Rome wasn’t built in a day. In fact, ancient Roman concrete structures could possibly still be building themselves to this day, according to a new study published by MIT earlier this year.
For decades, researchers have remained puzzled as to how the ancient Romans created such durable structures that remain standing to this day. However, a team of researchers at MIT and Harvard might have cracked the code behind the Romans strong structures: self-healing concrete.
In a paper recently published in Science Advances, researchers proposed that Romans used a process called “hot-mixing” when creating concrete, which allowed concrete to repair cracks on its own. Hot-mixing occurs when using quicklime, a dry and very reactive form of limestone, as opposed to the normal method of using slaked lime, which is limestone that is combined with water first.
Using quicklime changes the chemical reactions in the mixing process, causing extreme temperatures to occur which create calcium deposits. Originally, researchers believed the calcium deposits found in ancient Roman concrete were the result of poor mixing methods, according to the study.
As it turns out, the calcium deposits could be the key regenerative concrete. According to the study, as water enters a crack in the concrete, it would dissolve the calcium deposits. Consequently, the dissolved chemicals can recrystallize and fill the cracks.
Researchers believe regenerative concrete could address a lot of problems in modern day engineering.
“Our current infrastructure is crumbling down,” explains Seth Nowak, an engineering instructor at Georgia Southern. “Right now, we don’t have a way to effectively slow down or reverse the process.”
Joey DeWane, a member of Georgia Southern’s regenerative concrete research team, hopes to gather more information surrounding the strength of the self-healing concrete.
“We do not know how the strength will compare,” said DeWane. “However, one of the benefits of conducting research like this is we have the chance to find something amazing.”
Researchers hope that self-healing concrete will not only result in stronger structures, but will also cut down the carbon emissions that come with manufacturing concrete.
Cement manufacturing accounts for at least 8 percent of the world’s carbon emissions, according to a 2020 report by the International Energy Agency. If cracks in cement were able to fill themselves, less concrete would be needed to repair cracks, resulting in less manufacturing and carbon emissions.