The Mystery Finally Solved: Why Has #RomanConcrete Been So Durable?
January 20th, 2023
"Rome may not have been built in a day, but it was built to last — or at least its concrete was, given that the pieces of the Roman Empire that have stood to our time, in one form or another, tend to have been built with it. That material has proven not just durable but enduringly fascinating, holding a great deal of not just historical interest but technical interest as well. For ancient Roman concrete appears to outlast its much more technically advanced modern descendants, and the complex question of why is one we’ve featured more than once here on Open Culture. Just this year, researchers at MIT, Harvard, and laboratories in Italy and Switzerland have found what seems to be the final piece of the puzzle.
"'For many years, researchers have assumed that the key to the ancient concrete’s durability was based on one ingredient: pozzolanic material such as volcanic ash from the area of Pozzuoli, on the Bay of Naples,' writes MIT News’ David L. Chandler. 'Under closer examination, these ancient samples also contain small, distinctive, millimeter-scale bright white mineral features.'
"Previously assumed to be nothing but imperfections in the process or the materials, these 'lime clasts,' in light of this most recent research, constitute evidence of 'hot mixing,' which involves heating to a high temperature ingredients including quicklime (or calcium oxide), a purer and more reactive form of lime.
"Undergoing hot mixing, 'the lime clasts develop a characteristically brittle nanoparticulate architecture, creating an easily fractured and reactive calcium source' that 'could provide a critical self-healing functionality.' In practice, this means that 'as soon as tiny cracks start to form within the concrete, they can preferentially travel through the high-surface-area lime clasts. This material can then react with water, creating a calcium-saturated solution, which can recrystallize as calcium carbonate and quickly fill the crack, or react with pozzolanic materials to further strengthen the composite material.' Here we have a convincing explanation of the reactions that, in ancient Roman concrete, 'automatically heal the cracks before they spread.'
"No such self-healing happens in modern concrete, the production of which has not involved quicklime for a very long time indeed — but perhaps it could once more. During their research process, writes Dezeen’s Rima Sabina Aouf, the team 'produced samples of hot-mixed concrete using both ancient and modern formulations, cracked them, and ran water through the cracks. Within two weeks, the cracks had healed and water could no longer flow through, while identical concrete blocks made without quicklime never healed.' Such findings 'could help increase the lifespan of modern concrete and therefore mitigate the notorious environmental impact of the material,' and the researchers 'are now working to commercialize their more durable concrete formula.' Even in the twenty-first century, the building industry could well benefit by doing as the Romans did."
https://www.openculture.com/2023/01/the-mystery-finally-solved-why-has-roman-concrete-been-so-durable.html
#AncientTechnology #Buildings #Architecture #SolarPunk
January 20th, 2023
"Rome may not have been built in a day, but it was built to last — or at least its concrete was, given that the pieces of the Roman Empire that have stood to our time, in one form or another, tend to have been built with it. That material has proven not just durable but enduringly fascinating, holding a great deal of not just historical interest but technical interest as well. For ancient Roman concrete appears to outlast its much more technically advanced modern descendants, and the complex question of why is one we’ve featured more than once here on Open Culture. Just this year, researchers at MIT, Harvard, and laboratories in Italy and Switzerland have found what seems to be the final piece of the puzzle.
"'For many years, researchers have assumed that the key to the ancient concrete’s durability was based on one ingredient: pozzolanic material such as volcanic ash from the area of Pozzuoli, on the Bay of Naples,' writes MIT News’ David L. Chandler. 'Under closer examination, these ancient samples also contain small, distinctive, millimeter-scale bright white mineral features.'
"Previously assumed to be nothing but imperfections in the process or the materials, these 'lime clasts,' in light of this most recent research, constitute evidence of 'hot mixing,' which involves heating to a high temperature ingredients including quicklime (or calcium oxide), a purer and more reactive form of lime.
"Undergoing hot mixing, 'the lime clasts develop a characteristically brittle nanoparticulate architecture, creating an easily fractured and reactive calcium source' that 'could provide a critical self-healing functionality.' In practice, this means that 'as soon as tiny cracks start to form within the concrete, they can preferentially travel through the high-surface-area lime clasts. This material can then react with water, creating a calcium-saturated solution, which can recrystallize as calcium carbonate and quickly fill the crack, or react with pozzolanic materials to further strengthen the composite material.' Here we have a convincing explanation of the reactions that, in ancient Roman concrete, 'automatically heal the cracks before they spread.'
"No such self-healing happens in modern concrete, the production of which has not involved quicklime for a very long time indeed — but perhaps it could once more. During their research process, writes Dezeen’s Rima Sabina Aouf, the team 'produced samples of hot-mixed concrete using both ancient and modern formulations, cracked them, and ran water through the cracks. Within two weeks, the cracks had healed and water could no longer flow through, while identical concrete blocks made without quicklime never healed.' Such findings 'could help increase the lifespan of modern concrete and therefore mitigate the notorious environmental impact of the material,' and the researchers 'are now working to commercialize their more durable concrete formula.' Even in the twenty-first century, the building industry could well benefit by doing as the Romans did."
https://www.openculture.com/2023/01/the-mystery-finally-solved-why-has-roman-concrete-been-so-durable.html
#AncientTechnology #Buildings #Architecture #SolarPunk
The Mystery Finally Solved: Why Has Roman Concrete Been So Durable?
Image by Benjaminec, via Wikimedia Commons Rome may not have been built in a day, but it was built to last — or at least its concrete was, given that the pieces of the Roman Empire that have stood to our time, in one form or another, tend to have be…Colin Marshall (Openculture.com)
rndeon •
DoomsdaysCW •
Alfred University News
August 6, 2024
Novel concrete developed at Alfred University to be tested against rigors of marine environment
"The collaboration between Alfred University and Silica-X studies how waste glass particles can be used in place of traditional materials (finely powdered stone) used in the production of cement. The process of making traditional Portland cement is a major contributor to greenhouse gasses worldwide; using alternative materials, such as waste glass, in creating cement is less harmful to the environment. This innovation can best be described as the first ever Roman Concrete analog – with significantly longer life spans and reduced material weight as compared to traditional concrete widely manufactured today.
The broader goal of the glass recycling research being conducted at Alfred University is to find ways to significantly stimulate a “circular economy,” one in which waste products—in this case glass—are put to use, rather than simply buried.
“The circular economy means we use what we produce,” Wilkinson said. “If we produce waste, we have to figure out how to use it. We have this excess glass here, and over here we have this problem with sea walls.”
Researchers believe the novel concrete will stand up to the rigors of a marine environment better than concrete made from Portland cement. It could potentially be used in the production of stronger, longer-lasting sea walls along the world’s coastlines, further helping the environment.
Samples of this Roman-derived concrete made from glass-fortified cement—in the form of four cubic foot blocks called “coupons”—will be placed in the Long Island Sound in early October to test its robustness in the marine environment. The coupons will be studied regularly for two years.
“We’re excited for the launch of these coupons,” said Gabrielle Gaustad ’04, dean of the Inamori School of Engineering and associate provost for Research at Alfred University. “They will be monitored by a team to see how they stand up structurally and how they work with the local ecology.”
The test coupons are designed to encourage sea life propagation, supporting ocean ecology. It is further anticipated that manufacturing of this innovative concrete, by Silica-X, which has produced these initial test coupons, will be done locally, resulting in the creation of new, green jobs, while reducing the environmental impacts of shipping concrete to Long Island and waste glass off the Island.
While the immediate goal of the research focuses on self-healing concrete in seawater, “what will come from it has potential application in all green building materials,” said Philip Galland, CEO of Silica-X. If scientists are successful in creating a Roman Concrete analog, the materials could be used not just in sea wall construction, but in the construction of buildings in communities around the globe.
“This project represents a shared vision between Alfred University, and Silica-X,” Galland said. “This experiment is being done with a focus on the benefit of the citizens of New York. However, what is happening here is that we are creating a potential model that is going to positively impact the entire world.”
https://www.alfred.edu/about/news/pressreleases/2024/08/novel-concrete-developed-at-alfred-university-to-be-tested-against-rigors-of-marine-environment.cfm
https://www.alfred.edu/about/news/pressreleases/2024/08/novel-concrete-developed-at-alfred-university-to-be-tested-against-rigors-of-marine-environment.cfm
Novel concrete developed at Alfred University to be tested against rigors of marine environment | Alfred University News
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