Why Roman Concrete Lasts for 1000 Years 

I doubt Roman concrete without rebar would stand up to modern uses. Rebar adds tensile strength, which is critical in bridges and other structures.

​@chrimony it may be a massonry bridge, but it still proves the point that roman contruction tecniques givevgreater longevity to most any structure. "The Pons Fabricius (Italian: Ponte Fabricio, "Fabrician Bridge") or Ponte dei Quattro Capi, is the oldest Roman bridge in Rome, Italy, still existing in its original state. Built in 62 BC, it spans half of the Tiber River, from the Campus Martius on the east side to Tiber Island in the middle (the Pons Cestius is west of the island)." The bridge has been in heavy daily use since 62 BC

Since the burn down of the library in Alexandria all ancient knowledge is burned to ashes... 🎉🎉🎉🎉🎉

​@@chrimonywell, romans used arches. Constructing without large tensile loads is one way to avoid cracks. We do this with pre-stressed concrete, but adding the crack- healing capabilities would propaply improve thing.

😊😊😊😊😅😊😊😊 9:59 😊

Or surpressed.

@@kittyhinkle3739 Ye probably mean either surpassed (exceeded, bested) or suppressed (ended by force), friend.

@@ginoclaves I misspelkkted. And definitely ended by force.

Damascus steel is one of them. Also there was that insulating material called Starlite.

Would increase the need for city planning, and likely more broad-purposed construction. If you build a pizzaria for example, just make sure that the structure is able to be easily repurposed. The bits which make it _particularly_ be a pizzaria need to be less permanent, while the basic structure should be more permanent. More than anything though, we would have to stop looking at the causes of 'urban decay' through rose tinted glasses.

The fact we aren't careful with planning is an obscenity in itself.

🤞

If Roman Concrete makes them less money... they will certainly try. Imagine if someone found the cure to all cancer? The person/team & findings would disappear.

@@AlanSanchez-ww9qb Veritassium channel just released a great video about concrete and they talk about this Roman issue. Worth watching!

Probably a lot did, but when it takes decades to see the benefit it becomes easy to overlook.

Almost surreal that they figured out to do that. Now you have to wonder how they found this out in order to incorporate it.

Either that, or damned lucky to come up with the procedure without understanding what was going on. I honestly wonder if they understood the existence of the self-healing clasts. Maybe they did, maybe they didn't. After all, don't fix what ain't broken, and they knew it worked.

@@chriswhite3692 or even this might be like the cancer cure that supposedly hasn't been found & will never be found even after many years of research & trillions of dollars of donations/funding

@@creativeideas012 There are cures or cancers. Just depends on which ones.

Welcome aboard! Thanks so much! 🙏

Maybe, and that would be an interesting test, but seeing as how our steel-reinforced concrete still usually doesn't last more than one or two hundred years, and that with constant repair of the encompassing concrete, yet the pantheon and other Roman constructions, such as their aqueducts, apparently have absolutely no steel reinforcement and are still standing after almost two thousand years, I wonder how necessary it is to continue putting rebar reinforcements into our concrete. If it's not necessary, save it for other uses.

@@koontroll3364 just cover it in lemon

you could coat the bars with a layer of something that doesn't react with lime, then cover the whole thing in lime before using it - sounds promising to me

​@@rtificial8292Funnily enough this would destroy the rebar. Concrete is a highly basic material (around pH 13 going from memory). Normally steel would be corroded in such an environment. But strangely enough at that high level of pH the surface of steel passivates and a thin layer of oxide forms that protects the rest of the material from further reactions. Things that increase the acidicity of concrete like citric acid or desolved carbon dioxide destroy and inhibit the reformation of this protective layer and greatly increase the rate of corrosion in the steel.

​@@josephnebeker7976Two thoughts on this topic - design flexibility and survivorship bias. 1) Most Roman construction exclusively used circular arches - which are very good in compression and well suited to concrete's material properties. However from a material efficiency perspective it's really bad. Let's say you want to build an interstate bridge over a 100' wide river, using a circular arch. A) You could design a single span but that means your bridge is now 50' in the air and has very steep or very long approaches. Something like a truck is only designed for going up a 1/10 slope (10% grade - I am using a very rough number) so you need a 500' long approach span on either side and all the material that requires or you have to accept maybe trucks can't use this bridge. B) Okay let's limit the height of the bridge to 10' tall to solve this problem - that means you need five 20' spans for this distance, and now you need to build four foundations in the middle of the river - pretty expensive and disastrous to boat traffic. C) Let's consider instead a circular arc; we can select a 100' long curve that runs between each side of the river and only 10' above the water. All the afformented issues are solved with this shape except that it is a very shallow arch, it is behaving much more like a beam and there are significant tensile forces in the section. Concrete is bad in tension, so let's use reinforced concrete instead. The only down side with this solution now is maintenance issues with the structure, it requires more attention and might not last as long. D) My question is how practical are solutions A and B? Can modern society accept the costs from those alternatives, or are we incompatible with them? Is the cost of a more disposable/vulnerable option like C worth it compared to the design flexibility it provides? 2) It is important to remember we only see the best examples of Roman construction, we don't see the buildings of Constantinople that were destroyed in earthquakes centuries ago. We don't see an old Roman bridge that was torn down because it wasn't capable of supporting the weight of modern car traffic. And stuff that we do see might be lying to us subtly - the Pantheon Dome was reinforced with steel chains in the Renaissance, and being culturally significant has been protected and maintained well for centuries.

Booo

No. Cause you aint did no science yet to proves it

No, ancient Incas didn't use mortar nor cement in their buildings. Instead they polished each stone until it was a semi-regular polyhedron, put it in place so the gaps between it and the nearby stones were tenths of a millimeter (repolishing the stones if needed) then placed more stones. The advantage of this method is that when earthquakes hit all the stones move within the walls, thus a great chunk of energy is dissipated thru friction, and when the quake's over they fall back in place. As the structure is made of non repeating patterns of stone (no two stones are the same shape) there's no single resonant frequency for the whole structure, in worst scenario only a section of the walls would colapse if a powerful earthquake hits that sections' particular resonance frequency. Disadvantage, of course, is that building this way is really slow and requires *massive* amounts of labor

Thanks so much! 🙏

@@DrBenMiles no problem! You're videos are really interesting and entertaining!

It would be nice to see, but I feel that a lot of our modern construction processes are intentionally substandard so that constructions companies can continue profits through repair and replacement. Quality is not a key tenet of late-stage capitalisms.

@@innerpeacesoundscape Regulation is a solution

@@triton62674 What if regulators get paid off by big construction companies?

Companies are already looking at it

The quality of roman concrete compared to modern concrete allows it to be a one time thing. Maybe there's a reason the simplicity of roman concrete wasn't understood until now.

You watch too many movies. Why didn’t big lamplighter stop the production of electric lights, if what you say is true? Or even better, Big Knockers should have stopped the production of the modern alarm clock.

We're smarter because now we know why a thing works, rather than simply knowing that it works. Also, we have no need to build gigantic solid pyramids anymore, especially not with earthen ramps and thousands of labourers.

Too much will shift ecosystems over time :)

Greg, you are contradicting a whole sect of science. You’re also going against the most rigorously peer reviewed piece of scientific literature ever (the IPCC report) where scientific experts in all fields come together to create and critique research on modern climate problems and also predictions about climate change to then form an extremely comprehensive report on. Quit being an idiot and do 2 seconds of research

It's definitely plant food that's why majority of carbon dioxide is absorbed by our seas leading to the acidification of our oceans.

you sound very knowledgeable

Oh yeah let’s use BCE and CE because common era so no religious references. I wonder what marks the common era? Your criticism is meaningless, just shows the kind of person you are more than anything.

Educated people who can value the human history, tradition and culture. You don't have to like many things, but you can rate the story behind it.

idiots flocks together on Internet

Bro, relax. I know this is way out there but consider the fact that this man just maaayybeee has it engrained after it being the customary way of denoting time for 20 years of his life. Try and focus your energy on things that actually have real world impact, your comment makes you look as if you're out in the town square waggin your pecker about in the wind as you spout crack pot conspiracy theories. So, even if you're correct, nobody will pay attention.

So worship government organizations instead? Just shut up. I hate being an atheist because of people like you.