With buildings erected just last century already slated to experience “advanced deterioration” in the coming decade, you’ve got to wonder: what’s keeping the Roman Coliseum standing?
A new study published in the “Proceedings of the National Academy of Sciences” point to one mineral in the ancient mortar that creates a more environmentally and structurally optimal building material.
Basically, Roman architectural mortar consisted of volcanic ash, fresh water, and lime, which they mixed with volcanic tuff and chunks of brick. Over time, according to the scientist’s X-rays, a crystal mineral called strätlingite would form to protect against cracking.
It “reinforces interfacial zones and the cementitious matrix,” says lead scientist and trained volcanologist Marie Jackson of UC Berkeley’s Department of Civil and Environmental Engineering. “The dense intergrowths 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.”
The Roman recipe is less porous and requires lower temperatures than that of Portland cement, the world’s most widely used concrete binder, which also happens to be responsible for about seven percent of the world’s greenhouse emissions.
“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 and also improve their durability and mechanical resistance over time,” Jackson says. For a brighter future, we merely have to take a look at the past.
by Janelle Zara