A team of researchers has uncovered new revelations detailing why Roman-era concrete is so long-lasting.
The extreme durability of Roman concrete has puzzled researchers for decades but MIT investigators have concluded the process of mixing the materials may have given the concrete self-healing capabilities, which have allowed Roman structures to remain standing to this day.
“The Pantheon would not exist without the concrete as it was in the Roman time,” MIT’s head of the recent study Admir Masic told the Guardian.
The study involved MIT and Harvard researchers, as well as researchers from Italy and Switzerland. The team of investigators analyzed samples of concrete from Roman times.
It’s been a mystery why Roman concrete often lasted thousands of years, but ours decays in mere decades.
Turns out they incorporated chemicals in a process that induces self-healing; scientists at MIT just figured this all out – in 2022.
Extraordinary.https://t.co/cOPyln0ifd
— Joe Lonsdale (@JTLonsdale) January 7, 2023
Lime clasts found in the concrete have been touted as being able to help the concrete heal cracks over time. Previously, researchers believed the lime clasts were merely the product of low-quality mixing. But Masic contested this widely-held belief.
“For me, it was really difficult to believe that ancient Roman [engineers] would not do a good job because they really made careful effort when choosing and processing materials,” Masic told CNN.
“Scholars wrote down precise recipes and imposed them on construction sites,” the MIT professor of civil and environmental engineering added.
The researchers’ analysis has concluded the process of mixing the lime and binding agent to form concrete was also instrumental in creating long-lasting concrete. By using quicklime, also known as calcium oxide, in its mixture process, the lime clasts formed at high temperatures. (RELATED: Archaeologists Just Unearthed A Pair Of Scary Looking Ancient Roman Boxing Gloves [PHOTOS])
Masic explained the two benefits of this process, known as “hot mixing,” in a press release. “First, when the overall concrete is heated to high temperatures, it allows chemistries that are not possible if you only used slaked lime, producing high-temperature-associated compounds that would not otherwise form. Second, this increased temperature significantly reduces curing and setting times since all the reactions are accelerated, allowing for much faster construction.”