Solve the mystery of almost two thousand years of existence of the Pantheon in Rome.
The famous building of the Pantheon in Rome stood for two thousand years and remained untouched, while many modern buildings made of concrete collapse after a few decades, which baffles engineers for a long time.
Why the Roman concrete structures of the Pantheon were so strong remains a mystery, and researchers may have finally uncovered the secret of ancient construction methods – and it’s all due to small pieces of lime that have the ability to “self-heal”.
How the Pantheon remained untouched for almost 2000 years https://t.co/q9cBQyuROh
— Daily Mail USA (@DailyMail) January 6, 2023
The Pantheon (Temple of All Gods) was founded in 27 BC. Mark Vipsanius Agrippa. It was rebuilt by Emperor Hadrian between 120 and 124 AD after fires in 80 and 110 AD damaged the building until Augustus.
Careful analysis of Roman concrete revealed small, shiny, white mineral lumps called “limestone”.
Initially, it was believed that this was the result of careless mixing or the use of low-quality raw materials.
Admir Masik, an environmental engineer at the Massachusetts Institute of Technology, said that although the Roman writer and philosopher Pliny the Elder pointed out that concrete gets stronger with age, it is unlikely that the Romans knew about the chemistry used or how long the material would last. .
“They knew it was a great material, but they probably didn’t know it would last for thousands of years,” Masek said.
Roman concrete was produced using blocks of lava rock and other aggregates held together with a mortar composed of ingredients including pozzolan (in the form of volcanic ash), a source of lime (calcium oxide), and water.
The team, which also included researchers from Harvard University and laboratories in Italy and Switzerland, used high-resolution imaging and chemical mapping to closely examine the lime layers.
They found that lime can actually help concrete “heal” itself when it cracks or breaks.
During the hot mixing process required to make concrete, lime crevices become brittle, creating an easily accessible source of calcium for the rest of the concrete.
This means that when small cracks form in the concrete, limestone blocks react with water and form a solution rich in calcium, which can quickly recrystallize and fill the crack.
To prove that this was indeed the mechanism responsible for the durability of Roman concrete, the team made samples of hot concrete using ancient formwork and deliberately split them, then forced water through the cracks.
Within two weeks, the cracks closed completely and water could no longer flow. While an identical piece of concrete made without lime never hardened, water continued to flow through the sample.
As a result of these successful trials, the team is working on marketing modified cement.
Their results were published in the journal Science Advances.
Source: Daily Mail