[Rockhounds] We Finally Know Why Ancient Roman Concrete Was Able to Last Thousands of Years

[Kreigh Tomaszewski]

The ancient Romans were masters of building and engineering, perhaps most
famously represented by the aqueducts. And those still functional marvels
rely on a unique construction material: pozzolanic concrete, a
spectacularly durable concrete that gave Roman structures their incredible
strength.

Even today, one of their structures – the Pantheon, still intact and nearly
2,000 years old – holds the record for the world's largest dome of
unreinforced concrete.

The properties of this concrete have generally been attributed to its
ingredients: pozzolana, a mix of volcanic ash – named after the Italian
city of Pozzuoli, where a significant deposit of it can be found – and lime
<https://en.wikipedia.org/wiki/Lime_(material)>. When mixed with water, the
two materials can react to produce strong concrete.

But that, as it turns out, is not the whole story. In 2023, an
international team of researchers led by the Massachusetts Institute of
Technology (MIT) found that not only are the materials slightly different
from what we may have thought, but the techniques used to mix them were
also different.

https://www.sciencealert.com/we-finally-know-why-ancient-roman-concrete-was-able-to-last-thousands-of-years