Why SpaceX Cares About Concrete

How does concrete stack up against rocket engines?
When a launch or landing pad fails, it can be worse than if it wasn’t there at all, creating high-speed projectiles that jeopardize the safety of the vehicle and its support equipment, not to mention its crew. It’s a nice reminder that even the humblest provision here on earth - a solid, flat, and durable surface - is an absolute luxury on another world and of the importance of infrastructure in our interplanetary quests.
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Practical Engineering is a KZbin channel about infrastructure and the human-made world around us. It is hosted, written, and produced by Grady Hillhouse. We have new videos posted regularly, so please subscribe for updates. If you enjoyed the video, hit that ‘like’ button, give us a comment, or watch another of our videos!
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DISCLAIMER
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This is not engineering advice. Everything here is for informational and entertainment purposes only. Contact an engineer licensed to practice in your area if you need professional advice or services. All non-licensed clips used for fair use commentary, criticism, and educational purposes.
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[@PracticalEngineeringChannel]

🏗 New to the channel? I have a whole series of videos about concrete! Check them out here: kzbin.info/aero/PLTZM4MrZKfW90PdaBFt70BLTbz1bTF6Mn 🥑 Get some free meals from HelloFresh with code PRACTICAL14 at bit.ly/3wQlgvG

[@gradientO]

឵

[@AyushKumar-ov9el]

How is this comment from 3 days ago?

[@meruem313]

@@AyushKumar-ov9el I was also confused but youtube allows upload plans etc, so maybe he had it for 3 days ready in the queue or something :)

[@marcteenhc9793]

Code for HelloFresh is not working here in the Netherlands... sorry, I wanted to support you a tiny bit by using it, but the website is not accepting it.

[@nick230699]

Yay the best way to instantly ruin the climate for less then 0 Reason. Fucking the climate more then a 1000 planes from JFk airport to London Heathrow in a single failed launch

[@theknightikins9397]

Watching this after the latest starship launch and seeing the crater in the concrete left behind gives this video a whole new meaning.

[@norliasmith]

It really does... Like, you're gonna need flame diverters and sound suppression here on Earth, on Mars and the moon it'll be less needed but still a good idea to pack something like a foldable pad that can survive one launch of the Starship itself until you can get the infrastructure needed to build a permanent landing pad with a raised platform and flame diverter.

[@thatguycarmine1]

@@norliasmithBiiiiiig expert over here.

[@artnull13]

Lol proves they still haven’t learnt anything - also using cheap concrete for their pad - what a 🤡 show

[@jstrick38us]

My dad was an engineer and told a story about a new highway being built that ran into a mysterious problem. From every batch of concrete they would pour two cylinders of the concrete and leave them sitting beside the road to cure and then test. And in most cases, one would pass and one would fail, by quite a large margin. Obviously this was raising questions about the quality of the concrete, but no one could figure out why one would pass and one would fail even though they were the same batch cured in identical conditions. Finally someone was assigned to sit and watch the concrete cure (what a job that was) and they found that one guy on the finishing crew would come along and kick one of the cans to see if it was hardened yet. This guy was doing his work just about the time the concrete was starting to harden up, but not quite all the way, so he was damaging the structure of the cement in the can that he kicked. Mystery solved. I didn't hear how hard they kicked that poor guy :-).

[@zumabbar]

lmao doesn't such curing process will have an estimated time for it to be finished? but probably that guy didn't know about such and how kicking the cylinder would affect the samples

[@Filterdissman]

Ugh 😩 god that would get on my nerves. I had guys tamper with my mix while mortaring. They’d add extra water as the mix started to thicken from curing.

[@elihavalot8111]

Good story. I wonder if the SpaceX engineers have reinforced the GSE tank farm tanks to withstand the blast of thirty, plus or minus Raptor engines firing just a short distance away and only twelve meters or so above a flat surface, without any diversion system to deflect the blast away from those huge tanks, some containing LOX and liquid methane. What am I missing? There is an earth berm perhaps ten meters high between the OLT and the GSE farm, but the booster will slowly rise the first few hundred meters, exerting quite a bit of lateral pressure on those tanks for many seconds.

[@sigmasquadleader]

Timemachine, they'd X-ray it and confirm failure, but essentially yes, they'd destroy what was damaged.

[@zyeborm]

@@elihavalot8111 I think they are a lot further away than they look in the pictures. The videos are taken with extreme telephoto lenses that make depth all screwy. The tanks themselves are also going to be pressurized to reduce boil off if nothing else. That gives them quite a bit of strength from everything except high speed bits of concrete. In addition to that they will be not flight weight tanks. While Starship might be a mm or two in most places I'd wager tanks that size on the ground are going to be half inch (12mm) steel with added insulation and such like. The force exerted on them by the rocket launch would be a small fraction of the force on them during a maximum hurricane I'd wager.

[@manitoba-op4jx]

someone i knew built their own house decades ago, he had a story about how he cast his fireplace out of concrete, and used it a few times before it completely dried. one morning, he was watching TV and the inner walls of it went bang and crumbled. the stress from the heating compromised the inside and made about an inch of the concrete strip itself out, violently. he lined it with fire brick later on.

[@anomalyp8584]

interesting!

[@slevinchannel7589]

@@anomalyp8584 Mind if i RANDOMLY recommend a cool Channel like Practical Engineering or Veritasium or Its ok to be smart?

[@manitoba-op4jx]

@A G N E Z_________ begone, bot

[@nenmaster5218]

@@anomalyp8584 Veritasium is also very interesting. Same goes for Legal Eagle and Cinema Therapy. But i think the best KZbinr i know must be Hbomberguy. Well, him or R Slash.

[@rustyshackelford7651]

Yea big mistake to do that. It's not if it fails but when and how spectacularly. Should have known better really, or consulted with someone. Any professional would know never to do that and what would happen if you did. Kinda the reason we have building inspections and codes because it's a safety issue.

[@scottgauer7299]

As an aerospace engineer I never thought I'd see the glory of rocket plumes grace your videos but here I am

[@pauljnellissery7096]

Hey just curious whats your work based on and where do u work?

[@scottgauer7299]

I work on launch vehicle rocket engines at a well known space company!

[@dsdy1205]

@@scottgauer7299 Whatever company that is, you're living the life man, keep doing what you do!

[@LeonvanRensburg]

I work with refractory a fair bit and know just a little about it, such as the curing process to drive off water: 1. Liquid free water (liquid water driven off using water vapor as propellant at +- 30°C to 60 °C). It's more efficient to drive water off here when it's liquid as when it heats up the channels can be overwhelmed by steam that can be up to 1600 times the volume of the liquid water, which is why step 2 is critical: 2. Steam release of free water happens at temperatures approaching boiling point of 100°C at sea level up to +- 120 °C and can be up to 150°C to drive off all free water if the refractory is thick and takes time to get heat to the core. Rushing this forces expansion of steam inside the refractory and usually causes catastrophic failure and chunks of refractory concrete flying. After these two stages are the dehydration of alumina and calcia hydrates (removal of chemically bonded water): 3. 149°C: Gibbsite 4. 299°C: Boehmite 5. 399°C: Calcium Hydroxide All refractories in industrial applications go through a lengthy initial curing process through all those stages (different rates for the different blends of Alumina, Cement, other bonding agents, needles/fibres and agregates), heating to a point and then either soaking at a certain temperature or very slowly ramping at as slow as 1°C per hour to get through critical stages such as at the boiling point of water, adding more heat slowly to replace energy lost from latent heat of evaporation, heating losses and still heating up thick refractory. However once the initial cure is completed, you only soak for long periods at certain temperatures if the refractory got wet (exposed to moisture when cold such as atmospheric moisture or even rain) to drive off free water. If it hadn't gotten wet, you pre-heat the refractory to a temperature as close to operating temperature as possible, often also at a limited temperaturegradient, so that when it experiences full heat load (such as steel pouring into a refractory lined ladle from steel smelting or indeed a sudden and very large flame impingement), it doesn't suffer as much heat shock. This is aided by fibres or 'needles' that conduct heat deeper into the material instead of relying on conductance of the refractory itself, which takes very long as, you know, it's refractory and is supposed to conduct heat very slowly. That launch pad was one or more of these things: 1. Not dry 2. Not pre-heated (or not sufficiently so) 3. Possibly not the right material (not talking castable vs bricks, rather Alumina content, inclusion of needles, etc.) 4. Possibly not cast with expansion allowance, although that quick a reaction suggests one of the first two, but if they got those wrong they probably did this, too.

[@doaimanariroll5121]

Super interesting, I work at a zirconium dioxide and alumina plant, we use arc furnaces to melt away the Silica content, and create the conditions for the reactions to take place so the zircon silicates seperate and attach to oxygen ( I think) A lot of our product are used for refractory. The zirconium makes super high heat refractory used to hold nuclear cooling rods (also the atomic structure is right for the job) For the zirconium we need heat of about 2800 degrees Celsius, and to make about a ton uses about 4300 kilo watt hours (which takes about 1 hour and 20 mins) 4.3 million watt hours!!! We run 24/7. Because we can’t let the furnace cool down, Like you say it’s slow to reheat. A normal cycle is 1.5 hours between tilts If the furnace is off for longer than an hour the next cycle takes 3 -5 hours to warm up If the furnace is off for more than 3 hours. then to restart it we have to have 1- 12 hour cycle the 2- 6 hour cycles , then a 3 hour , then back to 1.5 hour cycles. ( though they do make for cruisy shifts) It was Interesting to read about the next step.

[@Murilo08LOL]

Hi there! Awesome comment, I also work with refractory, and on our lab we have been working with numerical simulations of this process! It is a very challenging subject and we want to make this process faster, trying to understand where do we really need to decrease the heating and where we can safely apply higher heating rates

[@doaimanariroll5121]

@@Murilo08LOL it makes sense, I mean even being able to heat at marginally faster rate would save SOOOO much power.

[@crissssseee]

wall of text

[@LeonvanRensburg]

@@doaimanariroll5121 That's awesome. We've done some work in such plants as well but mostly just supply of the Combustion system solution and recently Zircon separation as well but under nda so can't discuss that part. Your process highlights yet another modern industrial balancing act we forget about unless directly involved in the process. The mass and energy balances for these processes are so crucial and any little deviation puts the production guys in a bind.

[@zacharysweeney978]

The shot of you taking concrete out of the oven had MAJOR hello fresh vibes

[@gus473]

😂 Yes, was looking for this comment! 🤣✌🏼

[@dasKeks28]

How did they deal with this problem when returning from the moon? 🤔

[@dasKeks28]

@@kitsuneneko2567 Oops, didn't mean to post it under this comment. However, I meant on the moon, before flying back. All that moon dust and rocks had to be blown up, because they didn't have a starting pad on the moon.

[@samn6498]

@@dasKeks28 they didn't land a rocket on the moon. They landed the Lunar lander module on the moon while the rocket was still flying around around the moon. It separates from the rocket and makes it's way to the moon surface. There's barely any gravity on the moon so it didn't take anywhere near as much force to launch or land compared to an actual whole rocket.

[@neuvocastezero1838]

With a side of recessed bolt anchors.

[@davidgrosser60]

Many years ago I was camping in a Massachusetts state campground with some friends. The fireplace was brand new and made of cement. About an hour after lighting our camp fire the fireplace exploded, showering us with bits of cement and burning embers. No one was injured and we extinguished all the embers. We concluded later that the explosion was due to uneven thermal expansion in the concrete. In retrospect, steam was probably a factor too.

[@kingofracism]

😂😂😂😂

[@anomalyp8584]

Cement and fire just don't mix too well 😂

[@MarcosElMalo2]

Steam pressure was THE cause-although I suppose you could call the explosion “thermal expansion”.

[@motss5651]

@@MarcosElMalo2 No, according to OP thermal expansion caused the explosion, that's why bridges all over the world explode during hot days XD.

[@chronicawareness9986]

It's dangerous to make fires in caves for this reason.. or to put rocks in a fire to heat up, they can explode

[@TheBookDoctor]

In college I had a part time job in a construction engineering firm's testing lab. My favorite test to perform was definitely blowing up concrete samples in the hydraulic press. That clip really takes me back!

[@bising4219]

ELON=GOD. Mars=New Earth. BTC and TESLA= KIngs. Rest=Servants. Non Holders work to Power energy for Bit coin!! Elon is Einstein, Edison, Newton, and Jesus combined. HE at least deserves several Nobel Prizes. Elon has more IQ than weight of Hater's Ug ly Prius and his F at Ho Combined!! MUSK = Iron MAN who will Crush Tha .nos and Haters Should use Cash to wipe Huge A.no.s. JUST Worship Him instead of other silly god!! GOD Elon will Punish infidels!! Go Emperor God Musk!! Elon's brain chips and AI will Control and Destroy any resistance. Green Ner-ds Hate Bit coin just it use Energy like Argentine BUT Space X AND TESLA all Have Bit coin. KING ELon Himself has both HOLY Bit coin and Ethe reum. Please don't do estrogen things.

[@TheBookDoctor]

Wow those are some really bad drugs you're on. You should ask your dealer for a refund.

[@ReneePowell]

When I studied mix design for my civil engineering degree, hydraulic press testing cylinders was easily my favorite part of the class. I got some amazing photos of the results!

[@fish2468]

*YES* the best engineering channel explaining something about my favourite topic, I can’t dream for better

[@paulhaynes8045]

Are you Peppa Pig's dad??

[@PiDsPagePrototypes]

Except, No. By the time he gets to mixing his own, there's still no mention of the Martyte.

[@janenkirote7071]

kzbin.info/www/bejne/o2nKaqqmibWNrbc

[@theleafshandsomedevil1552]

so much spam everywhere wtf

[@michaelthomson81]

You looked like you really enjoyed making that one - and it was an excellent crossover between two topics I enjoy. Had not considered landing ejecta being a threat to orbiting spacecraft, so once again Practical Engineering taught me something new.

[@janenkirote7071]

kzbin.info/www/bejne/o2nKaqqmibWNrbc

[@janithl]

Now waiting for the eventual Grady/Scott Manley crossover episode.

[@GeoffCostanza]

I hadn't given much consideration to launch pad failure, and just assumed it was a non-issue, since we've been launching rockets for so many decades. That was very interesting and informative.

[@_Tuuri]

Fun to watch this again after starship blew up the pad when it did its test launch last week. Was surprised to see the rebar was still intact while all the concrete was gone.

[@nitehawk86]

I had forgotten about this video. Shows that SpaceX learned basically nothing in the last year.

[@weekiely1233]

@@nitehawk86literally not the case. It was only needed for that one launch anyway and it was the ground underneath becoming volcanic that was the issue not the pad itself This was investigated by NASA scientists due to the fact it’s never happened before

[@laveturnerjones3954]

refractory concrete is a bi*/ç to work with. most are mixed pretty dry and then have to be poured underneath a form. the one we use is about as hard as normal concrete when it's at it's normal usage temp of 1450c. ours is most often a high alumina ultra low cement mix with glass microfibres in it

[@29wildfire55]

I'm in the market for some refractory cement to reline my forge got any recommendations??

[@laveturnerjones3954]

@@29wildfire55 where are you from?

[@janami-dharmam]

Regular cement contains lots of water. You need to use fireclay bricks with fireclay cement. High silica or high alumina cements set with minimum water (commonly used in furnace lining) can be more useful.

[@29wildfire55]

@@laveturnerjones3954 western United States

[@actualperson1971]

"is about as hard as normal concrete at its normal temperature" Okay, sounds normal "At 1450 C" bruh

[@wellwelp313]

Perfect timing, was about to have dinner

[@Eastern1]

It's ( evening)5:46 in South East Asia

[@Pablotome97]

2 p.m. in Spain

[@hodor3024]

Perfect timing, taking a dump.

[@mylestechnological7031]

I haven't even had breakfast yet it's morning for me very early morning 🌄

[@Sethjxl]

OK, where you from buddy? I can't work it out.

[@dorkvadorgd4015]

I remember this moment at 0:22. I was watching live on the NASASpaceFlight stream. A couple days prior, SN8 had conducted a static fire for a couple seconds, just like this one, and it had thrown up sparks as well. When this happened, our first indication that something was wrong was not the engines stopping, as they had been a regular duration static fire, but red-orange, glowing liquid coming from one of the Raptor engines. The damaged rocket was unable to vent excess pressure from the LOX header tank, and it was later found out that had a burst disk not released that pressure, SN8 might have been lost. It was a very close call, and, if I remember correctly, valves were installed on SN8 and all subsequent prototypes to prevent this from reoccurring.

[@bigsquatch]

Something to note about the length of time SpaceX fires their engines during static fires: Static fires are only a couple seconds long. Duration burns with the engines are done without the vehicle in specialized stands. Static fires with the vehicle are just to make sure they were installed properly which they can see with the very short burns.

[@nuarius]

that is true, but at the same time, His blowtorch test that ran longer than most static fires, was also only hitting it with (a clean) ~1000ᵒ flame moving slightly faster than a soft breeze and exerting about as much force. as compared to +1500ᵒ, 410,000 lb f exhaust moving many times faster than the speed of sound :P (per engine)

[@slevinchannel7589]

@@nuarius Mind if i RANDOMLY recommend a cool Channel like Practical Engineering or Veritasium or Its ok to be smart?

[@nuarius]

@@slevinchannel7589 already long time followers lol. This is the primary contetnt i watch on youtube lol

[@slevinchannel7589]

@@nuarius Nice. May i say something to that? "Cliffside and Starship Goldfish are both COMEDY GOLD". Yep, random sentence, but if you know, you know. Oh, and even if you dont know, you can just type it into the yt-searchbar.

[@slevinchannel7589]

@@nuarius But about YT-Cahnnel overall, there's surely stuff you dont know yet and will learn-and-then-enjoy thanks to ME!! Which makes ME happy. So here, let me TRY: -Legal Eagle. -Cinema Therapy. -Professor Dave Explains. -Hbomberguy. -Viced Rhino. -Believe it or not. -Michio Kaku!!

[@Merlmabase]

"You can never have too many small concrete cylinders" I'm sure Grady's wife is 100% on board with this statement

[@mfaizsyahmi]

they make excellent landscaping blocks if I might say so myself!

[@kevinvermeer9011]

Some little kids play with plastic Duplos. Others are building fireproof infrastructure!

[@slevinchannel7589]

@@kevinvermeer9011 Hi

[@slevinchannel7589]

@@kevinvermeer9011 Excuse the Randomness but here you go, have some warm Recommendations, cause the Learning never Ends! (Thats the entire reason, yes) -Veritasium. -Professor Dave Explains. -It’s ok to be smart. -Krimson Rogue. -Michio Kaku. -Multiple channel with the word Engineering in it. -The Best for Last: Hbomberguy!

[@woods-garage]

Hey, she let him use the oven didn’t she? 😂

[@RobertWilliams-mk8pl]

I was five years old. My oldest brother and a friend of his were chewing on some bubble gum and blowing bubbles. Naturally I wanted some gum seeing that they had some. I should have known better when my brother so readily gave me a perfectly round purple ball. This is 55 years later and can remember how the anticipation had my mouth watering. My teeth and jaw rebounded off of it when I bit down with my molars. It was a concrete ball painted purple.

[@saltrocklamp199]

Kids were brutal back in the day! And I thought I had it rough getting my Pokemon cards stolen. It's like everyone born before 1980 was guaranteed to be traumatized as a child.

[@jayakrishnanm2975]

So a dislocated jawbone or a brooken tooth?

[@joelx77]

I hope your dad wailed on him!

[@lordofthesandvich171]

This reminds me of when I was in elementary school, my friend gave me a wasabi pea when I thought it was those small yogurt balls called “Yogos”

[@kakerake6018]

Oddly specific

[@nathanoy_]

that aged very well. the concrete is gone again today (first super heavy + starship launch; April 20th 23 )

[@sk4lman]

Looks like they didn't solve this problem when launching starship the other day. The damage to the pad looked insane, like a drone strike :o

[@rael5469]

Once there was a large, commercial, lift lock on a canal that they closed down to refurbish. It was built in the 1930s around the time of the Hoover Dam. They needed to resurface the concrete walls and at one point tried to use explosives to blast away a few inches of concrete. They detonated the charges and when the dust settled.....not much happened. They realized that the original builders really knew what they were doing when they formulated the concrete.

[@pvic6959]

thats a lot better than the whole thing getting destroyed LOL. but also now after this video, i learned that they may have done some invisible damage by using explosives

[@timderks5960]

No, those oldtimers didn't "know what they were doing", they just used a HUGE safety margin, exactly because they didn't know a whole lot. What do you do if you have no way of calculating if something is strong enough? You over-engineer it, and then you over-engineer it again. If you can calculate exactly what something requires, you don't need a large safety margin. If you're only guessing, you better use a huge safety margin to make sure it'll survive.

[@ClumsyCars]

@@timderks5960 and that way of thinking is why everything doesn't last anymore.

[@timderks5960]

@@ClumsyCars And that way of thinking is also why you can afford literally anything. If cars were built like they used to, they'd be so expensive hardly anyone could afford one. Also, you may wanna take of your pink glasses. Old stuff isn't good 99% of the time. There's a reason why old buildings come done, and most old cars aren't around anymore.

[@MePeterNicholls]

A few years ago there was a searing fire at multi-storey car park in Liverpool, UK. The aftermath showed how the concrete had essentially got so hot it lost all cohesion and completely crumbled away. Fascinating lesson

[@davetir]

I studied engineering in college and I love watching many of the KZbin channels about engineering, but I have definitely learned the most from your channel by far.

[@demondoggy1825]

"it isn't feasible to pinpoint a rocket landing atop a fancy flame diverter" Meanwhile, In Texas, What if we caught it with chopsticks.

[@rocketmanfossel1174]

the error is only allowed in one axis. I wonder how they are going to land that booster

[@broudwauy]

4:46 My favorite pastry: cylinders of ready-mix concrete 😍

[@slevinchannel7589]

Excuse the Randomness but here you go, have some warm Recommendations, cause the Learning never Ends! (Thats the entire reason, yes) -Veritasium. -Professor Dave Explains. -It’s ok to be smart. -Krimson Rogue. -Cynical Reviews. -Michio Kaku. -Multiple channel with the word Engineering in it. -The Best for Last: Hbomberguy!

[@dominick253]

I have been in the concrete industry my whole life. One of the foundations of society. I love it. Liquid rock. Still amazed by it.

[@itsnotyasir]

I started watching your videos when I was in High school equivalent in my country. Now I'm 3rd year into Civil Engineering and your videos are just as interesting as they were back then. I have enjoyed gradually beginning to understand the Engineering terms of your videos throughout this period of time. I hope this message finds you because I just want to appreciate your work you put here in KZbin. Thank you for inspiring me. ❤

[@Spoonishpls]

I love your new pattern of basics videos (water hammer or concrete) and failure videos (Oroville dam) and you do a great job at being sensitive when there was loss of life.

[@greglane3978]

Usually an imbedded mesh system on top of regular concrete then the refractory concrete is shot into the mesh to the desired thickness (usually 6 inches to 12 inches). The refractory concrete protects the underlying concrete and can be periodically replaced as needed. .

[@EliStettner]

She knew who she was marrying.

[@Hallowed_Ground]

@@EliStettner what lol

[@CriticalRider]

Those oven-baked concrete burritos must be the next Hello Fresh meal 😉

[@jamesengland7461]

I've made gravy with similar properties!

[@Goabnb94]

They are the concrete pills my parent want me to take so that I harden up

[@cornbreadfedkirkpatrick9647]

Spent to long in the microwave

[@kovona]

I recall using portland cement once as a binder for a clay crucible I was making for smelting aluminium. I fired the crucible in a pile of burning charcoal before it had completely dried, and a small piece of it spalled off and crack my eye glasses.

[@slevinchannel7589]

Mind if i RANDOMLY recommend a cool Channel like Practical Engineering or Veritasium or Its ok to be smart?

[@kovona]

@@slevinchannel7589 already subscribed

[@jonathangroh9591]

What a great video! There's so much infrastructure and thought behind any advancement. You do such an amazing job of pointing all that out and explaining the details. Thank you!

[@stuck_around]

my favorite part of these videos is the goofy clips at the end of you cooking with your family lol

[@slevinchannel7589]

Ok, but grammar though?

[@cmdr1911]

Water is also used to dampen the forces applied to the launch pads.

[@erikpetto3672]

I was hoping this would be mentioned, but I guess we can't have everything

[@mikeunleashed1]

Because water isnt being used for starship/spaceX

[@gbcfan204]

@@mikeunleashed1 it is. There is a water deluge system on the sub orbital pads and there will be one on the orbital pad

[@gbcfan204]

I think the water is mainly used for sound dampening

[@maitele]

@@gbcfan204 I always saw the roles as one and the same- super loud sound makes for massive pressure spikes which the water helps dissipate, lessening the energy forced against the concrete and local support structures

[@frattman]

I learned about moisture clog spalling when I placed my charcoal chimney on a sidewalk in my yard to get the coals hot. After ten minutes or so I saw it shoot up about five feet and spew red hot charcoal everywhere, as well as the concrete from an 18" wide 2" deep crater in the sidewalk. A lesson I won't forget :)

[@dpenton]

Oh man, I love your content. You explain everything in such a great manner. Well done!. ALSO- PLEASE DO MORE CONTENT ON SPACEX! I am crazy about this endeavour and there is so much to talk about. Take care!

[@Richardincancale]

In Peppa Pig her dad (Daddy Pig) is an internationally renowned concrete expert. He tests samples by tapping them and listening to the ringing - easier to carry than a hydraulic press!

[@NoNameAtAll2]

Didn't know I'd get to learn Peppa pig lore in the comments

[@mfaizsyahmi]

pls tell me that's a joke... you're really tempting me to watch Peppa Pig right now 😂

[@wednesdayaddams4425]

Daddy pig loves being dug out of concrete. Everyone loves being dug out of concrete.

[@paulhaynes8045]

But he can't knock a nail in the wall to hang a picture, without making a huge hole in the wall!

[@Martinit0]

Didn't Daddy Pig once forget to return a book about concrete to the library for 10 years? Yes: kzbin.info/www/bejne/sGe6paqNpsynaas

[@TheDieselndust]

I’ve been down to Boca Chica ,Texas. It is incredible the amount of construction they have done in such a short time.

[@AaronShenghao]

Did aliens help them? (This is a joke)

[@tihspidtherekciltilc5469]

@@AaronShenghao The term is undocumented workers.

[@TheDieselndust]

Bahahahaha

[@williamconklin161]

👽we are here to help you build better concrete slabs👽

[@TheDieselndust]

@@williamconklin161 😆

[@3rd_Millennium_Engineering]

A truly remarkable and enjoyable as well as informative series and I thank you so very kindly for sharing this with us. In fact, I am "Googling" all kinds of key words for better preparation for my future garage build where the concrete work is concerned. Married with a toddler no less, I cannot fathom HOW you make the time to create these segments and share this information; I have no children at home anymore although I drive a professionally for a living ( truck driver) and my spare time is practically nil, Thanks again Grady! Just great stuff!

[@d.t.4523]

After every launch the pad has to be relined. Patching it is a recipe for disaster. I think the "patch" idea is similar to patching a tire. Yeah, it might last, but it might not. Thanks for the video. 👍

[@NoNameAtAll2]

Well, it's better than nothing Are you suggesting re-cementing after every launch?

[@d.t.4523]

@@NoNameAtAll2 I knew an employee of the company that did the pads for the shuttle program. They had to replace the lining after every launch. It wasn't to expensive, but it never failed to hold up.

[@clairel34]

@@d.t.4523 Most of the space shuttle's thrust came from solid fueled SRBs though, which Grady talked about. The exhaust is filled with white hot solid particulates, so it also acts like an insanely powerful sandblaster. Rockets that are only using liquid fueled engines aren't that hard on their launch pads.

[@CHMichael]

In the scheme of things pouring a new layer of concrete shouldn't be a big thing- if you planed for it.

[@michaelcrockis7679]

@@CHMichael If you plan to launch 3 times a day it can become a little bit of a problem though.

[@patrickcrouch49]

Love these videos and the focus on concrete. Would love to see more coverage on in situ concrete production on the moon and mars!

[@manangupta6458]

really fascinating video topic this time Grady!!!

[@kurtweinstein8450]

I really expected that this would focus on the vibrations of a launch. I didn't expect heat as a core issue. Thanks.

[@normalicious9734]

Not something I had ever thought about, this was very informative and interesting

[@C-M-E]

Best spalling simulator for a rocket, minus the extreme thrust: molten metals from a refractory of course. =) Why I always work over a dirt/clay surface: let a new driveway absorb enough rain and spill a few drops from, say, molten brass or iron or your crucible cracks at an inopportune time, now you've got molten metal at 2400* to deal with ALONG with exploding concrete to dodge around your feet and legs!

[@Kineth1]

At least the exploding concrete won't send the molten metal splashing around even more... Oh, wait.

[@biglogdogg]

Last year we used the same refractory concrete as SpaceX in a burn building for firefighter training. The refractory the engineer was asking for required a 24 hour 3500 degree "Burn in" for curing after installation. The refractory supplier suggested the refractory they had just installed at starbase. This stuff is great, no burn in and much better at withstanding high and low temperatures.

[@timeflysintheshop]

That was a great episode! Eye opening to an issue most of us have never even imagined! Plus its always cool when you demonstrate testing stuff! Thanks!

[@jamescutchin2064]

Tremendously relevant video after Starships test flight today.

[@SpamwiseTheMeat]

I didn't know this was possible, but you've ignited an engineering passion in me I didn't know existed. Thanks for all the cool videos, I'm learning a lot

[@lucasrem1870]

you play with LEGO cranes too? found more crane fanboys here!

[@JamieStuff]

Grady, thanks for the explanations that you do on your channel. As an EE, I appreciate the insights you give of the other engineering disciplines.

[@jefff6167]

You make the complex understandable. Thanks for all the great content.

[@twothreebravo]

"Jet Fuel can't melt steel beams!" But it can seriously degrade your concrete's structural capacity.

[@flamethrower883]

And even then, steel has lower fire resistance than concrete

[@francismallard5892]

Jet fuel can’t melt steel beams, but it can heat steel beams enough so that they weaken and bend.

[@JaxMerrick]

@@francismallard5892 As Trenton Tye from Purgatory Iron Works said back in the day.

[@MikeK-js3hi]

Concrete flame deflectors can also make use of ablative materials to prolong their life, though we've been trending away from concrete towards sacrificial steel plates or water-cooled steel structures depending on the application. Testing, launch, and now landings each involve their own service environment-specific requirements to consider during design; time of exposure to thermal loads, size and intensity of those loads, frequency of use, and maintenance schedules and costs.

[@bahopp9872]

Well done Grady. Thanks for posting.

[@bobbyrp9881]

Thank you Grady for dropping another high quality content for us curious minds.

[@crowman5936]

When you use a torch like you did you need to back up the tip around an inch to a inch and a half more than you had it to maximize the flame heats sweet spot. Just a tip from a plumber.

[@pravi5065]

I simply love your videos. Especially those videos where you find the supposedly little things and share very interesting knowledge and insight! Thanks for your consistent work on all of your high quality videos! :)

[@joshuadesouza7647]

Perfect - great description and introduction to the matter.

[@notmuch_23]

"That's one of the reasons we use [concrete] in so much of our buildings and infrastructure: it doesn't burn." Chlorine Trifluoride molecules: "Allow us to introduce ourselves."

[@sudoscience5084]

Well in that case nothing but god and/or a good pair of running shoes will save you.

[@Hyrum_Graff]

How on earth do you make/store chlorine trifluoride? That sounds even more terrifying than O2F2 ...which would probably also set concrete on fire.

[@notmuch_23]

@@Hyrum_Graff Ask the electronic companies that use it for cleaning chemical vapor deposition chambers

[@sudoscience5084]

@@Hyrum_Graff ​ @Hyrum_Graff apparently it's storeable within certain metals if they are prepared correctly; if you're very careful apparently you can form a layer of fluorine-metal compounds atop the metal that stops them from reacting. Although of course if that gets worn off or damaged then you'll probably have a very, very bad day.

[@TheSeppentoni]

Do you remember that scene in James Bonds Moonraker when they are traped in the rocket pads exhaust room? I saw it as a kid and had nightmares for weeks beeing trapped there myself. So thanks for bringing that up I guess 😉

[@hubriswonk]

I do! And that table that folded flat into the ground was amazing as a kid! And something else to think about................Doesn't Elon look a little like a younger version of Drax?

[@slevinchannel7589]

Mind if i RANDOMLY recommend a cool Channel like Practical Engineering or Veritasium or Its ok to be smart?

[@RobertSander]

Thanks for this video, very interesting, I enjoyed all of it. You talked about things that I had never thought about.

[@heathholman2552]

Excellent video! Thank you for continuously charging your expertise

[@Dingomush]

I’ve had my fill of refractory cement products in the casting unit of a steel mill. Had to spray and hand finish the inside of tundish boxes. That’s the box that the steel coming out of the ladle goes into before it goes into the mold area. That way when one ladle runs dry you can swap them out without stopping. I don’t know what was in that mix that we used, but that stuff stunk sooo bad!

[@laveturnerjones3954]

So damn true! The calderys dryram we use smells so goddamn bad

[@phailupe2941]

Not as strong as kerbal launch pads, I can put 50 mammoth engines on those bad boys and they won’t break

[@pranavghantasala6808]

Oh sure, they may _seem_ indestructible, but fire a *single* Oscar-B fuel tank fast enough at it and it crumbles like a dry cookie

[@phailupe2941]

@@pranavghantasala6808 so true

[@pranavghantasala6808]

@A G N E Z_________ SHOCKING!! YOU WILL NEVER SEE AVOCADOES THE SAME WAY AGAIN!!1! kzbin.info/www/bejne/moLaZapvjMyLmbM

[@TCGill]

Thank you for the video. I learn't a lot more about the material we see around us all the time. Great work sir (and team)

[@Mediumdave1983]

Yesssss! The Practical Engineering / SpaceX mashup we've all been waiting for! :D

[@coenogo]

As someone studying Civil Engineering, and with hopes of applying it in the Aerospace industry, this video is absolutely perfect!

[@slevinchannel7589]

Mind if i RANDOMLY recommend a cool Channel like Practical Engineering or Veritasium or Its ok to be smart?

[@jimsvideos7201]

Speaking of surviving high heat, apparently the motor in the Sprint missile had zirconium staples in the propellant to conduct heat into the unburnt layer so it wouldn't explode from the thermal shock.

[@ryanjohnson3422]

I have literally learned so much from you today ! Thanks for the awesome content 😄👍🏼

[@brandonshane8321]

Awesome video, as always Grady! thanks!

[@AaronShenghao]

This is also one of reason why there are water towers near launch pads and dump water onto the pad. For one it absorbs the sound, the other is cool down everything on,under and around the pads. Also, China landed a quite large probe with a rover on Mars going all the way down using reentry rockets. Satellite image shown the blast area in the ground is similar to Curiosity rover’s. So it isn’t that big of an issue on Mars. (Technically it is the latest rover/probe landed on Mars, after NASA’s)

[@lukephillips5618]

Curiosity's landing affected the ground much less than the Zhurong's did. The Zhurong lander made a small crater under itself, which can be seen here. kzbin.info/www/bejne/l4S2pGl8m6efnbs

[@theyellowdart6039]

I don't want to tell you what topics to pick for your videos, I'm not your boss, but I do want to say 'HELL YEAH' to learning more about space-specific engineering.

[@jakespivey3716]

the PracticalEngineering Channel has become my new favorite channel, these videos are great.

[@optimagroup11]

The SpaceX Mechazilla grabbing system obviously protects the launch pad, something I totally missed. Your explanation of the SN8 explosion and description of the special recipes for concrete used in pads was excellent. A major reason I love watching your episodes -- expanding my horizons. Over the years, I've noted the many types of concrete used on freeways, sometimes with poor effect, especially one section which was quick-drying and made for an awful surface when vehicles drove over it. Thanks so much for taking us into your 'laboratory' and the highly instructive demo. Look forward to your next video!!

[@filanfyretracker]

Lunar regolith is very coarse stuff, I bet it could make some pretty amazing "sand" for a concrete mix. Of course getting the cement there would be problematic due to the as mentioned weight issues.

[@Technomancr]

"Why SpaceX cares" is a better title than what you had before, but I would have watched this eventually anyway. :)

[@itemushmush]

what was the original title?

[@janithl]

@@itemushmush "What are launch pads made of?"

[@av8orbob829]

Great stuff Grady. Good on ya...

[@Watchyn_Yarwood]

You have the most interesting and informative videos! Thank you for sharing with us!

[@jubb1984]

This was super interesting, something i have never thought about a whole lot.

[@KnowArt]

oh my, one of my favourite youtubers covering one of my favourite companies?! it must be Christmas

[@Monkey80llx]

Ditto!

[@beansinacan500]

These kind of engineering videos are awesome. You're always putting out something that teaches me a little bit more each video. Thank you

[@freundron]

Your comment on required landing / launch infrastructure is very thought provoking. It'll be interesting to see the solutions put forth!

[@joshmyer9]

I feel like Grady should adopt a riff on Ivan Miranda's "Spacers!!!": "Coupons!!!" (or "Samples!!!", but that's less fun)

[@Extremecheesing]

Civil engineering husband “Honey can I use the oven I wanna bake my concrete?” Wife “whaaaat”

[@hubriswonk]

I would never allow that in my oven! And I am a man! hahahaha! My food does not need to be exposed to baking concrete of any kind!

[@Xatzimi]

I loved this video, it combines space and the more humble engineering that I always took for granted. If you do more like this, perhaps have a Scott Manley collab?

[@switzerland]

Two of my favorite topics just crossed, awesome!

[@bernhardjordan9200]

Thanks for the metric

[@markhottman2652]

That pesky Anhydrite, cement, always adds strength and unit weight to our mix designs. Refractories have always been used in smoke stacks, allowing for HIGH temperatures with out spall, delaminates, or failure. For as dumb as concrete is it sure has some complexities. Cheers to: SCIENCE!

[@its_jjk]

You have one of the most informational and interesting channel on KZbin. Thanks for posting!

[@jwstanley2645]

Untested hypotheses are great fun. Testing them is hard work and often frustrating. Thanks for the video.

[@zarfmouse]

This raises the question: how DOES SpaceX intend to land Starship on Mars and take off again with only loose regolith below? If chunks of a landing pad can be destructive at launch then why wouldn't chunks of blasted regolith also be destructive to landing or relaunch?

[@user2C47]

SpaceX has shielded the wiring since then.

[@loganwalker8537]

Also mars has more gravity and a atmosphere, so its better than moon landings

[@zarfmouse]

@@loganwalker8537 I'm not sure how that helps. It helps prevent the "debris blasted out at escape velocity" problem that the moon has but it doesn't help with the "on earth we need to build launch and landing pads out of specialized concrete or else our ship gets damaged on launch or landing" problem.

[@loganwalker8537]

@@zarfmouse what i mean is, the moondust is incredibly sharp because the moon has no atmosphere, meaning no wind, no wind means no erosion on the dirt or moon dust, mars has all this though so itll be like landing in the desert Which doesnt help but its better than tiny sharp needles flying out atescape velocity

[@loganwalker8537]

@@wadewilson6628 you do know that you dont need much fuel once you escape the gravity of the planet right? You simply float through space at what ever distance you stopped using the engine thrust after escaping the planet

[@nosegrindv4951]

i know that adding 0.1% graphene by wheight can increase concrete strength by up to 30%, but i wonder what effect adding it has on heat resistance.

[@Keister87]

Thanks for another great video, Grady!

[@poormantravelers311]

love this episode I'm a huge fan of space and rockets and your channel nice little clash!!!!

[@addisonmartin730]

Elon Musk said in his interview with Everyday Astronaut that the launch pad was harder to build than the rockets and engines themselves

[@slevinchannel7589]

Elon's Personality worries me though... ...

[@pauljnellissery7096]

@@slevinchannel7589 oh please....hes not as bad as the media portrays him.

[@michaelcrockis7679]

Looks like the stratospheric blimp-launchpad or railgun satellite launchers were not that insane ideas after all. You can not destroy concrete if you don't have one.

[@slevinchannel7589]

@@pauljnellissery7096 He's also as competent and epic as HE wants to be portrayed, though? ?

[@slevinchannel7589]

@@pauljnellissery7096 Actual Essays about him portray him as very bad... because... you know... facts?

[@donnkelley6823]

You should get a good look at how the Space Shuttles pad was done back in 1983...... We didn't have all mixes we do today. There was a 30ft radius at center of all three engines that was 8in deep. When the rest of the flame bucket was done we went back to pour the 8in recess..... It's the only time I've done (Vacuum process concreat). Form mounted vibrators, vacuums hoses 2ft on center. It was pretty trick for the 80s..... I only wish I knew then what I know now I would have paid more attention to things like mix design. Let's face it I was a 19 year old apprentice an just kept my head down an mouth shut...... Still got to do an see things that only a handful of men ever will GOOD TIMES

[@pamdemonia]

That's amazing!

[@tullyselengut7185]

your really good at explaining things thanks we need more channels like this

[@hgbugalou]

Great timing Grady - I am working on making a concrete firepit.

[@jortand]

I can just imagine his wifes reaction when he is putting concrete cylinders into the oven haha

[@scottwhitesell5476]

It's probably preferable to a transmission in the bathtub.

[@tomboyd7109]

Cookies!

[@General12th]

She probably loved it as much as he did.