If you've ever wondered how buildings from the ancient Roman Empire have withstood for more than two millennia, science might have the answer.
The secret to the brilliance of the ancient Roman architecture could lie in none other than volcanic ash. According to Sci-News, the mortar used to construct buildings such as the Colosseum and Pantheon was 85 percent volcanic ash, fresh water and lime.
Meanwhile, most modern buildings are constructed using Portland cement, produced by Manufacturing Portland. This cement is made by heating a mix of limestone and clay to 2,642 degrees Fahrenheit, emitting enough carbon into the air to account for about 7 percent of all the carbon emitted into the atmosphere in one year. That's a much higher percentage than the amount which is emitted by volcanic ash.
Not only does ash emit less carbon, the concrete it produces is met with much greater resilience than that of Portland cement. So upon discovering the phenomena, scientists looked into why it was so.
“We obtained X-ray diffractograms for many different points within a given cementitious microstructure. This enabled us to detect changes in mineral assemblages that gave precise indications of chemical processes active over very small areas,” Marie Jackson of University of California, Berkeley, said.
In other words, they used images to find out exactly where, how often and to what extent cracks in the cement occurred.
Jackson added the volcanic ash mortar resists much of the micro-cracking seen in modern cement through a process called " through the crystallization of platysträtlingite, a durable calcium-alumino-silicate mineral that reinforces both the structure and its adhesive edges.
“The dense inter growths of the platy crystals obstruct crack propagation and preserve cohesion at the micron scale, which in turn enables the concrete to maintain its chemical resilience and structural integrity in a seismically active environment at the millennial scale," Jackson explained.
Jackson noted the significance of the discovery, especially as it relates to limiting the amount of carbon emitted into the atmosphere.
“If we can find ways to incorporate a substantial volumetric component of volcanic rock in the production of specialty concretes, we could greatly reduce the carbon emissions associated with their production also improve their durability and mechanical resistance over time,” Jackson said.
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