The legacy of ancient Rome has survived to the present day with a level of preservation unprecedented in the past centuries. Now a study has revealed the secret with which the Romans built their empire and has survived until now.
A new analysis carried out by researchers from Massachusetts Institute of Technology (MIT) reveals that the brick structures of Pompeii are still standing thanks to the ancient Romans who used a type of self-healing concrete that lasts for thousands of years.
Two years ago, associate professor at MIT Admir Masicand his team published a paper explaining how Roman concrete was made, describing a method called hot mixing.
In this process they mixed dry lime fragments with volcanic ash and other materials, and water was only added at the end.
When water comes into contact with the dry mix, it generates heat which traps the lime inside the concrete in the form of small white pieces. These pieces can then dissolve and fill the cracks, which allowed the concrete to repair itself.
But in a recent discovery, the team discovered that the ancient Roman architect Vitruvius He wrote a book on architecture in which he claims that the Romans first added water to lime to form a paste, then mixed it with other materials.
This differed from what the MIT professor had discovered in his lab tests, and given Vitruvius’ historical importance, Admir Masic He didn’t dare contradict him.
Now researchers have discovered an ancient work in Pompeii, well preserved after the eruption of the Vesuvius volcano in 79 AD. C., and collected piles of raw materials, tools and walls at different stages of construction, which allowed them study self-healing Roman concrete as it was made, the same that was applied to the architecture of the time, even in Pompeii.
Masic and his academic collaborators collected samples from dry material piles, unfinished walls, finished walls and repair sections during their visit to Pompeii with the aim of re-evaluate the self-healing concrete of the tank.
They found fragments of lime in the concrete, as in the previous study, but they also found fragments of unreacted quicklime in the pile of dry material, demonstrating that the Romans mixed lime dry and used the hot mixing technique. To study the materials, the team used stable isotope tools to track their evolution over time. Thanks to this, they were able to observe the difference between hot mixed lime and lime previously slaked with water.
The results showed that the Romans used quicklime, ground it, mixed it dry with volcanic ash and They then added water to create the binder.
The researchers also studied volcanic ash with pumice, which gradually reacted with water in the concrete. This reaction created new minerals that helped strengthen the structure over time, and these minerals They fill the pores and provide greater stability.
This research does not aim to exactly copy Roman concrete, since modern construction requires different materials and standardsbut to learn small lessons from the past that can help create modern self-healing concrete that lasts for years, like in Pompeii.
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