Top 10 Myths in Concrete Construction
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- Опубликовано: 28 сен 2024
- Get a candid look at ten popular, but mistaken ideas that still exist in concrete construction. Using examples, interviews, and demonstrations, this revealing video from the Portland Cement Association exposes and explains the most common misconceptions associated with the cement and concrete industry. The video is designed as an educational training tool for workers of all experience levels. Running time: 17 minutes © 2005 Portland Cement Association
Reminds me of the training videos that the military and civilian servants are subjected to. Usually after lunch and in a darkened room. It's almost like an experiment to see what percentage of the class can remain awake!
Mark Jones and sitting next to some guy with horrible BO. Lol
Unfortunately, trying to educate some people in the industry is like beating your head on concrete.
Stop trying to sound special. Every and any job needs knowledge and training. Ur just another slave like everyone else
ruclips.net/video/4lbI-cBhkm8/видео.html
6:00- BELIEVE ME.. the terms "over finishing and premature finishing" haunt ALL of us.. not only concrete finishers. :(
not sure about "over finishing" there champ :D
14:56 Seems this video is 16 minutes longer then needed.
I had to go into settings and watch it at 1.5X speed. I still nodded off.
I liked that almost all of the myths had a practical, counter recommendation in the body of the video. Also came a way with a greater respect for concrete application.
MrNateSPF has
thanks
I just put this on for my toddler's nap time, worked a treat! Thanks uploader.
LutonMassif don't be surprised if he/she wants to go into the construction industry when they get older
I attended a concert school in Texas years ago , 50 some , things have changed I know, this video was a great refresher . I was taught on the job , boy was I shocked to learn a lot of it was incorrect . Worked mostly on federal jobs under precise specs , some in earth quake zones 5 , both of these are quite a different horse of a different color . Remember, different place different rules.
The acting though, perfect
Old video but still very true today. The only problem I have is not added water. In a state were it is super hot almost everyday of the year, adding water is sometimes the only thing you can do.
yup i agree and for that reason if the job required 3000 psi i ordered 3500 psi
Half Star Films I live in Nevada, so I know what you're talking about. Back when I was running a triple trowel on a pour one day, the wind was already kicking in by 4:00 am, by the end of the day & 38000 ft. they had figured out the wind was sucking 300 gl. an hr. out of the slab! Yea, a big part of it had to come back out.
Half Star Films If you lay the nylon under the concrete it will dry much slower and concrete be stronger .
smash that thumbs up button if you looooove concrete
hahahaha
Another myth they forgot: Concrete contractors make great actors!
@Colby Erik What the fuck has that got to do with concrete?
Great viedo!!!!!!!
as a concrete amateur, I learned an aufull lot!!!!!
Sadly, there are idiots in the concrete construction business that make these very mistakes and cause VERY expensive problems for the property owner later on. These same idiots give those folks in the business that ARE reputable a bad name.
They also sweater that they are correct and will argue that they know what they're doing. This video is old but still true today.
A Curry True story, there are so many that if it were not for the union couldn't even pass for a journeyman.
this is because ....and i quote...."i dont have to live there".....or "you cant see it from your place....dont worry".....tragic.
If i was sober I'd give a fuck.
Looks good from my house
Very helpful info , not many people remember to check that agregit is smaller than one 1/5 the thinnest part of concrete
This all makes alot sense now ive been a groundworker for about 3 years and still learn and understand new things everyday about the most basic of things like the concreet itself
If i ever saw a finisher walk on a placement to determine when to finish, that would the last job of mine he ever worked on!
I have seen that crack a slab after curing.
You walk on it with the trowel machine anyway DUH
What is the correct way to tell if it is ready?
@@DigitalAwareness feel it with your fingers
Great and informative video, thank you for the hard work!
There's a real art to the whole process. I wish all concrete people watched this because I see a lot of shoddy work in the some of these new developments.
larjerr No many good tradesman left .
They always joke and say “job security” why not make it good u know
Hm. They missed a big one. MYTH: Every load of concrete you get from a Ready Mix company will be a fresh load. FACT: Some Ready Mix companies sell 'old concrete' IE 'hot concrete' to make extra profit. The only way to make sure your local concrete service is selling fresh concrete is to spy on them and see if their trucks are always dumping any left over concrete from the previous delivery and washing out when back at the plant. IF you see trucks with their drums turning going into the plant, go straight into the fill area, then drive back out and head to a new delivery, there's a good chance they're selling old concrete. Selling old concrete is a detestable practice, because each load gets hotter and so hardens faster, leaving less time to work it. Plus more and more water must be added to keep it from hardening in the chute. It's gets crazy the longer the process is drawn out.
dkeith45 its called stacking loads a lot of company's do this on foundations
It probably wouldn't matter for footings, but flatwork? Sidewalks, driveways etc? I once had to deliver a load of concrete to a home-owner doing a sidewalk, late afternoon, with concrete so hot, I emptied my water tank into the load just to get it to come down the chute, and before half of it was unloaded, it started hardening in the chute. I had to dump the rest of the load on the poor saps lawn so my truck wouldn't be fucked up. And my boss expected that homeowner to pay for the whole load to, 0_o. That's how bad it can get. Most contractors that used us, because we were cheaper than all the other ready mix companies, would only order from us first thing in the morning to just past noon, because they knew there'd be less chance of getting old concrete in their loads, or if they did, it wouldn't be too hot to deal with. With the exception of a few who had large crews and NEVER got old concrete. Never ever. I imagine they had a talk with my boss at some time and told him they'd hurt him if he ever did that to them, lol.
MYTHS
1.) Concrete only last 5-6 years.
2.) You need an aggregate like marbles.
3.) You can't add dyes.
4.) One hour of setting is too early to carve your initials.
5.) You have to wait for it to stop raining to start pouring.
6.) It's tricky to make full size sculptures.
7.) You need a wheel barrow or a hopper.
8.) O'Dell can't get it on.
9.) You have to have a screed or float.
10. You need water for the mix.
Must see video for anyone involved in the concrete industry. Thanks PCA.
Myth #11: Slump has any bearing at all whether concrete will pass strength tests or not. Yes, added water makes concrete less strong. Water reducer, (Plasticiser) some retardant to keep it from setting up too fast, and if you feel like working really fast, add some glenium. Added on site. Comes out like soup. No added water, it makes a dry 1-2 slump into about a 10 or 11. But... you got @ 30 minutes max before you'll start having problems if it's not in place.
There is so much to consider for poring concrete. I poured 2.2 yards for a 12x16 pad for my shed with my wife. I had a slope of about 12 inches on the 12 foot side. The digging was a nightmare. Clay, rocks, bricks and roots which pulled back each meager shovel full. I finally got frustrated and shored up one side using a 2x12 as a form board. I thought this was going to be a disaster. It has been over twenty years with no cracks. I have been looking for a good source book on setting proper forms. Do you know of a good one? Thanks for posting the video!
+robert morin Just make sure your forms are straight, level, plumb and well-braced. Unless you are going into professional work, $90-$150 dollars for a technical manual is needless. It sounds like you did a great job on the 12x16 project. www.concreteconstruction.net/table-of-contents/magazine.aspx has always been one of my favorites for seeing what is possible to do with concrete, if you want to look into the concrete construction field.
My first recommendation for any concrete work is to have a stable base to place it on.
+robert morin plumb leval square. and brace it more than you think you need. once a form starts to push. its almost Imposible to push it back!
That's a slope of 8% generally you want a slab to have a slope of 3-5 max
TheTomBevis thanks for the link your awesome
One thing that has always intrigued me is why plastic ties are not used to connect reinforcing together prior to pouring the concrete. Extensive enquiries here in New Zealand have always drawn the same response: it is not known what the structural importance of steel tie wire is, and it is not known what the objection to plastic ties might be. Can you throw any light on this issue? Regards from NZ
Kind sir, there is no structural integrity or advantage in tie wire. The amount of the tie wire used in structural concretes design is to keep the Rebar in place at the spacing and coverage specified during concrete placement. Rule of thumb double your wire on heavy mats or columns and high traffic areas. Single ties are sufficient for flatwork such as slab, mesh and light foot traffic. Gauge 15 for bridges and 16.5 for medium to light work.
@@steeltown416 Many thanks for this comment. Thought so.
@@steeltown416 This is what I have thought for very many years now. Really strange that no one in the local concrete industry can confirm this. Thanks so much, cheers.
@@evanpenny348 No worries!! Greetings from California! What also is a good indicator that Tie Wire holds no Structural integrity is that you will not find it mentioned in any of the Structural details called out in the plans. Which means it's not taken into consideration when the engineer makes his calculations. It's just a industry standard tool. Means and method for the contractor to secure Rebar in place. Similar to precast concrete spacers that hold up the Rebar, just a means to hold the bar in place. Cheers 🍻, From a Ironworker on the other side of the world.
exelent vid.....wish you had covered salt exposure better.....and ferro-concrete cancer.....and a bit on pouring in extreme heat.
yes im an aussie....cement drying too fast is standard here....though big pours have it sorted.
That was very informative.... thank you!
Georgia DOT used to place slab repairs starting at midnight and have Interstate traffic back on it five hours later in metro Atlanta. Try doing that with your 4+ inch slump, you guys.
very informative. thank you!
Since this video was not supposed to be reproduced I feel deliciously naughty watching it
old school rules...lol.
im playing it over closed circuit TV
if pouring at a 5 or 6 slump,weaker by just a little than a 4 slump...JUST UPPING YOUR SPEC FROM 4000 PSI TO 4500 is cheap by adding a half sack per yard ...at a $5 yard cost!!!///in the U S,we have made EVERYTHING so complicated that our costs are crazy...i believe in vibrators and 4500 psi concrete...and rebar UP OFF THE BOTTOM OF THAT SLAB!...tearouts where old rebar is laying on the bottom of the slab!...are so common....THESE 3 THINGS are easy,cheap and important..
Length of time is perfect. Great edu
This is by far the best top 10 myths in concrete construction I have seen to date
This is a lot more complex than it needs to be. Engineers have a safety factor, batch plants have a safety factor, and on down the line. If Losing 200PSI is a problem just buy a lot stronger mix to start with, the difference in price is minimal compared to a failure. Concrete is cast all over the world by 2 guys with a shovel and some buckets, yet the results are overwhelmingly satisfactory. Do not try to cast a suspension bridge this way, but a house slab is very low tech.
So, ya he has some valid points, getting it wrong is not as bad as he suggests.
It's good to have rules of thumb and calculated values but nothing beats experience!!!
No mention of how much trouble water reducer will get you in and how hard it is to get a flat floor with plasticizer
Concrete studies in 2019 are still underway.
What else will we learn about it tomorrow.
Example, Bamboo was used hundreds of years ago in China, as rebar. (no cracks - no rust).
Your concrete professionals of today in the USA don't want to talk about that. I wonder why ?
is it necessary to pour water in newly build pillars and concrete?temperature=26.5'c?what if not poured water on it?
Oldie, but goodie
U go by p.s.i 3000 3500 4000 the humidity has to do a lot with it and u can put water in it there's water reducer u can use to make slump rader to pour and there's other ways just make sure your grade is right and compacted and joints saw cut in it u'll be ok
Still using calcium chloride in the US? That stuff does not prolong the life of reinforced concrete. It acellerates rebar corrosion.
Yeah, pretty stupid, right?
dykodesigns2yt
Here in the United States calcium is not used to prolong the life of the concrete. It is used to accelerate the set up and cure time of the concrete.
Joe Riley But I suppose it's not used on reinforced concrete? Here in the netherlands we had many issues with precast floors from one or two manufactures who used that stuff in the 70's to speed up their production (they could not keep up with the demand and started cutting corners). A lot of those floors where used as ground floors above crawling spaces, and they often got rebar corrosion due to the use of calcium chloride (which is now more or less banned for use on reinforced concrete as the eurocode only allows really small amounts of it). It became a serious problem for home owners and the like as repairing these precast floors can be expensive.
Calcium chloride? That's a posh name for cooking salt.
That would be Sodium Chloride.
Jack and the beanstalk , and the tooth fairy are good tales. They are popular stories but not quite as popular as like the Bible and Santa Claus and Humpty Dumpty, Bigfoot, the Loch Ness Monster
Myth 11, this video is good
so the ways to increase slump onsite are still add water.
when you order concrete and it turns up coming out of the truck in huge blobs dry as all hell lets face it. your gonna wet it up.
tubestick00 add chemical agents
Wayne Robinson yea right.
Wayne Robinson admixtures are amazing tools if you know how to use them.
A big point is; using superplasticizer you don't need to add as much water. You'll never finish a pour if you need to pull it off the chute with a shovel, but the admix can grease it up. You can add less water, not none.
Guys like you keep us structural engineers up at night. NEVER add water at the site. If the mix is not workable, it's the redi-mix suppliers problem, not yours! Be prepared to add water reducer or super-p but not water. Period!
0:20 Then why in the world should we believe anything in the video?
This is the U. S. of A., where you have a right to believe whatever you want. It seems the Portland Cement Association believes in protecting themselves from clever rapacious litigious jerks. I believe I'll have a beer.
Where is the test at the end of the movie? I was ready to ace this one...
Very good information
do a video about Pervious concrete tne myths ect
myth pervious is the greatest. fact. it is not. sub divisions in the northwest have been using it. but unless its kept clean and clear it wont work as advertised
New subscriber from Davenport Iowa
Lots of guys on youtube are doing quite a bit to keep some myths alive.
Didn't answer or touch on the use of a vapor barrier (10 mil plastic) and its conflicts with concrete finish and its proper installation in stem and spread footings in a monolithic pour.
what is this?
How can I get a job in construction company as fresher.
9.29 this is also advisiable when building near ocean salinity of soil
I went from watching a video on non linear time to this. How the hell did I get here???
theory meets guesswork
Lol. The wonders of just letting it go to the next video. No telling where you will end up. I am sure there is some Quantum Theory to govern it, but you would be hard pressed to find it.
Answer: youtube
a good theory needs a good foundation
how did i end up watching this?
Also is there a part 2. i need to know if there are more mistaken ideas
Watching this video is like watching concrete dry
I think myth six was in Schindlers list, where the female engineer was shot because the nazis ignored her advice and they botched the pouring of cement
nosuchthing8 I
The so-called pros are just plain silly sometimes. I would love to get them out on a job in mid-summer with the sun bearing down. We'll see how long that 'no adding water' bull lasts.
lol heard dat
I rarely put anything on the ground less than a 5, and most of the time it's a 5.5 or 6 & have never had to replace anything not to mention jobs I'd done 20 or 30 yrs back, I still see quite a few because they're at friend's houses or businesses I frequent! It's a 100 degrees, this shit's gonna go fast, fuck yea. . .give it another five gallons cuz we're not scrubbing!
on some jobs i have been on their was an inspector monitoring the water used also 3 cilinder samples were taken on each load and they were tested . if truck got to dry and no more water aloud it was sent back . of course you dont have these issues with concrete inspections on residentual or even most comerciaal jobs
a light mist will compensate.
kreteman777 yup been there... then you sometimes have to deal with the truck drivers sayin they only got enough water to wash their chutes...grinds my gears😑
Now things r starting to make sense
house slab knocked back by inspector because builder took photos of concreter add water to the mix. the slum weaken and have they ripped the salt and start again. lesson to learn. order your slum higher so if you add water it will not affect the strength of the concrete.
I've been a working construction for 25 yrs some these are myths some are not. There are what we call engineering and architectural standards, and in the field standards. At no time did I see anything that would help anyone in the field when dealing with a very hot load or when concrete trucks stop coming halfway through a pour or trying to talk to a concrete driver or concrete office about what you need, when you need it, and where you need it. This video gets a thumbs down for me
A man making a living as a concrete contractor knows all this shit and someone who isn't doesn't need to.
Curling? Never heard of it
slump is?
It's 2018, unless one absolutely needs it, (in certain applications) a Barrel truck should never be used. On site truck is the way to go. Why would you risk getting a hot load, or the driver fucking the mix up by adding too much water. Because a barrel truck can't add sand n cement......anbody who disagrees is not very bright
Concrete Johnny. Guys career was set from the beginning by his parents. 7:49
A myth involves the perennial philosophy, nature of duality, transcendence, and is essentially a guide to understanding consciousness and manifestation in human form through symbolic wisdom. It is not a lie, falsehood, or not understanding. You are talking about mistakes, or misunderstanding in your ten point program, not myths.
wow i am impresed ya'll know your concrete.
so i guess i am an artist in the job as well as in every day life.
When pouring concrete do you take into consideration the curvature f the eaarh the math is 8inch per mile squared. 666 feet per 10 miles. I had never learned of this curvature. I've always built stuff on a level plain.
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Plane.. unless you work in Kansas
Amazing how the old world [ romans] could make concrete that has lasted a 1000 years and is still strong . But now the concrete companies can't get their stuff past a service lifetime of 50 years before it starts cracking and cumbling . It must be called profits .
Roman concrete also never saw the kind of stresses that we put on our concrete. Roadways in particular.
Actually it's the rebar. Roman concrete was never reinforced with metal bcs they never had to deal with the loads we do.
7:36 you think we should cover this concrete with some blankets or something? Wtf hahahaha
This video needs an update, to cater for product containing high alumina..
As it's being sold as, as good as Portland, without paying for the brand name.
Another myth!
Someone needs to do a TL:DW on this, it'd only be a couple of sentences.
so... avoid water?
Nice!
I worked for several concrete companies as a mixer driver for a long time and seen every job there is.
Contractors and homeowners in RDU region in N.C., reply for the best concrete contractor in the area. Stevens Concrete Llc
11:25 Chris Farley today had he lived
What about putting dishwashing liquid in as a plasticer?
Soap is used to add air to the mix....much different than super p....super p is used for less water, but sets up faster in hot humid weather.
water reducer at the sit hu......yea rite
spraying concrete down with water after pouring and finishing is something from the 80s lol the new mixs out now dont require that bullshit
9:50 I'm still triggered that they never mentioned the ways on how to thaw frozen ground
It's rarely done, at least in the midwest. The plant I worked at for three years mostly shut down once the ground started freezing up. Then they'd lay off almost everyone and only do pours that were indoors, like at a steel mill or some such.
cover the pour area with concrete blankets. the ground puts off some heat, even in the winter
In the Midwest the ground can freeze down to 3 or 4 ft in an extreme winter, one year in our Iowa area we had lots of rain in the fall, then temps went below zero for a couple weeks before the snow came, by spring the frost was as deep as 72 inches, causing water lines from street to homes to break, or even homes with well heated basements having to keep water dripping to avoid freeze ups, my own water was coming out of faucets at 33 degrees, that was one of our most extreme winters ever as far as cold temps
That made more issues all that summer as everything thawed out, some areas had to replace sewer lines as well as the ground thawed some areas turned into a quicksand like surface, due to being so wet, ground wouldn’t even support a person walking on it in these areas.
I use sunshine.
Close cement concrete subject. also reinforced cement concrete. O
I thought concrete was full of dead bodies and concrete dust was the cremated remains of dead children - is that not true then?
#1, Not to mention aggregate type.#4/ 6:28: Delamination only occurs when lamination has occurred. Catching edges by hand when working with a power trowel will cause laminations if the surface around the edges are "closed' and the wop-wop machine impinges on the hand troweled areas. I fought for years over who has the right of way. I finally gave up and just started flat-troweling edges then walking away. If the power trowels couldn't get it closed in time, tough titty. Portland ore. Union finishers can't hand trowel to save their lives. These seem more like Bob Villa-type homeowner mis-conceptions rather than myths in the trade. NOBODY with half a clue pours on frozen ground. Number 8 just freaked out Somero.
There are so many union finishers that if it were not for the union, they'd never find a job, everything they fuck up is "It wasn't me" or "I don't know" or "what rolled edge? And as for the short hand floats & swimming pool trowels that they think they're not leaving any marks with, well you know what I'm saying, the idiots talk a good game before mud hits the deck then have some excuse for all the chatter marks, missed edges, steps that look like loaves of bread, crooked joints & cat faces that sends em' driving home thinking they actually know what they're doing! I think I can retire in three more yrs., not that I've saved any cash but at least I can get away from the retards, I think I hate the job I spent so much time learning how to be one of the guy's that most every other finisher in town would say "he's a good fuckin' hand". The ones that know me do, the ones that can't finish might not because they don't like the way I pointed out all their fucked up shit (you get tired of fixing it every day) but I'm not sure if it's much of a reward or not! Know what I mean?
chuck lane
I got tired of walking onto a new job and having ignorant cunt's think I needed to prove something. I'm fifty now with half my pelvis and one hip made of titanium and ceramic, fake knees and a bionic shoulder. Plus a bunch of little shit like fucked up vertebrae and wrists. Now I live on disability payments and am not allowed to have more than 1,000 bucks in the bank. Oh, yeah. I'm a vet, too. Twenty bucks an hour was top dollar for a finisher when I started laboring in the 80's and it was top dollar for a foreman when I was forced to quit in 2006. Fuck work. it's a scam.
I hear ya, I'm 59 & use my mag as a crutch every time I get up off my knees, I wasn't as good on a speedway bike as I am with a trowel. As for being a vet; Thank you sir for risking all for our USA, too bad it's turning out the way it is.
Thanks for keeping the trade from going to shit, Chuck.
omg too long too slow. just get to the points
I don't need to watch this video, the pimply faced 1st year engineer on my project knows everything about concrete. He learned everything about construction in his books. He will tell me how to do my job.
34 years finishing concrete, I will pour and float 10 yards in less time than it takes to watch this video, Most of this video is impractical and ridiculous to say the least.
Myth One starts at 1:00. You're welcome.
Everything said on here protects the concrete plant....notice its always someone elses fault for concrete failure never the concrete mixing plant...that never came up one time
@ Brad R Yeah, like the selling of old hot concrete mixed in with new loads to make extra profit for the plant boss. Very few people know of this nasty practice. And the only way you can find out if it's happening is to spy on them.
I was hauling 10.5 yds. of gunnite for a pool job with a screwed up mix design. Instead of putting in 1 gallon per yard it put in 1 gallon for the whole LOAD! The manager came down after I hollered and figured out what happened and we got it slumped out. Went to their other plant and it did the same THING, 1 gallon in 10.5 yards. Was trying to get it wetted up when the big boss told me to just go. I told him to stuff it because the load wasn't right. He mumbled something about the plant always standing behind the drivers, like I knew it was the truth. I hollered that I'd leave when it was right and I did. He was gone when I got back good thing because I was hot enough to fry an egg on. Transferred out for a quarry job shortly thereafter and he got fired shortly after that. The guy that helped me got his job. No more c.d.l. for me.
The video is about myths, concrete mixing plants making mistakes isn't a myth.
Brad R They put so much chemical in it they don’t tell anyone so it doesn’t dry in the truck .
plastic metal bars
I often ask myself if there is a easy way to recycle concrete for the average contractor replacing sidewalks and driveways.
Being a cement finisher brought me here.
Finisher for 14 years, and I cringe when someone calls it cement 🤦♂️ it's not just cement, ya know
The disclaimer is worthless and would not hold up in court.
This video is concrete evidence that most people in the business have it cemented in their heads that they know what they’re doing.
Noon chloride so it won't kill the steel.
J Stevens water on truck 6 slump layer wants it Easley to lay. Sign for water no 15years on mixers. And meshdown lift up take to next job. Seen it all lessss nz
Wait WHAT, The tooth fairy isn't real!!!!!! My life is meaningless now
Another late night RUclips failure. I am watching, and seem interested in, concrete 'slump'... weird...
These people are kinda slow in the head. Speed up to 1.5x for regular video
These comments lol
REALLY...REALLY...REALLY??? WHY DO PEOPLE WHO HAVE NO IDEA ABOUT MY TRADE MAKE THESE VIDEOS ???