The durability of Roman concrete that made possible structures that: pantheon in rome Standing for nearly 2,000 years has long baffled experts.
But scientists now believe they have rediscovered quicklime, the secret ingredient in an ancient recipe that makes building materials self-repair.
Experts at MIT and Harvard found that adding quicklime to the mixture caused an ultra-hot chemical reaction that left calcium deposits clinging throughout the concrete.
Importantly, cracks begin to appear at a later stage, and when water penetrates, these calcium deposits recrystallize into calcium carbonate, filling the gaps. Heals before it damages.
Learn how to build the world’s largest reinforced concrete dome in the pantheonDedicated in 128 AD.
Some ancient concrete aqueducts still supply Rome with water. Hadrian’s Wallits core reinforced with ancient concrete survives.
As Pliny the Elder wrote in his Naturalis Historia in 79 AD, the concrete structures of the harbor, though beaten down by sea water, “would become a single mass of stone, unable to withstand the waves, become stronger,” he said.
New discoveries could enable modern engineers to build structures that last thousands of years. It was created after experts began studying the ancient concrete calcium deposits known as limestone. They were previously ignored as a product of sloppy mixing practices.
Admir Masic, professor of civil and environmental engineering, said, “The idea that the presence of these limestone lumps was simply due to poor quality control has always haunted me.
“If the Romans put so much effort into making superior building materials, following all the detailed recipes that have been optimized over the centuries, why did they produce a well-mixed final product?” Little effort was put into ensuring production?? There must be more to this story.”
To prove that limestone is involved in durability, the team created samples of hot mix concrete incorporating both ancient and modern formulations and intentionally cracked them to prevent cracks. I poured water into
Within two weeks the crack was completely healed and water stopped flowing. The same concrete block made without quicklime never cured and water continued to flow through the sample.
The team is working to revive Roman concrete as a commodity.
“Thinking about how these more durable concrete mixes not only extend the useful life of these materials, but how we can improve the durability of 3D-printed concrete mixes. is exciting,” said Professor Masic.
This research was published in Science Advances.