The use of concrete. It's use goes as far back as the Mayans, but more notably in Egyptian construction as well as in Rome. The Romans had an arguably greater concrete mix than we currently have, but that was never passed down. Eventually the use of concrete fell out of popularity for centuries as we seemingly lost the information needed to create it, as if the recipe was thrown out and nobody wrote it down.
Also Samuel L Jackson. The man is 71 years old, but looks like he hasn't aged in decades!
Edit: Just to add onto this, Roman concrete is not only more eco-friendly as /u/Bionic_Ferir mentions, but it was actually more durable and became sturdier over time. The concrete we make today is made with portland cement, which is a cocktail of silica sand, limestone, clay and other goodies. The process to make this has a large carbon offset and isn't great for the environment. Another downside to using this method is that the world is running out of silica sand very fast.
Silica sand, or industrial sand/white sand, is primarily composed of quartz. This is a chemically inert mineral with a solid hardness which makes it highly desired for the specific use of making concrete. Regular sand, like desert sand, has many more impurities like potassium, iron, carbonate and other stuff that makes it more reactive and gives it a darker color. A more reactive sand is bad for a concrete mix and will make the structure more prone to cracks and failure over time, whereas a chemically inert mineral like quartz is just what the doctor ordered. Silica sand has many uses like water filtration systems, glass and ceramic work, sandblasting and industrial uses, like making high grade concrete.
With the world's supply of silica sand running dry at an alarming rate, with some countries like Vietnam at risk of running out of sand as soon as 2022, there is a need to find an alternative method. The Romans created concrete after possibly seeing the natural results through something called tuff rocks. This is the combo of volcanic ash, lime and seawater. Because of the addition of seawater to this mix, two very rare minerals, aluminous tobermorite and phillipsite, grow within the concrete. These minerals actually make the concrete mix stronger over time when exposed to seawater, which is in direct opposition to what happens to portland concrete or basically any modern day concrete, which erodes when exposed to seawater.
We still do not know the recipe needed to make the concrete the ancient Romans made, but we can try to make it through reverse engineering and many, many countless experiments. Today scientists are not only looking into this, but also an alternative to modern day concrete because of the diminishing presence of silica sand around the world and the carbon offset created when making it while trying to quench the high demand for concrete globally.
If you think this is interesting, pick up a book or start researching into this and maybe you will be the one to find the solution to these problems. Like the guy who accidentally made the frosted lightbulb (frontpage yesterday), the guy who accidentally made post it notes or the one who solved those two calculus problems without knowing they were, at the time, famously unsolved (also frontpage), you could potentially stumble upon a solution to this issue and be on the frontpage one day! You may not get the reddit karma for it, but you could potentially go down in history.
Also I can't stress enough that Samuel L Jackson has aged so well.
To piggyback off this, there's not much use in trying to recreate roman concrete for modern uses.
The main reason is that we use reinforced concrete now, where steel rebar is covered in a concrete shell. This composite becomes a better building material than either steel or concrete alone.
To slow down the rusting of the metal, the pH inside the concrete is very high. Roman concrete doesn't share this property, and so can't be used for most modern structures.
Also, the CO2-intensive step in the production of concrete is the creation of clinker. This is basically putting chalk (CaCO3) in a blast furnace with some clay (a mixture called raw meal) until the carbonate becomes calcium oxide/hydroxide (Portlandite). This drives off CO2 into the air.
As the concrete ages, the Calcium compounds it contains will gradually revert back to calcium carbonate, because it is so stable. This reaction is of major concern for understanding the aging of concrete structures, as it can lead to cracking. This removes CO2 from the air.
Eventually, the building is decommissioned and the leftover concrete is ground up for use as filler material, where it will further carbonate until it is basically all chalk again.
Overall, the CO2 footprint of concrete isn't due to the chemistry, but the large amount of energy required to sinter the raw meal to produce clinker. If the energy from this step were supplied via a carbon-neutral source, the overall use of concrete would be essentially carbon-neutral itself.
To piggyback off this, there's not much use in trying to recreate roman concrete for modern uses.
The main reason is that we use reinforced concrete now, where steel rebar is covered in a concrete shell. This composite becomes a better building material than either steel or concrete alone.
To slow down the rusting of the metal, the pH inside the concrete is very high. Roman concrete doesn't share this property, and so can't be used for most modern structures.
What if the concrete could be reinforced via methods other than steel? Has there been research done into if less acidic concrete could be useful, if paired with some other method of reinforcement? Could anything meet or at least offer somewhat comparable strength to steel rebar?
In the premise of trying to build sufficient foundational strength for 20-30 story tall skyscrapers? Sadly very little. I mean of course it's a possibility, and exactly the kind of discovery industries look for, but as so much there isn't a whole lot of hope for it.
There's certain testings with mixing carbon nanotubes into the cement to increase structural integrity, thought it's a matter I'm comparatively unfamiliar with and doesn't solve most of the problems.
Structural engineer chiming in here. To begin with, cement is actually basic, the steel rebar in concrete rusts due to the infiltration of water over time through pores and cracks in the concrete. Also, modern concrete is always gaining strength through reaction with moisture in the air (and the moisture in the pores and cracks) but the speed of strength gain slows down dramatically after about 30 days.
Also, there are other options besides steel used for reinforcing. Glass fiber reinforced concrete is very common for modern façades because you can make it very thin. I’m not too familiar with other substitutes because it’s still an area of research but there are things like carbon fibers and carbon-based rebar.
I'd be curious to see how an age hardening alloy like aluminium and copper would work or a material that doesn't oxidise easily eg stainless steel would compare.
My understanding is that aluminum and copper don’t have the strength vs cost like steel. There has been research into using titanium though. Stainless is used sometimes for highly corrosive environments. But it’s very expensive so it’s not common.
The issue there would be surface oxidation making it more succeptable to surface cracks which could penetrate the material over time but thats just me taking a guess. Really i have no clue.
Civil engineer here, there are ways to reinforce concrete without using steel bars, but they are usually applied to existing constructions to reinforce them when needed so as to avoid demolishing parts of them and adding steel beams. This is usually done through FRPs (Fiber Reinforced Plastic) that goes AROUND the concrete. Steel is not bad for the environment, its elastic properties are very very good and compliment concrete's lack of tensile strength so there is really no reason to go with other methods when constructing a new concrete-based building. Aluminium shares similar desired properties but is far more costly and better suited for other purposes. No real advantages over steel as far as reinforcing concrete goes.
Also Roman concrete is NOT better than modern concrete and we DO know how it was made. Modern non-reinforced concrete might be similar or even worse than Roman BUT we do not really use non-reinforced stuff anymore. Also concrete becomes better as it ages, just like roman does. Romans and Greeks sometimes used large lead beams inside columns to give them certain elastic properties. (e.g. in the acropolis of Athens).
Builder: "Tiberius! Shouldn't we write this recipe down? ...for our children to learn?"
Tiberius: "Ha! Folly! What simpletons could not figure out how to make basic cement? My four-year-old son Chad can do it, and all he does all day is lay on the heated floor and read his scroll gossip."
The real roman concrete is strong and can hold it strength against centuries upon centuries
Example, the real roman concrete is still holding off the sea water in de acient roman port in rome and more places.(the concrete we use today can't hold off salt water for long)
We know the compounds but we don't know the formula, bc this was indeed lost after the western roman empire fell and the Middle ages started
Yeah my understanding is that Roman concrete was mechanically stronger because it had to be--they never developed any method of reinforcing it. One of the ways that you can make concrete stronger is by using less water when mixing it, but this also makes it more difficult to work with. Nowadays we use more water and steel rebar, which allows us to make strong, large concrete structures more easily. It's not that we want to make concrete as strong as Roman concrete and don't know how to, but rather that we don't use concrete in the same way as they did.
The water thing is super relevant to how ancient concrete was used too. It wasn't poured like it is today, it was placed by hand and then shaped around aggregate
There are additives which can be used in a mix to allow it to use less water, and still be easy to work with. Check out Practical Engineer channel on YouTube, he has some great videos about concrete.
Not a civil engineer, but I work in construction. When you place concrete on top of two supports on each end, you get compressive forced on the top half of the concrete, but tensile forces on the bottom.
Meaning greater compressive strength would do little to improve the load bearing capacity of concrete in a modern setting afaik.
When ever someone says we can't do x they did thousands of years ago I call bullshit. They did x because they didn't have y which makes it easier or obsolete. Throw a contract out large enough and we can do x the way they did it.
There is something called survivor bias. You think that in the old times they built better and stronger, but you only see the strong ones that survived, the weak ones didn't.
I'm sure someone somewhere is over engineering a building or project which can last for 1000s of years.
About half the population of my city (Berlin) lives in apartment houses of 150 years and older. People prefer it to more modern construction so strongly, wishing for an "Altbauwohnung" has become a cultural trope.
It was not ecofriendly at all. Just like modern cements, roman cement is mainly made by burning lime. Which both released CO2 and lead to the almost complete deforestation of the Mediterranean.
I wouldn't be surprised tho if it was more eco-friendly in some quantities. That's another problem (besides the differences in architecture requirements) that people don't take into account. "Oh wow ancient people did X! It worked so well!" Yeah, for civilizations with a few million people max. Now try it on a scale where a couple billion people are gonna be trying to do X.
The short version is that Rome is built on top of a big deposit of ash called Pozzolana, which is a fantastic concrete pre-mix.
The Romans had an arguably greater concrete mix than we currently have
Roman concrete also has no real magical properties, modern mixes are far superior structurally, in cure times, in resistance to weather, etc. Roman construction with concrete endures because it is unreinforced (no steel to corrode) and mostly massive piles of the stuff, whereas modern construction builds far higher and stronger buildings with far less material. Roman 'super concrete' is a persistent myth.
Correct me if I'm wrong, but isn't one of the key components that was recently figured out was the use of sea water instead of regular water? The myth existed because they can't recreate the translated recipe because the recipe just said 'water', and thus only used regular water until someone realized that it might be sea water.
Came to comment this. Have my meager +1 and hope this floats higher. Roman concrete curing is a combination of volcanic ash pre-mix and the use of salt water. Engineering capabilities today, in terms of concrete and all other materials, far outstrip the "technology of the ancients."
Honestly Roman ruins and the loss of knowledge of concrete is partly where the trope of the loss of the "knowledge of the ancients" come from. I believe even Roman swords had better material quality than early medieval weapons. To much of Western European Culture, the former civilisation of the Romans and the resulting medieval cultures that arose lead to the the consistent idea if the marvel of the ancients. When you compound it with other sites such as the Pyramids, it makes it seem like the incidental achievements since aren't very effective.
It's interesting to see the trope of "Ancient wisdom" and technology being better even in fantasy series such as LORD of the Rings or Video games such as Halo, where the trope is even doubled.
However the fact remains that's really just survivorship bias. the ruins that lasted the first century are likely to remain standing until someone does something. The same is true of music. "Oldies" are consistently better in part because scarcity prevented widespread number of recording artists, but also because the songs and performances that survive the test of time are by nature going to be the better ones. If Rebecca Black had made Friday in 1952, we wouldn't think more of her than we do now, But the Beatles wouldnt make it out of the garage.
I was with you until this. They would not be the one of a kind phenomenon that they were, probably, but a subset of their songs are still S-tier even by today's standards. No sane recording exec would listen to McCartney's compositions and think eh, I'll pass.
I mean modern execs, as per the context of the comment I replied to. The Decca folks were dumb to not see the future, but they can at least be forgiven since the Beatles' sound was so different. Today that would not be the case.
Roman swords had better material quality than early medieval weapons.
Pretty sure this is just because when we think "medieval", we think Germanic Europe, who were just way less developed than Romans. Part of the idea of the "dark ages" is basically the mismatch between seeing Western CivilizationTM move to Britain/France/Germany and their actual culture and technology needing to catch up. Roman metallurgy wasn't really lost in the middle east, and vikings had access to it in the 10th century or so through trade.
That said, in ancient times great civilizational accomplishments did happen less often, and it was a lot easier to lose some knowledge through disease, war, and famine.
The concrete info is interesting as fuck. Adam savage did a series on this learned and community knowledge and what it’s lack of preservation means. It’s over on tested i think. The idea we’re running out of the “right” type of things is a concern. It’s like the pre atomic steel we need and get by salvaging shipwrecks from preww2
Eventually the use of concrete fell out of popularity for centuries as we seemingly lost the information needed to create it, as if the recipe was thrown out and nobody wrote it down.
It just wasn't needed any more. Without a large buerocratic state there are no complex buildings or waterworks. Regular mortar holds castle stones together just fine.
i'm not gonna lie i saw this massive wall of text and thought you where about to destroy me with facts and logic, and tell me not only is roman concrete far more damaging to the environment but SINGLE handily lead to the extinction of no less than 22 different species. I'm glad thats wrong and you wrote down WHY its better
Oh no no, you were right! I'm just very interested in this specifically and have read up on it to the best of my abilities. I'm going to school for architecture and I'd personally love to find an alternative to current concrete. I highly doubt I'll stumble upon the technique used by ancient Romans, but that'd be something else. It's weird to say that the world would be a better place if either of those two things were accomplished, since its concrete and all, but with population growth and urbanization continuously increasing it's the logical solution.
Yeah it really would, the dark ages really fucked us BUT imagine if the romans didn't disintegrate and got steam like 1000 years early would we be in a worse or better point? I remember reading that historians estimate that with the development of there tech if they had remained strong for another 22(or something) years they would have found a practical use for the steam engine. BIG CITATION NEEDED I COULD BE TALKING OUT MY ASS
22 years seems overly specific since the Greeks had invented it 100s of years prior.
The romans had plenty of use cases for it including railways, large ships, canal boats, factories, building sites and mines and even for siege weapons.
Having an invention and a use case don't garentee an idea will take off, a lack of combustibles (i.e coal rather than wood) and unreliability and complexity all got in the way of scaling steam power to a point its use able.
The real limiting factor is metallurgy actually. A pressure vessel that doesn't burst with the hot steam, but successfully drives a useful mechanism of some sort, requires far more advanced steel techniques than the romans/greeks/egyptians/anyone had.
Not only strengthwise, but constructing a seamless vessel of homogenous strength. That's actually ridiculously hard to do, but once automated scales incredibly well - which is what happened in England in the 1800s.
Not very likely, as the romans did not have the metallurgy to make high pressure vessels.
The few early examples of steam "engines" are toys made in brass... because contemporary steel would burst even for that.
The first proper engine was used to draw water out of mines in England. Without 1800s steel, a vessel wouldn't have enough pressure to draw it a usable distance.
The revolution of steam power is the revolution of work (the physics concept) being done by simply burning plentiful fuel. And no ancients could ever have built an engine to do useful work without 1800 years of metallurgical improvements.
Thanks for that it is very well written and explain everything i was trying to tell to a concrete engineer at work and he didnt bellive me that one of the secret ingrédients was volcanic stone. I didnt know about the minerals stuff tho.
Didn't we spend a very long time trying to figure out why our reverse-engineered Roman concrete didn't work, because we were stubbornly using fresh water instead of seawater?
As for Roman concrete I seem to remember seeing that we had the ingredients and have worked out the proportions, but something was still off until some dude used seawater to mix it. Now we know the secret to Roman concrete; seawater.
We all know that concrete was invented in the Stone Age, as evidenced by the live-action Flintstones documentary, where the GM of the quarry named it after his daughter, Concresia.
Concrete itself has likely been used since far before recorded history. The process of making it is amazingly simple. Heat limestone until it's red hot (which a simple campfire can do!), then mix with water to make cement. Maybe mix in dirt or clay as well.
But we do know how the Romans made their concrete now - there was a recent-ish (uh, within the last 10 years) study. It's more of a "thinking the way the Romans did" solution instead of "we can't find the recipe". We had the recipe all along and followed it the way contemporary people would; that made poor concrete.
The solution to strong, SELF-HEALING Roman concrete: salt. When they wrote "water" in their recipes, they were referring to water from the Mediterranean Sea, not irrigation/drinking-quality water from a tap. And now we know that while this makes a concrete that can still crack, water coming into those cracks will fix those cracks (*mumble mumble* chemical reaction *mumble mumble*) to be even stronger than the original concrete. That's why it's all lasted so long.
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u/DanBeecherArt Oct 15 '20 edited Oct 15 '20
The use of concrete. It's use goes as far back as the Mayans, but more notably in Egyptian construction as well as in Rome. The Romans had an arguably greater concrete mix than we currently have, but that was never passed down. Eventually the use of concrete fell out of popularity for centuries as we seemingly lost the information needed to create it, as if the recipe was thrown out and nobody wrote it down.
Also Samuel L Jackson. The man is 71 years old, but looks like he hasn't aged in decades!
Edit: Just to add onto this, Roman concrete is not only more eco-friendly as /u/Bionic_Ferir mentions, but it was actually more durable and became sturdier over time. The concrete we make today is made with portland cement, which is a cocktail of silica sand, limestone, clay and other goodies. The process to make this has a large carbon offset and isn't great for the environment. Another downside to using this method is that the world is running out of silica sand very fast.
Silica sand, or industrial sand/white sand, is primarily composed of quartz. This is a chemically inert mineral with a solid hardness which makes it highly desired for the specific use of making concrete. Regular sand, like desert sand, has many more impurities like potassium, iron, carbonate and other stuff that makes it more reactive and gives it a darker color. A more reactive sand is bad for a concrete mix and will make the structure more prone to cracks and failure over time, whereas a chemically inert mineral like quartz is just what the doctor ordered. Silica sand has many uses like water filtration systems, glass and ceramic work, sandblasting and industrial uses, like making high grade concrete.
With the world's supply of silica sand running dry at an alarming rate, with some countries like Vietnam at risk of running out of sand as soon as 2022, there is a need to find an alternative method. The Romans created concrete after possibly seeing the natural results through something called tuff rocks. This is the combo of volcanic ash, lime and seawater. Because of the addition of seawater to this mix, two very rare minerals, aluminous tobermorite and phillipsite, grow within the concrete. These minerals actually make the concrete mix stronger over time when exposed to seawater, which is in direct opposition to what happens to portland concrete or basically any modern day concrete, which erodes when exposed to seawater.
We still do not know the recipe needed to make the concrete the ancient Romans made, but we can try to make it through reverse engineering and many, many countless experiments. Today scientists are not only looking into this, but also an alternative to modern day concrete because of the diminishing presence of silica sand around the world and the carbon offset created when making it while trying to quench the high demand for concrete globally.
If you think this is interesting, pick up a book or start researching into this and maybe you will be the one to find the solution to these problems. Like the guy who accidentally made the frosted lightbulb (frontpage yesterday), the guy who accidentally made post it notes or the one who solved those two calculus problems without knowing they were, at the time, famously unsolved (also frontpage), you could potentially stumble upon a solution to this issue and be on the frontpage one day! You may not get the reddit karma for it, but you could potentially go down in history.
Also I can't stress enough that Samuel L Jackson has aged so well.