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Does Early Form Removal Impact Concrete Durability?
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- เผยแพร่เมื่อ 15 ส.ค. 2024
- This video investigates how early form work removal reduces the durability of concrete. The research shows that if forms must be removed early then it is best to apply a curing compound. However, this does decrease the durability of the concrete.
You can find the report here: www.dropbox.co...
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Excellent video. Only thing I would've like to see is after completely curing, the strength difference between the different methods. Thinking using a hydraulic press, monitor the psi applied, then attempt to see what the crush pressure is and if it meets the 4,000 # or whatever you're using listed rating.
A doc, I have a suggestion for you and testing ... using this testing method... and ''service life''...
Please, consider grabbing some concrete curb that is being replaced by your municipality... (use that because, it will have a ''spec'' that was used that you can use values from - confirmable by the concrete load ticket)... Then you can take the ''cut and removed section'' (NOT jack hammered as that would or could damage or corrupt the test sample)...
With all that said, we have a three sided exposed sample (the concrete above the street level AND you have concrete that was ''left in the form'' (well, they backfilled very quickly and created your three sided form below the surface... hopefully, you can find a sample curb that is 15 plus years old and do your testing on... This would give you a more accurate ''365 life'')?
Hopefully, you can find a sample that was installed in ideal concrete installation time period / weather... which would be overcast day, 70 degrees, backfilled immediately and forms that were left on for three days, etc... my thoughts...
Thanks Tyler for your content... take care.
Thanks! I think this is a good idea. I would be open to doing this if I had an owner that would let me take the cores and would pay for the testing. This is the type of stuff that we need to learn. To really draw strong conclusions we would want to take samples from several places, but I think this is how we learn new things.
I built wood forms for a foundation wall and covered them with 4 mil pvc. I did not remove the forms for about 2 weeks. I guess that was good.
Love your content!
What are your thoughts on a good mix design for residential construction with ICF's?
Thanks!
Great info Just poured a root cellar domed roof and the forms underneath will stay in place for 30 days but the top is open to the air. Tarped for 4 days.
what if you let it stay for a week or more ? and wet down the wood molds too would you get a better stats :)
.
Is concrete that is left submerged underwater considered the best form of curing?
YES - ponding is the best.
As long as the mix was good
Thank you for all the info and details. I'm getting free education from you. Thanks again!
Thanks for watching.
So, ICF forms sound like a great idea, you never actually take them down. And, 3-7 days of wet curing the tops would be ideal.
So, does the foam suck the moisture away?
We are building a new home, and builder began pouring around 8am and by 5p same day, took off form boards.
Is that concerning?
On a production schedule putting up a 70 story poured in place concrete highrise this dudes the first to go....
Thanks Tyler for the videos. It's a great refresher for me since it's been so long since I took my concrete class in college. It may be dumb question, does it mean you can remove the formwork after the concrete reaches its "final set" (thought technically we do not know exactly is the final set)
This channel is excellent! I'm curious about the affect of the fine skin of concrete being pulled off during demolding. I'd like to run the same test but use silicone for the rubber due to its amazing release properties and virtually no remaining concrete skin left in the mold. My question is, would keeping the skin intact help with moisture retention? Also, what affect does vibration cause during demolding/handling at 12 and 72 hours? I would guess that the fresher concrete will be more affected by vibrations/stress from demolding. Thank you for the chance to geek out!
What if the fiorms are left on for 2 weeks? My contractor left them on and went on vacation.. can they permanently stay on?
love your vids. Subscribed! Now if we can just make every person pouring concrete watch these, we'd have a much better and safer world out there! There's a new highrise job, they are still using coated for the patio deck/porch piece, and uncoated for the vertical poured pillars.
What about the new styles of foundations for basements and homes using the ICF blocks. Are those potentially better for the structure of the concrete?
Hmmm, so pour one day and strip the next morning is not great eh. Well I guess I will have to start delaying all my jobs by one 24 hour period after placement.
Good for you. We need more like you.
Why did wood forms lose less mass than steel or rubber forms? I am curious since I would normally except wood to absorb moisture.
It does initially, but then _it gives back that moisture to the curing concrete surface._ So the surface is soon slightly better hydrated than the interior.
Also curing concrete is shrinking. The moist wood fibres are resilient, so it tends to stay in better contact than impermeable forms.
this is probably not going to get answered when I need it (now), I have csa rapid set in a pvc 1 inch I want to remove and submerge in water. It’s been an hour and a half; I don’t recall if you mentioned rapidset in this video. Your videos are awesome though!
Hey Tyler great job. I would like more information on your concrete mix design. Please share more videos.
Calvin,
I made a playlist of all of my mix design videos. You can find them here: th-cam.com/play/PLRq6Z9d0kCT-lQ7xM6Jh6HZVUjUObsz_8.html
@Tyler Ley, what if you kept a constant mist of water on the surface instead of just relying on the burlap?
I have see people use rolls of sponge half to 3/4 in thick instead of burlap. They would soak them 2 to 3 times a day and this in temperatures in the 40's C. How will would you think that works.
Did your burlap have a soaker hose while wraped in plastic. After a compressive cylinder shows to have a 15 mpa strength, usually after 2 days, we are able to remove our forms if we use burlap, saoker hose and white plastic for up to a minimum of 96 hours since the concrete pour. Ministry Of Transportation of Ontario, O.P.S.S. Standard
“You can increase your service life by 33 %”
Ackshually 🤓 it is ~50 %, because the base is the reduced life, so 100 % (leaving forms enough time) / 66 % (removing forms early).
k, I have asked a builder and he said the forms are really hard to get off if left on for 48 hours even.
Thanks for creating this channel and educating me.
I plan on building every thing out of concrete for the structure of my home and out buildings. Is there any real gain to leaving the forms on for more than 72hr say 6days or more?
The difference between 1-3 days is much larger than 3-7 days for curing and strength. At 3 days you achieve ~50% design strength, 7 days ~70% and 100% at 28 days (this is a generalization, concrete admixtures can effect the early curing and strength). If you can wait 7 days to pull forms, great. If not just use curing compound after they get stripped off.
@@brianhelmold1332 I think he is emphasizing on leaving the forms for 6days or more. what is the recommendation for it?
@@halalmeatshophk best practice is 7 days for things like walls. Keeping them covered keeps the concrete from drying out and helps curing and there is less risk of damage during form removal. Any longer than 7 days has little benefits as the most important part of cutting is over. Slabs it's less important for forms since the area is so much smaller than the top surface. For slabs it's more important to keep the top from drying out after initial set. Curing compound, curing blankets or even wet burlap work well.
Great content; thanks; though I suggest considering another factor that would impare concrete quality due to preterm form removal which is caused by the force inflected on structure while removing the shuttering; many times you could notice chopped off corners of concrete columns because of fast removal of framework; that raises concerns about existance of hairy cracks within concrete elements; isn't right?
I like concrete but still confused the relationship between a dry mix being stronger and keeping it wet during curing. Do we only want to retain it's moisture content tent or do we want to add water during cure? If you could submerge curing concrete in water for a few days will that be better? What's the relationship here? I do some ferrocement formless work and we always spray it with a water hose as often as we can for several days to help it cure, sometimes we use tarps but mostly just the water hose.
Ben,
My video tomorrow till talk about this. You can also find more here: th-cam.com/video/8XApTsnDmgY/w-d-xo.html
Hi Tyler. I have a question for vertical concrete (i.e. walls). Normally when wet curing with burlap with formwork on, the water is retained on the flat surface on top, does this mean that the side of the walls doesnt cure as much as the top due to less contact with water. Is that assumption correct? Or will the water from the top of the surface somehow provide enough moisture for the top and the side of the wall? The way I see it, only the top of the surface is sufficiently cured, while the side of the wall only get minimal water contact from water that flow down from the top through the small opening between the formwork and the wall.
thanks dr tyler for those valuable infos !!
Thank you Hamza!!!
If you’d ever do this experiment again, can you do a 3 day, 7 day and even maybe a 28 day? I think that would be interesting.
Thanks for making these videos!
Thanks!
Are you talking about leaving the forms in place for that long?
Tyler Ley yep
Tyler Ley the reason I’d be curious about that, I’ve heard it a lot over the years.
“Concrete was better back then! My basement doesn’t have any cracks and it was poured 50 years ago!”
And there does seem to be a bit of truth in that. You can go in a lot of old houses and while the basement is the darkest dankest dungeon you’ve ever seen it’ll be dry as a bone.
But I wonder how much of it was the quality of the concrete and how much comes from the fact that they left the forms on for days or weeks?
Thanks Richard!
Leaving the forms on helps. Having water in close contact with the concrete over time will also help. There are so many variables that go into these things that it is hard to know exactly what wins the day. However, I don't think concrete was better in the past. Our craftsmanship, construction plans, and effort may have been higher but we can make better concrete today than anyone ever in history. People also have a survival bias towards things that last. They don't remember the things that fail.
Take care and keep watching!!!
Have you ever stripped forms that been on for 3 days?
So with a wood form left on for 72 hours on a vertical wall...should I cover the open top with plastic as well?
Other comments indicate that ponding (immersion in water) is best. Plastic film over the water slows evaporation. Burlap over level surfaces also holds moisture, but probably not 72 hours, so re-wetting is needed. Unless the wet burlap is covered with plastic.
when can you take forms off of concrete curbing to do the Finish trowel work
Do You have a video explaining why mass change is a measure of strength or quality?
i just knocked the forms off a slab i poured yesterday and i dont want to watch this video.
Ha ha ha...
.I strip slab forms as soon as I can. Wall forms always in less than 24 hrs. I think most slabs get ripped back out for what ever reason before they hit 20 years anyways.
No worries, just keep it wet with a hose. 😉
I am considering building a shed with aircrete using 24in. slip forms as I did with a previous shed made with on site mixed concrete. After watching this and previous videos I am thinking of puting wet blanckets under plastic sheeting on the aircrete after I remove the forms but how to do it when I move the forms up for the next pour. Do you have any suggestions.
Thanks, very informative, I’ll leave them on for 72 hours💪🤣❤️
Great information. Can you share your knowledge on when residential framing can be installed on new concrete? Thank you.
On big Island Hawaii they are framing up 3 bedrooms homes on concrete they poured YESTERDAY!
What about the weight of the concrete, loading itself without support, before it has developed enough strength?
Wouldn’t this also depend on the exposed surface area? For instance if you’re pouring a large slab for a foundation, the ratio of the forms’ surface area compared to the surface area of the exposed top horizontal slab is very small.
Need advise sir my newly slab only as of now 24 days still with forms showing on top of the slab rust is this a big problem, thank you
Thank you, excellent info and well presented.
Anyone know how many samples of each method were tested? The type of concrete mix? Environment tested in (indoors, outdoors, temp?)
6 days after i removed my concrete columns forms, what can u say about it? is it bad because its been days not hours? or it is more durable, please answer thanks
How about soaking concrete in water? Also temperature?
if i am building a house myself and i own the forms with no hurry in removing them, then what would be the best time to remove them?
Very educational! Thanks!
What if you were able to build out material for forming that you could leave in place for grade beams? This video would suggest maximum strength.
Thanks for the information. It helps me a lot.
They just pour 3 days ago here in NJ 40degrees steel form they removed the forms today 3 days
I don't know man. It going
6 story building
very informative, thank you.
What is Pam>?
Nice!!! ( I never knew about curing!!!)
Great tutorial... Thanks
how often does vertical concrete come in contact with chlorides? I guess I'm more curious about parking structures and not bridges. specific to parking structures I can see at the base or if drains are near columns but would like to know your thoughts on exposure conditions. maybe even weakness of horizontal construction joints between elevated decks and next lift of vertical and the how this exposes the design to elements
He was using chlorides to test permeability.
Do that mean the concrete strength at final setting is still less than the design strength of concrete?
How the hell does rubber and steel entrap moisture less than wood? That feels very paradox.
For anyone reading/wondering about this (a year later), wood absorbs moisture and keeps it in contact with the concrete as it cures. Rubber and steel don't, and gravity will pull it away. That's what's meant by trapping here, not the air permeability or evaporation prevention. That's also why burlap works, but not as well in a vertical setup.
If it's your pet project, pour on Friday, strip on Monday.
Awesome channel
Thank you
Great videos!
Hey, question.
How applicable is this type of thing for Insulated Concrete Forms?
Hyperstrike,
Most of the time the forms are left in place for the insulated concrete. This means that it will seal the concrete and keep it reacting. This means that insulated concrete forms would be even better.
Liked and subscribed, good stuff!
A higher camera angle would be more flattering
Sir,
In fick's law equation, Should we consider the initial chloride content in the concrete???
It should be small.
If submerging the concrete in water is an option, would it be better to remove the mold as soon as the concrete is able to be moved without damaging or leaving it in the mold a bit longer? Submerging the concrete seems like it will produce the best curing, but I'm not sure.
Submerging concrete is not practical in the field and this is why I suggest leaving the forms in place as long as practical. If you are making smaller items then applying water to the surface will help you improve the quality of your concrete. I hope this helps.
@@TylerLey -- With submersion, I would worry about leaching of the cement at the surface if there was enough water present for any dissolved solids to be diffused away throughout the water. With a wet horizontal cure using burlap, there isn't enough water present to leach much away.
@@TylerLey Hi Tyler love your channel. I am a high school physics teacher in New Zealand and teach some of my younger male students the gentlemanly art of making reinforced concrete. We then test sample blocks until failure by seeing how many students they hold. What I would like to ask is, do you know of any simple experiments we could conduct for project work for student science fair projects for kids of about 14 years age? One project we looked at is the use of unwashed marine beach sand vs clean sand but have no idea how we could test this. The second is looking at the effect of heating on concrete (inspired by one of your videos) the issue hear in Auckland is our aggregate is basaltic lava that is very stable with temperature. I am reasonably sure that the University of Auckland would help us if we could develop a reasonable project. I would greatly appreciate any ideas you may have.
What is MICA in concrete production?
What are its Affects?
Do you mean the mineral? I think it can have ASR problems. Check this video: th-cam.com/video/qiF89HFLY2A/w-d-xo.html&lc=Ugyt-XBycNUzb44u5PB4AaABAg
I’m not sure about all this , people have been slop forming walls for a while now.
But I always thought that wood let's the slurry leak and sucks the water of concrete.
Ideally would love to leave forms, specially vertical forms min 72 hours but scheduling and project costs always determine our push. We tend to us curing compound on all of our concrete, @ slab, columns and beams, coupled with the admixture of HRWR -- which we have noticed it helps tremendously achieve faster reach to our psi goals.... any other ways we could expedite without sacrificing quality?
Good job!
Thanks Amir!
Shit we've poured 4 ft walls before and stripped em that day
I keep the forms of the slabs 28 days, 😁😁😁
I love your informative videos. You're one of the few channels I subscribe to. But what's up with the weird faces you make in your video thumbnails? Some of them kind of freak me out. Keep up the good work.
Thanks so much! I am a freak. I can't help it. =)
Have you seen the technique where they install sacrificial zinc wires in along with the rebar? Maybe you've mentioned that already in one of your videos. Awesome videos, thank you!
I adore those fun faces! Made me watch the video in the first place instead of regular text/chart/normal looking expressions-Doctor Tyler looks like he is KEEN!! Keep it up mang!
Great
For some reason my forms stay on at least 5 days... Because everyone hates stripping... 😅😅😅😅
Yeeeeee...Hawaiian Cement!
Daddy Pig would be proud (Reference Peppa Pig if you dont know why!)
I'm a big fan of concrete too, so plastic!
Any lady’s on here???
meeeee, love it
Me too! Fascinating! Trying to sort out best practices to request my contractor do for my front step and driveway concrete-now up all night glued to concrete videos! Lol so much to learn!
waste of time resources, move on to adding silica to increase flex ablity, non functional removal of forms lol, gain in strength over time, non lost over time regained , amen
who do you think your target audience is, 8 year olds?
Make your own video.
Shocked at the armchair criticism! Boo “John Smith” Now lead by example and stop acting like an eight year old!
so freaking lame. no mention of mix . avrg consumer ?no idea how contractor has mixed concrete when truck shows up for doing the driveway
What if the forms had an impermeable liner that stays behind for a while when you take them off? Or more extreme, since it's a vertical wall just leave the liner in place as part of the structure.
Good question. Makes a case for ICF walls IMO.