The researchers now know why ancient Roman concrete is so superior. They extracted from the floor of Italy’s Pozzuoili Bay, in the northern tip of the Bay of Naples, a sample of concrete headwater that dates back to 37 B.C. and analyzed its mineral components at research labs in Europe and the U.S., including at Berkeley Lab’s Advanced Light Source. The analysis, the scientists believe, reveals the lost recipe of Roman concrete, and it also points to how much more stable and less environmentally damaging it is than today’s blend.
That’s why the findings, which were published earlier this month in the Journal of the American Ceramic Societyand American Mineralogist, are considered so important for today’s industrial engineers and the future of the world’s cities and ports. “The building industry has been searching for a way to make more durable concretes,” Jackson points out.
Another remarkable quality of Roman concrete is that its production was exceptionally green, a far cry from modern techniques. “It’s not that modern concrete isn’t good—it’s so good we use 19 billion tons of it a year,” says Paulo Monteiro, a research collaborator and professor of civil and environmental engineering at the University of California, Berkeley. “The problem is that manufacturing Portland cement accounts for 7 percent of the carbon dioxide that industry puts into the air.”