How to Make Roman Concrete (4 Different Materials, 4 Different Strengths)

[@htme]

Get 20% off your first monthly box when you sign up at bspk.me/how2 and use promo code EVERYTHING20 at checkout!

[@mobiousenigma]

as always thanks for the videos. im impressed at your level of preparation and skill for this video in the past you efforts were uninspiring while this is a functional usable product where you have used the beginnings of an assembly/production process where if you scaled time and cost could come up with a meaningful value for the product. and you have produced a product that was marketable and of market quality.

[@dildoshwagins2222]

Damn I’m pretty sure your supposed to use river rocks instead of gravel

[@sarchlalaith8836]

Roman concrete was also compacted, and had chunks of terracotta tile. I think there's too much lime in your mix and perhaps pumice is less effective than actual volcanic ash?

[@mobiousenigma]

@@sarchlalaith8836 lol the pumice would have been used as an aggro ate like we use gravel today , it was used in the pathanon in its upper dome areas because it is lighter . modern portland and ancient roman concrete are different and have different properties granted they both when hydrolyzed complete there chemical reactions and leave a coherent solid mass which continues to harden . sand and aggregate ..whatever was at hand broken tile was fine as was shell its a filler for the cement to bind . as for the amounts and proportions its like baking the recipe changes a little from cook to cook and day to day so as long as it sets theres not too much or not enough of any one component its cost or its strength or its time to cure are what drives the proportion requirements

[@sarchlalaith8836]

@@mobiousenigma? Did you watch the video? He used pumice in place of volcanic ash and yeah, everyone tweeks things, true fact. Compacting did increase strength though, not unlike pise, and it's thought that the tiles adsorb excess moisture. Anyways, have a great day.

[@sirflimflam]

The professionally made red brick was at a bit of a disadvantage since you had it resting on a small stone in the back, creating a pivot point and a good place to snap. If it were laying flat I imagine it would have stood a better chance at breaking until higher pressures were applied.

[@dillonvandergriff4124]

The wood wasn't really given a chance either. He crushed it in it's weakest dimension.

[@markhep]

I though the same. The test were not true as some brick were definitely focusing on one small point. others were perfectly flat spreading the load. So hard to tell the strength really. Great video though love this stuff 👍👍👍👍

[@CraftsmanOfAwsomenes]

Axe test in the previous episode was also kind of... unscientific is what I guess the term would be.

[@zyanidwarfare5634]

Yeah I noticed that too, big sad

[@richardhortle3414]

The error he made when trying to compare the force needed to destroy each type of brick was termed "point loading". In order that the different breaking strengths are ONLY due to the nature of the material it is essential to apply the force over an identical area of the specimen AND have a sample preparation procedure that ensures the force is applied evenly across that identical area. A small stone (e.g. a piece of the aggregate used in the Roman concrete) lying either under the top plate (between the pressure plate and the brick) or beneath the specimen (between brick and table) will produce erroneous results if it resists crushing for even a short period. Such point loading means all the rams force is directed at a very small area of the brick's surface (a very high pressure > the apparent final breaking pressure) causing the break to fail before it would have.

[@SirBoden]

Lesson #1: Don’t use round rocks in concrete. Roman cement is not used for its strength but its resilience to weathering as it cures over 30-50 years. A crush test is testing the wrong property.

[@ClokworkGremlin]

If the cure time is measured in decades, a crush test of months-old at most concrete is also testing on the wrong timescale.

[@Hundura]

I was looking for this comment. I was going to say the same thing. A crush test for Roman concrete after such a short cure time doesn’t showcase its amazing properties and potential. Roman concrete continues to cure and strengthen over much longer periods of time.

[@bamjo8750]

Round river cobbles were used in concrete until at least the 1960's. They are not as good as angular aggregate for high strength applications, but for many structures round rock is 'good enough'. I just worked on a highway bridge built in 1961 with a river cobble concrete mix that is holding strong after 50+ years of heavy truck traffic.

[@MsHumanOfTheDecade]

there is no real point to buildings standing for that long. that is just wasting the land of future generations.

[@Slouworker]

@@MsHumanOfTheDecade you must be American

[@robertjeffery3237]

As someone who tested concrete for a living, I really wish you would revisit this using a modern testing lab and the advice of a professional engineer as to how to make your samples, and how long to cure your concrete. Modern concrete is designed for a 28 day ultimate strength but it will continue to gain strength (asymptoticly) for 56 years or more. I would be pleased to collaborate with you concerning modern and ancient building materials.

[@talyn3932]

Cob also takes 1-2 years. Nothing was really given a fair chance here.

[@simonesmit6708]

That would be very neat to watch

[@reluctantheist5224]

Noooooo. I don't want a pro helping !!I love the amateur nature of this channel.

[@TBButtSmoothy]

​@@reluctantheist5224 amateurs are about learning, as this channel. im sure he would want to know if he rlly likes knowledge

[@shikhag5326]

Hi, I would like to get in touch with you as I am looking for organic cement materials for my project. Will look forward to your reply. Warm regards Shikha

[@aster5977]

This series is like Journey Mode in terraria, where you have to get X amount before unlocking an infinite supply

[@ziocrielo6148]

Yeah

[@therealArchmageTeslar]

I actually prefer Master mode to Journey mode, because of the challenge.

[@KainYusanagi]

More like Journey Mode is like HTME, considering how old it is. :P

[@therealArchmageTeslar]

@@KainYusanagi yeah

[@Alsry1]

@@therealArchmageTeslar if you want difficulty, play in journey mode with 2.95 difficulty, same damage and more Hp as master mode with none of the benefits of master mode

[@sevandor]

I remember reading that the seawater is supposed to be used when making, not as a later soak. Can you try that recipe too? I'd love to see what happens!

[@KainYusanagi]

It's both; seawater soak after the fact continues to make it even stronger.

[@sevandor]

@@KainYusanagi do you remember a source for that? I've never heard this, roman concrete is a weird love of mine, and I wanna read it!

[@jinxsterr_Dispenser3741]

When you use that method it can become stronger then concrete

[@kyidyl]

That’s what I was going to say. The secret to Roman concrete is using salt water while making it.

[@TheHeroPercy]

@@sevandor there was an article a few years ago discussing that the recipes for Roman concrete discuss using “common water” as it translates. And that for year they just assumed it meant fresh water but then the realized that with fresh water still being a precious resource during the Roman times that it must have meant the far more abundant and undrinkable salt water. After some experiments it was showing to be significantly stronger than previous tests using fresh water and even some modern concretes

[@princecharon]

The version I read fairly recently (not sure where, though) was that the water they used for Roman concrete was seawater.

[@kbee225]

Why does that help?

[@RedKrossSquad]

@@kbee225 Makes the seawater and Volcanic ash reaction happen before you expose it to seawater. + it will be more than just the outer layer that gets the benefits from the reaction.

[@EmmaAppleBerry]

Yeah ive read/heard that too at some point maybe a documentary or something...

[@John-lx8iu]

I was about to say the same thing but see you beat me to it. I can't remember where but remember someone doing extensive studies to eventually determine that seawater was most likely used and then they tested the same recipe with regular water and the seawater one was considerably stronger

[@morrigankasa570]

I heard somewhere that Roman Concrete for the bathhouses also used a little bit of clay when mixing it together.

[@EmmaAppleBerry]

You: makes a bulletproof chest plate without even trying Me: looks for my phone while im holding it

[@JavaBum]

That's awesome.

[@lokilyesmyth]

The pozzolan ash was used for the underwater concrete they used. For the above ground concrete they used specific types of ash ( harena fossicia and carbunculus) that had to be freshly mined to make sure it was chemically active. You can try to calcine the ash you have to see if you can get a reaction. The aqueducts were lined with one part lime to three parts testa- underfired clay tiles milled to a powder. Essentially calcined clay that contained a sodium or potassium containing mineral used as a flux.

[@maxmag981]

thumbs up 13:35 - materials showcase 13:41 wood ~4800 psi 14:01 cob ~180 psi 14:20 sun dried brick ~220 psi 14:40 fired brick ~250 psi 14:58 professional modern brick ~500 psi 15:19 plaster ~160 psi 15:53 stone ~1000 psi 16:00 roman concrete ~1200 psi 16:47 modern concrete ~2500 psi

[@MrLins-wv3tg]

it is alwasy beautiful when you return home after 7 hours of school (next week there will be 9) and find Andy welcoming you home with a new video, and more importantly with a topic you like. Thank you.

[@masondipperpines5009]

I have Online School

[@shadow13kill]

I graduated.

[@MrLins-wv3tg]

@@masondipperpines5009 We go school 2 times a week online and 3 times a week in person, and i think is BS

[@Rugiball]

@@MrLins-wv3tg i am remote

[@masondipperpines5009]

@@Rugiball i said this

[@ryanwaterbury]

Doctor stone this week was awesome

[@kheivin8211]

Yes and l learn about Medusa

[@gavinli1368]

Chrome got that Yo guy so good!

[@electron2219]

It was *elegant*

[@darkfangnightcrow]

This is one of those times my local city comes into play as I live near Bath in the UK that has one of the only Roman Baths that still stands today. Thanks to this invention.

[@alfredorotondo]

*laughs in Pompei*

[@talyn3932]

@@alfredorotondo Careful, or you may lose your head like it's namesake. :P

[@alfredorotondo]

@@talyn3932 no worries I don't live in Pompei, I went there only twice I live in sicily, only near the highest active volcano of Europe

[@Rusty_Raine]

When you revisit the cured Roman concrete brick I would also see a clay brick that was fired broken back down and mixed in with a new brick, then refired. This was a common practice Where you would use failed bricks that were ground and reused. They were supposedly a lot stronger.

[@WulfgarOpenthroat]

Yeah, they mentioned using crushed fired clay as a strengthening agent previously but somehow misunderstood and thought it was only applied to the surface, not mixed in.

[@maxipoo2]

I would love to see you remake it in light of the new discoveries about roman concrete regarding them using quick lime.

[@gavinli1368]

Naturally occurring porous glass! That’s so cool! Modern concrete additives also includes low density glass micro bubbles that helps make it light. You can even build a canoe out of this special concrete!

[@hogfry]

For those finding this video today science has recently solved the big mystery of Roman concrete. Either by processing accident or by design the large chunks of lime in Roman concrete would devolve out of the substrate when exposed to water and "heal" fissures and cracks in the concrete. The Roman empire invented man's first self healing meta material.

[@MORNINGSTAR827]

i wonder what crap he will have to go through when he gets to the steam area he will have to build a fricken train XD

[@vysakhak191]

I hope he doesn't make a Heron's engine (aka 'aeolipile') and call it a day. I would like to see something atleast similar to a oscillating cylinder engine.

[@krungstar4541]

@@vysakhak191 followed by a pulse rocket made with that crappy bronze knife :)

[@drk5orp-655]

You mean "go through"?

[@mobiousenigma]

the greeks had a steam engine the concept is simple but the materials and sizes for "trains" requires metal work and machining . the first engines were for water pumps and were hand forged wrought iron things more related to a pressure cooker than a train

[@MORNINGSTAR827]

@@drk5orp-655 yea my english kind sucks its not my main languge

[@lurchie]

I think you should explore the development of Ikeatite, which is the main ingredient in those extremely useful Ikea bags.

[@jmartin9059]

*In addition to your chosen ingredients, "Roman Concrete" might have been made with salty sea water And VOLCANIC aggregate material. Some claim that the layer of play-do consistency blend was added in layers and into each layer the workers pounded up to fist sized volcanic stones ... then the next layer of mortar mix was pounded in such a way as to fill the pores of the volcanic stones. This layering continued until the desired size and shape was complete.*

[@bamjo8750]

For everyone hating on the methodology here.. it's fine. Certainly good enough for a qualitative test of different materials. What they are using here isn't that different from ASTM C39. In construction we test concrete specimens after 28 days of curing, and that is good enough for the bridges we drive on and the buildings we live in. As a a broad comparison on youtube, I think these guys did a great job.

[@PotatoesAssistant]

So one thing you can try for your concrete is using aggregate with sharper edges rather than smooth and soft, because it will help it to lock together better and be stronger. Also it looks like your concrete was a little dry maybe.

[@sangyoonsim]

Can you revisit this topic now they finally rediscovered the way of Roman concrete?

[@TheJCJexe]

The sponsor segment is actually interesting, I watched the whole thing without skipping. 👍

[@dieselphiend]

He needs to redo the factory brick test- it was sitting on something that caused uneven pressure, and premature failure.

[@cuzzynot2759]

Can you do it again with the actual recipe for Roman concrete that has just recently been discovered

[@seltaro]

The beetle part was really nice. Thank you for that.

[@comradesoupbeans4437]

i truly love that you put a timer on your sponsorships, you're the best about that

[@dondelabruce6054]

10 weeks later: "In the 1960s they used this kind of primitive tools to shoot a man to the moon. See if we can reclaim this ancient technology for our own moon mission!"

[@theprussian4616]

They finally figured out how roman concrete was made. You should probably look it up and revisit it.

[@erkdoc5]

This episode reminded me of that time in class when a concrete cylinder exploded from the pressure of the press. Kinda nervous with him just sitting next to it like that without a shield.

[@darwinism8181]

Ikea bags are ridiculously sturdy and I am glad to see I'm not the only one who's noticed this

[@williamh123456789]

In Practical Engineering video about Roman concrete, he says that the biggest problem in modern concrete is the amount of water and the using of steel structure, which deteriorates the concrete overtime. Another thing Romans used to do was to put concrete under pressure and relive tension, that's one of the reasons why they build huge monuments.

[@randomcow505]

we still do that, its called prestressed concrete

[@cynthiaaiken2424]

@@randomcow505 the Seattle space needle is made from prestressed concrete. It had a fail. Designed by a guy named Holmquist. he was a friend of mine’s dad. My friend is no slouch in the BRAINY department, either.

[@randomcow505]

@@cynthiaaiken2424 uhhh cool?

[@austinhoward6557]

Nice to see you back in action with the traveling and doing stuff more! Cool to see

[@PaleGhost69]

So when are _you_ making a steam engine car? XD

[@razor-wd2pc]

Im waiting for a hydrogen powered car which would solve fuel problem

[@yay468]

Honestly 📠

[@Nicolas-lo8db]

@@razor-wd2pc it would not since hydrogen is produced with electricity. which is reliably produces with fossil fuel.

[@hioyua650]

Cant wait!

[@black_rhino241]

@@razor-wd2pc the way hydrogen or water fueled cars work is through electrolysis but the thing is you use more power to split water molecules apart then you get out of it

[@Freqsheux]

I know its probably been said a million bajillion times..but man this series is awesome. I would say its "TV" quality but that almost feels like an insult. Keep it up man!

[@spobe1610]

30 years from now: "today we Will make a GPS satellite, and launch it into orbit"

[@inertproductionsalternate9114]

I feel like we're watching a real world version of a video game progression with your channel. "Congratulations you've unlocked concrete"

[@doloinc]

I thought what made roman cement unique (stronger) was the addition of salt, which formed a type of crystallize structure that reinforced the cement and made it more resilient?

[@someczechguy4261]

Can't wait for the heavy machinegun episode.

[@awesomeboy4353]

Dr stone and htme is the same mission from starting from scratch

[@tomkaneen3211]

Liked the style of this out in the field and talking about the history of concrete etc. nice vid

[@James-nr4sj]

This channel is way too underated.

[@fhorst41]

There are companies using glass from recycling to make a kind of lightweight fill material that, essentially, is artificial pumice. I have hauled bulk bags of it to jobsites, and an antire tractor trailer load was under 15k lbs.

[@ButtahDawgMcDouble]

Ive been watching your channel for around 2-3 years now and I absolutely love what you guys do. I know you get hate all the time, but I learn more and more every video. Keep up the good work!

[@Bird_Dog00]

Afaik the main reason why opus caementicium lasted so long was the lack of rebar. Rebar inside concrete rusting is afaik the main reason why concrete structures fail after a few decades. Look at hydroelectric dams made from concrete without steel reinforcements. Some were built over a century ago and are still good, while you see modern structures made from reinforced concrete crumbling after a few decades.

[@kyrionbookshield2205]

Thank you for gifting me this video. I finally can explain and understand why concrete works. :) But with your video I have a way to communicates this better to my future students :) Yes I am gonna make them mix concrete :) And then we will use them as safety plates for experiments. ^^

[@cameronknowles6267]

You sound like an amazing teacher

[@gavinli1368]

You might want to check out the Practical Engineering channel. He has an excellent series on concrete too.

[@kyrionbookshield2205]

@@cameronknowles6267 haha I am still on my way to bachelor. ^^' but I have a goal in sight.

[@kyrionbookshield2205]

@@gavinli1368 I will do that. Thank you :)

[@alfredorotondo]

@@Mrwaffleandmilk as an Italian I'm even more confused because cement in italian is malta cementizia or simply malta (yeah like the country) and concrete is cemento

[@error0x996]

I id just like to say that this dude is awesome he has made so much progress as a person since this has started and has gained so many new skills doing so it, i dont think making new goals for yourself is easy but dang this dude does it all the time for that gg

[@dasloth1435]

Awesome video man keep up the good work. I'm always fascinated by your projects and stuff you make.

[@Stevme0001]

I am so fascinated by this. You've got me hooked!

[@The_Keeper]

0:18 It could also be said that we live in the Glass age, as Glass is used damn near *Everywhere* ... Hell, there is more glass in the windows of a single skyscraper than there was produced throughout the entirety of history up until like the late 1800s.

[@EmmaAppleBerry]

That just blew my fkn mind so ta for that 😂😂😂 this is like the rime someone told me there were more dead people than alive no matter how big the population gets. Which i mean is obvious af but like you dont think like that so when its pointed out its like super spooky and you cant unknow it.

[@BloodHawk31]

I'm very interested in this, I am studying civil engineering and from what I know modern cement is the same recipy as roman cement, though as all processes, we refined it to a molecular level to get the maxim stength. Problem is though that in order to create any cement there is a massive amount of carbon dioxide released into the air to creat your klinker, which in ancient times was your fly ash which came from the original carbon dioxide sources, volcano's, but today we do this ourselves in factories, heating limestone to extreme temperatures, so we became the volcano's...concrete has helped us develop so far, but as engineering students we are constantly asked to look into new ways to create cement or to find a way to nuetralize the fumes produced. There is a lot of depth in this, and I love how you remind people of all the generations of knowledge we have access to today, we are in a rapid developing era. The age we're in, I don't think there is a name yet since ages are hostorical periods used to classify information periods, after iron age was middle ages, pre modern etc, we are past the post modern, this age will probably known as the nuclear age from what happened in it and from how we have developed with nuclear energy, another fun thing to watch out for is nuclear fusion energy, which could change how we live, nearly unlimited sources of energy. I just want to build in space one day, being like a space civil engineer, it could be awesome.😁

[@LENZ5369]

The fly ash equivalent is the volcanic pumice. Both uses 'lime' -it's just that we process it far more that just simply heating and hydrating it.

[@Hades9898z]

Yes, dr.stone fan yes!!

[@akabami2161]

just watched it the third time

[@CreativeGaming96]

Love that short clip of a Dash 8 Q400 Crosswind landing @ 0:23

[@Hades9898z]

Asari gen: Honey bake it Honey okay I understand. Making plastic in stone age

[@D_oktor]

That was tungsten toothpaste, cook the powder in sodium hydroxide, add sea shells, hydrochloric acid and ammonia to crystalize it then bake it and mix with honey xd

[@Archionus]

Again great video! I love the doodle eyes running joke :D. You guys and gals are awesome! Keep up the great work

[@flea214]

Them googly eyes are a nice touch!

[@jacob_chesser_1115]

Ik were in the iron age now, however me studying to be an archaeologist is allowing me to ask questions, I've smelted everything from copper to iron. Failed alot learned alot and soon had successful attempts. But the question I'm answering now for myself is, what if another metal was found instead of copper at the beginning of the copper age? And as of now I found zinc to be very useful. Low melting point as well as a hard enough edge to be used as a cutting tool or tough enough to be used as just about anything. I'm asking if you could plz look into this further, zinc tools and possibly weapons. I can send you pictures of what I have atm if needed. But it would great if someone else could answer these questions. Ooooor orichalcum. My favorite metal besides bronze lol. Great vids like always keep it up

[@alfredorotondo]

Well i think that maybe they discovered zinc after tin so they directly passed from copper to bronze Although I don't think that they "discovered" copper first but they discovered how to cast metals after how to handle them Copper can be found in nature as a nugget so they probably learnt to model it and then that it can be cast Maybe gold was an alternative to copper because it can be found as nugget to But copper does shatter so you can treat it as obsidian too so it is more versatile

[@peacemanner8831]

Mans gonna make a biplane soon enough

[@mitzuu3010]

NOW the fun is starting

[@adengoldstein5130]

Hi there

[@lillywerk4642]

Hello

[@josetelles6536]

Howdy

[@thesultanpepper9413]

Ello

[@nickg5250]

best channel on youtube. would be curious about concrete made using baked shells, lots of oysters here in the PNW

[@Just_Sara]

Edit: not a "fun fact" because people are no fun, and now I shall call it a "fun opinion I heard" Fun opinion I heard: I recently heard an argument stating that the limestone blocks of the pyramids were maybe poured, not cut. Wut.

[@christophersnedeker2065]

Not how stone works

[@buckadillafilms]

It's a very compelling argument!

[@Bolognamonster]

It’s not likely due to limestone cracking on its own In such large ammounts

[@D-Vinko]

You mean fun opinion, There's no evidence of that. Literally every stone I've ever seen from the pyramids has clear chisel marks. Who told you this?

[@FrauWNiemand]

The comparison to also the modern stuff is extremely cool, so we can see directly how it comes up

[@christopherrodriguez8154]

As a Civil Engineering Major, this personally hurt to watch. Entertaining and informative nonetheless.

[@loganstrong5426]

Oh man, same. "That Roman concrete needs more water." "Why aren't you tamping!" "Fill in the voids! Come on!" "Did you keep it moist while curing???"

[@brutusthebear9050]

Ikea bags are awesome, who would have thought a bag in the shape of a box would be so versatile.

[@Flumphinator]

Remember guys: lift with your back.

[@jamescanjuggle]

Manual handling is a must, no point wearing down a great tool like our body faster than need be

[@johnpaulshanley6073]

I love this series so original and interesting keep up the good content ! 👍🏻

[@typhooni8]

Anyone else worried about Andy's legs during this? Like worried things would shatter and shrapnel would go into his legs

[@ehodzic155]

No

[@thenikko8292]

we're in the age of glass, Adam savage and jimmy Heineman said so on a Ted Talk they did a few years ago, explaining why

[@HrafnkelHarthrathi]

"Welcome to the hydraulic press channel..."

[@seirramoon388]

Today we will be testing this brick to see how well it holds up, ready?

[@athenapatrick5447]

has he been able to make a miniature plumbing system? i think thats one out of hundreds of our greatest inventions

[@amistry605]

"The plastic age" is the saddest thing I've ever heard. 😆

[@StoicNatsoc]

only because humans of lower iq in various states around the world pollute their environment. Plastic in itself is a magical compound, lasting centuries, which made many technological marvels possible. do not blame the material for inferior cultures which give it a bad name by dumping it all around.

[@amistry605]

@@StoicNatsoc I totally agree. I think people just take it for granted and didn't know how to handle it. And BTW I was just replying to what was said in the video, not bashing plastic.

[@josephbenson4413]

How about the Polymer Age instead?

[@amistry605]

@@josephbenson4413 meh.. lol

[@talyn3932]

@@josephbenson4413 That's more accurate. There was neolithic plastics in use in the form of resins. Plastic has a term usage beyond polymer plastic. It leads to some confusion.

[@Mynameismegalex]

Jesus Christ the footage at 03:03 is so trippy I had to look at it five times to realise what I was seeing and the perspective of it.

[@dorito_mauller]

Make damascuss steel.

[@NoName-sy3di]

Damascuss steel (woot steel) doesnt exist unless its artifacts....the "damascuss" now is just patern welded steel....just looks pretty

[@dorito_mauller]

@@NoName-sy3di you misspelled wootz.

[@Cropduster1985]

Did you try vibrating the molds to get air pockets out?

[@CorysCat]

*Advancement Made: Roman Empire*

[@Paethgoat]

Watching this channel sometimes feels like a Dwarf Fortress crafting chain in slow motion.

[@michaelp9707]

Roman concrete,when the advanced techniques used is tougher and more durable than modern concrete no question.There are many examples of 2000 Year old Roman structures in tact,while many modern concrete structures start cracking apart within 10 to 50 yrs for example

[@hedgehog3180]

Michael P That is not universally true, most buildings you encounter tend to be made to only stand for a few decades so the concrete is optimized for strength so you need less but we can also optimize for durability and that is done with things like nuclear bunkers and dams which need to stand for a long time. Roman concrete also has the benefit of having been used in very mild climates which don't have to deal with a lot of rain and frost which is usually what leads to structural failure. Also there are a lot more examples of Roman structures that aren't intact you just don't ever think about those because well they aren't here anymore, something like 99,99% of all Roman structures have collapsed totally and of the remaining 0,01% a lot of those have partially collasped. The ones that stayed owe just as much to maintenance as they do to the durability of their materials.

[@thelonemoomin]

Nice to see a good old IKEA bag being put to good use. Can't imagine many others have been used to collect pumice..... they have now probably been used to carry everything 🤣

[@tinashemuzorori5427]

These guys are like dr.stone

[@jameshill2450]

The thing is, we still don't *really* know how they made Roman concrete. The "recipes" we have from records are woefully incomplete, and despite our best efforts at trying we still cannot replicate the same quality even with modern methods. Our modern concrete is good. But it's like comparing iron to steel. Roman concrete really is that much better, and we still can't quite figure out exactly why.

[@ilychan3580]

While we're here it's important to remember that concrete is wonderful, but comprises over 8% of global greenhouse emissions.

[@Serahpin]

It's cold right now so it's obvious we're not using enough concrete.

[@caiawlodarski5339]

@@Serahpin ok boomer

[@jesst5474]

When compared at exactly the same size say 3x3 for example, a patio made from concrete has a lower carbon footprint than one made from timber, requires less maintenance and will last considerably longer.

[@Serahpin]

@@jesst5474 Watch out, you'll be reported for posting hatefacts.

[@Couchyrick]

i love the idea of your channel this always bguis me when i cant make something myself

[@ydnark83]

channel name edit "how not to make anything" or "we totally unlocked iron from scratch, right??" watching for years and it just gets worse every episode, its like watching a train wreck..

[@juancarlospalomo9646]

I was just watching a whole series of your videos about how to make glass and you said something interesting in this one about how obsidian is formed. You said it forms when volcanic lava cools under pressure. This takes me to the video where you tried to make a knife out of obsidian that you melted and poured into a mold. If obsidian forms when it's under pressure then it makes sense that if you reform it, it should be pressurized when it cools. The other a method I was thinking of was to heat the mold so the obsidian cools faster and doesn't crack from the air in the environment.

[@chyraxion]

i hope he can get to the point of really making some money off all this

[@alexdibosco]

dude.. he have sponsor, ads, paternon, item shop, and a mail box where fan send stuff.. whit 1.5 milion sub and 500k of vies for evry vid and one sponsor in almost evry video he make nice money.. (proof? he have a stuff for shooting the video and editing and also helper)..

[@budomojhayarer.2611]

Yesss finally you thought to make a one of the invention that roman and our modern civilization really needs.....and I also wait for you to make a roman technology....thanks a lot

[@Kurotama11]

Hearing the term “ Concrete Age” made me so incredibly sad for a sec because it’s honestly the perfect description for the modern era

[@seanprudden6335]

Why? Concrete is an ancient material that we have now mastered in our own new and amazing ways to build incredible structures. concrete is something that has been with us humans for a long time and our modern concrete world is a built on the backs of thousands of years of human ingenuity and engineering. Stone masonry is something ancient and beautiful but still, nothing really represents the long-standing human pursuit of construction like concrete. Especially when you consider how tied together modern concrete construction is with iron working, another very old and special human skill, a concrete building is a marvel of the history of humanity and our innovation.

[@Kurotama11]

@@seanprudden6335 in the sense that, a vast majority of our current world consists of concrete…as opposed to say, a “green age”

[@Kurotama11]

@@seanprudden6335 we cover the ground with concrete, just to have the population buy expensive cushioned shoes cause the ground is too hard

[@Kurotama11]

@@seanprudden6335 I’d much rather and age of balance, where we can fuse human society with nature rather than covering nature with it

[@sterlingodeaghaidh5086]

In a corning advertisement Adam described us as in the Glass Age. I know its an ad but maybe there is some merit?

[@user-oy8qp6bq3b]

Fake, he didn't use a diamond pickaxe for the obdisian (joke btw)

[@pagnedaman3777]

(thanks for the btw)

[@chrisfox961]

Another ROCK SOLID episode!

[@GreedyGabriel]

I miss the times when thumbnails didn't need an exagerated fake reaction face

[@kanderssen7629]

15:03 brick was at an angle. Meaning it broke easier. Also you should have a look at the Egyptians brick glue.

[@twitchbitbandit9426]

By the end of the series andy will have made an entire company where he makes everything from axes to phones to cars

[@josephbenson4413]

I know it probably isn't good for the video, but have you considered wearing a mask while doing some of this work? Or maybe having a fan pull the dust away from you? When flint (or obsidian) knapping, or I should imagine, crushing the pumice, you are creating dust which you are going to breathe in. Since you aren't spending day in and day out doing this, you are probably fine and unlikely to get silicosis. But... for the cost of an N95 mask or a fan to send the dust out a window or something, why risk it.

[@jlgibbens89]

Really looking forward to seeing the sea water concrete

[@molly4243]

im loving these thumbnails

[@tsmspace]

One thing that's not usually stated in these little videos, is that the way that the concrete was used would have been different. Modern concrete cracks quickly on highways, but highways are designed to get the maximum load onto the concrete, the design of the road itself does not prevent and minimize stress, instead, it uses the concrete in "crazy ways" making the most of the strength, but ancient roman buildings and infrastructure may have been designed to minimize stress on the concrete, They would still use efficient shapes, and generally more stable organization of the building materials. This makes sense because in the modern era, we are willing to sacrifice lifespan in order to gain space or capabity (yes, a straight flat bridge is the most stressful way to implement concrete, but we really don't want to do it another way, because a minimal size bridge is the most desirable trait for urban planners). Roman structures used building architecture that was developed for weaker building materials, and those structures that were "modern" actually often did not last. The ones that DID last, look like the buildings that came before the concrete.

[@jhyrumgrant]

The best example of the strength and longevity of Roman concrete is when it was under load. They understood the value of post tensioning.

[@alfredorotondo]

They understood that using arches instead of architraves is more likely to put the load in the form of compression instead of tension In the modern days we simply use metal to strengthen the cement but obviously the romans disvovered that as the metal expands it breaks the material (if you wonder Greeks used to cast lead directly in holes in their columns but romans didn't)