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The ancient Roman secret to concrete resilience in seawater (2017)
- smackeyacky 3y agoIt woyld be funny to me if it turned out the secret was urine instead of seawater. One of the bits of received wisdom i got from my grandfather was peeing on your hands toughened them up. He claimed it as a bit of advice he was given on his first day chopping hardwood for a steam engine at a tin mine. I figured it as a first day prank like being sent to find headlight fluid in modern times but he said it was true. Before major industrialisation, people used what was at hand. I think the peeing on your hands thing has been long debunked but in roman concrete it may have worked.
- thworp 3y agoUrea is very effective at moisturizing and is an ingredient in many heavy-duty lotions, so peeing is probably overkill but not without benefit.
- fbdab103 3y agoPractical questions abound. Do you wash your hands after peeing on them? Do you pat dry? Towel dry? How do you close up your pants without spreading a non-negligible amount of urine onto your pants? Would you want to pee on your hands every trip to the bathroom or more a once-per-day thing?
- Eumenes 3y agoWater jackets for machine guns would often be filled with urine by soldiers if water wasn't available.
- a_c 3y agoThanks for making my day https://www.youtube.com/watch?v=s_0THARUP9A https://www.youtube.com/watch?v=s_0THARUP9A
- bigbacaloa 3y agoLots of baseball players used to do this.
- interestica 3y agoYou're in for a big surprise: https://www.smithsonianmag.com/science-nature/from-gunpowder-to-teeth-whitener-the-science-behind-historic-uses-of-urine-442390/ https://www.smithsonianmag.com/science-nature/from-gunpowder...
- chaosjevil 3y agoIt's a bit off-topic, but the role of urine in teeth cleaning reminds me one of Catullus' poems, poking fun at someone who was a bit too eager to laugh/smile as trying to show off how much urine he drunk. For context: Celtiberians used urine to brush their teeth. The Romans were aware of that, but they thought that it was disgusting. (The poem is Catullus 39, if anyone is interested. Link: https://en.wikisource.org/wiki/Translation:Catullus_39 https://en.wikisource.org/wiki/Translation:Catullus_39 )
- mymythisisthis 3y agoFor most of human history pee urine was left to get stale, turning it into ammonia, and used for doing laundry. Washing clothes in ammonia is really great at getting out oil and grease stains. Though now you just buy ammonia directly from a good hardware store.
- qup 3y agoHi, nerdy hacker here, could use further advice: Can I screw the ammonia up, like how bleach ruins clothes? Any recommendation on amount? Do I add it to a wash cycle? I have a lot of grease-stained shirts that are some of my favorites.
- shrubble 3y agoMixing ammonia and bleach gets you basically mustard gas, so be cautious about what is in any other detergent you use at the same time...
- mcpackieh 3y agoSpecifically it makes chloramine gas, the same stuff that (in fairly low concentrations) makes swimming pools stink. It can be lethal so definitely take it seriously, although it's not nearly so gnarly as real mustard gas. Here's an incident where a woman inadvertently made chloramine gas in an enclosed space while cleaning and was breathing it for 30 minutes. It nearly killed her and she was hospitalized for a week: https://www.nejm.org/doi/full/10.1056/NEJM199909093411115 https://www.nejm.org/doi/full/10.1056/NEJM199909093411115
- leetrout 3y agoHere's one where a restaurant manager died after someone mixed cleaners right on the floor. https://www.cnn.com/2019/11/08/us/massachusetts-buffalo-wild-wings-worker-death-cleaning-agent-trnd/index.html https://www.cnn.com/2019/11/08/us/massachusetts-buffalo-wild...
- pfdietz 3y ago
- tomjakubowski 3y agoBaseball player Moises Alou famously claimed he peed on his hands to ward off calluses. He's one of the few modern players not to wear batting gloves. https://slate.com/news-and-politics/2004/05/can-peeing-on-your-hands-make-them-tough.html https://slate.com/news-and-politics/2004/05/can-peeing-on-yo...
- nonethewiser 3y agoJorge Posada and Vlad Guerrero too. All from the Caribbean.
- twic 3y agoI would expect the opposite - urea is a keratolytic, so it should break down thickened skin, and make the hands less tough. That said, urine is 1-2% urea, and typical medical urea solutions are 5% or more, so i wouldn't expect much of an effect.
- nonethewiser 3y agoLots of baseball players used to do this. Particularly Dominicans. It mostly stopped in favor of batting gloves but some players continued doing it such as Moises Alou.
- CoastalCoder 3y agoThe story mentions volcanic ash. If the Roman recipe became popular again for marine use, I wonder how much ash is currently available without terrible mining operations.
- ajot 3y agoFly ash (i.e. ash from industrial chimneys) is being used for this same purpose, as pozzolanic (volcanic ash) deposits are not that big or common around the world. The key here is, by the opinion of a cement researcher close to me, the availability of non-cristalline (i.e. an amorphous or vitreous form) silicon dioxide. I've been slightly following the papers on roman concrete for a decade or so, and as far as I remember, they've been discovering different cristalline aluminosilicates that would explain the resilience of these concretes, so maybe there still is some need for pozzolanic, or for adding aluminium to fly ash.
- Projectiboga 3y agoI hope they can perfect this and use it in places like coastal New Jersey.
- jboy55 3y agoWe can build concrete that can withstand maritime conditions, we just choose not to due to cost. We also really don't know how much Roman concrete only lasted 100 years.
- throw0101c 3y agoSee also "Why was Roman concrete so durable?" from January 2023: * https://news.ycombinator.com/item?id=34280239 https://news.ycombinator.com/item?id=34280239
- al_be_back 3y agosadly no concrete evidence on the recipe - not surprised. Romans were excellent engineers but as so often, we're left with little documentation in this area (sciences). The humanities (law, politics, literature etc) has fared better, with way more surviving records.
- TechBro8615 3y agoI wonder how much documentation we have for the practicalities of modern construction methods, and how much of it is passed down orally by the construction workers who are actually building stuff, or locked within internal company manuals. I mean sure I can look up formulae for concrete, rebar etc. on wikipedia, but for actual step-by-step instructions with specific machines and materials? I bet that information is a bit more discombobulated.
- treeman79 3y agoMax dad worked for McDonald Douglas, later Boeing. Tons of little tricks to build things that weren’t documented. Made union strong. Replacement workers couldn’t reproduce parts to spec when following instructions. Things like adding strings to foam molds in just the way, etc.
- boeingUH60 3y ago> McDonald Douglas, later Boeing. Later Burger King :)
- MilStdJunkie 3y agoToday's tech content would fare worse than you might imagine. So much is tied into byzantine ERP/PDM systems . . or contains specialized processing instructions for a particular black box editor/processor . .OR juggles actual techdata with the entity peculiarities of a CCS (component content system) that itself can result from any number of nebulous engineering fads. I guess, short version of what I'm trying to say, is that today's tech data doesn't have narrative. It's a bunch of little pieces floating around and needs a living org to put it together. If you froze it, Pompeii-style, future generations would find themselves facing dead ends all over the place.
- pengaru 3y agoWe have a tendency to promote premature failure of seawater-exposed concrete structures by reinforcing them with rust-prone materials. I don't think any amount of secret Roman concrete recipes is going to prevent crumbling apart due to the expanding forces of rotting rebar.
- Oarch 3y agoStories about Roman concrete appear to flood the Internet about once per year. No idea why... See also: seaweed reduces cow farts.
- AlbertCory 3y agoMaybe because 2000 years later, some of it is still standing?
- kibwen 3y agoAnd in 2,000 years there will still be some structures made of Portland cement still standing... although not any with rebar inside. The Hoover Dam could stand for 10,000 years (it's not even done curing yet, 100 years later). Don't overlook survivorship bias; the vast majority of structures made of Roman concrete are not still standing.
- AlbertCory 3y agoI think you are ignoring all the civil engineers who ARE impressed with it. Getting better in salt water is a seriously impressive feat. Hoover Dam is fresh water.
- saqadri 3y agoIt is fascinating how some ancient techniques had remarkable properties even though they didn’t have the tools or science to explain it back then. I recently learnt that ancient concrete has self healing properties because of the reaction of air/water with lime and volcanic ash. Makes you wonder how far we can get with trial and error.
- peteradio 3y ago> Makes you wonder how far we can get with trial and error. And millennia long test periods.
- kfarr 3y agoYes, the survivorship bias is strong in this case
- deleted 3y ago[deleted]
- sorokod 3y agoGot us from cingle cell organisms. Just trial error and time.
- teeray 3y agoIt’s been amazing learning some knots these past few months, realizing what you can do with them once you have a good repertoire to draw from, and then realizing that many of them have been used since antiquity.
- steve918 3y agoThe problem with modern concrete falling apart prematurely is usually the use of rebar as a reinforcement.
- thechao 3y agoAnd we use rebar because we like long, flat bridging spans that can hold hundreds of tons at a time — something Roman concrete has no hope of ever doing, unreinforced.
- otikik 3y agoNot necessarily countering your point, but perhaps giving some perspective. The City I grew in (Cordoba) has a roman bridge[1], originally built 1st century BC and still standing. It supported a 2-way street until 2004, when it was pedestrianised. Caveats: * It has gone over a great deal of renovations/partial rebuilds on its history, so its durability can not really be attributed to roman concrete alone. Only 2 of the original 16 arcades remain. One could argue that "it's not the same bridge" any more (Theseus' Bridge). * I ignore wether they used concrete to build the original one. I'm not an architect. For all I know, the initial construction could have been mortarless stone, and cement (as well as reinforcement) could have been added in some of the later renovations. That said, all bridges require periodical servicing/renovations anyway, in order to remain functional. And this one has stand for 2000 years. [1] https://en.wikipedia.org/wiki/Roman_bridge_of_C%C3%B3rdoba https://en.wikipedia.org/wiki/Roman_bridge_of_C%C3%B3rdoba
- masklinn 3y agoThis doesn’t really give perspective, it’s basically what they’re saying. Roman bridges are gravity structures, the entire thing is in compression and heavy, the arches have really limited spans. Compare to the Millau Viaduct for instance.
- otikik 3y agoWell in order to compare things properly we would have to check if the Viaduct is still there 2000 years from now.
- AlbertCory 3y agoThere actually IS a contemporaneous source on how to do it, without exact proportions, unfortunately. They didn't know why it worked, of course. https://en.wikipedia.org/wiki/Vitruvius https://en.wikipedia.org/wiki/Vitruvius https://news.mit.edu/2023/roman-concrete-durability-lime-casts-0106 https://news.mit.edu/2023/roman-concrete-durability-lime-cas... "pozzolanic material such as volcanic ash from the area of Pozzuoli, on the Bay of Naples." They shipped this all over the Empire. Now we have a better idea why it got better in seawater, instead of deteriorating.
- nunuvit 3y agoOld article from 2017. More advances were published earlier this year: https://news.mit.edu/2023/roman-concrete-durability-lime-casts-0106 https://news.mit.edu/2023/roman-concrete-durability-lime-cas...
- bloopernova 3y agoThat's really cool research. Using quicklime heats up the concrete a bunch more than some other methods, and the result is concrete that fills its own cracks.
- PaulHoule 3y agoPeople who think A.I. will kill us should be worried that concrete will kill us. There are many materials that could be superior in quality and environmentally benign than Portland cement-based concrete not least the Sulfur concrete which is commonly used in China today https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7660051/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7660051/ and particularly Geopolymer concrete https://en.wikipedia.org/wiki/Geopolymer https://en.wikipedia.org/wiki/Geopolymer but all of these face resistance from the Portland cement industry which has already standardized products for regulators.
- digdugdirk 3y agoHaving seen the state of concrete buildings in China, I'd prefer the alternative.
- nunuvit 3y agoIt's not a conspiracy. Fly ash contains heavy metals that would leach out of the cement. There are more challenges remaining to be solved than the Wikipedia article suggests.
- leoc 3y agoObligatory mention of leading concrete-engineering YouTuber https://youtube.com/@TylerLey https://youtube.com/@TylerLey . He’s discussed Roman concrete in eg. https://youtu.be/U86tlUiFM1s https://youtu.be/U86tlUiFM1s .
- satellite2 3y agoI'm completely new to ancient Roman civil engineering. So I ask completely innocently,could it be survivor bias?
- unwind 3y agoThat is a popular counter-argument against many things, but if we have visible (dare I say concrete) evidence that Roman concrete structures in seawater are still here, while now there's like a whole field of infrastructure/construction people who know that typical current concrete can't do it, then it has to be something there, right?
- chaosjevil 3y agoRelevant tidbit: hot mixing with quicklime was key for this self-healing property[1], as it allowed the creation of small lime clasts across the material. [1] https://arstechnica.com/science/2023/01/ancient-roman-concrete-could-self-heal-thanks-to-hot-mixing-with-quicklime/ https://arstechnica.com/science/2023/01/ancient-roman-concre...