A scientist recently discovered the technique the Romans used to ensure their structures would last for many years: a paste made from limestone and water. The scientist, Admir Masic, tested mixing volcanic ash with limestone, then adding water to create a paste-like substance to fill cracks in building surfaces.

While Admir Masic and his collaborators were able to successfully make this substance, the technique they used was not the exact same one as the Romans used, as stated by a Roman architect named Vitruvius, who wrote that the paste was created with only limestone and water before adding any other materials into it.

Masic said that the paste-like substance he and his collaborators made became hot after they combined all the materials. This hot mixture was then placed into cracks in walls and ceilings to give off those “self-healing” properties that helped to keep the cracks filled in and stay put together longer. Now, Masic started selling this paste to help architects and builders keep the walls they make secure without the cracks becoming bigger problems.

Masic stated, “Having a lot of respect for Vitruvius, it was difficult to suggest that his description may be inaccurate. The writings of Vitruvius played a critical role in stimulating my interest in ancient Roman architecture, and the results from my research contradicted these important historical texts.” So, even though he may have found a new way to create this paste, it wasn’t as accurate as the one Vitruvius said was used in his De Architectura.

Masic first learned about the self-healing concrete while on a trip to Pompeii, where he went to a site of old buildings that earthquakes had destroyed, then broken down even more over time. His trip there led to his inspiration for trying to replicate the paste-like substance they used back in the day. After his trip there, he spoke, “I walked into an excavation in Pompeii a year-and-a-half ago, and it was like travelling back in time to a construction site in the Roman Empire.”

The team figured out that the Pompeians used quicklime and volcanic ash at first by mixing the two dry materials before they finished by adding water to the mixture. They found the same substance when they checked older Roman buildings. That’s when the news from Masic and his team got out that Pompeii and Rome had used those clever mortars, which are the mixtures. This use of the mortars helped not only to fill in cracks in walls, but they were also widely used with tiles to keep them better secured to the floors.

Thanks to Masic and his team’s revelation, people nowadays are able to make the same kind of mortars that will help the buildings hold together much better than they were before. People are buying these hot mixtures for their new projects to build with, as a way to preserve any walls and tiles when cracks begin to arise.