Roman mortar, found the secret used in ancient Rome will create an ecological cement
Roman mortar. Strong chemical reactions among the components of the mortar used by the ancient Romans donated to concrete resistance comparable to that of many modern materials. This is confirmed by a new study by a researcher at the University of California at Berkeley.
NEARLY two thousand years the Markets of Trajan have stood hugging the slopes of the Quirinal, surviving wars, storms and earthquakes. The complex, which dates from the second century AD, is just one of many Roman monuments arrived substantially intact (at least on the structural level) to the present day. The results of the analyzes conducted two years ago in the Roman port of Pozzuoli Bay in Naples did think it was the contact with water to make cement particularly strong. Now a new study published in the Proceedings of the National Academy of Sciencesfornisce new elements that explain the incredible strength of the concrete of ancient Rome. The research, conducted by a team of American scientists, Chinese and Italian, in fact analyzed the chemical composition of the mortar used in walls of ancient Rome, discovering that particular chemical reactions among the components supplied to the material resistance comparable to that many of today’s cements. An ancient secret, which according to researchers today could point the way to produce new building materials, durable and eco-friendly.
The formula of the mortar in question is a recipe perfected by Roman builders around the first century BC, and remained in use for over 500 years. The main ingredients of the compound are the pozzolan (a mixture of volcanic ash and silt extracted at the time the Campi Flegrei Pozzuoli and Lazio) and lime, which were fragments of tufa, bricks and pieces to form the so-called cement, one of the first examples of concrete history. To discover the secret of this material, the researchers reproduced the exact mixture used in Roman building and they let harden for 180 days, observing the mineralogical changes that were taking place inside and comparing the results with samples taken from the walls of Trajan’s Market.
They found that when the Roman mortar hardens the materials present inside react with each other, creating crystals of a mineral known as extremely resistant strätlingite. When the mortar is completely dry these crystals are then formed in its interior a scaffold that prevents cracks to propagate, making the material extremely durable and resistant to mechanical stress and seismic surveying, even for today’s standards. According to the researchers, as well as witness the great ability of the builders of ancient Rome, the discovery could prove valuable for developing new cements low polluting.
The production of modern cements is in fact responsible for about 7% of the CO2 entered the atmosphere each year. The concrete used by the Romans instead contains 45-55% of fragments of tuff and brick, and is created at temperatures much lower than the current ones. For this, the researchers said, its use would result in a significant reduction of carbon dioxide emissions.
“If we could ourselves to incorporate a significant amount of volcanic stones in making cements could significantly reduce carbon dioxide emissions,” says Marie Jackson, a researcher at the University of California Berkerley who led the study, “also increasing durability of the material, and its resistance to mechanical stress. “
“In secula seculorum”, for ever and ever. So be it: once built a building, in ancient Rome, there you could forget. Except unpredictable earthquakes, all were certain that he would never collapsed. Because the cement mix used at the time of the Empire was better than what we do today. More resistant, yes, but also more sustainable environmentally
To understand just looking at the Roman ruins still standing after more than two thousand years. And to put it down on paper is a study by an international team of scientists, and may help those who build to do from here on in a better way. Scientists and engineers have noticed the erosion resistance and the water of Roman concrete used in the construction of ports, pefettamente still preserved in many cases. The engineer Marie Jackson of the University of California at Berkley makes the numbers:
“Compared to the Roman, Portland cement, what we commonly use for 200 years, in these conditions would not last more than half a century before starting to erode.”
To understand the properties of the Roman concrete, the team analyzed between Europe and the US a sample extracted from the Roman port of the Bay of Pozzuoli, Naples. The secret is in the use of particular minerals, including volcanic rock and lime, which in contact with water made the concrete particularly solid. And that to be produced, it had no need of a dispersion of carbon dioxide in the atmosphere equal to 7% of the total, as it does now. The combination lime-volcanic ash there is in Portland cement. And then “a few years later began to fracture, as opposed to the Roman one,” explains Jackson. Use today those construction techniques is a challenge for the entire industry. But then you would then access a more solid material and environmentally friendly to produce. Alongside other sustainable solutions for the environment in which the world now have access, now there is another answer that comes from the distant past.