The concrete walls of Trajan's Markets in Rome have stood the test of time and the elements for nearly 2,000 years. They have even survived a major earthquake in 1349. Photo courtesy of Marie Jackson, Berkeley
Posted on 12/19/2014 2:10:42 PM PST by SunkenCiv
No visit to Rome is complete without a visit to the Pantheon, Trajan's Markets, the Colosseum, or the other spectacular examples of ancient Roman concrete monuments that have stood the test of time and the elements for nearly two thousand years...
Working at ALS beamline 12.3.2, a superconducting bending magnet X-ray micro-diffraction beamline, the research team studied a reproduction of Roman volcanic ash-lime mortar that had been previously subjected to fracture testing experiments at Cornell University. In the concrete walls of Trajan's Markets, constructed around 110 CE, this mortar binds cobble-sized fragments of tuff and brick. Through observing the mineralogical changes that took place in the curing of the mortar over a period of 180 days and comparing the results to 1,900 year old samples of the original, the team discovered that a crystalline binding hydrate prevents microcracks from propagating.
"The mortar resists microcracking through in situ crystallization of platy strätlingite, a durable calcium-alumino-silicate mineral that reinforces interfacial zones and the cementitious matrix," says Marie Jackson, a faculty scientist with the University of California (UC) Berkeley's Department of Civil and Environmental Engineering who led this study. "The dense intergrowths of the platy crystals obstruct crack propagation and preserve cohesion at the micron scale, which in turn enables the concrete to maintain its chemical resilience and structural integrity in a seismically active environment at the millennial scale."
The mortars that bind the concrete composites used to construct the structures of Imperial Rome are of keen scientific interest not just because of their unmatched resilience and durability, but also for the environmental advantages they offer. Most modern concretes are bound by limestone-based Portland cement.
(Excerpt) Read more at eurekalert.org ...
The concrete walls of Trajan's Markets in Rome have stood the test of time and the elements for nearly 2,000 years. They have even survived a major earthquake in 1349. Photo courtesy of Marie Jackson, Berkeley
Whoops, that was supposed to be platy strätlingite.
Fascinating-I’ve had several conversations with the contractor I work with about Roman concrete-we would like to make some of it, but volcanic tuff and ash are in rather short supply here...
I imagine that there are good sources of ash closer than you think, and tuff is all over as well. Tuff is simply consolidated volcanic ash. It’s usually a soft rock, easily worked.
Of course, environmentalists would scream about digging out even something as common and worthless as volcanic ash. They make enough noise about digging out sand for glass, even.
Since this is actually related to (what else?) the global warming hoax, it is only a matter of time before the Roman concrete ingredients are not only available, but required, all over the world.
Have been in the Pantheon and it’s amazing. Forms for concrete had detail to replicate the look of wood trim on the concrete.......has withstood two millenia of earthquakes with no problem......
Seems you could get better results making ultra-high performance concrete with more common pozzolans such as fly ash, silica fume and the like.
They did a nice job building that one, didn’t they? :’)
Probably not for long, though-those same hoaxers will claim that the mining of the volcanic material-the tuff and ash-is somehow contributing to climate change and must stop.
Remember in the 70’s when they said we had to stop using paper bags because we were killing all the trees, so along came plastic ones-now they are insisting everyone use paper again, or those germ factory re-usable cloth ones.
Those people don’t know anything, so they just throw s*** at the wall to see what sticks...
Three words — Roman concrete overshoes. ;’)
No tuff here-but no shortage of rocks-the whole area is limestone and was a sea bottom-there is a pricey product called Austin shell limestone that contains pretty snail fossils-it is cut into bricks and used for facades of homes...
I lived in Naples for a time, there is a section of the original road to Rome near Arco Felice that is still being used. It is rough as it is cobblestone type road. The Roman engineers who designed this method of construction would no doubt be proud to know that their efforts are still doing their job over 2000 years later. Simply amazing.
There are a lot of exotic concrete formulations.
A lot of people don’t understand that concrete develops strength in a curved progression. Usually mix designs are for a specific compressive strength at 28 days of age. The concrete has developed most of its strength by that time but is still develops more and more crystalline strength as it continues to cure and age.
50 year old concrete is stronger than one year old concrete, weather exposure aside. Some mass foundations are so large that the interior continues to cure for many months and years depending upon the size.
Sebastos Harbor at Caesarea is still visible despite being under water, made with faulty aggregate and being 2,000 years since Herod placed it.
I love the Pantheon. Because it became a church it has been continuously maintained. It’s like a time machine showing what the buildings in ruins would have looked like back in the day.
Outside of that, what have the Romans ever done for us?
Should be noted that the high energy component of Portland cement is expensive. Reducing it might make economic sense.
That’s a pozzolanic mixture, IIRC, and the ingredients used to be sold by coal-burining utility companies. Chemically speaking, however, coal, seems to be incompatible with Indonesian homosexuals.
The Aqueduct?
Even the lime putty of a hundred years ago beats modern cements. There are building all around that are literally disintegrating because they replaced the lime putty mortar with portland cement.
I looked high and low, and could not find a local source of the hot lime I need to make good lime putty. When I was a kid, it was in every hardware store.
I read just the other day that the interior walls of St. Patrick’s Cathedral are manufactured concrete stone above the 30 foot mark. The exterior and the interior below 30 feet are Tuckahoe marble. I did not know that.
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