This is why ancient Roman concrete lasts thousands of years

  • 7 years ago
SALT LAKE CITY — Researchers in the U.S. have recently revealed the secret to the longevity of the Roman concrete.

Roman concrete was typically made with a mixture of volcanic ash, rock and lime. It is known for its superb durability, and some structures made of this material have lasted thousands of years. Meanwhile, modern concrete structures have significantly shorter life spans. The Roman mixture of mortar has proven to be well-suited for the construction of harbors and piers.

Researchers from the University of Utah and Berkeley Lab studied samples of 2,000-year-old ancient concrete from marine structures in various places in Italy. They found out when seawater enters the concrete through tiny cracks, it reacts with the volcanic ash and lime to produce a crystal called tobermorite in a process known as pozzolanic reaction. The tobermorite crystals bind the concrete particles together, which strengthens the concrete and increase durability.

"Romans were fortunate in the type of rock they had to work with, They observed that volcanic ash grew cements to produce the tuff. We don't have those rocks in a lot of the world, so there would have to be substitutions made," Marie Jackson, University of Utah geologist and lead author of the study said in a press release.

Researchers are experimenting with seawater and volcanic rock in order to create a mixture that could be used to build marine structures with longer higher durability.

The study was published in the journal American Mineralogist.