HYDRAULIC PRESS AGAINST CONCRETE OF DIFFERENT AGES

[@lolno3906]

Excellent demonstration. Especially as a quick reminder for someone who will keep telling you that it is okay after two days.

[@holymontezuma1319]

Way too green after 2 days, they should do a water bath vs spray and see the huge differences there

[@MyDogIsGoth]

Define "okay". To walk on? To strike formwork? What recipe? What is the strength supposed to be? You can never generally say that concrete is or isn't strong enough, it all depends what the situation and purpose is.

[@77Fmydog]

@@MyDogIsGoth for your mom to step on needs more than 2 days :P

[@n-tape6798]

according to regulatory documents, it takes 28 days to load a concrete structure with a project load. This is the base. but you need to understand what you're using concrete for. you also need to understand that concrete is gaining strength constantly when operating conditions are met

[@Bowhunters6go8xz6x]

Generally 48 hours is good enough to walk on and to start framing a wooden house but that is it !

[@ubikii5926]

Congratulations for having waiting for 130 years before running this experiment !

[@Nookdashiddole]

That's the dedication to his fans😂

[@XabiBello]

"I devise and bequeath this concrete cube to my grand grand grandson, so he could squash it in a KZbin video", signed Crazius Hiddraulison, 1899.

[@hansdampf640]

such tests are done permantly since we use concrete in modern day construction,big construction sites have often a local testlabor

[@antoinepallascio3944]

@@XabiBellolmfaooo 🤣🤣🤣

[@kylelopez629]

@@XabiBellohow do he know wath is KZbin

[@oifmarinesgt]

The one major thing you did wrong when you originally made the blocks was you didn't vibrate all the air out. That is very critical to the strength of concrete.

[@kpag3030]

That’s what I was thinking. Way too many air pockets

[@brucehemmerich9653]

True, but for me was best not to as no one vibrates driveways.

[@enochpowelghost]

I agree totally i used my wifes vibrator took ages but it worked ,for when i made foundations for a shed. However she was hopping mad ,as the sand made the device rough.

[@madb132]

@@brucehemmerich9653 i have always vibrated concrete drives or any slab of concrete. {retired now} 👍

[@Pseudify]

The important thing is they were all treated the same so we get a fairly accurate sense of relative strength with time.

[@billj5645]

I'm a structural engineer- that looks like lots of fun. (We did similar tests in college.) Concrete has been studied and tested for a long time, people tend to do that sometimes. There are pretty well understood curves for concrete strength over time, in construction typically we specify concrete according to its strength at 28 days and beyond that it may gain another 15% or 25%. At 7 days it should be around 70% of its design strength at 28 days. There are variables that will affect this a little bit- how much cement, how much water, how is it cured, what other chemical admixtures does it contain, etc. Some types of modern concrete with special curing conditions has very high strength at 2 days for instance. You can't compare concrete you mixed with ancient concrete because you don't know what is in it. If you want to know what is strongest then modern concrete will win that comparison, concrete has been made that achieves compressive strength almost equal to mild steel. Your beams without reinforcing failed as expected. Your beams with reinforcing actually failed in shear not in bending due to the ratio of length vs. height that you had. With more length you could have gotten them to fail in bending.

[@ПавелПудиков-п1ю]

Thanks for your comment man. Pretty good explanation for those, who have not learned civil constructions. Hopefully he will do another beams with shear reinforcement, and we all will see the difference.) Greetings from russian civil engineer.

[@noway1]

It would also have been cool to see pre-stressed concrete. Basically the same as reinforced, but with endplates and nuts putting the rebar under tension and the concrete under compression.

[@poopjeans1135]

Tell that to the Roman collosseum

[@JoshBeards]

I've opened a bridge deck at 3 days. 3 bridge decks actually on steel beams as we had 3 deck rehabs that year. All over 200ft long. If concrete is at 85% of f'c, it can be loaded. A 4500psi bridge deck needs 3825psi. Day 3, we had equipment on it. By day 9, we had concrete trucks on it pouring parapet walls. That was 2016 and the decks are still doing fine. They get semi traffic regularly from local farmers.

[@bricenoh]

I wonder if the 28 day strength can be affected negatively by stresses in the previous days? how much stress can what get during those days without affecting it? eg that 2 day sample that broke iirc at 14% of 28 days limit, if it had been subjected to 13%...every day, would the 28 day limit be the same?

[@jeffpiatt3879]

Pro Tip- If you find yourself bidding on coring holes in 50+ year old concrete, double or triple what you usually charge- or put a cost adjustment charge in the contract. A client converted a 70 year old parking garage into apartments and the first coring company pulled out and the next one had an escalation charge of $48K over what was originally bid. Making holes in old concrete is "hard" (pun intended). : )

[@Cyrenaicia2099]

I don’t like you much because of the pun

[@snoutysnouterson]

That's not a pun

[@stestar09]

How did the pre dynastic Egyptians do it ? Google- core sample 7 can see a spiral shaped cut in it , looks like a thread

[@madb132]

@@stestar09 YAWN!

[@jozefmagat17]

I cannot undestand this ...

[@mrmiscast]

My wife asked me "Why would I watch this channel and Why would this guy do all this stuff to compare"... Why Not? If I had that press equipment I would test everything too....

[@nammi895]

She is a woman. They don't have any interest in building, history etc. All they r interested in office gossips, drama & complaining 😂

[@silenceswhisperer7631]

... Pressing wife vs pressing the girl next door ? Prevented due to lack of equipment.

[@Zorro9129]

☕

[@BionicMilkaholic]

Good demonstration of how concrete continues to cure and gain strength over time. This has been a good chunk of my career. But those samples were not cast or tested according to proper testing methods.

[@geomac49]

I think you still get the idea

[@AndrewJillings]

Question: if we were to leave one of those ‘new’ samples for 130 years, would they be as strong as the fortress sample, or did they make concrete differently then? TIA

[@DellFargus]

@@AndrewJillings No. The samples in the video were not correctly made and had visible air holes and the curing conditions are unknown. Also, the concrete in the video appeared to be from a bag and hand mixed, which shouldn't be used for structural purposes - every wheelbarrow mixed would be different. That stuff is okay for anchoring fenceposts, a small patio floor on the ground, or maybe a sidewalk on private property, but you wouldn't want to drive over a bridge made out of it. It's all about the "recipe" used to make the concrete, which would make the compressive strength vary wildly. Concrete does strengthen with time, but after 28 days or so it's pretty much at it's max - for small pieces like those used in the video.

[@bigoldgrizzly]

@@DellFargus There are many factors affecting the final strength, one if which as crudely demonstrated here. Perhaps the commonest faults in diy concreting arise from adding way too much water and insufficient compaction and keeping moisture from escaping. For most diy work the rough mix, pour and forget are probably going to meet the needs for that job ... but beware if you are expecting predictable structural strength in your project

[@K_Pppp]

​@@DellFargus не усложняй

[@rakeshchauhan8856]

Brother! There is a specific branch of engineering called civil engineering. According to them, you can achieve 100+-year strength in just 7 days because concrete has multiple grades. High-strength grades like M-80 or higher can achieve relatively higher strength in different grades.

[@rakeshchauhan8856]

You can make concrete stronger or weaker, depending on the mix. This don't clarify that 100years can make Concrete stronger as video shows.

[@deeeeeeps]

As a contractor this is very useful information. I always thought 7 days for driving on concrete but it's pretty clear 14 is much better.

[@mazi6829]

The last two failures are concrete strut failures meaning the tension rebars didn't fail. If the section had vertical shear links, it would have increased the capacity. Also the aggregate size for the last two specimens were a bit too large.

[@gicking3898]

I bet only certain people will like this video, like me. But I really enjoyed watching it. Thank you for taking so much time and effort to prepare, carry out, video and edit this

[@DanielAluni-v2t]

This is excellent content. Made some sidewalks and patio sections last summer, and now i see why i used mesh and rebar and kept the slabs covered and wet for several days. Thanks!

[@Ryan-ff2db]

Yeah, I've had to drill into old buildings many times. One project required over 2,000 six inch rebar embedment. Let's just say 100 year old concrete is no joke.

[@thebasicquestion2853]

This needs more attention! 24 hrs after a foundation Pored a Site Supervisor was having a Framing company work on a 6,500 square foot home. Let’s just say that builder took a $300,000.00 hit against them. When the marble floor tiles cracked on the first floor!!!! Later they took a $997,000.00 hit when the future home owner got a Radon positive test result from the floor cracks!!!!

[@jegr3398]

Well... That ain't good.

[@DellFargus]

The hand-mixed concrete from a bag is great if you want to make a walkway in your back yard, but that stuff would never be allowed for structural concrete in a building or bridge for many reasons. You should contact a concrete plant near you, they keep sample cylinders of their concrete in water and after a while they throw them out - maybe they would give you a few.

[@yodaiam1000]

Bags are used structurally when you only need small amounts, for areas that are hard to get into, or remote locations. You can actually get very strong mixes with different classifications.

[@daveevans7438]

I was impressed with the plywood holding up..😂

[@billj5645]

That's an indication that the concrete he made was fairly low strength. Concrete used in normal construction should have allowed the plywood to squash pretty flat before failing the concrete.

[@basin397]

wood is pretty strong in compression, you wood be surprised how much weight it can support. check out how boats are supported during construction/fabrication in a harbor and how they are launched out to sea.

[@billj5645]

@@basin397 It is pretty strong in compression. However they are loading the wood perpendicular to the grain and the allowable stress on pine perpendicular to grain is about 1/10 the compressive strength of normal concrete. (I don't believe their concrete was anywhere near normal strength concrete.) Wood is much stronger in compression when loaded parallel to the grain direction but still is less than the compressive strength of normal concrete. I've done the calculations on wood blocks relative to the recent drydocking of the Battleship New Jersey and they get by with it by using a whole lot of big blocks. I think originally a lot of those blocks had hardwood covers, hardwood being stronger than pine but not nearly as strong as concrete. In some situations where they topped the blocks with layers of plywood the plywood appeared to be squashed pretty good. The battleship being in the ballpark of 50,000 tons, it was supported on 300 blocks about 4' x 4' square. Counting on just the concrete strength that amount of weight could be supported by 20 of those blocks. They have to use a lot of blocks to spread the weight out over the entire hull of the ship and that gets the load on each block down to the point where the wood surface on the block can work and not be crushed.

[@Yoyiiii]

​@@basin397 nice pun!

[@petefox5187]

Thanks for the warning I nearly bought a 100 ton press for the shed just so I can confirm your results. 😂😂

[@kensmith5694]

Nice demo. If you really want to get it strong with the re-bar in it, pulling a tension on the re-bar while the concrete sets will do that. Basically you can see that the concrete failure starts at the bottom of the beam where the concrete is being asked to work in tension. Pulling on the bar makes it some that that part is under compression up to a heavier weight. BTW: There are also additives you can mix into concrete. Some of them slow the hardening but also tend to make concrete that is tougher in that cracks don't start as easily

[@bigoldgrizzly]

pre-tensioned concrete can be a real hazard in demolition !

[@kensmith5694]

@@bigoldgrizzly Yes, it is a danger but it is one that the folks who do the job know to protect against.

[@massimox8256]

Mi sembra di ricordare che progettare, impastare, Vibrare, tensionare i ferri nel cemento sia un'arte che richiede molta perizia, esperienza ed il rispetto di moltissimi parametri. Solo così può dare il meglio di se. Hai fatto del tuo meglio, bravo. Ma si possono ottenere valori di molto più elevati rispettando le procedure opportune.

[@mearalain3006]

Lui non ha probato l'antico cemento romano.

[@LeicaM11]

Concrete (Beton) really does not have to dry, but to harden. So it may harden under water as well! 😊

[@noobdotiro]

Que ótimo vídeo! Parabéns do Brasil!

[@user-bh4xh1ig6r]

Beam Test. Reinforced concrete breaks down by shear forces.It's different from testing pure concrete. Which breaks from Moment Force.You must add a Stirrup Steel to produce the same test results.(Breaks down by Moment Force)

[@1922DPenny]

The limiting factor in cured concrete is the strength of the aggregate. If you notice, the last sample has failed aggregate.

[@andyhug90]

Nice. I bet the bigger stones in the bunker concrete are helpful bc they interrupt internal cracks similar to what happens to metal grainstructures after heattreatment

[@JoshuaSilverstein777]

Concrete Inspector here: 1. Make sure all air escapes the samples before finishing your casting 2. Make sure the concrete stays in either a water bath with lime, or a mist room at 73.5⁰ +/- 3.5⁰ for the entire time they cure 3. Use neoprene pads or cap the concrete cubes with sulfur or gypsum for a better respresentation of the cubes strength. 4. Verify that the mixed concrete is the correct water to cement ratio when mixed so it is representative of the real strength it can reach. Edit: 5. Load the cubes at only 50-100 psi per second to ensure you are not shocking the cubes and are not getting a false reading that will read stronger. At 28 days you can pre load them to 50% of their last reached strength before metering.

[@madsli]

Dude really just built a fortress and then waited over 100 years to make this video. Talk about commitment.

[@Seoulhawk01]

Love to see Roman Concrete.

[@compfox]

Not allowed to drill a hole into the Pantheon!

[@BritishMappingOfficialWKGR]

4:21 That’s roughly 60,962.81 kilograms

[@Zaphorix_Official]

How

[@mongoloid_hunk]

1 ton 1000 kg . that's how

[@lumpyfishgravy]

Great demos take me back to my uni days (Electrical Engineering but we studied Materials). It's interesting to see the difference between steel and fibreglass rebars. Glass may have a great UTS but is let down by a low Young's Modulus.

[@carrot_slayer_of_patatos]

Nice to know your great great grandpa helped 😂

[@AdamPalomino]

Normies be like: iT's DrY nOw, ReOpEn ThE rOaD

[@arwood111]

I love watching this…and this one was real world education as well

[@phenogen8125]

My understanding is that keeping wetted for the entire 28 day cure time can improve strength by up to 50%. Can you maybe qualify this "myth"/statement and maybe demonstrate differing aggregate mixes and admixtures utilizing lime. More mileage in concrete for you yet, including testing ancient Roman samples?

[@xZeroOffical]

I thought wetting is only for helping concrete to not develop cracks as it cures.

[@Will-ll4gv]

Ah, I’ll get back to you😄

[@stevenferro]

That's a myth. When cement comes into contact with water the curing process starts. you keep it wet to ensure all of the cement has a chance to react. It will never increase strength by 50%. And you don't keep concrete wet for 28 days . A week is fine. The reason why we use the 28 day because the mix design says the concrete has to reach a certain strength by the 28th day so on the 28th we crush a sample to see if we reached the designated strength. If you don't and it's structural concrete there's a problem

[@randallharbour6230]

@@stevenferro The Portland Cement Association states that concrete must be kept wet during the entire curing period. 21 days is optimal, after that point the rate of strength increase drops off. But, the strength will increase for years. When I was in school, I took a concrete class, and the data proved this.

[@davidhenningson4782]

​@@randallharbour6230 that must have been a 'hard' course😊

[@cjackmond]

There are many types of concrete, from the lowest quality (sidewalk concrete) to highest, using an aggregate of man made materials. Of the latter, un-reinforced manmade aggregates can rated at over 8000 PSI. Rebar can be of different thicknesses and different number of rebars, depending on the load that is expected. MK Diamond Products lists the following: Heavy Rebar: #6 (19mm) Rebar every 12" on center or 2 Mats of #4 (13mm) Rebar every 12" on center. Medium Rebar: #4 (13mm) Rebar every 12" on center. Light Rebar: Wire Mesh, single mat. Military fortifications may often have double reinforced concrete, where the concrete is thicker and has a second layer of rebar.

I just had a new driveway apron installed and the concrete guys said it's ok to drive on after 4 days. So far so good.

[@SupportPalestine985]

2 days: 2,056 kg 3 days: 4,151 kg 7 days: 7,742 kg 14 days: 12,059 kg 28 days: 15,007 kg Concrete from 1890: 18 tons The one after that: 60 tons Concrete without reinforcement: 750kg Concrete with steel reinforcements: 2,897 kg Concrete with fiberglass reinforcements: 2,182 kg

[@wicanhascool]

when I saw the thumbnail I thought the guy went into a concrete museum or something and stole the 130 year old priceless concrete 💀💀💀

[@RayanChiranti]

Good Iam Algerian 🇩🇿🇩🇿🇩🇿

[@Jvo_Rien]

1 2 3

[@Nellie-H]

Great examples! Interesting to watch! Imagine Philippine Hollow Blocks (Concrete Blocks) for house construction. 96 pcs are made with one bag of cement (50gk). It's pretty much like compressed sand. And then you've been told, the plaster is what gives the wall strength! LOL

[@Mykhos]

Gotta sharing that on our cement construction group ! ✅️👌

[@stevej00]

Thanks for the video. This hack engineer geeked out over it.

[@Gold_Gaming_GG]

“I like my concrete aged bruh”

[@loverboy8947]

very very extremely helpful vdo 🙏🏼🙏🏼🙏🏼

[@0_thezero]

03:19 Result

[@krzemin]

Very cool demonstration, yet I'd like to do one more with beams properly reinforced, because there were no stirrups reinforcement, the beam celarly failed due to shear, so it doesn't really show difference between steel and glass fiber

[@EricaMTB]

Looks like mortar -sand and cement. No aggregate visible

[@ALIHAIDER-gg2bz]

I love your this video most ❤❤

[@jstoney6471]

Spent 25 years as an ACI 1 ACI Advanced & ICCI Concrete Inspector..Know all of what you show. Did all in NYC 1998 to 2020 . 1000ft Down (Water Tunnel #3) to last high rise (86 stories)...8=)

[@IcekSzechter]

Those beams have been improperly reinforced. They had long bars against bending, but no stirrups against shear force. So the beams have been cut long before reaching maximal bending capacity.

[@Dr_piFrog]

Have you tried to make clay bricks; seems like they could be made very hard with the high pressure.

[@АлексейКулак-ж8з]

Проверь пожалуста присадки для П4, пенетрон и вибоирование. Вопрос очень важный, думаю почти для всех строителей. Поддержите ребята.

[@ilycode]

really intresting angle for hydrolic press , like howNot2 break test machine but inverted ^^, you could do more sample of each not only one

[@yodaiam1000]

You want to make the span of the beam longer to test the bending strength. The short span causes shear to more or less govern over bending (there is a interaction between the bending and the shear which is why I say "more or less"). You essentially found the shear strength of the beam. The unreinforced one was governed by bending since the bending capacity is so low.

[@buffayboy3340]

first time here, YO HANDS BIG ASL THAT GRIP STRENGTH CAN RIVAL GORRILAS

[@Maefdul]

How should i get a Hydraulic press into my house xD

[@chrisalex82]

Adding steel to concrete was a good idea

[@АндрійЮришинець-у6ы]

Дякую за відео. Але теоретичну підготовку треба проводити ретельніше. По першій частині: набір міцності бетоном дуже сильно залежить від температури. При +25 градусах цельсія він за пару діб набере повну міцність. А при +8 градусах будете чекати півроку. Друга частина взагалі безглузда. В другому та третьому випадках чітко видно, що руйнування зразків відбувалося через косі тріщини, що йшли від опор до центру зразка. Як тут уже писали спеціалісти, в реальному житті з цим бореться поперечне армування, яке у вас повністю відсутнє. Ви здійснили тільки повздовжнє армування, яке в роботу практично не включалось.

[@mosiondz7997]

Go on the frontline to your comrades or learn english.

[@LionelN]

Some researches raised that coffee ground added to concrete made it much stronger. I was wishing that you would also consider a block of coffeeconcrete... maybe in a next video ?

[@athgt6630]

the "don't try it at home" thingy is really funny, I bet most people have a hydraulic press at home and don't know how to use it

[@marshal_mathers]

Being a civil engineer it reminds of practical i did in my college days 😁😁

[@Mr.Strange635]

6:49 such a nice beat 🪘

[@JAAS-b7k]

Can you test how much weight it will need to pull a rebar out of a reinforced concrete column. Just a straight rebar embedded in concrete then have an exposed part of the rebar so you could anchor it to something and pull it

[@ВячеславКазаков-р5ь]

Спасибо за ваш труд.

[@krisg822]

in addition to what other said about air in the concrete samples, i think there might have been too much sand in them, especially seeing how the 28 days sample crumbled....it should have exploded, and not crumble, surely if there were air pockets in there as well, that might have contributed to the failure. Would be interesting to see same test but with a mixture without any air pockets, and with different amounts of sand. 🤔🤔

[@NorthAmericanPrimate]

They made everything better in the good old days!

[@carrot_slayer_of_patatos]

I don’t think everything

[@efimkrivov]

Честно говоря есть такое ощущение что бетон был переувлажнен при изготовлении. Механическую прочность он не набрал должную.

[@stoner27th]

the fact that you had your ancestors to prepare the block of concrete for this video way back from 134 years ago is amazing... that,... or you're a vampire or something.

[@rodrigofilho1996]

It was cut from a fortress built in 1890...

[@JamalJpg-kr2ux]

Please experiment beton dengan campuran pasir dari berbagai negara.salam INDONESIA🇮🇩

[@bobpourri9647]

I used to do this for a living. Yep, concrete gets stronger the longer it cures. I wish the tester in this video would have followed "official" collecting and storage methods: Specific material, size & shape of containers (plastic, about 1 gallon cylinder) and storage methods (in a tank of water), concrete when collected should be rodded or vibrated to remove air voids. Also, why the plywood? Just adds a weak link to the test. Plus, in my experience there are several different qualities of concrete: I have had 28 day concrete absolutely detonate when crushed in the hydraulic ram. The concrete here was pretty damn wimpy.

[@allengoodwin7043]

I honestly thought the new cement would go up faster. The old cement did NOT disappoint! 😮

[@LittlemouaLM]

It look so good😊

[@VansNarayan]

Concrete will take atleast 20 days to be solid enough

[@AlphatecEngineering]

great video! love it

[@Carbine6082]

Building a fortress in 1800 without any degree is still better than modern day builds

[@dabj9546]

What was the rating of the concrete you used? The concrete from the bridge was high strength concrete of course.

[@danielmoraes9637]

Great work thanks

[@FryerLifter77]

130 year old concrete be thirsty with this one😂

[@DXT61]

Dang, i just poured the flooring in my shop but i will be 130 yrs old before i can drive my heavy equipment on it.

[@emrebey2244]

Normall we got 7 days strength nearly 75% of 28 days strength. However, you have got 52%. So, your fault comes: 1-What is your mixing receipt? According to which standarts or specifications? I think only mixing random sizes and I can see at 0:06 not enough mixed the concrete. 2- Wooden mold we can't using due to wood can absorb water that we have to supply water for cement for it's hydration and also aggregates need water too! Also wooden molds have to oiled inside a little bit block of absorbing water and getting specimens easily. Also if your mold not good, your specimen size and texture gonna fail. 3-You cannot use hammer as vibration, you have to fill molds half and rodded a rod 25 times and fulling molds after than rodded 25 times again and getting glating the top surface. 4- 0:36 actually, you even don't need cover that only protect heat and sunlight is enough. 5- 0:29 and 0:32 you can't leave specimens in molds 2 days, you have to dissasamble molds after 24 hours pouring. Also you have to drop out the curing pool at 19 degree and potassium ionised water in it. Not getting wet before crushing. The cement hasn't enough hydrated!

[@ImmenseBRPlayer2852]

Your knowledge on concrete and your grammar is literally a farther gap than the Mariana Trench

[@emrebey2244]

@ I can accept that my English is bad but my knowledge is not. My intern and course at college is already about concrete. Are you sure about your knowledge is true?

[@ImmenseBRPlayer2852]

@emrebey2244 I'm only in 8th grade and I have much better grammar and possibly vocabulary than that

[@K_Pppp]

Люди, не усложняйте. Видео носит информационный характер, а не лабораторный

[@ricardocanos6353]

Yo trabajado con un geologo en una obra grande y nos dedicabamos a hacer las pruebas al hormigon, la maquina estaba en una sala con mamparas de plexiglás, es cierto que las muestras eran bastante mas grandes, unos cilindros de 50 centímetros de largos, tambien hay que señalar que yo hablo de hormigon, no mortero como en el vídeo

[@calebmhorvath]

concrete really be powering up over time

[@hulkthedane7542]

There is a reason, why commercial concrete units are let to dry for 28 days (and under water, chemical drying...) before being used. In that time span, the concrete achieves approximately 95% of its strength.

[@vanskis7618]

beams failed through shear in the last two test, add stirrups

[@strme1]

Please do some video with wood. What is the possibilities of Vertically placed timber 2 by 4 in house construction. Thank you

[@Zeddify]

can you change to a gear pump, the pump you’re currently using is loud

[@papercrafts-mr7iz]

1:55 nah thats a sponge

[@edwardwillis1736]

Here in Sydney the developers of high rise apartments (condos)are painting the walls after a week.

[@BenComedy-ie5hy]

Concrete be like, the older you get, the stronger

[@Raptorman0909]

I would have radius'ed the edges in contact with the concrete blocks as sharp edges magnify stress. It appeared to me that the blocks fractured at or near the points of contact so radius'ing them would have given higher numbers.

[@denysvlasenko1865]

It's not an exercise how to make the blocks stronger. It's a comparison of strength of the *same blocks* at different times.

[@Raptorman0909]

@@denysvlasenko1865 I understand that, but good practice would involve NOT imposing a limitation if you don't actually need to impose that limitation. In addition to not wanting sharp edges you also want to make sure the test item is properly centered and that the faces are parallel to the anvil crushing it. That is, there are basic engineering controls that should be employed whenever possible. Without employing those controls the data you get is going to be suspect!

[@tomweuts]

concrete reaches its max pressure strenght in around 28-30 days that u reached about 15 tons tells me u are using a very minor grade concrete around c10 of strenght value we use this typical for a working floor where later the better concrete comes over a c30/35 the concrete from the fortress is build pretty good holding up to 60 tonnes i am amazed they reached that in those early days nowadays thats considerd an expensive concrete

[@pookatim]

I found it interesting that the concrete did not appear to adhere to the fiberglass re-bar as well as it does to steel re-bar. That seems to be a problem because fiberglass bars are much more flexible than steel bars. If the concrete doesn't hold onto the re-bar, then the re-bar doesn't add much strength.

[@michaelmcknight9394]

They should use this to build buildings its hela strong

[@farooqbichumani7045]

😭😭

[@dinamiteurdinamiteur2324]

Do that for solidity of different widh or wood structural pieces under different lenght

[@neils5539]

First test is bogus. Those are mortar mixes, not concrete mixes. There's no coarse aggregate. Then you're comparing it to an old sample that is a concrete mix (you can see the coarse aggregate). Comparing apples and oranges.

[@stargazer7644]

Anyone who has had to drill holes in 50 year old cinder blocks will tell you this isn't bogus.

[@benj-cook]

@@stargazer7644 It's not that there's no strength without coarse aggregates, but if you look at the failure modes of the video, you'll notice the concrete "crumbling". Coarse aggregates help stop that by redistributing and randomizing the load vectors.

[@stargazer7644]

@@benj-cook Yes, and if you made concrete out of titanium it would be much stronger. But that isn't the point of the video. None of that has any impact on what the video is demonstrating: That the longer cement cures the stronger it gets. Making samples big enough to hold aggregate wouldn't change the results of the test.

[@benj-cook]

@@stargazer7644 The point neils is making that you missed is that what we see in this video isn't even technically concrete. Without coarse aggregates, what we're looking at is not concrete but mortar. No one is arguing that aging (drying) application of cement doesn't increase its compressive strength.

[@stargazer7644]

@@benj-cook Yes, we all understand that concrete contains aggregates to make it a concretion. But what difference would adding aggregates have made to the conclusion? None. Then arguing that this isn't concrete is absolutely irrelevant in the context of this video. The test isn't bogus.

[@RuerlKhan]

I would not call the old concrete from the armored bunker "antique" but I am not surprised it's more durable, I mean, it's reinforced concrete.

[@christopheryarnold2150]

Shame you didn't include the most common reenforced concrete in the UK that's with fibers added to the mix as well as steel rebars but a good video anyway thanks

[@Clampetron]

Fibers added to the mix is to help control cracking. Rebar is added for tensile strength. Neither has any appreciable effect in a compression test. The test of the rectangular piece includes rebar and is a test of tensile failure. The one thing not defined is the mix design. Can make a huge difference...

[@dontbetreadin4777]

So was the 130 year crete the same Crete they lay now? Should try them with less air as well

[@avc_bass_booster]

I am not surprised for the concrete, I am surprise by how those woods support that

[@Mike-bs5xi]

I try telling my builders to let it cure for atleast 3 days minimum before backfilling