the city during high tide and storms that can cause flooding. The Malecón in Havana, Cuba, for example, is a five-mile-long roadway and seawall that guards the infrastructure of the city. Seawalls are used around the world in countries like the United Kingdom and Australia.
It turns out the ancient Romans had the perfect recipe for water-resistant concrete. The material, called opus caementicium by the Romans, is made from a hydraulic cement, meaning it can set underwater or in wet conditions. The Romans mixed this cement with volcanic ash found in regions around modern Naples. The volcanic ash added a mineral called phillipsite to the concrete, and a study published Monday in the American Mineralogist reveals that aluminous tobermorite crystals grow in the Roman concrete when it is exposed to water. These crystals, the scientists believe, could provide the structural reinforcement that makes Roman concrete so durable.
