Just a quick rebuke those that say potato quality... i’m learning about concrete from a professor thousands of miles away, its amazing and its free... from the UK, thanks Prof Ley!
RUclips's algorithm dropped me into this teacher's video for the very first time. Can you plesse tell me why and what the reference to "professor potato" means? Thanks.
In my town (near Racine, Wisconsin), we have some sidewalks in the older neighborhoods that were laid down from 1902 to 1905 that are practically perfect. We also have a lot of sidewalks from the 1970's-80's that are in need of replacement due to cracking/spalling. I don't know if it is the formula (the concrete is a little darker than concrete used today) or the workmanship, but those turn-of-the-20th-century guys who were using horse-drawn wagons, water from barrels and brute strength really knew what they were doing.
A large amount of survivorship bias, the only building work we see from 100 year sago is the stuff that survived. The badly made and poorly designed stuff has been replaced.
Ian Griffiths while it is true that survivorship bias is at work here, that doesn’t change the fact that the workers in 1902-1905 did a better work (or invest in better materials, etc.) than the 1970-80s. While nowadays we got better concrete technology, it doesn’t mean that poor concrete constructions (in our current age) that are worst than the ones built on the past didn’t exist
George Ford, funny you should bring this up. I just had a stucco guy tell me that stucco over the years is not as strong as it used to be. He thinks it's the quality of cement that has gone down. I wonder?
You can spec whatever concrete you want at any time. "Back then" and "not as good as" always come from people that don't know standards. People that know standards can compare apples to apples at any time. Customers are the cheap ones. They hire the cheap guy and then whine about quality.
I'm a mechanical engineer, specialize in fibreglass structures (Pat pending).. It's a perfect explanation to generally sought after questions. But I find still something missing in all research carried out.. Hope to make necessary tests before publishing in scientific journal OR may be apply for a Pat. But kudos to your presentation..
hey Tyler just a shout out for ya. Reall appreciate the videos you do. I've worked as a a project engineer and now assistant superintendent on a number of IDOT projects in Illinois. Unfortunately I now work in MN doing commercial roofing but I still love concrete. I wish your videos/knowledge/passion for the crete was more widespread. Thanks, and please continue!
Other benefits of FRP rebar are no electrical conductance, no RF interference, no corrosion, and reduced cost of shipping, handling, and installation due to it’s light weight. I am planning on building a house and shop, so I am learning about materials, methods, and build science. FRP rebar in ICF structure has my intrigue.
Ive been doing a patio expansion; multiple sections (Im doing it all myself, so each section is small enough for 1 or 2 people to work.) Wrapping the patio from the back yard around the garage, and to connect to the driveway. Ive have been overbuilding much of it, so I can be confident it will last, and one of the things I was so excited about was finding this fiberglass rebar. I use regualr steel rebar inside the each slab, so I can bend it and weld it together, but then use the fiber glass to tie each section together through the expansion joint, so I dont worry about corrosion creeping into the slab as if I had used steel bar to tie each section together. Though I do run a #6 solid copper to continue the equipotential bonding plane.
I’d love to see a video comparing quality in steel rebar. I own a remodeling firm in Florida and it’s amazing how much harder it is to cut steel from homes built in the 1950-60s vs the new steel. The old steel and concrete is much more difficult to cut and break. When we remodel things from the 80s and newer the steel cuts like butter.
Rebar would not be the issue because the changes in the ASTM specifications have increased the tensile strength of rebar. What I believe you are see is the fact that concrete strength increases with age. Concrete hardens by hydration and never stops. We normally use the 28 day strength for the standard, but others use the 90 day stregth which can be 15% greater. If you investigate the time increase of the stregth of concrete you will find that very old concrete is significantly stronger especially if it is in a damp envionment. Water helps the hydration process and is why concrete is steam cured.
As far as the steel itself is concerned, where it was made might make a difference in it’s strength and toughness as well as to what standard or specification. What was the spec in 1960 vs contemporary?
I'm an electrician in the DC area, I've worked for a concrete cutting specialist company as well, and even as an electrician I sometimes have to drill holes for conduit or sleeves for MC. Sometimes in this area in old buildings, you will encounter concrete that is remarkably hard, and will wear out bits/blades before you finish the job. The older guys tell me that is typical of DC, when the old companies used to use dredged up Potomac River stones. Nowadays they use more sand and some other kind of pebbles.
I know its been years now since this video was made but FRP rebar is now similarly priced if not even cheaper than steel rebar now. Some of the new FRP rebars are both strong and flexible now as well where they dont fracture as easily and will bend and flex back in place which solves some of the ductile concerns compared to steel.
What we need is not more advertisements for basalt rebar, but design standards enabling us to design buildings that will be unaffected by design loads - whether earthquake, storm, or whatever - and fail in a slow and obvious way when impacted by loads beyond their design. That's the part steel is supposed to be really good for, having concrete beams and suspended slabs that will visibly sag without falling when they fail, although as we saw from Christchurch, steel reinforced concrete doesn't always work out like that in practice.
Great video, I work with carbon fibre and believe carbon fibre costs will continue to go down. I think we are about a decade away from seeing carbon fibre rebar in mainstream usage.
Could you look into the Stuttgart train station chalice/goblet pillars? They put in soooo much rebar and say the expected life span is 70 years. From a European perspective 70 years for the main part of a train station is absolutely ridiculous (also given the costs and time to build). They said the pillars are absolutely cutting edge and "never done before". In my opinion carbon fiber would have been such a better alternative. The pillars have a complex shape that could have made far thinner (saving money) with carbon fiber. 30x more sound crazy for standard applications, but here it sounds like it could have ended up being cost competitive, given the complex shape and repetitive nature. And it would have actually been innovative.
Saw this stuff at Menards for about the same price, but didn't know who to ask about whether or not it is better. Considering flatwork applications. Glad you made a video!
Yea the glass is cheaper at menards right now than steel - seems like it might be worth using in places like driveways that get constantly attacked by chlorides. Wonder if rate of expansion and contraction would be more or less of an issue with glass over steel.
Yow Tyler, I was just about to present on GFRBs as a solution to steel corrosion in concrete. but when I looked on the negatives in your video ...I had to call it off :). Thanks for the detailed info. I'm from Jamaica.
I started seriously researching the use of glass about a year ago, a few months before you made this video. It was about 2 years after one of my suppliers first told me it was available. At the time they first got it the glass cost about 1/3 more than steel. Last spring the price had dropped to a bit cheaper than steel, maybe $0.25 per 20 ft bar. Seeing this video is the first I have heard of the basalt or carbon fiber bars so they apparently are not available here. My supplier told me that these bars are not even approved for vertical applications so he would only sell it to me for use in flat work, not in structural work.
This is an excellent presentation and well referenced. Time and building materials march on. Thanks much! However, comparing two or more product's relative performance(s) down to percentages can only really be honestly made when all variables involved are removed ("zeroed-out") and that is first and foremost the differences between batches of concrete. If all the tests were made on the same day using one singular batch of concrete then yes, the results hold scientific credence. All of us who have handled building projects using concrete know all too well how one batch of concrete will vary from the next one delivered in both the mix and especially the amount of water from batch to batch.
Basalt FRP seems like it could be a great product. Unfortunately, the catalyst for price reduction is product demand. People/industry wont use it until they know it will work better than steel. Great video Dr. Ley!
Thanks David! There is a lot of energy needed to produce FRP and so it is not a cheap process. I do agree that basalt FRP is a cool product and I encourage people to find ways to use it.
@@TylerLey It takes more energy to produce Aluminum than Basalt roving! The barrier to entry is acceptance. Cost being equal, Steel Rebar: manufacturing, warehousing, sales fabrication, etc. will fight tooth and nail before they allow FRP to put them out of business. And, what if the roads, bridges and building were to cost less and last longer??? The Horror!!!
@@Dave-Pro it's very difficult to introduce new products into a market that is so dominated like this one. New and better products are squashed all the time because they will hurt a particular companies bottom line.
@@Maulakus and Dave Watson ; Good points about entrenched interests (cabals and mafias) resisting (killing) competition from better products, and also the economies of scale that work against the introduction of improvements, at least initially. A good example of both those forces acting in the concrete field, is how cheap the massively energy-hungry Portland cement is compared to the vastly superior magnesium oxide (though it takes a fraction of the energy and infrastructure), and how much effort and tap-dancing goes into propping up the fundamentally flawed D.O.A dinosaur of steel reinforcing.
I am so satisfied to be told the facts and as a bonus have these facts explained to me in detail. I have just learned about Basalt rebar yesterday and now I have the facts. I also have learned about the different matting and cloths that are made from Basalt . My hobby was building airplanes and will be in my future so I am trying to learn of every material that I can use for cost , safety , work-ability and accessibility . Thanks for the info.....
Tyler - Thank you. Food for thought. One unanswered question: The carbon FRP rebar material cost is 30 times higher than steel bars. But aren't steel bars themselves a small fraction of the total concrete structure cost? How much is the overall increase in structure cost (i.e cost of the finish pier, or column or floor or whatever)? If the carbon FRP-bar structures are superior, we'd have to ask how much that superiority is worth in overall cost. (Still might not seem like a great deal, but probably cheaper than the occasional occurrence of the kind of failure we recently saw in Florida.)
I don't think it's quite that much of a small fraction but it is a fraction. Obviously there is concrete cost, labor, formwork, and that is just the structure. You have to add in wiring, plumbing, air conditioning, architectural exterior and interior materials, etc.
I've been thinking about this in light of the recent Florida collapse. The codes have changed to increase building integrity after the Oklahoma City collapse but maybe we should do more. Better concrete helps with reduced corrosion and spalling but otherwise doesn't help integrity for other types of damage such as blast. Non-corrosive reinforcing prevents the corrosion and spalling but doesn't have enough ductility and wouldn't help with integrity. So I'm wondering if we shouldn't investigate dual systems. Maybe use FRP reinforcing for the strength but include supplemental reinforcing to provide ductility and resistance to fire and collapse. My mind leads me to having concrete beams with FRP primary reinforcing and a central core of PT reinforcing. PT reinforcing now is available with total encapsulation which should help with long term durability, and it would boost the ability of the structure to hang together after undergoing severe damage from deteoriation or some external event such as blast, collapse or fire. (Thinking about beams we would need a new way to provide shear reinforcing, can't easily form FRP reinforcing into stirrups and ties.
Fibre reo can be formed into bends however you want them in the factory. You just can't bend them on site, which means your engineer has to list the components for your materials order.
as You also mentioned, fire safety is another issue, esp with carbon fibers, as it burns pretty well. up until now I haven't thought about that. In another video You also mention galvanizing, and using micro and macro fibers - these are also interesting ideas
We use to use water proofing solutions in basement areas, it was fairly toxic but it made the concrete less porous. Secondly the standard is 50mm cover in Australia and most "blowouts" are probably half that, through lack of care. In Canada they salt the roads I saw for ice and this was also an excellerent in pavements and bridges.
Like the new gray background. This was an informative video not only about concrete reinforcement but about the general idea of stress strain curves. I thought I was familiar with that but the clear cut explanation added to my understanding. On the video before this I mentioned what appeared to me to be the very good performance of the concrete used to construct the Monterey aquarium 36 years ago. In general, what was best practice 36 years ago for building concrete structures in close contact with saltwater spray? Maybe in a future video you might talk about how well they are doing at making concrete structures on the east coast that need to contend with road salt. I noticed a lot of bridges with substantial rust damage when I was in MA recently.
Hello, I was watching an old mason/concrete man on RUclips from the East Coast (I believe his name was Haddock?). He absolutely eschews steel rebar and uses nothing in its stead in pads, walks, driveways, slabs, etc. etc. Claims in rusts in less than thirty years and destroys the concrete. I have been around the residential side of that for decades and while I have seen rebar rust it has not been a huge problem in my area. Now keep in mind I am in a coastal temperate rain forest so rust is huge here. His premise is that unreinforced concrete is better than reinforced. I was somewhat amazed that any long time (the guy is in his sixties) professional would hold that view. What do you think? PS Although I have been watching you previous to discovering TexasBarndominiums I think it is a great collaboration between you two and look forward to more. Take care. Doug
There were debates years ago about rebar in roads - that's over steel wins. Yes rust is the killer but so is time and cost - all engineering is a compromise of the triple constraints.
Seems to me that comparing the bend tolerance of a short length of steel rebar to a short length of fiberglass rebar in a bench vice leaves out some important variables. It's clear from the demo that the gfrp rebar lacks the ductility of steel, but I believe the gfrp has superior tensile strength, so i would be interested in comparisons with different types of rebar that are imbedded in concrete and tested to failure. Also if carbon fiber rebar is 30x the cost of steel; how about instead using a good fiberglass rebar like aslan 100; only use twice as much as the carbon? Would that provide the equivalence of the strength of the carbon fiber, without the cost (while using twice the amount as carbon)? Finally I think the corosion resistance of gfrp is a major advantage over steel.
I feel like FRP would be best combined with special concrete containing extra binders within the pour mix so as to mitigate the cracking issue. I would only really see a need to use FRP if the structure I’m designing is meant to be in a highly oxidizing environment
A few things are twisted. When you bend steel as you show using that short piece it bends however your guy bent it back physically. Steel does not return by itself like that it stays bent- basalt before cracking bends and returns like a pole vault. Remember these are encased in concrete not open air. So in a seismic event I want my building to return to straight not stay bent over. You are right about high and ultra high performance concretes. Basalt is less expensive than stainless or galvanized or epoxy MMX types of rebars and comes in 328 feet coils up to 1/2 inch so less overlaps and loss of rod in long runs, less ties time and labor AND no replacement down the road like steel almost everywhere will need. The thing no one thinks of is that there is no regulation that says only ONE type of rebar has to be used. Put the better steel when needed deep inside then use FRP (basalt is best) near the surface where forces are greatest. By code 2-3 inches of concrete are required over steel to protect it from corrosion. You can many times save using a lot less concrete because the FRP does not need that cover as it will never corrode. Basalt Chopped fibers and mesh also add great properties to the solution. basalt-rebar.com Nick
Nick, Thanks for the comments. I don't feel anything was twisted in the video. I bent both bars the same amount. The FRP snapped and the steel bar just bent. This is called yielding and has a lot of advantages in a concrete structure in high load events like and earthquake. Because FRP does not yield then we have to use much larger safety factors in design. This is not my decision. This is what the committees at the American Concrete Institute has decided. Because of this we can't count on the full capacity of the FRP bars. This means the size of the FRP bars are not much smaller than typical reinforcing bars because you are not allowed to count on the high strengths. At the end of your comment you talk about reducing the cover on the reinforcing. Cover is not just for corrosion. It is also for fire. I didn't talk much about FRP in fire but the data is not good. Plastics do not last in fires. Further, the few inches in the cover of the concrete do not significantly impact the capacity of the member. I like the idea of using two types of bars but more work is needed to see if it is feasible. I am worried that once the FRP bars break will the rebar be able to have enough strength to hold it together? How much rebar is needed to do this?
Nick, basalt has good, interesting applications, and an excellent weight to strength ratio. It does not have ductility. For at least larger structures, you need that for seismic survivability etc. Your analysis and video critique appear to be based on incentive to sell basalt rather than on engineering principles.
I've always heard that basalt rebar is shipped essentially as a giant coiled up spring. It is supposed to be very bendable. I just wish that there were some video showing people actually demonstrating this property somewhere.
@@nobreighner No I was commenting on the guy bending the steel back by hand-it does not return by itself. I personally think steel needs to be deep inside concrete that has water protective additives and basalt needs to be surrounding it near the surface where all the spalling we see happens. Best of both worlds- no law says only ONE type has to be specified-it is time engineers figured that out!
Hey Tyler! I try to listen as often as you get your videos out. One subject I have not seen a lot of is a product call "Helix". For those of you that also read these messages, Helix is a small steel, almost toothpick like, that is added to concrete to cut down on Rebar with more strength. What are your thoughts on this?
Wait a minute. Basalt FRP rebar is not basalt rebar. Basalt rebar is rebar made from basalt continuous filaments. Basalt is a common volcanic rock, found throughout the world where volcanoes have erupted and sent lava to the surface. Compared to steel, basalt filaments are much stronger for the same diameter, a fraction of the weight for the same strength, and impervious to acids, alkali, and corrosion. Basalt rebar can be bent, but has a strong memory like a spring. If you bend a straight basalt rebar, it requires a lot of force, and when you release it, it returns to its original straight form. This allows basalt rebar to be shipped in coils of 100-500 meters. It can then be uncoiled on the job site and used in the straight form. In short its ductility is far far greater than that of steel. The only disadvantage I see is that it is far more expensive than regular steel rebar but is competitive with stainless steel rebar in price.
I just bought an original homestead up in the mountain and it has the original pioneer cabin and I plan to restore it but I want to build a foundation to last 1000 years and i know that means no steel rebar. I would love to talk to you about how to do this
@@beringstraitrailway I was thinking about that as well, not sure if you can actually buy SS rebar I havent found it in my search, i am thinking that carbon fiber rebar might be the way to go
From what I have learned Roman concrete has a sand/salt polymer mix that chemically gets harder with age, like an epoxy. Adding ocean mineral salt water makes it harder with age, remelts the minerals over and over to strengthen the bonds
Galvanized Rebar Problems - Limited hot dip coating thickness (metalizing Zn-Al is better); field bending cracks galvanizing; drilling concrete for insertion of fasteners damages galvanizing at rebar contacts, requiring insertion of chemical bond for fastener to cover damaged galvanizing; drying shrinkage cracking in concrete can break galvanizing coating at crack, and, of course, there is no field welding allowed. When increased base metal strength is factored all of the above, with the possible exception of field welding, are not issues with Chromx steel, marginally more expensive than hot-dipped galvanizing and about the same as metallizing for added thickness and bond strength.
If we ( somebody) could efficiently produce some sort of carbon fiber wrapped coated rebar... Rust protection for the steel... Extra scratch durability for that coating when wrapped in carbon fiber.. And perhaps that much Stiffer. While maintaining flexibility in the worst case scenarios... Obviously costly but it would be down to somebody's R&D work to be able to produce it in a cost efficient manner. ..
Dear Sir, as far as I know, the concrete is an alkaline solution and the steel do not rust inside. So, indeed, best way to protect the steel rebar against corrosion inside RC concrete is to make the concrete impervious.
I have been dying to ask this question. As a fan of concrete and Discovery Channel Curse of Oak Island. They unearth a concrete structure. Is there a test to tell it's age, and were it's components came from?
THANK YOU for making this video! Long awaited. I love looking at the alternatives to steel. In addition to rebar, I'm also curious about the use of chopped FRP fibers to replace steel fibers: How does the actual cracking performance compare? If we strive for low-permeability ultra-high performance concrete mixtures sealed with a lithium silicate hardener, can chopped FRP fibers help reduce spalling in a fire the way PVA can? How long does FRP actually last? It's nice to say "no corrosion" but how long does it take for polymers to break down inside concrete? How does it behave as a reinforcing material after the polymer breakdown has begun? Can we monitor it?
Thanks! I talk about fibers here: ruclips.net/video/jWFncYgbCCg/видео.html Comparing FRP fibers and steel fibers is tough. The modulus of the fibers are very different but the amount of FRP fibers that you can add to the mix is higher. This has a lot of advantages of not changing your mixture proportions. I have never seen FRP fibers in a fire test and so I don't know the answer to that. I would think they would perform well. Previous versions of FRP did break down over time in pore solution. The new version is improved and I am not sure anyone knows how long they will last. I would guess hundreds of years but it is only a guess. Once the polymers break down you will lose the bond between the fibers or bars and the matrix. This means that you are only relying on the mechanical deformations to transfer the load. We can definitely monitor the performance over time.
That's why I mentioned graphene having a future in this situation because doing that with graphene would solve the weakness in these products. "You're the man" You are the one looking into this. Why? Because your the one that will find the answers. I know what it's like to have such a curiosity when you can see that something can be done much better and you want to find the best answers. The problems with graphene is that it's very new and production is still in the devoloping stages but it will become bigger than plastics... Solve this and you got the market for a time. Hope to see you like Elon Musk!
Awesome video, you perfectly explained what I was looking for, thank you. Looking for stainless steel rebars next as an alternative, you must have addressed that too.
Steel may be less resilient but it is still a tougher material. The graph plot you showed is engineering stress-strain curve. You should also see true stress strain curve if you are really into properties of materials.
So would Basalt FRB be useful to reinforce the slab in a commercial shop floor? I am concerned about cracking under heavy loads. However, I am reluctant to use rebar due to corrosion (as explained in one of your videos) in Colorado where the roads a liberally treated with chlorides in the winter months. Thank you for all of your videos, I've learned a lot and they are extremely interesting.
I think that you shall select the type of rebar depending on which part of the structure you want to reinforce and the properties of it. That way you may be able to control the way a structure fails if there's some outside force impacting the structure like an earthquake.
TL;DR steel is tougher than composites, but the ultimate strength is lower. In practical use we are worried about longevity and ability to handle deformation. You have to design concrete structures for the worst case scenario, steel fails in a predictable manner and the structure largely stays intact. Composite reinforced structures will fail in a friable manner and will not stay bound together.
You can start designing using BOTH not just one type. Good steel deep inside surrounded by FRP topside. Add macro mini-bars, mesh and chopped fibers for the ultimate solutions and use water crystallizing agents, keep water out is job one. UHPC and high performance concretes are best. Using both is a far longer lasting better solution than one or the other.
I agree, This is what I said in my video when I talked about the ductility. The stiffness of the FRP is also a big deal. The cracks will be larger than conventional rebar.
If your worried about corrosion up your mpa an use 3cc.... An it's all about doing it as cheap as you can for a builder.... An the cracks are usually 30mm surface cracks... They use a lot of fibre mesh today
Ironically, it still get mass of papers trying to promote use of omnipotent FRPs. I’m always impressed by the intro part when I review some journal article about FRP reinforced OPC/GPC.
I used fiber bar for about a year. Don't like it at all. I did a job that got moisture under the slab from a neighbor that sloped his garage towards the slab I poured and come winter....The slab heaved and snapped that fiberglass like dry twigs. If I had used #4 the cracks would have been minor, and the slab would have settled back down in the summer.
I remember the video you did about epoxy coated rebar and it being banned but I'm still seeing it being used in all type of projects just getting your thoughts on it. Thanks
What about glass FRP, you mentioned basalt and carbon but glass FRP seems to be more popular at the moment. I’m interested in the stress strain comparison with steep, the cracking potential and the usability, ie any special vibration requirement so not to damage it! How careful do you need to be when fabricating it?
ok so carbon fiber is 30 times more expensive but think about the long term maintenance that will save, as soon as corrosion enters into the rebar the clock starts ticking and soon it will need 2b demolished and rebuilt again and again, the highway system comes to mind as an example, bridges too, this constant teardown and rebuild cost $ but the biggest foe is the time lost, for a big power hungry city time is very important and road repairs are a nuisance
Great video thanks! 2 questions, what's the current cost for carbon FRP these days (year 2021), and second question, you said it isn't good for most applications but does FRP work for the residential driveway in Canada & Northern USA where you have the wide temp changes.
In Britain huge issues have been shown with RAAC (steel reinforced autoclaved aerated concrete). Since AAC does not protect the steel reinforcements as well as regular concrete, would using FRP be a viable alternative, especially for RAAC used in flat roofs?
I like steel, no radio waves inside my home, a quiet environment due to the Faraday Cage formed by my home. I will experiment with metal fibers for my auto lift base, and I may add non metalic stuff as well. Small projects lend themselves to experimentation, and considering this video, I don't see any reasons to hold back, glass fibers, steel, aluminum, nylon, and other plastics may perform exceptionally well, time will tell.
In the god olden days (India) we used limestone and stone to build our temples, palaces etc. It was probably the most safest and long lasting way to construct buildings. We still have buildings standing tall and strong as old as 400 or 500 years old.
Thanks for great videos on this great topic. It looks like the biggest weakness with FRP is "catastrophic failure". Question: couldn't that weakness be compensated for by putting some nylon ropes in the concrete to "take over" if the FRP rods fail? That plus non-steel fibers - wouldn't that qualify as no-maintenance, last forever concrete?
Yes, perhaps FRP rebar is best specified for structures where the risk of catastrophic failure does not exist or is if so, the failure is not an immediate safety risk.
@@user-tv5dt3nm9y The nylon-rope idea won't compensate for "exit time" in event of catastrophic failure? I'm looking for set-it-and-forget-it concrete. Steel rebar is asking for spalling trouble, right?
The idea that FRB combined with concrete could last almost forever is worth adding extra fire protection and extra bar so a structure never has to be torn down, inspected or replaced. Looks like a good long term investment. Now if someone can fix the pressure treated wood issues some of these building might make it more than 50 years...
Thanks for this highly informative video. I was hoping to build modest aircrete, dome-homes for poor people in typhoon ravaged SE Asia. With a 5 meter diameter floor and about 10 cm thick shell of polymer, and fiber enriched super quality aircrete. Some suggested 6 mm basalt rope as re-enforcement. Do you have any comments or suggestions ? I didn't know much about the basalt rebar, but this vid really hit the spot.
Please tell us more about crystalline material And what the difference between brands In warranty time Maximum depth underwater Dosage Resistance of different types of chemical
Tyler, what do you think about using FRP rebar for residential construction with ICF, or AAC blocks? Arguably they could do even without rebar... Thank you!
This was awesome Tyler! I knew you'd have useful information to share that I hadn't seen anywhere else. Thank you so much for this. For another topic suggestion, how about aircrete? It seems really interesting, I've watched other videos on youtube about people experimenting and building with it - all on small residential scale. Still, it seems like it's pretty easy for people to use.
Thanks, great lesson. I imagined fiber reinforcement would be weaker than steel reinforcement. I haven't been able to find a video showing the real-use of stainless steel reinforcement....
Davon ChadEwick White If 100% of the USA’s stainless capacity was switched to make stainless rebar it still wouldn’t supply enough to meet just the demand for all rebar much less all the other things stainless are made out of.
Isn't there also concrete that doesn't use rebar and instead just has the glass fibers mixed into the slurry so the whole thing is fiber reinforced? How does that compare? And the negatives of FRP, would they be relevant if you were just pouring a concrete pad as a foundation?
@@dp7933 fiber rienforced concrete can be used with less rebar but not without it entirely, the negatives are of frp when pouring a pad are still relevant because tension forces still effect the pad anytime load on the pad isn't completely evenly loaded. I think this video actually is misleading with its conclusion though of FRP because it doesn't consider using it in conjunction with the Fiber rienforced concrete you mentioned, Fiber rienforced concrete is actually much more ductile and can bend along with FRP without cracking making a significantly stronger structure, combining that with cost savings from using smaller FRP than steel rebar you can actually get a stronger structure for similar cost with FRP+fiber concrete combination in most cases. This strength also gets amplified over time as the steel rusts and becomes weaker and FRP doesnt.
Question Tyler.... Wouldn't bundling small diameter GFRP like 2 #3 GFRPs for 1 #4 blackbar address to some degree the stiffness and costs of using GFRP.... I realize it doesn't address ductility, but 2 strands do have advantages over a single thicker strand do they not?
Does anyone have any idea on how should I design to compensate for the lack of ductility in ULS limit? Should I overdesign a bit and then accept the brittle failure mode?
![[DOKKAN BATTLE] Worldwide Campaign Announcement Video Part 2!](http://i.ytimg.com/vi/JpT5Voak6WA/mqdefault.jpg)
Just a quick rebuke those that say potato quality... i’m learning about concrete from a professor thousands of miles away, its amazing and its free... from the UK, thanks Prof Ley!
RUclips's algorithm dropped me into this teacher's video for the very first time. Can you plesse tell me why and what the reference to "professor potato" means? Thanks.
@@danielfronc4304 - potato is a meme style descriptor of poor video quality… _”what did you film that on? A potato”_
In my town (near Racine, Wisconsin), we have some sidewalks in the older neighborhoods that were laid down from 1902 to 1905 that are practically perfect. We also have a lot of sidewalks from the 1970's-80's that are in need of replacement due to cracking/spalling. I don't know if it is the formula (the concrete is a little darker than concrete used today) or the workmanship, but those turn-of-the-20th-century guys who were using horse-drawn wagons, water from barrels and brute strength really knew what they were doing.
A large amount of survivorship bias, the only building work we see from 100 year sago is the stuff that survived. The badly made and poorly designed stuff has been replaced.
Ian Griffiths while it is true that survivorship bias is at work here, that doesn’t change the fact that the workers in 1902-1905 did a better work (or invest in better materials, etc.) than the 1970-80s. While nowadays we got better concrete technology, it doesn’t mean that poor concrete constructions (in our current age) that are worst than the ones built on the past didn’t exist
George Ford, funny you should bring this up. I just had a stucco guy tell me that stucco over the years is not as strong as it used to be. He thinks it's the quality of cement that has gone down. I wonder?
I believe the quality has went down myself. Can't help but think it's likely do to epa regulations and or faster curing formulas.
You can spec whatever concrete you want at any time. "Back then" and "not as good as" always come from people that don't know standards. People that know standards can compare apples to apples at any time. Customers are the cheap ones. They hire the cheap guy and then whine about quality.
I'm a mechanical engineer, specialize in fibreglass structures (Pat pending).. It's a perfect explanation to generally sought after questions.
But I find still something missing in all research carried out.. Hope to make necessary tests before publishing in scientific journal OR may be apply for a Pat.
But kudos to your presentation..
Please update. I have an idea for fiber structure in a totally different field.
hey Tyler just a shout out for ya. Reall appreciate the videos you do. I've worked as a a project engineer and now assistant superintendent on a number of IDOT projects in Illinois. Unfortunately I now work in MN doing commercial roofing but I still love concrete. I wish your videos/knowledge/passion for the crete was more widespread. Thanks, and please continue!
Other benefits of FRP rebar are no electrical conductance, no RF interference, no corrosion, and reduced cost of shipping, handling, and installation due to it’s light weight.
I am planning on building a house and shop, so I am learning about materials, methods, and build science. FRP rebar in ICF structure has my intrigue.
I'm not in construction business. I did not know shit about concrete just a few months ago. But i just. cant. stop. watching.
Appreciate the informative content. As a cost estimator it’s a great way of staying informed of what the industry is doing.
Ive been doing a patio expansion; multiple sections (Im doing it all myself, so each section is small enough for 1 or 2 people to work.) Wrapping the patio from the back yard around the garage, and to connect to the driveway. Ive have been overbuilding much of it, so I can be confident it will last, and one of the things I was so excited about was finding this fiberglass rebar. I use regualr steel rebar inside the each slab, so I can bend it and weld it together, but then use the fiber glass to tie each section together through the expansion joint, so I dont worry about corrosion creeping into the slab as if I had used steel bar to tie each section together. Though I do run a #6 solid copper to continue the equipotential bonding plane.
I’d love to see a video comparing quality in steel rebar. I own a remodeling firm in Florida and it’s amazing how much harder it is to cut steel from homes built in the 1950-60s vs the new steel. The old steel and concrete is much more difficult to cut and break. When we remodel things from the 80s and newer the steel cuts like butter.
Rebar would not be the issue because the changes in the ASTM specifications have increased the tensile strength of rebar. What I believe you are see is the fact that concrete strength increases with age. Concrete hardens by hydration and never stops. We normally use the 28 day strength for the standard, but others use the 90 day stregth which can be 15% greater. If you investigate the time increase of the stregth of concrete you will find that very old concrete is significantly stronger especially if it is in a damp envionment. Water helps the hydration process and is why concrete is steam cured.
As far as the steel itself is concerned, where it was made might make a difference in it’s strength and toughness as well as to what standard or specification. What was the spec in 1960 vs contemporary?
I'm an electrician in the DC area, I've worked for a concrete cutting specialist company as well, and even as an electrician I sometimes have to drill holes for conduit or sleeves for MC. Sometimes in this area in old buildings, you will encounter concrete that is remarkably hard, and will wear out bits/blades before you finish the job. The older guys tell me that is typical of DC, when the old companies used to use dredged up Potomac River stones. Nowadays they use more sand and some other kind of pebbles.
I know its been years now since this video was made but FRP rebar is now similarly priced if not even cheaper than steel rebar now. Some of the new FRP rebars are both strong and flexible now as well where they dont fracture as easily and will bend and flex back in place which solves some of the ductile concerns compared to steel.
What we need is not more advertisements for basalt rebar, but design standards enabling us to design buildings that will be unaffected by design loads - whether earthquake, storm, or whatever - and fail in a slow and obvious way when impacted by loads beyond their design. That's the part steel is supposed to be really good for, having concrete beams and suspended slabs that will visibly sag without falling when they fail, although as we saw from Christchurch, steel reinforced concrete doesn't always work out like that in practice.
Great video, I work with carbon fibre and believe carbon fibre costs will continue to go down. I think we are about a decade away from seeing carbon fibre rebar in mainstream usage.
Could you look into the Stuttgart train station chalice/goblet pillars? They put in soooo much rebar and say the expected life span is 70 years. From a European perspective 70 years for the main part of a train station is absolutely ridiculous (also given the costs and time to build).
They said the pillars are absolutely cutting edge and "never done before". In my opinion carbon fiber would have been such a better alternative. The pillars have a complex shape that could have made far thinner (saving money) with carbon fiber. 30x more sound crazy for standard applications, but here it sounds like it could have ended up being cost competitive, given the complex shape and repetitive nature. And it would have actually been innovative.
Saw this stuff at Menards for about the same price, but didn't know who to ask about whether or not it is better. Considering flatwork applications. Glad you made a video!
Yea the glass is cheaper at menards right now than steel - seems like it might be worth using in places like driveways that get constantly attacked by chlorides. Wonder if rate of expansion and contraction would be more or less of an issue with glass over steel.
Yow Tyler, I was just about to present on GFRBs as a solution to steel corrosion in concrete. but when I looked on the negatives in your video ...I had to call it off :). Thanks for the detailed info. I'm from Jamaica.
I started seriously researching the use of glass about a year ago, a few months before you made this video. It was about 2 years after one of my suppliers first told me it was available. At the time they first got it the glass cost about 1/3 more than steel. Last spring the price had dropped to a bit cheaper than steel, maybe $0.25 per 20 ft bar. Seeing this video is the first I have heard of the basalt or carbon fiber bars so they apparently are not available here. My supplier told me that these bars are not even approved for vertical applications so he would only sell it to me for use in flat work, not in structural work.
This is an excellent presentation and well referenced. Time and building materials march on. Thanks much!
However, comparing two or more product's relative performance(s) down to percentages can only really be honestly made when all variables involved are removed ("zeroed-out") and that is first and foremost the differences between batches of concrete. If all the tests were made on the same day using one singular batch of concrete then yes, the results hold scientific credence. All of us who have handled building projects using concrete know all too well how one batch of concrete will vary from the next one delivered in both the mix and especially the amount of water from batch to batch.
Basalt FRP seems like it could be a great product. Unfortunately, the catalyst for price reduction is product demand. People/industry wont use it until they know it will work better than steel. Great video Dr. Ley!
Thanks David!
There is a lot of energy needed to produce FRP and so it is not a cheap process. I do agree that basalt FRP is a cool product and I encourage people to find ways to use it.
@@TylerLey It takes more energy to produce Aluminum than Basalt roving! The barrier to entry is acceptance. Cost being equal, Steel Rebar: manufacturing, warehousing, sales fabrication, etc. will fight tooth and nail before they allow FRP to put them out of business. And, what if the roads, bridges and building were to cost less and last longer??? The Horror!!!
@@Dave-Pro it's very difficult to introduce new products into a market that is so dominated like this one. New and better products are squashed all the time because they will hurt a particular companies bottom line.
@@Maulakus and Dave Watson ; Good points about entrenched interests (cabals and mafias) resisting (killing) competition from better products, and also the economies of scale that work against the introduction of improvements, at least initially. A good example of both those forces acting in the concrete field, is how cheap the massively energy-hungry Portland cement is compared to the vastly superior magnesium oxide (though it takes a fraction of the energy and infrastructure), and how much effort and tap-dancing goes into propping up the fundamentally flawed D.O.A dinosaur of steel reinforcing.
Asa licensed stucco contractor I share your passion for anythingI just wished I shared your intellect.Thank you.
wow i had never been this focused on a video. Thank you for your explanation. Btw i am doing GFRP study for my degree. Wish me luck!
I am so satisfied to be told the facts and as a bonus have these facts explained to me in detail. I have just learned about Basalt rebar yesterday and now I have the facts. I also have learned about the different matting and cloths that are made from Basalt . My hobby was building airplanes and will be in my future so I am trying to learn of every material that I can use for cost , safety , work-ability and accessibility . Thanks for the info.....
Man, i'm from Brazil and your videos are great!! Thanks for the information!
Tyler - Thank you. Food for thought.
One unanswered question: The carbon FRP rebar material cost is 30 times higher than steel bars. But aren't steel bars themselves a small fraction of the total concrete structure cost? How much is the overall increase in structure cost (i.e cost of the finish pier, or column or floor or whatever)? If the carbon FRP-bar structures are superior, we'd have to ask how much that superiority is worth in overall cost. (Still might not seem like a great deal, but probably cheaper than the occasional occurrence of the kind of failure we recently saw in Florida.)
I don't think it's quite that much of a small fraction but it is a fraction. Obviously there is concrete cost, labor, formwork, and that is just the structure. You have to add in wiring, plumbing, air conditioning, architectural exterior and interior materials, etc.
Your explanation about concrete are very precise and crispy. You are doing a wonderful job by spreading required knowledge. 👍👍👍
I've been thinking about this in light of the recent Florida collapse. The codes have changed to increase building integrity after the Oklahoma City collapse but maybe we should do more. Better concrete helps with reduced corrosion and spalling but otherwise doesn't help integrity for other types of damage such as blast. Non-corrosive reinforcing prevents the corrosion and spalling but doesn't have enough ductility and wouldn't help with integrity. So I'm wondering if we shouldn't investigate dual systems. Maybe use FRP reinforcing for the strength but include supplemental reinforcing to provide ductility and resistance to fire and collapse. My mind leads me to having concrete beams with FRP primary reinforcing and a central core of PT reinforcing. PT reinforcing now is available with total encapsulation which should help with long term durability, and it would boost the ability of the structure to hang together after undergoing severe damage from deteoriation or some external event such as blast, collapse or fire. (Thinking about beams we would need a new way to provide shear reinforcing, can't easily form FRP reinforcing into stirrups and ties.
Watch the footage of the "collapse"
Fibre reo can be formed into bends however you want them in the factory. You just can't bend them on site, which means your engineer has to list the components for your materials order.
as You also mentioned, fire safety is another issue, esp with carbon fibers, as it burns pretty well. up until now I haven't thought about that. In another video You also mention galvanizing, and using micro and macro fibers - these are also interesting ideas
We use to use water proofing solutions in basement areas, it was fairly toxic but it made the concrete less porous. Secondly the standard is 50mm cover in Australia and most "blowouts" are probably half that, through lack of care. In Canada they salt the roads I saw for ice and this was also an excellerent in pavements and bridges.
Like the new gray background. This was an informative video not only about concrete reinforcement but about the general idea of stress strain curves. I thought I was familiar with that but the clear cut explanation added to my understanding.
On the video before this I mentioned what appeared to me to be the very good performance of the concrete used to construct the Monterey aquarium 36 years ago. In general, what was best practice 36 years ago for building concrete structures in close contact with saltwater spray? Maybe in a future video you might talk about how well they are doing at making concrete structures on the east coast that need to contend with road salt. I noticed a lot of bridges with substantial rust damage when I was in MA recently.
Hello, I was watching an old mason/concrete man on RUclips from the East Coast (I believe his name was Haddock?). He absolutely eschews steel rebar and uses nothing in its stead in pads, walks, driveways, slabs, etc. etc. Claims in rusts in less than thirty years and destroys the concrete. I have been around the residential side of that for decades and while I have seen rebar rust it has not been a huge problem in my area. Now keep in mind I am in a coastal temperate rain forest so rust is huge here. His premise is that unreinforced concrete is better than reinforced. I was somewhat amazed that any long time (the guy is in his sixties) professional would hold that view. What do you think? PS Although I have been watching you previous to discovering TexasBarndominiums I think it is a great collaboration between you two and look forward to more. Take care. Doug
That's Mike Haduck you speak of. Great guy I have watched quite a few of his videos.
There were debates years ago about rebar in roads - that's over steel wins. Yes rust is the killer but so is time and cost - all engineering is a compromise of the triple constraints.
Seems to me that comparing the bend tolerance of a short length of steel rebar to a short length of fiberglass rebar in a bench vice leaves out some important variables. It's clear from the demo that the gfrp rebar lacks the ductility of steel, but I believe the gfrp has superior tensile strength, so i would be interested in comparisons with different types of rebar that are imbedded in concrete and tested to failure. Also if carbon fiber rebar is 30x the cost of steel; how about instead using a good fiberglass rebar like aslan 100; only use twice as much as the carbon? Would that provide the equivalence of the strength of the carbon fiber, without the cost (while using twice the amount as carbon)? Finally I think the corosion resistance of gfrp is a major advantage over steel.
there are a lot of research papers in this field
I agree with you. The corrosion resistance is what is all about, you can use more of it and get the same strength. Totally worth it.
good content. use both! basalt and steel, basalt for long lasting, steel for unexpected catastrophic forces
I feel like FRP would be best combined with special concrete containing extra binders within the pour mix so as to mitigate the cracking issue. I would only really see a need to use FRP if the structure I’m designing is meant to be in a highly oxidizing environment
Beautiful, more to think about FRP than I realized. I raise my finishing trowel to you. Cheers 🍻.
Thanks so much!
A few things are twisted. When you bend steel as you show using that short piece it bends however your guy bent it back physically. Steel does not return by itself like that it stays bent- basalt before cracking bends and returns like a pole vault. Remember these are encased in concrete not open air. So in a seismic event I want my building to return to straight not stay bent over. You are right about high and ultra high performance concretes. Basalt is less expensive than stainless or galvanized or epoxy MMX types of rebars and comes in 328 feet coils up to 1/2 inch so less overlaps and loss of rod in long runs, less ties time and labor AND no replacement down the road like steel almost everywhere will need. The thing no one thinks of is that there is no regulation that says only ONE type of rebar has to be used. Put the better steel when needed deep inside then use FRP (basalt is best) near the surface where forces are greatest. By code 2-3 inches of concrete are required over steel to protect it from corrosion. You can many times save using a lot less concrete because the FRP does not need that cover as it will never corrode. Basalt Chopped fibers and mesh also add great properties to the solution. basalt-rebar.com Nick
Nick,
Thanks for the comments. I don't feel anything was twisted in the video. I bent both bars the same amount. The FRP snapped and the steel bar just bent. This is called yielding and has a lot of advantages in a concrete structure in high load events like and earthquake. Because FRP does not yield then we have to use much larger safety factors in design. This is not my decision. This is what the committees at the American Concrete Institute has decided. Because of this we can't count on the full capacity of the FRP bars. This means the size of the FRP bars are not much smaller than typical reinforcing bars because you are not allowed to count on the high strengths.
At the end of your comment you talk about reducing the cover on the reinforcing. Cover is not just for corrosion. It is also for fire. I didn't talk much about FRP in fire but the data is not good. Plastics do not last in fires. Further, the few inches in the cover of the concrete do not significantly impact the capacity of the member.
I like the idea of using two types of bars but more work is needed to see if it is feasible. I am worried that once the FRP bars break will the rebar be able to have enough strength to hold it together? How much rebar is needed to do this?
Nick, basalt has good, interesting applications, and an excellent weight to strength ratio. It does not have ductility. For at least larger structures, you need that for seismic survivability etc. Your analysis and video critique appear to be based on incentive to sell basalt rather than on engineering principles.
I've always heard that basalt rebar is shipped essentially as a giant coiled up spring. It is supposed to be very bendable. I just wish that there were some video showing people actually demonstrating this property somewhere.
LOL! It just doesn't exist. Nowhere. Don't go look for it.
@@nobreighner No I was commenting on the guy bending the steel back by hand-it does not return by itself. I personally think steel needs to be deep inside concrete that has water protective additives and basalt needs to be surrounding it near the surface where all the spalling we see happens. Best of both worlds- no law says only ONE type has to be specified-it is time engineers figured that out!
very relevant right now.
Strain is not the deflection/length but elongation/length but a very useful video - thanks.
Hey Tyler!
I try to listen as often as you get your videos out. One subject I have not seen a lot of is a product call "Helix". For those of you that also read these messages, Helix is a small steel, almost toothpick like, that is added to concrete to cut down on Rebar with more strength. What are your thoughts on this?
great video man, i watch many of your video and what i like about it is you show many of the latest research in the field, as new as 2019!
Wait a minute. Basalt FRP rebar is not basalt rebar. Basalt rebar is rebar made from basalt continuous filaments.
Basalt is a common volcanic rock, found throughout the world where volcanoes have erupted and sent lava to the surface.
Compared to steel, basalt filaments are much stronger for the same diameter, a fraction of the weight for the same strength, and impervious to acids, alkali, and corrosion.
Basalt rebar can be bent, but has a strong memory like a spring. If you bend a straight basalt rebar, it requires a lot of force, and when you release it, it returns to its original straight form. This allows basalt rebar to be shipped in coils of 100-500 meters. It can then be uncoiled on the job site and used in the straight form. In short its ductility is far far greater than that of steel.
The only disadvantage I see is that it is far more expensive than regular steel rebar but is competitive with stainless steel rebar in price.
I just bought an original homestead up in the mountain and it has the original pioneer cabin and I plan to restore it but I want to build a foundation to last 1000 years and i know that means no steel rebar. I would love to talk to you about how to do this
What about using stainless steel?
@@beringstraitrailway I was thinking about that as well, not sure if you can actually buy SS rebar I havent found it in my search, i am thinking that carbon fiber rebar might be the way to go
From what I have learned Roman concrete has a sand/salt polymer mix that chemically gets harder with age, like an epoxy. Adding ocean mineral salt water makes it harder with age, remelts the minerals over and over to strengthen the bonds
as a working steel fixer (or rod buster as you call us stateside)i found this very interesting
Thanks for the comment adrian! I am glad you enjoyed it.
Galvanized Rebar Problems - Limited hot dip coating thickness (metalizing Zn-Al is better); field bending cracks galvanizing; drilling concrete for insertion of fasteners damages galvanizing at rebar contacts, requiring insertion of chemical bond for fastener to cover damaged galvanizing; drying shrinkage cracking in concrete can break galvanizing coating at crack, and, of course, there is no field welding allowed. When increased base metal strength is factored all of the above, with the possible exception of field welding, are not issues with Chromx steel, marginally more expensive than hot-dipped galvanizing and about the same as metallizing for added thickness and bond strength.
This is very informative and great for learning especially with graphs thank you!
Thanks for the comment and I am glad you like it.
Amazing content delivery, Tyler. Great videos!
Your friends from Canada
If we ( somebody) could efficiently produce some sort of carbon fiber wrapped coated rebar... Rust protection for the steel... Extra scratch durability for that coating when wrapped in carbon fiber.. And perhaps that much Stiffer. While maintaining flexibility in the worst case scenarios... Obviously costly but it would be down to somebody's R&D work to be able to produce it in a cost efficient manner.
..
Dear Sir, as far as I know, the concrete is an alkaline solution and the steel do not rust inside. So, indeed, best way to protect the steel rebar against corrosion inside RC concrete is to make the concrete impervious.
Interestingly pinkbar is now cheaper than steel rebar where I'm at. Total winner from my perspective at this point.
I have been dying to ask this question. As a fan of concrete and
Discovery Channel Curse of Oak Island. They unearth a concrete
structure. Is there a test to tell it's age, and were it's components came from?
Indeed. Yes they could.
Tyler, you’ve blessed my life so much with these videos. God bless you and keep going 👏🏾👏🏾👏🏾
THANK YOU for making this video! Long awaited. I love looking at the alternatives to steel.
In addition to rebar, I'm also curious about the use of chopped FRP fibers to replace steel fibers:
How does the actual cracking performance compare?
If we strive for low-permeability ultra-high performance concrete mixtures sealed with a lithium silicate hardener, can chopped FRP fibers help reduce spalling in a fire the way PVA can?
How long does FRP actually last? It's nice to say "no corrosion" but how long does it take for polymers to break down inside concrete? How does it behave as a reinforcing material after the polymer breakdown has begun? Can we monitor it?
Thanks!
I talk about fibers here: ruclips.net/video/jWFncYgbCCg/видео.html
Comparing FRP fibers and steel fibers is tough. The modulus of the fibers are very different but the amount of FRP fibers that you can add to the mix is higher. This has a lot of advantages of not changing your mixture proportions.
I have never seen FRP fibers in a fire test and so I don't know the answer to that. I would think they would perform well.
Previous versions of FRP did break down over time in pore solution. The new version is improved and I am not sure anyone knows how long they will last. I would guess hundreds of years but it is only a guess.
Once the polymers break down you will lose the bond between the fibers or bars and the matrix. This means that you are only relying on the mechanical deformations to transfer the load.
We can definitely monitor the performance over time.
That's why I mentioned graphene having a future in this situation because doing that with graphene would solve the weakness in these products. "You're the man" You are the one looking into this. Why? Because your the one that will find the answers. I know what it's like to have such a curiosity when you can see that something can be done much better and you want to find the best answers. The problems with graphene is that it's very new and production is still in the devoloping stages but it will become bigger than plastics... Solve this and you got the market for a time. Hope to see you like Elon Musk!
Awesome video, you perfectly explained what I was looking for, thank you. Looking for stainless steel rebars next as an alternative, you must have addressed that too.
Steel may be less resilient but it is still a tougher material. The graph plot you showed is engineering stress-strain curve. You should also see true stress strain curve if you are really into properties of materials.
So would Basalt FRB be useful to reinforce the slab in a commercial shop floor? I am concerned about cracking under heavy loads. However, I am reluctant to use rebar due to corrosion (as explained in one of your videos) in Colorado where the roads a liberally treated with chlorides in the winter months. Thank you for all of your videos, I've learned a lot and they are extremely interesting.
I think that you shall select the type of rebar depending on which part of the structure you want to reinforce and the properties of it. That way you may be able to control the way a structure fails if there's some outside force impacting the structure like an earthquake.
That is a good approach!
What about the solid basalt bar we've seen, then? It doesn't have a polymer binder.
TL;DR steel is tougher than composites, but the ultimate strength is lower. In practical use we are worried about longevity and ability to handle deformation. You have to design concrete structures for the worst case scenario, steel fails in a predictable manner and the structure largely stays intact. Composite reinforced structures will fail in a friable manner and will not stay bound together.
You can start designing using BOTH not just one type. Good steel deep inside surrounded by FRP topside. Add macro mini-bars, mesh and chopped fibers for the ultimate solutions and use water crystallizing agents, keep water out is job one. UHPC and high performance concretes are best. Using both is a far longer lasting better solution than one or the other.
I agree,
This is what I said in my video when I talked about the ductility. The stiffness of the FRP is also a big deal. The cracks will be larger than conventional rebar.
If your worried about corrosion up your mpa an use 3cc....
An it's all about doing it as cheap as you can for a builder....
An the cracks are usually 30mm surface cracks...
They use a lot of fibre mesh today
Thanks Tyler!
Ironically, it still get mass of papers trying to promote use of omnipotent FRPs. I’m always impressed by the intro part when I review some journal article about FRP reinforced OPC/GPC.
I used fiber bar for about a year. Don't like it at all. I did a job that got moisture under the slab from a neighbor that sloped his garage towards the slab I poured and come winter....The slab heaved and snapped that fiberglass like dry twigs. If I had used #4 the cracks would have been minor, and the slab would have settled back down in the summer.
I remember the video you did about epoxy coated rebar and it being banned but I'm still seeing it being used in all type of projects just getting your thoughts on it. Thanks
What about glass FRP, you mentioned basalt and carbon but glass FRP seems to be more popular at the moment. I’m interested in the stress strain comparison with steep, the cracking potential and the usability, ie any special vibration requirement so not to damage it! How careful do you need to be when fabricating it?
ni cequests! coud you sand me your material? for my research in fiber glass beams/slabs pre formed
¹
ok so carbon fiber is 30 times more expensive but think about the long term maintenance that will save, as soon as corrosion enters into the rebar the clock starts ticking and soon it will need 2b demolished and rebuilt again and again, the highway system comes to mind as an example, bridges too, this constant teardown and rebuild cost $ but the biggest foe is the time lost, for a big power hungry city time is very important and road repairs are a nuisance
New sub here. I am currently using GFRP for slab with a combination of Steel rebars as top bars.
What applications for FRP rebar? I guess in water-front substructures where corrosion resistance is key factor, any other applications?
Great video Tyler! Greeting from Scandinavia!
I've been making concrete fence posts and struggling to find 8-in quarter inch rebar. What do you think about the FRP for fence posts?
Craig
Thanks for informative video !
u have awesome knowledge buddy..
Great video thanks! 2 questions, what's the current cost for carbon FRP these days (year 2021), and second question, you said it isn't good for most applications but does FRP work for the residential driveway in Canada & Northern USA where you have the wide temp changes.
In Britain huge issues have been shown with RAAC (steel reinforced autoclaved aerated concrete). Since AAC does not protect the steel reinforcements as well as regular concrete, would using FRP be a viable alternative, especially for RAAC used in flat roofs?
Any chance of an update to this for current technologies and developments since 2019?
I designed a wall system using fiberglass re-bar.
I like steel, no radio waves inside my home, a quiet environment due to the Faraday Cage formed by my home.
I will experiment with metal fibers for my auto lift base, and I may add non metalic stuff as well.
Small projects lend themselves to experimentation, and considering this video, I don't see any reasons to hold back, glass fibers, steel, aluminum, nylon, and other plastics may perform exceptionally well, time will tell.
Aluminum is a very very bad idea in concrete. It has a chemical reaction with it. It's not pretty.
In the god olden days (India) we used limestone and stone to build our temples, palaces etc. It was probably the most safest and long lasting way to construct buildings. We still have buildings standing tall and strong as old as 400 or 500 years old.
Thanks for great videos on this great topic.
It looks like the biggest weakness with FRP is "catastrophic failure".
Question: couldn't that weakness be compensated for by putting some nylon ropes in the concrete to "take over" if the FRP rods fail?
That plus non-steel fibers - wouldn't that qualify as no-maintenance, last forever concrete?
Yes, perhaps FRP rebar is best specified for structures where the risk of catastrophic failure does not exist or is if so, the failure is not an immediate safety risk.
@@user-tv5dt3nm9y
The nylon-rope idea won't compensate for "exit time" in event of catastrophic failure?
I'm looking for set-it-and-forget-it concrete.
Steel rebar is asking for spalling trouble, right?
Do make a video on GFRP as well
What about pouring a lot of plastic pellets into the concrete will that not give the concrete more strength just like the rebar???
use both Steel/ GRFB and benefit from both materials
ThankQ
The idea that FRB combined with concrete could last almost forever is worth adding extra fire protection and extra bar so a structure never has to be torn down, inspected or replaced. Looks like a good long term investment. Now if someone can fix the pressure treated wood issues some of these building might make it more than 50 years...
Hola, saludos desde Buenos Aires, Argentina. Quería preguntarte si sabés de algun método para reutilizar o reciclar fibra de vidrio. Gracias!
Thanks for this highly informative video. I was hoping to build modest aircrete, dome-homes for poor people in typhoon ravaged SE Asia. With a 5 meter diameter floor and about 10 cm thick shell of polymer, and fiber enriched super quality aircrete. Some suggested 6 mm basalt rope as re-enforcement. Do you have any comments or suggestions ? I didn't know much about the basalt rebar, but this vid really hit the spot.
Please tell us more about crystalline material
And what the difference between brands
In
warranty time
Maximum depth underwater
Dosage
Resistance of different types of chemical
Do you know that this composite rebar resin degrades in concrete due to alcali environment?
I'm resident in the Caribbean. How do we access this alternative reinforcement? Basalt products, once competitive the product can take off.
do you have a video regarding Alkaline application testing on all FRP rebar products compare to steel. thank you
Tyler, what do you think about using FRP rebar for residential construction with ICF, or AAC blocks?
Arguably they could do even without rebar...
Thank you!
love your vids. Great and interesting content.
I appreciate the information, was wondering if you could do a video about concrete made from plastic and sand
What about making rebar out of Polymer? My Glock 43X polymer lower is so strong and also flexes.. Just a thought
This was awesome Tyler! I knew you'd have useful information to share that I hadn't seen anywhere else. Thank you so much for this. For another topic suggestion, how about aircrete? It seems really interesting, I've watched other videos on youtube about people experimenting and building with it - all on small residential scale. Still, it seems like it's pretty easy for people to use.
Thanks Ryan,
Aircrete is coming. I have a few more videos coming on reinforcing. Thanks for hanging with me!
I'm curious what happens when aircrete is mixed with chopped basalt. Durability is a big issue with aircrete.
Thanks, great lesson. I imagined fiber reinforcement would be weaker than steel reinforcement. I haven't been able to find a video showing the real-use of stainless steel reinforcement....
Davon ChadEwick White If 100% of the USA’s stainless capacity was switched to make stainless rebar it still wouldn’t supply enough to meet just the demand for all rebar much less all the other things stainless are made out of.
Hey man there is something like composite fiber rods used for construction it.would be great if you help me out with this.....
It's about fiber glass
By a company name MRG Composites
Isn't there also concrete that doesn't use rebar and instead just has the glass fibers mixed into the slurry so the whole thing is fiber reinforced? How does that compare?
And the negatives of FRP, would they be relevant if you were just pouring a concrete pad as a foundation?
no
@@protonneutron9046 No to the foundation question I assume.
@@dp7933 to any concrete that is not only subject to compression.
@@dp7933 fiber rienforced concrete can be used with less rebar but not without it entirely, the negatives are of frp when pouring a pad are still relevant because tension forces still effect the pad anytime load on the pad isn't completely evenly loaded. I think this video actually is misleading with its conclusion though of FRP because it doesn't consider using it in conjunction with the Fiber rienforced concrete you mentioned, Fiber rienforced concrete is actually much more ductile and can bend along with FRP without cracking making a significantly stronger structure, combining that with cost savings from using smaller FRP than steel rebar you can actually get a stronger structure for similar cost with FRP+fiber concrete combination in most cases. This strength also gets amplified over time as the steel rusts and becomes weaker and FRP doesnt.
Great video, Tyler!
Thanks so much!
Question Tyler.... Wouldn't bundling small diameter GFRP like 2 #3 GFRPs for 1 #4 blackbar address to some degree the stiffness and costs of using GFRP.... I realize it doesn't address ductility, but 2 strands do have advantages over a single thicker strand do they not?
Can't they coat the steel rebar in frp material?
I was there during one of your presentations at Illinois...it was amazing!!!... I can't imagine what it would be like to work with you!
Does anyone have any idea on how should I design to compensate for the lack of ductility in ULS limit? Should I overdesign a bit and then accept the brittle failure mode?
What about steel cored FRP rebar? Not sure it exists