Was Roman Concrete Better?
Vložit
- čas přidán 25. 08. 2024
- Comparing modern concrete to that of the western Roman empire.
Errata: “More viscous” should be “less viscous”.
More Videos About Concrete:
- What is Concrete? ( • What is Concrete? )
- Why Concrete Needs Reinforcement ( • Why Concrete Needs Rei... )
-Does Rebar Rust? ( • Does Rebar Rust? )
In this video, I discuss a few modern techniques that help improve design life of concrete, including roller compacted concrete (RCC) and water reducing admixtures (superplasticizers). There are a whole host of differences between modern concrete and that of the western Roman empire that I didn’t have time to go into, including freeze/thaw damage. This is such and interesting topic, so here are some references if you’d like to learn more:
-www.romanconcre...
-www.usbr.gov/t...
-en.wikipedia.o...
Watch this video and the entire Practical Engineering catalog ad-free on Nebula: go.nebula.tv/p...
-Patreon: / practicalengineering
-Website: practical.engin...
Tonic and Energy by Elexive is licensed under a Creative Commons Attribution License
Source: • Elexive - Tonic and En...
This video is sponsored by Brilliant.
No one does it quite like the Romans did, I can speak from experience... just saying.
when is the bible 2 coming out
9x19mm it a work in progress after all Rome was not built in a day.
@@maxineclark2399 The world was created in 6 days though, so how long can one book take?
@@romaliop smh jesus be lacking on his book releases
Nailed it Jesus!
I have put down a LOT of concrete in many different countries in my time, but I keep learning more and more watching your videos. I love them. Keep up the great work
I love your videos man. Thank you. I study these things on my personal time, because I didn't really have a shot at school the first time, and I don't have much money now. I don't think I could ever get a job doing this but I really like learning it and going to the library. But that gets so lonely alone. I apologize for sharing so much, but I really really really want you to know how great it is for me to have access to educational content.
Thank you as always for the video! I am always amazed at the little experiments you set up to demonstrate the many concepts you teach ppl about.
I can totally relate.i learned programming and electronics all by myself using online(mostly free) resources.i also don't know if I'll ever get a job in those fields but I sure like learning them :)
I've been making concrete deck piers without forms for years (80's). I mix a nearly dry mixture. Using a 16" segment of a form shaped like desired column, I tamp/pound the cement into the segment and raise it as I go like a slip form. You can go 32"-48" increments before having to let lower section harden a bit before continuing higher. If you do all your piers at the same time and skip from one to the next every 24", you never have to wait by the time you come back around to the first one. There are many tricks that enable you to do this in a narrow deep hole. This cement ends up being so incredibly harder. Years later, I would strike the side of a pier, it actually resonates like solid granite would, while any other would be closer to hitting lead.
This is awesome, I'm so glad people like you exist!
what is your recipe?
@@M-L450 Well, I never really considered myself having a 'recipe'. I always used standard Portland cement and mixed a 1-2-3 ratio (Portland-sand-aggregate), with the aggregate always being crushed granite, never eroded (rounded) river gravel. The amount of water is barely enough to moisten the mixture, giving it the consistency of feed grain for cattle mixed with molasses where it seems almost dry but compacts like a snow ball. The water becomes apparent as it is compacted. The water is added slowly, a little at a time with an aerating head attached to the water hose. I have only used fiber once when making dock piers for added strength against floating ice masses.
and you think it's going to last thousands of years? Give me A break
@@tonys4396 point out where they said they thought it'd last that long 😅
Buddy, I'm so glad I found your channel! I am already an engineer but just love learning more on all these sort of topics. Great content.
Your channel is amazing. It's the best piece of entertainment from civil engineering that I'm studying and almost half my class watches your videos. Keep up the great work!
This man has given me an appreciation for concrete that I never thought I'd have
The Peterborough Lift Lock, when opened in 1904, was the largest un-reinforced concrete structure in North America. Still standing and being used for it’s intended purpose 100+ years after it’s opening. 😁 I’ve been through a couple times by boat. R. B. Rogers was a pioneer in concrete, was recognized by both the American Society of Mechanical Engineers and the Canadian Society for Mechanical Engineering. He also used in-reinforced concrete in the conventional locks he designed. Peterborough, Ontario, Trent-Severn waterway. 🇨🇦
Thanks for this look into the Roman stuff.
The Romans used sea water to help cure the mortar plus the crushed lava which produced the phillipsite and al-tobormorite after about 10 years. The secret is that it bends rather than shatters under stress. With lime like cement it can take years to stop curing, up to 7 years. I have also added molasses to keep frost at bay as used in India.
The longer it takes to dry the harder it becomes, the lime putty mortars have a bit more give and are 'self-healing' which is why you can see some great slanting buildings like the Crooked House Pub in Dudley, England. It also absorbs carbon dioxide and has great acoustics than cement.
Hey, Grady! Great video! Your videos are so interesting and educational. Especially this series on concrete. Well done, and keep uploading great videos like this!
I worked at a limestone mine/cement plant for years. There are recipes for great cement, they just aren't price effective for most applications. I know they had a recipe for cement so strong it didn't need rebar. They had another recipe with silica that would harden underwater and was mainly used to fill exhausted oil reservoirs. Both were 4 to 5 times the cost of average cement.
Some of the critical concrete the romans made also used ash instead of aggregate rock so it was very strong and water resistant but also very expensive.
@@RARufusConcrete is cement with limestone filler, and sometimes added gypsum for quicker set times. So saying they used ash instead of rock is an ignorant statement. They use ash in modern day cement. Modern day ash comes from coal power plants, as a by product from the coal burning process. Same with synthetic gypsum vs natural gyp. Modern day cement plants use both types of gypsum, depending on price, availability, and region. The only difference between roman ash and modern day ash is the romans used volcanic ash. It didn't have magical properties. They primarily make lower quality cement these days because it's cheaper and keeps construction companies in business. They do make high quality, it's just expensive and not as in demand.
I’m sorry what? Used to fill exhausted oil reservoirs? Romans didn’t have oil besides wale oil
He said civil engineering, career what does he do?
Also, they cure much slower. Many project have time constrain and can't wait forever.
8:13 that's a bridge in Zaporizhzhya that has been in construction since 2004. I guess some structures are meant to stand for 2000 years and some to be built for 2000 years.
Good video btw.
Dat baburka feel...
@@comradawsum :) yeah.
Sheit! You stole my joke!
Well done though)
24pavio, it all depends on how the building contract is written and enforced. The first time I heard two industry execs talk about a certain construction company as "They make their money standing around." it boggled my mind. But there used to be a tendency to reuse old building contract texts which did not specify penalties for not completing work on time. In many places this changed since, I believe.
THANK YOU, I was looking for the name of that bridge and the dam from 4:38 because they looked interesting. Such a bad luck they didn't finished it :( we can always look for renders and dream
I'm a landscaper and we sometimes use plasticisers in our mortar because it is supposed to add strength to the set product and I was never taught why it worked, this video explained it perfectly. Thank you!
The usage also plays a big role I think. The heavyest things they had are feathers to what we have today. A bridge from them was way shorter than ours today. They only needed to hold maybe a few hundret people at best but ours need to hold 1,000 of cars and trucks every day.
People can be surprisingly heavy. A dense crowd is a lot heavier than a line of cars.
This channel is always official with the information, and the guy hosting it is really chill
I gotta say I absolutely love the theme music to this channel.
Another reason might be that the structures we made today go through way more use ? using a bridge, i.e. having a huge number of cars using it daily is not the same thing as if it had way less usage. It literally contributes more to stresses within the structure that eventually degrade it faster :)
Would be exciting to watch your take on even more exotic constructions like the concrete used in Giza or the stonework in Baalbek
What concrete structures in giza?
@@randybobandy9828 used somewhere in or nearby pyramids, can't remember
I just read the MIT News article about the use of quicklime and "hot mixing" in Roman concrete. It was super interesting, but I didn't really understand exactly what they meant: they seemed to conflate using quicklime with mixing the concrete at a high temperature, which seem like two different things to me. I'd love you to make a video explaining their findings. Your videos are the best!
When you add quicklime to water it creates Heat and calcium hydroxide (CaOH).
Basically instead of warming up the concrete with something like a fire or boiling water they just used a chemical reaction. So it's not exactly conflating as them saying "they used quicklime TO mix the concrete at high temperatures". I know this is like a year after you asked, but it's nice to learn new stuff.
Climate also plays a role, Rome doesn't have the as many or as extreme freeze thaw cycles as other areas. If that roman architecture was in northern Michigan it would have crumbled a long time ago.
shoutout to cristina applegate
@@gregorylangsdale8277 eric andre
AND salt was rare and expensive. They did not throw it on their roads.
On the other hand in Rome it has to withstand significantly more earthquakes than in northern Michigan.
@@eljanrimsa5843 the us earth quakes are way bigger then the earth quakes in Rome.
The magnificent Roman Pantheon, that we look back on in wonder and awe after 2000 years, was itself a memorial to that glorious structure that came hundreds of years before even it, the Greek Parthenon. There is a tremendous irony in this saga of old knowledge and new knowledge- the ancient Greeks knew that if they reinforced their marble with iron that it would rust, expand, and damage the marble. The modern Greeks did not, and in an effort to repair the ailing Parthenon in the early 1900s, they pounded steal bars into the original marble pieces, which eventually rusted, expanded, and damaged them permanently.
I was in Las Vegas recently and visited the Hoover Dam. During the tour, we were told that some of the concrete on the inside of the structure STILL hadn't cured! I was hoping you might consider doing a video on that. Thanks for all the new knowledge!
That's also an important factor Grady didn't mention - the strength of concrete depends a *lot* on how fast it cures! Slow-curing concrete can be much more durable, but it of course takes much longer to reach that full strength. Roman concrete took many years to fully cure - a duration that would be wholly unacceptable for most modern structures. We actually can use such slow-curing concrete today; I recall seeing one structural report from a Buddhist temple in Hawaii whose design requirements involved "should be able to last a thousand years", and they used an *extremely* slow-curing concrete to pour the foundations. But for most applications, you need your concrete ready to take load much sooner, especially for constructing really tall structures that require lower layers to be solidifed enough to support construction of upper layers!
I believe that's a misunderstanding. The Hoover dam's concrete, *if* it had been poured the normal way, would indeed still be curing to this day. However, since they needed the thing done and in operation, they instead poured the concrete in "pillars" - smaller segments of much lesser total width & height, so that it would actually cure in a reasonable amount of time.
Practical Engeneering, the channel you didn't know you needed.
For some reason I can't put my finger on, this is the 3rd video I watched back to back and they're oddly satisfying. Not just when you blow up you test station, the air lock one -while missing any failiure - was nice to watch as well.
Some chemist figured out the formula for Roman concrete a few years ago and put the test videos on youtube. It handled around 5,000 to 7,000 psi before breaking due to the glass crystals in it from the volcanic ash. Blows away any of the strength tests you did with modern concrete. And it actually keeps getting stronger over time in the ocean due to absorbing minerals and making a new more reinforced latticework.
I have been working in precast for about 15 years as a mould fitter and the rebar side of precast Thank for show and tell about concrete in your video's... Very interesting..
The Pantheon isn't the only example of ancient Roman concrete that still stands, you will find it all over the ancient Roman Empire, I've seen it in several countries.
Even in ruins that aren't preserved as the Pantheon, I'm always amazed by the condition of the concrete itself, how well that has resisted failure.
When you visit the Pantheon, it's amazing how perfect the building is, the engineering, the architecture and the symmetry are all breathtaking, modern construction is nowhere as precise, especially the finishing work.
Incidentally, while using the weight of the structure to keep everything in compression, I understand that the Parthenon (Pantheon? I always confuse these) used pumice for its low density to keep the weight as low as possible and that the dome gets thinner the higher up in the dome and the less weight it has to carry.
When building with blocks they joined the blocks with iron butterfly inserts, larger than the cavity but filled with molten lead the ductile properties of which presumably gave an added benefit.
Parthenon is the structure in Athens, Greece. Pantheon (Pantheon meaning "all of the gods" Pan=all theo=religion/gods) is the structure in Rome. Super easy mix-up!
What makes your videos so good is your ability to explain things in ways so simple that even a dumb plumber like me can understand....
I had a cousin whose company did concrete testing. I found it very fascinating. Thanks for posting the video.
I've read of recipes calling for volcanic ash to be used.
And the plastizers and low water is a game changer for my occasional small pour. Maybe can tweak my mix. Cool. Thank you for this video.
I really like the ending of your video where you explain the duties of the engineer. I've seen many freeways move over time like rivers. Traffic changed so greatly in my city in two decades it didn't make sense to save all of the old roadways. I guess it's a good thing they were only built to last 20 to 30 to 40 years. Thanks for this fresh insight!
Have you ever seen a "Roman road"? This is a 2000-year-old Roman road in Spain that is used to move cattle between summer pastures and winter pastures. The Romans had a lot of skill, for example on one side of the Roman road they put stone posts or monoliths every 50 meters, so as not to leave the road if it was covered by snow : czcams.com/video/YBM-p0uNxk0/video.html
@@TheMariepi3 I've trampled all over Rome, Koln and Berlin. There are ancient roads everywhere, most of the are shut to modern auto traffic. Many are open to scooter traffic but that illustrates my point.
Really good analysis and clear explanations. Next time I need a concrete repair will use less water and more compaction.
I love these concrete series! Thank you!
There's also a very heavy survivor bias.
For the uninitiated, the bias goes like this:
During WWII many planes were being shot down, so armor was to be added in the most important parts. So they started logging every bullethole in every returning plane to log where the planes got hit the most. They determined thevmost hit areas were the wings and tail.
They armored said areas but planes kept going down. How could this be so! They were armoring every single sq inch that planes got hit in! Baffled they went back to the drawing board
Then someone postulated that maybe, hits were distributed evenly, and that they could try armoring the areas that remain un hit in the returning planes. Said person theorized that no plane returned with hits in the cockpit or fuel storage areas because a hit there would cause the plane to go down. therefore creating these "missing hits"
Desperate, they tried it and immediately they saw more and more pilots returning to base safely.
This is the survivor bias. they saw the bullet holes of the survivord and thought "this is why planes go down" instead of "a hit here is not fatal, but that area with no survivor having a hit means that it must be vital"
Now, we see these structures and compare it with any old building from today. However, these building are not any regular buildings; those are the building that survived.
From what I remember as a construction worker,
Is that concrete comes in a variety of strengths, 1200-4200,
Depending on how much Portland was used.
And I remember using Berlex in concrete as a water barrier.
I work in quality control for a large concrete supplier. We have a 12,000psi mix that utilizes fly ash, slag cement, micro silica, and several admixtures such as plasticiser and hydration stabilizer to maximize flow while minimizing water usage and retaining consistency. It's really incredible how scientific concrete production has become
Small injection here on the colloseum, its a hybrid structure made of lighter materials at the top and heavier at the bottom.
Remember several years ago I saw a program about how they were using halved bamboo trunks as reinforcements instead of rebar, and if memory serves the result was superior.
They do that in India
Love your content man! Keep it up!
I love watching videos about how to avoid or stop corrosion on steel bars. Some people paint those bars with pure cement paste. Thanks for sharing.
4:39 I knew I recognized that site! That's the Taum Sauk Hydro Power Station, out in Missouri. That swath through the forest (top left) is from when the previous reservoir failed, spilled 1 billion gallons of water. Luckily no one was killed.
4:32 if anyone's interested, that weird dam is basically a huge battery in the top of a mountain: it's the upper reservoir of the Taum Sauk hydroelectric power station. They pump water with excess electricity in the night and use that water to generate electricity during demand peaks. The dam doesn't get any natural influx of water.
That's very interesting! Where is the power to pump the water coming from? Can't it be stored at the source to avoid transmission and conversation losses?
@@ravinderkhakh3918 specifically in this case, not sure, but in general (this is not only done here) from excess electricity generation (more electricity is produced by nuclear/coal/hydro/wind than is used by consumers) during the less demanding hours (mostly in the night).
*EDIT* : Now that I remember, that specific dam it's just next (above) a bigger hydroelectric plant and it stores it excess power. So it's actually at the source. But in general, storing the energy right at its source would be logistically counterproductive in most cases. Batteries don't have enough density/affordability enough yet, and no energy storage system is unaffected by inefficiencies.
@@ravinderkhakh3918 i think because of the amount of power we're talking about , that only stuff like these gravity batteries or whatever they are called, are the only way to store THAT much energy. especially if safety is a concern. you've seen how cell phone batteries go up, now times that by millions of times.
It's not a commonly known material but basalt rebar has one big advantage over steel rebar, it can never rust. We need to look into using basalt rebar and fiber in concrete structures more often, it has several advantages over traditional rebar and fiber additives.
But it’s also much more expensive, which is why it’s only really used on structures that are at a very high risk of corrosion. For normal buildings, steel reinforcement is just fine for the intended purpose.
@@justinblin It is a little more expensive but considering corrosion of rebar is the leading cause of concrete failure using basalt rebar would extent the life of the concrete making the added cost cheaper when factoring in the life of the structure. It should be a no-brainer for construction anywhere near salt water and on roads where salt is used as for deicing.
@@phillhuddleston9445 basalt rebar isn’t just a little bit more expensive though, I looked online and found 8 mm basalt rebar at $1.70 per foot, while 0.375 in (about 9.5 mm, slightly thicker) steel rebar was only $1.00 per foot. Projects have to balance life-span with up-front costs, if corrosion isn’t a major problem, it’s really not worth paying 70% more, which is why it’s only commonly used in things like ports, which have to deal with the accelerated corrosion caused by salt water. Normal rebar for normal buildings work just fine.
@@justinblin It's about 30 to 40% more for the same size rebar if you buy it from the right company, like anything else buying from some online sites can cost far more than buying from other sellers.
@@phillhuddleston9445 that’s still a substantial cost if you’re using it for anything that isn’t at large risk of corrosion, especially since it won’t increase the life-span of the project 30%-40%.
to be fair roman architecture didn't need to hold up nearly as much weight as cars/trucks
did you watch the vid? They put weight on it to make it *stronger*.
Great video, I’m a civil engineering student and these videos are inspiring. Thanks again
Any good sources of plasticizer for DIY scale projects?
I think you should do a video on best practices for DIY craft concrete thats become pretty popular on CZcams, or just do a project yourself.
Soooo many people who do these seem to have jumped into it without any knowledge of concrete, and it would be really great I think if some better practices and procedures were injected into the YT DIY scene.
Awesome idea! I would watch that series and publish it around to my DIY friends!
I would also share those.
For non structural applications, increasing the water/cement ratio (not too much) to make it easier to work shouldn't be a big problem.
Using additives without good knowledge and lab testing of your mix is never a good idea for structural uses of concrete.
Youre local hardware store should have them. If you live in a very hot or cold climate they may have it already added in the cement mix bags.
This explains why there are so many Italians that own concrete and terrazzo companies in the construction industry near me in the Chicago area.
Love how you put a plexyglass protection sheet on the second test, after exploding the concrete on the first xD
Never knew learning about concrete could be so interesting.
I always use Portland Concrete when I'm mixing up a fresh batch of cement! :D
I always have a cement truck deliver the concrete to the pour site where i place the 'ment.
I remember reading how they used to insert chains into some of the ancient concrete to reinforce it like we do now with rebar.
I really appreciate this, and also appreciate that you didn't bother with any of that, "Roman concrete would set underwater," nonsense. Very informative and balanced.
Does Brilliant have a course on installing acoustic tiles straight and level?
😂
Accepting that Romans used sea water in their mux, I am curious if a sea water admixture affects the superplasticizer or the subsequent concrete strength as opposed to freshwater
Concrete is one of the reasons i got into becoming a building/ welding inspector. Concrete is such a fantastical building material. Our ancestors could never have dreamed of a better material to use. Its very interesting.
0:20 Couldnt you have practically engineered the sound tiles to be level and parallel?
That type of engineering isn’t practical.
Well put together video, thank you
I saw your comment on another video entirely different one. Your image is so attractive to me. It is easy to remember haha. What does Tsetsi mean?
You touched on a point I have long wondered about; Why not simply coat/paint the rebar?
That's a great shot of the Taum Sauk Reservoir on Proffit Mountain @4:33 . The roller concrete dam is a replacement for the one that failed in 2005, you can see the scare in the upper left where the water scoured the forest down to the bedrock. I did surveys on that mountain.
As of summer 2021 it is starting to seem like we won't have to wait 2000 years to find out how long concrete lasts.
We have concrete structures that last a long time. The CN Tower has a design life of over 400 years.
Concrete dams built today will likely last for well over 1000 years.
My dad built a ramp in our garden just out of concrete ontop of dirt, when we took it up about 30 years later it was just crazy strong all the other concrete in the yard fell to bits but this one ramp was pummeled with a 16lb hammer for like 10 mins to even get part of it to crack. Dunno what it was made of but bloody hell was it strong.
Andrew Joy
There are all kinds of mixes and types out there, could have been a more expensive high density/high strength mix with less water than normal.
Ash was human remains, the strength came from all the horse glue in it, and it didn't crack due to your weak arms.
Is your dad Roman?
Good job Dad.
Classic "dad overbuilding"
I spent a very long lifetime upon major building works, a Clerk of Works, I was always taught that any coating will prevent the natural adhesion between concrete and rebar, we were always ensured that the mill scale was removed, usually by weather, one of my main problems was preventing the pump operator from adding water to the concrete, a 75mm slump will pump OK provided the is maintained
I would love to see an updated version of this video if there's a way to address the relatively recent findings on Roman concrete
Great video, but there is a significant mistake in the thumbnail. The Parthenon is Greek and is made of marble. There is a difference between the Parthenon (Greek) and the Pantheon (Roman). I hope that Grady will fix this issue!
Survivorship bias is very useful to be aware of. It may be simply that only the highest quality, and highest durability structures of the Roman era survived to this day and age, while all the mediocre and sh;tty ones deteriorated due to the passage of time. Like, yeah, one Colosseum still stands after 2000 years, but we don't talk about a hundred other Colosseums that don't exist anymore, because guess what. We don't even know that they existed, because they're no longer there.
We're drawing conclusions based on grossly insufficient data.
Good point
Thank for this videos, your videos are replacing my construction teacher at college. Regards from Aguascalientes Mexico!
I used to work for a fiberglass protrusion facility that specifically made fiberglass rebar replacements to ward off deterioration. Cheap and extremely effective.
Concrete sidewalks in KC from before the 1970's (they are marked) appear to outlast newer sidewalks, curbs, bridges, etc. The newer the concrete, the more I expect it to fail. This is especially true in government projects for some reason and less so on residential concrete.
That explosive protection system was built really well 6:25
my dad always talked about dry mix. Wheel barrow and a hoe. He put a formed, underground wall 4"x12" all around the house. Of his dry mix; the roof had a 36" eve extended past the buried wall.. hard rains never unstabilized the soil around the house. 40 years later somebody told me it was called an Apron. Being underground, it may very well still be there. A curb you never see.
Omg I love these historical engineering videos! Can you do one on Incan stone masonry please? Trying to figure out how Cuzco was built is mind boggling.
Somehow I wound up designing ultra high strength concrete,as a formulation chemist.
I was always fascinated with Roman cement.
The longevity is beyond belief,but it takes up to a Year for the Roman cement to cure.
My concrete formulations [24 of them] use ancient Roman materials ,with zero Portland Cement.
I hate Portland cements.
1:00 I like how all the reinforcement you’re showing is rusted
This was the last place I expected Upper Stillwater Dam to make an appearance! Thats is gorgeous country, I love that area.
I believe cathodic protection is one way to reduce rate of corrosion in reinforcement. What is done is to use some direct current to keep the rebar under a slight charge and it would almost not corrode. I do not know how common this technique is for urban and infrastructure constructions but I have seen it in use in industrial structures.
They've figured it out guys a few days ago- its lumps of calcium that dissolve when water hits em and recrystallise to seal cracks.
Came across your channel looking for tips on making concrete that will help me duplicate my 8X great-grandfather's recipe. You have a great ability to explain complex engineering in easily understandable ways for the layperson. My ancestor (born late 1600s) was a mason who built castles in Europe and was hired by France to come to the new world to build Fortress of Louisbourg. He did a beautiful job with arches everywhere and fortress foundations sitting in salt water. There is a weed in coastal areas that if I'm interpreting correctly is a rubbery/plastic like plant that would be burned in huge piles on the beach and mixed with sand and there's also a lot of clay in the area. I don't know much about this but would the rubbery qualities be effectively burned off when making the ash? It's very high in magnesium so I'm not sure if I have the correct plant. Would high magnesium be a problem? It was used for medicinal purposes sometimes -- magnesium deficiency when made into a soup or tea -- but otherwise just burned as a weed. I'm still not 100% certain the plant I'm going to use is the correct one but if it is, how best do I test my sample to see how it holds up to the salt water? Another potential problem is that the beach sand in this area has really high iron content which I worry will just rust when exposed to salt water? I'm not sure if his masons would have used the local sand or brought some from another area that has less iron. any advice would be appreciated!
I came across your comment and I think the research you are doing is very interesting, and exciting.
I have been studying ancient building techniques for several years and recently discovered a French chemist and author from the 1750s who wrote two remarkable books on this subject.
His books explain very simply, by quoting and comparing the old authors, what it is necessary to know to understand what we now call the chemistry of geopolymers.
I made a transcription and I can send you the automatic translations in English, as well as the originals in French if you wish.
This video needs updating 👍🏻👍🏻
Hey, that was Taum Sauk reservoir, I worked on that project, and live near there.
On what you said about engineers. An optimist says the glass is half full, the pessimist says it's half empty, the engineer says the glass is twice as big as it needs to be 😁
I don't know about the Colloseum in Rome, but the one I saw in Arles in 2018 looked like it had been built yesterday. The level of preservation that Colosseum has achieved over the thousands of years is just spectacular. The Romans built their structures to last, and a lot of them have.
Later generations used the Colosseum, etc. as a quarry. They simply took the pre-cut stone away and built their palaces out of it.
Apparently they used salt water, a rare mineral forms during the chemical reaction that strengthens the concrete..
love your videos
You can't use salt water in modern concrete... we use steel not to mention its not good for the concrete in general. Look into why we don't use sea sand for concrete and you will realize it's because of the salinity.
this is such a great series, thank you! i would be interested in hearing you explain in more detail why the arch and dome forms maximize compression and reduce tensile pressures - i think i can visualize it to understand but would love to hear your explanation! thanks!
Quote about an engineer designing a bridge is just superb.
They have time and patience. We have greed and deadline.
So what you’re saying is you prefer to pay much higher taxes so that public structures can be over built?
@@neilkurzman4907 I prefer higher taxes not only so that we have reliable public infrastructure, but affordable healthcare, investment in research and development, more efficient, less polluting energy production technology, good public transportation, affordable education, wealth redistribution to reduce the gap between the poor and the wealthy. In reality, we might not even need to rise taxes so high if we wouldn't spend so much money on pointless endeavors like war, corruption and bailing out corporations and the rich every time they screw up.
@@Horny_Fruit_Flies
I don’t disagree with you. But the majority of Americans do. They only want the government to spend money that directly benefits them. If it benefits somebody else then now they’re against it. Even things like infrastructure. They will complain about it fight against it even though it indirectly benefits them. Then many of them will complain I pay taxes why am Are my roads so bad.
Instead of rewarding for shoddy work. Reward for work that lasts Stop the bonuses for finishing ahead of schedule. It is only rewarding quick shoddy final product. Instead reward a bonus for a product that lasts long. If it has a lifespan of 20 years and lasts 25-30 years. Give them a bonus rated on that.
@@Smarty1171 I agree on quality over quantity. That's the pride of America.
I'm positive that with everything we know about concrete today, we are capable of building structures to last as long, or even longer than roman structures. Unfortunately, our government would rather do it as cheaply as possible so it needs maintenance or repair more often, then claim that they can't afford the repairs, even though they saved all that money by not engineering it to last. We could have roads that hold up to countless trucks for hundreds of years, but asphalt is cheap so lets just replace the asphalt every 10 years
There is no concrete that would hold up to hundreds of years of driving on it with trucks weighing 30k+
That said, we should spend more on infrastructurr.
Most structures are not built by government. There is a philosophy called 'capitalism' that encourages people in business to spend less to make a product so that they can make more money.
@@jtoddwalsh they are subcontracted to the lowest bidder, yes. But they are techbically funded, and thus built, by government.
This is where the phrase, "good enough for government work" comes from.
Which usually means..."it aint the prettiest, but itll work."
Edit: interestingly enough, the phrase used to mean the opposite. So exacting that it would help the us win the war (ww2)...
Cost aside there is also the issue of bulk. Arches and domes can be very strong but they don't give you a nice flat surface to build on top of and the wider the arch becomes, the taller it becomes. Particuarly with things like road over road or road over rail bridges a flat reinforced deck can give you much more usable room under the bridge for a given height difference than an arch would.
Kudos to these awesome and very easy to understand videos! Learned a lot and appreciate concrete processes and properties
❤️
What is amazing to me is that it can “dry” even in water getting also stronger with time. Amazing
I'm not sure if its true, but I heard many years ago that concrete in parts of the Colosseum still haven't fully cured.
When talking about centuries old concrete, you have to factor in the elements. A place that rains 75% of the time will deteriorate concrete much faster than a place with no rain and little wind, snow, etc.
Heavy: Very true about climate. Italy has a very moderate and relatively dry climate. Quite conducive to long term life of concrete.
How much does that matter when there's no rebar (in the ancient concrete)?
@@seneca983 It actually still matters a fair bit. What is really killer on concrete are freeze-thaw cycles, especially wet freeze thaw cycles. North East coast of North America is not a friendly place to masonry and concrete due to conditions allowing a cycle of water freezing and cracking a bit, which thaws and lets water deeper into the crack to then freeze again...
But even without the freezing action, the water can erode some minerals or wash away some materials to help accelerate the breakdown process. It might not be the worst or most harmful thing to happen to concrete, but it sure isn't what one could call helpful.
RealLuckless well it does help that roman concrete seals itself, so no water penetrates into the surface.
I think that the worst enemy of buildings isn't in the climate, but fires, earthquakes and purpose destruction.
I'm in medical school, why am I watching this?
don't get me wrong, i love it!
Just a similar username passing through...
4:10 sick reading bro. I need to get into the second edition I have so much reading ahead of me.
Im a former aci tester i believe you also work or have worked in the field as you are using beams cylinders and a compression machine. I did gradations cleaned molds and specimens as well as a field tester i was not certified for gradations but was forced to do it by the CEO's son . i find this amazing as ive never heard of this. I also noticed you did a 7 day break as we do 7 14 and 32 in my lab.
I've lived a long time and the one thing I am absolutely certain of is that everything always comes down to. . .Money. . .And the goal of most people who are responsible for creating things is to do it as cheaply as possible. They do this because THAT is how they build their reputations as great business people. Their reputations and careers are not really built on the quality of whatever they are responsible for, but on how little money they spend. And no matter how much they say this is not true and that they really care about quality. . .It is true for most of them and quality is not the main concern for most of them.
Another factor. Why is the Pantheon waterproof (except for the central "oculus") (I presume)
while the seattle Kingdome, an example of the largest reinforced concrete dome in the world, had to have a roofing job every eight years or so. (The Kingdome was destroyed after some twenty two years by a combination of politics with a dash of city hubris and the Parthenon still stands after 1000 years). Economics lesson, anyone?
Probably because of the thickness and density of roman concrete means it takes a long time for the moisture to soak through.
@@700gsteak roman concrete is weather resistant. So moisture soaking through? Not possible
archive.seattletimes.com/archive/?date=19940828&slug=1927603
Thanks for video. You ended video without answering a key question that is what life span concrete engineers typically have to choose from. And the cost differences per sq metre.
At 4:59 you say "Generally, we like our concrete more viscous." But I think you meant to say ...less viscous... since viscosity is the measure of Resistance to Flow, i.e. more viscous = harder to move, less viscous = easier to move... Keep up the great videos!
"Concrete reinforced with steel bars is the foundation of our modern society."
If you say so, Grady.
That must explain why everything is falling apart. :(
@@patrioticwhitemail9119 The stainless steel rebar reinforced concrete pier bridge in Yucatan Mexico is still standing after being built and used since the 1930s!
@@darthvader5300 yeah, so is the foundation of crumbling houses. Things *can* be made to last, but don't count on it when the people you contract have a vested interest in making sure their service never cease to be needed. Planned obsolescence. If you want something done right you have to do it yourself. Have faith in no one. Don't trust police, don't trust the medical industry, don't trust police, don't trust government, don't trust corporations... if you can't reach out and physicaly hurt someone who crosses you then what reason do they have to treat you fair in return? That's why 2A exists. That's why the free market works. You can financially starve those who don't give good produce. Construction companies make shit because the politicians who contract them use no-bid system instead of the biding system because the chosen company donated to the politicians. Apple and all those other companies would have actual competition weren't not for the government strangling small businesses and stopping the bulk of little people who could challenge them from rising up. F the system. All the people who say they want the system changed are just sellouts. They don't want the system gone, they want to be the ones profiting from it.
@@patrioticwhitemail9119 I could not agree more with what you said!
@@patrioticwhitemail9119 The free market only works when well regulated. The free market put plaster of paris and asbestos into bread to make it cheaper than using flour or lead for sweetening things instead of more expensive sugar. Leave the market to do as it wishes and it will, and the consequences are rarely good for the end user of such products. So you need proper regulation to keep them honest and to stop them killing people all in the pursuit if more profits.
So why aren't we building infrastructure that lasts? Imagine not having to put up with construction in your lifetime? I think it would be worth it
Because a lot of the infrastructure has to be replaced or resurfaced for other reasons. Bridges and roads frequently need to be upgraded to handle wider or heavier traffic, for example.
Firstly, expense.
Secondly, only a few buildings from Rome “lasted”. The colluseum collapsed in 1300, saying “ half the colluseum lasted” is kind of an oxymoron.
all the other Roman buildings are well and truly past commission. And the ones that did last only lasted because nobody used them for the thousand of years after Rome’s collapse and is now protected and maintained. They would need serious reconstruction to actually be used.
The Roman roads are amazing, but they are not roads anymore, they are strips of rocks.
Thirdly, durability comes at other costs like comfort and practicality. You could make a shoe out of solid steel and never have to buy a shoe again, but I’d rather buy a new pair of rubber shoes every few years.
Forthly, we probably don’t even have enough materials on earth to build everything out of 5, feet thick concrete. It’s just wasteful.
Not to mention what was already said, redundancy.
Why spend more resources on something to last for ever when in 20 years it will be so outdated and technology is further ahead the infrastructure is no longer even needed?
Imagine spending the entire country wealth on indestructible roads, only to have hover cars invented 10 years later.
@@doaimanariroll5121 it was two earthqukes that demolished half of the colluseum, not the concrete failing.
@@2394Joseph I know, but earthquakes happen. If you wanted something to last you’d need to engineer for that.
It looks like that blue shop towel is the hero here, stayed intact under more pressure than the concrete :D
I find this channel very much interesting and highly valuable to me, thanks author! (I am no engineer or construction worker by far..)
Pyramids of Giza: *laughs in stone-blocks since 2000 BC*
AHAHAHAHA
Eh, those things are _not_ designed for human occupation the way, say, Pantheon is.
@@7636kei They _are_ designed for human occupation. Well... dead humans, that is.
Why doesn’t anyone encase their steel rebar with a plastic coating?
Then it’ll have all of the same properties that make steel rebar great, as well as eliminate it’s one weakness.
Practical Engineering actually touched on that very idea (though only briefly) in their previous video: czcams.com/video/PLF18H9JGHs/video.html
Epoxy-coated reinforcement is a real thing and is used all the time in high-exposure concrete such as vehicle bridges and marine structures. It's expensive and you have to handle it carefully and re-coat every ding you make on the epoxy coat. It also increases the lengths required for the rebar and concrete to bond together. All of the disadvantages mean it is only specified if it is really needed.
Probably the same reason they don't use stainless steel for rebar: cost.
@@trucid2 *Some DOTs are actually using stainless steel rebar for the decks of very important bridges these days to avoid costly maintenance shutdowns. Pretty sure it's only the decks, though. Other concrete elements can be repaired with less disruption, and they aren't exposed to de-icing chemicals.*
Isn't stainless steel also typically weaker than carbon steel? (Though I've read somewhere that some forms of stainless steel have higher than typical carbon content improving the strength somewhat but at the cost of reducing the corrosion resistance.)