Geologists and engineers from around the world team up in Berkley to create concrete that is tougher and more resilient. They found the answer from an ancient maritime concrete found in Pozzuoli Bay, Italy, which was able to withstand the elements of nature for more than 2,000 years.
Using the Advanced Light Source located in Berkeley Lab, the team of researchers from University of California studied the composition of the Roman concrete. The discovered a combination of extremely durable components - calcium-aluminum-silicate-hydrate or C-A-S-H – was used to build the most lasting structure in the Western civilization.
The latest discovery can help in improving the stability of modern concrete, which usually shows sign of dilapidation within just 50 years, especially near ocean settings.
Constructing Roman concrete leaves less carbon footprint compared to modern methods. In processing Portland cement, a main ingredient in modern cement, entails fossil fuels burning calcium carbonate or limestone, and clay at approximately 2,642 degrees Fahrenheit. This activity contributes to seven percent of the world’s total carbon dioxide emission annually. However, Roman concrete is much cleaner and would require only two-thirds of the temperature.
Marie Jackson was the lead author for the Journal of the American Ceramic Society and American Mineralogist wrote about the material. She wrote that the Romans durable construction of structures near oceans were intentional. Since the Roman Empire strongly relied on shipping as the link for economic, military and political stability, they needed their harbors to be very well-built.
Concrete was the Roman’s material of choice. It was also used by the Roman Empire in building other monuments, like the Pantheon in Rome, as well as breakwaters, wharves, and other structures near oceans. Most interestingly, the team was impressed on how Roman concrete survived the ruthless underwater environment.
In 30 B.C., Octavian engineer Marcus Vitruvius Pollio revealed the secret ingredient as volcanic ash, mixed with lime to make mortar. They then packed the mortar into wooden molds to be later immersed in seawater. The Romans harnessed salt water and turned it into an essential ingredient of the concrete.