What's new

top of the heap to third world status in one generation

Brother Nature

Brother Nature

Well-known member
Gry said:

Science | AAAS

www.science.org www.science.org

The ancient Roman Empire still makes its presence felt throughout Europe. Bathhouses, aqueducts, and seawalls built more than 2000 years ago are still standing—thanks to a special type of concrete that has proved far more durable than its modern counterpart. Now, researchers say they have figured out why Roman concrete remains so resilient: Quicklime used in the mix may have given the material self-healing properties.


The work could help engineers improve the performance of modern concrete, says Marie Jackson, a geologist who studies ancient Roman concrete at the University of Utah, but who was not involved with the research.


The Romans were not the first to invent concrete, but they were the first to employ it on a mass scale. By 200 B.C.E., concrete was used in the majority of their construction projects. Roman concrete consisted of a mixture of a white powder known as slaked lime, small particles and rock fragments called tephra ejected by volcanic eruptions, and water.

Modern concrete, in contrast, is typically made from Portland cement: a mixture of limestone, clay, sand, chalk, and other ingredients ground and burnt at scorching temperatures. It also starts to crumble in as little as 50 years.


Scientists have previously tried to explain why Roman concrete is so long-lasting. In 2017, for example, researchers found that—at least for structures exposed to the ocean—seawater reacted with the ingredients of the concrete, creating new, tougher minerals.


But were there other explanations? To find out, Admir Masic, a chemist at the Massachusetts Institute of Technology, and colleagues gathered concrete samples from an ancient city wall in Privernum, a 2000-year-old archaeological site near Rome. Back in the lab, they focused on small calcium deposits embedded in the concrete known as lime lumps.
Other scientists had speculated that these tiny chunks were simply a result of the Romans mixing their concrete poorly. But Masic and his colleagues wondered whether they were instead caused by the Romans using quicklime in their mix before setting it with water. The widely available white powder, made from burning limestone, would have reacted with water during mixing, sparking a chemical reaction that produced significant amounts of heat. This would have prevented the lime from fully dissolving, resulting in the lime lumps.
And indeed, when the researchers tried to make their own Roman concrete in the lab with quicklime, they ended up with material that was “identical” to the samples they gathered from Privernum, Masic says.
When the team created small cracks in the concrete—as would happen as the material aged—and then added water (as would happen with rainwater in the real world), the lime lumps dissolved and recrystallized, effectively filling in the cracks and keeping the concrete strong, the researchers report today in Science Advances. “This has an incredible impact,” Masic says.
Modern concrete typically doesn’t heal cracks larger than 0.2 or 0.3 millimeters across. The team’s Roman-inspired concrete, in contrast, healed cracks up to 0.6 millimeters across.
Masic hopes the work will inspire today’s engineers to improve their own concrete, perhaps with quicklime or a related compound. Indeed, he says, a startup concrete company plans to employ the new discovery. The material wouldn’t just be less expensive than current self-healing concrete, Masic says, it could also help fight climate change: Cement production accounts for 8% of greenhouse gas emissions.
“Romans made extremely intelligent decisions based on excellent empirical observations,” Jackson says. “The more we can learn from ancient construction technologies, the better.”

Jacklin Kwan​


Science | AAAS

www.science.org www.science.org
Click to expand...
What a great read with my morning coffee and bong. Thanks Gry. I do wonder if those making the concrete back then were aware of this, I don't think we give ancient cultures enough credit.
 
buzzmobile

buzzmobile

Well-known member
Veteran
Brother Nature said:
What a great read with my morning coffee and bong. Thanks Gry. I do wonder if those making the concrete back then were aware of this, I don't think we give ancient cultures enough credit.
Click to expand...
The Pantheon in Rome was much more impressive than the Vatican.
eandt.theiet.org

The Pantheon: still the world’s largest unreinforced concrete dome

The Pantheon in Rome, now a church, was built as a temple to all the gods. It has been a shrine for architects since the Renaissance. It is also a worthy tribute to the skills of the ancient Roman masons and engineers who built it and the incredible alchemy of their concrete mix.
eandt.theiet.org eandt.theiet.org
 
tobedetermined

tobedetermined

Well-known member
Premium user
ICMag Donor
buzzmobile said:
The Pantheon in Rome was much more impressive than the Vatican.
Click to expand...

True, except for that damn hole in the ceiling. :rasta: The Roman mix would also set underwater (sea water) so they could build jetties and seawalls.

Saint Peter's is more like awesome architectural candy than a wonder. Hagia Sophia is a wonder and I am seriously pissed that shithead supremo Erdogan changed it back into a mosque.
 
Gry

Gry

Well-known member
Veteran
The silver mines that produced the wealth are seldom spoken of.
They required a nonstop source of labor, slavery was the
means by which the mines were worked.
 
Gry

Gry

Well-known member
Veteran
His last show he opened for Jeff Beck.
Bolin's tour for Private Eyes would be his final live appearances. He opened for Peter Frampton and Jeff Beck. In his final show, he opened for Beck on December 3, 1976, in Miami, and encored with a rendition of "Post Toastee." He also posed for his last photo, sitting backstage with Jeff Beck after the show, which appeared in Rolling Stone.[7] The article in Rolling Stone stated, "Just before Bolin's final concert, Jon Marlowe of The Miami News, after an interview with the guitarist, told him, 'Take care of yourself,' to which Tommy replied, 'I've been taking care of myself my whole life. Don't worry about me. I'm going to be around for a long time.'" (Issue No. 230; page 14). Hours later, Bolin died from an overdose of heroin and other substances, including alcohol, cocaine and barbiturates.[8][9] He is buried in Calvary Cemetery in Sioux City, Iowa.[10]
 
moose eater

moose eater

Well-known member
A piece of the past that was a ritual to listen to every May 4.

A gift and a wonderful man. He was present at McPherson Sq. when I was in D.C. writing for/about OCCUPY after leaving OCCUPY in Manhattan; the majority of my notes still sitting rain-smeared on my desk today, having refused to publish any more stories beyond the first one as a result of the insult many brave persons received via the misrepresentations by the media, left, right, centrist, and other..

I didn't know he was there (McPherson Square, in D.C.), or I'd have likely offered to wash his feet. I maybe even spoke with him directly without knowing it was him. Shame on me.

Laugh, cry, shake your head in disgust, nod in approval, all in the same hour and a half.

 
Last edited:
Brother Nature

Brother Nature

Well-known member
moose eater said:
A piece of the past that was a ritual to listen to every May 4.

A gift and a wonderful man. He was present at McPherson Sq. when I was in D.C. writing for/about OCCUPY after leaving OCCUPY in Manhattan; the majority of my notes still sitting rain-smeared on my desk today, having refused to publish any more stories beyond the first one as a result of the insult many brave persons received via the misrepresentations by the media, left, right, centrist, and other..

I didn't know he was there (McPherson Square, in D.C.), or I'd have likely offered to wash his feet. I maybe even spoke with him directly without knowing it was him. Shame on me.

Laugh, cry, shake your head in disgust, nod in approval, all in the same hour and a half.

Click to expand...

Dick Gregory and Paul Mooney are some of the best and most under appreciated comedians in our recent history. Thanks Moose, that was a nice release after my shitty work day.
 
You must log in or register to reply here.

Latest posts

Latest posts

Top