A team of researchers has solved the mystery of the durability of cement used by the Romans, of which the Pantheon in Rome is evidence, and the discovery can contribute to reducing the environmental impact of concrete production.
The “ultra-durable” nature of cement used by the Romans is due to its use of quicklime – which boils at a very high temperature when in contact with water – resulting in The ability to self-repair From the article, the team concluded.
The remains of roads, canals, ports, and buildings built by the ancient Romans still exist, after two thousand years, and some cement structures are still intact, as is the case with the famous Agrippa Pantheon, in the capital of Italy, which was built in 126 AD. While the modern concrete buildings collapsed in a few decades.
solve a puzzle
After decades, many researchers tried to solve the mystery “Ultra-durable old building materials” The progress was made by a team from MIT and Harvard and labs in Italy and Switzerland. Massachusetts Institute of Technology in a statement.
The magazine reported the discovery of ancient cement manufacturing processes used by the Romans that give it a great “self-healing ability”. Science advancesin an article by MIT Professor of Civil and Environmental Engineering Admir Masek, former doctoral student Linda Seymour, and four other researchers.
For many years, scholars believed that the explanation for the durability of ancient cement was its use in the mixture of “pozzolanic materials, such as volcanic ash from the Pozzuoli region in the Gulf of Naples, (…) distributed throughout the vast empire used by the Romans in construction and described in reports by architects and historians of the time as a major component of cement.”
But a closer look at ancient samples of the material is also revealing Bright white metallic elementsknown for a long time as an ever-present ingredient in Roman cement which was lime sourced from.
“These elements have fascinated me ever since I started working in ancient Roman cement.”says Admir Macyk, quoting the statement, indicating that he questioned the fact that they are not present in modern cement composition.
Characterization of these fractions through high-resolution images and the use of leading chemical mapping techniques It allowed the researchers to learn more about their potential role.
The explanation behind the white fragments
Musk and his team determined that the white parts “are made of different shapes of… Calcium carbonate (the substance that lime becomes when mixed with water)”, with spectral examination providing “evidence that it formed at extreme temperatures, as would be expected from the exothermic reaction (with the release of heat) produced by the use of quicklime”.
The conclusion was that “The hot mix was actually the key.” for durability.
“The benefits of hot mixing are twofold,” says Musk, explaining that the higher temperature allows for specific chemical reactions and specific compounds, as well as “dramatically reducing processing and setting times (…), allowing for much faster construction.” .
During the hot mixing process, the limestone rock fragments develop properties that the researchers say may facilitate the material’s self-repair by filling in cracks once they begin to form within the cement. Thus ‘reflexes’ occur spontaneously Automatically fix breaches before they become widespread“.
The final test
To prove their hypothesis, the team produced samples of cement with an old and new composition, broke them up and ran water through the gaps. After two weeks, the cracks in the Roman cement sample were completely repaired, preventing the flow of water. And those samples made without quicklime never sealed, and the water kept running off.
In view of the good test results, the A team “working on marketing this modified cement material”..
“It’s exciting to think about how these more durable cement formulations could not only increase the life of these materials, but also improve the durability of 3D-printed cement formwork,” says Masic.
environmental impact
The MIT researcher hopes to extend the service life and develop lighter types of cement “Help reduce the environmental impact of producing” these materialsis currently responsible “for about 8% of global greenhouse gas emissions,” according to the statement.
The lab Musk heads is also working on other formulas to produce cement that can “suck carbon dioxide out of the air,” an improvement that, along with previous improvements, “may help reduce cement’s impact on the global climate.”
“Hardcore alcohol maven. Hipster-friendly analyst. Introvert. Devoted social media advocate.”
