The ancient Romans were so skilled at making concrete that breakwaters poured more than 2,000 years ago are still doing fine. The modern stuff? Give it 50 years before it starts eroding in seawater. Now, however, scientists think they've figured out how the Romans did it—and the findings could make today's concrete not only much stronger but more environmentally friendly, reports Bloomberg Businessweek. The Roman formula involves a combination of volcanic ash and lime that modern concrete lacks, and it uses a different "glue" to hold the components of concrete together, say researchers at the Berkeley Lab. (The resulting compound is "calcium-aluminum-silicate-hydrate" for the technical-minded.)
An example of the Roman ingenuity:
- “For underwater structures, lime and volcanic ash were mixed to form mortar, and this mortar and volcanic tuff were packed into wooden forms," say the researchers. "The seawater instantly triggered a hot chemical reaction. The lime was hydrated—incorporating water molecules into its structure—and reacted with the ash to cement the whole mixture together.”
What's more, the Romans used less lime and baked it at lower temperatures, meaning the process was greener because it released less carbon into the atmosphere, says History.com
. By contrast, today's process is a big source of industry pollution. Says a Berkeley scientist: "The question remains, can we translate the principles from ancient Rome to the production of modern concrete? I think that is what is so exciting about this new area of research."