Comparing Steel and Fiberglass Rebar - SURPRISING results
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- Опубликовано: 30 сен 2024
- Welcome back to The Build Show! In this episode, we dive into the fascinating world of rebar with our engineer Witt Smith, comparing traditional steel rebar to the innovative glass fiber reinforced polymer (GFRP) rebar, specifically the MST bar.
We start by comparing the weight of GFRP rebar to steel. You'll discover that GFRP rebar is significantly lighter, making it much easier to handle on job sites. This difference in weight can improve efficiency and reduce strain on workers.
Next, we delve into the material properties of fiberglass rebar. Unlike steel, GFRP rebar has a higher tensile strength and bonds more effectively to concrete. This results in enhanced durability and performance of the reinforced structures.
Worker safety is a major consideration, especially in hot climates. Weitzman explains how GFRP rebar stays cooler in the sun compared to steel, reducing the risk of burns and the need for heavy gloves. This aspect makes GFRP a safer choice for construction crews.
We also discuss the design differences when switching from steel to fiberglass rebar. Our engineer explains how the change in material properties requires adjustments in the design process. It is crucial to incorporate these changes early in the project planning stages to avoid costly redesigns later.
Rust prevention is another significant advantage of GFRP rebar. Traditional steel rebar can rust over time, causing concrete structures to spall and degrade. GFRP rebar, on the other hand, is resistant to rust, making it ideal for use in areas prone to moisture and salt exposure.
In terms of cost, we explain that while GFRP rebar may not always result in immediate savings on smaller projects, it can be cost-effective on larger scales. The long-term benefits of reduced maintenance and increased longevity also contribute to its overall value.
Finally, we highlight the potential applications of GFRP rebar and the importance of early planning in incorporating new materials into your projects. Proper planning ensures that the benefits of GFRP rebar are fully realized.
Stay connected with us for more insights and updates. Follow our 24-part series on the Reisinger Build project to see this and other innovative materials in action. Don't forget to subscribe to our channel for new content every Tuesday and Friday, and stay updated by following us on Facebook and Instagram.
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The requirement to wear gloves when handling this material implies the glass particles could be in the surrounding air. Especially when cutting it. It seems to me it would be prudent to wear respirator or mask when handling fiber glass rebar.
Yes, like with cutting metal rebar.
The glass coming off the cut bar or slivers should not be confused with the fiberglass insulation. they have completely different shape under microscope. fiberglass insulation are J-Hook shape vs fiberglass dust from cutting are Solid round particle. you can treat them just as concrete dust and wear a regular mask. imagine fiberglass boat industry that has been making boats and hot tubs for years. no issue with the people who worked in those industry for 70 years.
nah you can inhale glass dust no problem. it's the same thing as steel dust.
@@ShBenEd "Yes, like with cutting metal rebar."
There is NO comparison between steel and glass dust!
Use a wet cutter and don't make dust. Problem solved.
A buddy of mine used the fiber rebar in the Bahamas right on the coast for corrosion resistance reasons. It has worked very well for him on a home that is now 20 years old!
I was thinking of the Florida building that failed.
@@jsbrads1 i think that basically can't be saved... it might prevent spalling, but things gonna broke with lack of maintenance
@@PrograError heard it was the rust due to the humid air 🤷
@@jsbrads1its not air, its just water in general and especially salt. Concrete chemically protects the rebar, but eventually with water exposure the concrete chemistry changes from the outside in until the rebar starts to rust, and salt speeds up the whole process. Then the rebar rusts and expands which breaks up the concrete and makes it really weak. The rebar is for tensile strength too so in places where tensile strength is the key factor the rebar rusting weakens the structure.
was that Bob Samia? he has been trying to get Bahamas to use fiberglass rebar forever
In school we were told that in an over stressed system, you need the steel to stretch first at the bottom (lower factor of safety) before the top concrete (higher factor of safety) catastrophically instantaneously fails. How does the fiberglass accomplish this?
It doesn't. The fiberglass will not stretch. It will catastrophically fail once stressed beyond its limits.
I talked to an old concrete guy who told me, "The thing about concrete work is that everything you do is simple, but every single thing is HEAVY."
Reminds me of Carl von Clausewitz, “Everything in war is simple, but the simplest thing is difficult.”
Glass rebar ought to be a lot lighter than steel.
@@comfortablynumb9342 300% i would guess. my only question is the shrink and swell difference as temp changes
@@comfortablynumb9342 25% lighter, so it's probably still a bit heavy.
@@FranciscoTChavez 25% less weight than steel is a big help if you're the guy carrying it.
As an architect, the huge advantage I see is not rusting. I'm worried about how much we've built with steel-reinforced concrete and how much of it we'll have to tear down. Once water gets to the steel it's over - you can't stop it, you can't replace it, you can't salvage the concrete it's embedded in. And eventually the water will find its way in. Our oldest buildings are unreinforced masonry because there's no steel in them to rust and destroy the structure (not that all unreinforced masonry buildings last that long, obviously). Of course, unreinforced buildings have other problems, especially with settlement and seismic loads, so we can't just leave the rebar out. That's why these alternative products seem so promising. I would love to see them become the standard for public buildings, infrastructure projects, institutional buildings, and anything along the coast.
The importance of this advantage simply cannot be overstated. Damage from corroding steel reinforcement in concrete has been conservatively estimated at $2.5 trillion PER YEAR! That's nearly %3 of the world GDP! Think of a market like China where excess amounts of infrastructure has been built in anticipation of future growth. How much of that will crumble away before said growth is ever even realized? It is INFURIATING how little this is being looked at in the current push for renewed infrastructure here in the USA. There is so much fretting over our roads and bridges that are crumbling after a mere 50 years of use and now we are in a hurry to replace them with materials that will only last another 50 years. A small increase in material cost today could easily double that lifespan and likely well beyond.
I was involved in trying to save a building on Bradenton Beach in Florida that was leaning towards the Gulf of Mexico. The pilings under it in the parking area were falling apart and we were told to grind the steel back and we painted it with some nasty 2 part paint. Then they were patching it. That was about 25 years ago and I'd be willing to bet that the building is long gone by now. The "repair" was a joke, but not funny. I was in my early 20's with zero experience with concrete and rebar building repairs and I could see that we were putting bandaids on bullet holes.
As a structural engineer, the repair to old reinforced structures did not have the quality of concrete as we have been using for the last 20 plus years and we did not understand properly the relationship between rebar and concrete. I designed numerous large dams about the world, the oldest reaching 4 decades, it has not one sign of spalling.
@@glynnepritchard2526 please go fix Florida. There are lots of buildings with concrete and rebar damage.
@@comfortablynumb9342 would love to but dependant on the original design, materials and construction, sometimes it’s cheaper to demolish. I have HR structures in places that have higher salinity and humidity than Florida with out issue.
I think one of the major benefits is spalling resistance because of no internal pressure developing from rust. This is probably ok for flatwork and foundations but I bet it'll shine in exposed columns and beams, such as bridges.
The big concern seems to be how any of these alternative rebars perform at failure. A steel reinforced concrete beam, when it fails in, say, an earthquake too big for it, the concrete shatters out and the steel bends, so if it's engineered right you should have a chance to evacuate the building or get out from under the bridge before the steel actually rips apart and everything falls down. A lot of the non-metallic rebars, when they fail, they shatter along with the concrete, so in the same earthquake these structures are at risk of collapsing without warning.
Of course, if a steel reinforced structure is old enough that the steel has started to rust, it will collapse without warning under that sort of stress just the same as if it had no rebar at all.
Been in the rebar business for over 2 decades. Pricing and availability limit the viability of GFRP. The only places you really see it is in extremely corrosive environments, where epoxy coated rebar won't be sufficient, or in places where you can't use steel, like foundations and walls surrounding MRI machines.
alot has changed in the last few years! contact your local WhiteCaps, Carrol supply or other rebar fabricator and ask for it.
@@bornahany I have worked for rebar fabricators my entire career. I've supplied bar to everything from small town churches to 50 story towers and everything in between. The only thing that has changed in the last few years is the contract drawings seem to be less and less complete at the start of each project.
@@Chad_H that’s so true lol
What’s MRI machines?
@@stevt77 magnetic resonance imaging.
What if the framer nails it when hammer drilling for anchors, do you lose the effectiveness of the entire embedded stick, or is the damage localized? Can you tell when you've hit one like with steel rebar?
Thats a really good question!
And also, i wonder if it can be pre tensioned also for other kinds of projects like wide bridge spans.
Hammer drill would go right through this stuff without much if any warning, though I doubt the occassional hit would be an issue, the designed tolerances are not that finely tuned.
I was looking at this stuff last year(mostly research papers and how the Germans use it) for its properties to not rust but also resistance to earthquakes. It’s generally a better material but if you don’t want it to snap in sideways motions(it can swing more and recover but snaps at its limits, unlike steel which can maintain some structural integrity), you need a lot more of it and potentially mix it with carbon reinforced rebar.
I wonder too about pairing it with fiber reinforced concrete.
@@alexdrockhound9497 I think it's a very new material science and there's a lot of experimenting to do to find the optimal design for each common context. But there's a lot of potential to fix a lot of problems by getting rid of steel rebar.
@@tealkerberus748 i think the biggest hurdle for it will be that it can’t be bent on site, it has to be fabricated with the bend in it. Thats going to be a lot of trouble for economies of scale to make it cheaper, and a lot of trouble for the people working with it, and logistics challenges too for transporting the bent rebar.
Stronger, yes, but 3X less stiff than steel. MST web site lists the modulus of elasticity of their GFRP at around 9,000 ksi (9,000,000 psi). steel is 30,000,000 psi. This means the MST GFR will stretch 3X more than steel under a particular load. The modulus of elasticity of 3,000 psi concrete @ 100 lb per cubic foot is around 2,000,000 psi. Whatever you reinforce concrete with has to be stiffer than the concrete - both GFRP and steel are stiffer, but for a particular amount of deflection, the steel rebar will hold more of the load than GFRP. The fact that GFRP is super strong in tension doesn't mean anything if you have to stretch the crap out of it to get to that stress. The concrete will break long before the GFRP breaks.
Good points. Stainless rebar imo is the ticket.
That’s true! Only if serviceability is the governing design. Keep in mind gfrp only strain goes to 2% so at some point gfrp can carry more load and stretch less. The reality is in largest suspended slab to achieve the same deflection you can use 15-20% more rebar and achieve the same deflection.
However, when you are using this material on slab on grade with deflection is not a problem then you can take advantage of 160KSI tensile and use less rebar…
Cheers
@@bornahany Thanks for the info! I don't understand your "GRFP only goes to 2%" comment. 2% is part of the definition of how to compute a materials yield stress. First you measure the length of the test coupon before you apply a test load, then apply and remove the test load. If the change in length divided by the original length (the strain) is 2%, then the load you applied is defined as the yield load (divide by cross-section area to get the yield stress). I know this definition applies to metals, but I don't know if they have a different standard for GFRP. However, it doesn't make sense to me that GFRP would stretch 2% and then stop stretching.
Regarding your "15-20% more rebar to achieve the same deflection" comment - am I correct in assuming you were referring to using 15 to 20% more GFRP rebar to achieve the same deflection? This also doesn't make sense since you have to reduce the load by 3X to get the deflection to equal that of steel because when designing concrete beams, they want you to assume the bottom half of the beam is cracked and that the load at the cracked zone is carried only by the rebar. Is there a different way to compute slab stress (I don't know, I'm sincerely asking), like maybe they allow you to assume the concrete does not crack up to the neutral bending stress axis?
As long as you don't bend it, glass/polymer fibre is strong. Once the polymer is crushed, the glass fibre is prone to shear.
That makes me question its application/uses. If used in a lintel.
They are meant to withstand flex.
the tensil strenght of fiber optic is high but tying it in a knot breaks it very easy as the knot gets tighter. seems like it becomes a different substance, but it is glass so i would like to know what vibration testing has been done
@@MinkieWinkle - When using MST BAR in lintel applications, the size and quantity of lineal bars may need to be adjusted depending on the span of the lintel. Our engineering department can give direction in this regard. Oftentimes a 1:1 conversion from steel to MST BAR applies.
Worked with structural Fibre rod, installed several thousand feet of it on a 220ft radio tower in place of steel cable on a site where corrosion was a concern, mfg claimed tensile strength of 50k pounds. I was also there 15 plus years later when it had to be removed.
Long story short, the rod had begun to turn to powder on its outer layers, it was very dangerous to handle new and old. Disposal and install was annoying with handling hazards (never allow it to slide through your hands gloved or not), it had added eye and respiratory hazards during disposal from the degraded rod.
Steel is still better overall IMO and safer. My former neighbor was an iron worker who spent his career working on bridges & dams with rebar and poly coated rebar I suspect he would say the same.
good info. to the industry, lets not hastily jump on the first alternative, nor abandon the mission because the first option didnt work out
It doesn't make sense to use this as a regular rebar, it should be some sort of hollow thick cylinder that gets filled with the concrete instead. GRFP isn't suitable for this kind of narrow and solid parts.
Epoxy rebar is crap too, galvanized rebar is the best bet for the near future.
I would also mention building longevity. Steel rebar will corrode slowly even with proper cover, which limits the design life of cement to a couple hundred years depending on climate. In comparison, GFRP reinforced cement is expected to last for thousands of years. That may not be a factor for many projects but I think it is noteworthy.
you're deluding yourself if you think epoxy is gonna last thousands of years. have you ever seen a piece of composite material that wasn't yellow and falling apart after 20 years?
Thousands of years.... Thats pretty hilarious.
@@Cs13762 UV radiation ( sunlight ) causes epoxy to yellow and deteriorate. As long as there is not a chemical and/or sunlight exposure problem, epoxy based composites have an incredibly long lifespan.
@@bradhuffjr777 There is also oxidation which will also degrade epoxy over time. The simple exposure to air will degrade the epoxy over time.
@@2drealms196 Oxygen is a chemical.
I used a bit less than half a mile of fiber rebar in a 30' X 40' garage I built. It worked beautifully. However, as they said, for applications in which a lot of shear force will be applied to the bar, I would revert to steel.
As worker safety was mentioned, you definitely want to wear a mask or respirator when cutting
any chance you do a video on basalt reinforced polymer? great video.
Same stuff but it's more expensive and it's not a residential product so they won't do it here.
Matt take a look at basalt rebar, it doesn't split like fiberglass bars.
Yep. Came here to screech this. GFRP is a temporary, cheap solution. Basalt Rebar is woven volcanic fiber and will outlast all of us for generations.
I've used the basalt, the gfrp and steel rebar on multiple projects. We've figured out the gfrp with the Kodi Clip system ends up being the Best overall solution. There's a little cost of entry but overall at about 20,000 square feet you've broken even and you've tripled or more your speed of installation. We also have a lot less problem with blowouts from incorrectly embedded steel. We're getting to a point where as soon as we can figure out the carbon issue concrete might be back in Vogue for almost all projects.
looking forward to the Vogue cover page…
Isn't the issue with GFRP/basalt rebar that it doesn't flex like steel, which I've heard you want for walls in earthquake prone areas?
You generally don't need tensile strength as much as flexural (?), right?
Also, where did you get the basalt rebar in the states? How did the price compare to GFRP?
@@MadLadsAnonymous that was a question that I had for the engineers because that's what I had always heard. They clean the overall strength is equivalent to steel. It just hasn't been tested to the extent of steel yet. It's being used in vertical applications all over the world and here by (at least) me. We were also told that we weren't allowed to use the Kodi clips on vertical due to them not being tested. Pretty ridiculous if you've seen how they work and on projects like I do with the amount of plasticizers we need to add to the mix for flow. You just need to get an engineer understands construction instead of whatever is on his computer screen only.
@@MadLadsAnonymous I come from the corporate world before I got into construction, specifically branding and sourcing. I just bring it in from overseas. It ends up being about a third the cost of steel here.
I first used this reinforcement in the Netherlands (then under the name ComBar) as a chief strucutral engineer of a precast concrete factory in concrete walls, where it supported the thinner faced concrete, thus acting as a thermal barrier (and no risk of corrosion). While some properties are better as opposed to regular steel rebar, the low adaptability on site (or even in a precast factory) is a major hindrance. That and the Eurocode has low adaptibility to replacing the steel for GFR. A lot of the formulas in the code have a basis in the fact that concrete structures warn the user before they fail (by cracking in a certain way for example) -- what does astructure say when the material stretches far more easily?
Essentially the only requirement is that GFRP is less fragile than concrete -> the reinforcement needs to be able to stretch more than concrete. Of course too 'stretchy' reinforcement will grow crack sizes and effect sustainability.
I've been using gfbar for at least a decade in swampcrete. it's so hard to find bar that isn't corroded in my area, this stuff rules in wet areas
I would love to see this rebar under a load test. Any videos out there?
Tyler Ley's Channel may have something
How does it hold up in fire (heat stress) compared to steel?
if you are cutting the Fiberglass rebar you also must wear N95 dust masks because of the fibers flying around
"Not sponsored, but they did give me a discount" LOL I love your videos, but that is silly.
Steel rebar may turn into powdered iron after 50+ years in concrete. I saw concrete reinforced with steel rebar, at a 70+ year old church that was being remodeled in a west Chicago suburb. The steel rebar had turned into powdered iron and had zero added strength to the concrete floors it was in. Very scary! GFRT can be driven into the ground with no effect to rebar, unlike steel rebar which cannot touch soil.
Probably because of a very poor cement or concrete mix quality. The correct mix and materials are as important as the rebar.
@@ramireznoythat maybe but you wouldn’t find out till years later. Need something better.
@@do4267 Oh! sure you can from the beginning. Just follow the recommended dosage. You can not expect to have anything durable just with a mortar mix or leaving the steel to close to the surface.
Some people even use ordinary Portland cement for reinforced concrete. So no wonder why the foul result.
There are plenty of reinforced concrete structures standing time pretty well all over the world. Even near the sea and some IN the sea
Surprisingly, reinforced concrete structures are only rated for about a 100 year useable lifespan. This is because the steel reinforcement does deteriorate over time. Romans didn’t use rebar and some structures are still standing.
The worrying thing is seismic. If it turns into 100% powder at 70 years, how much strength has it lost at 20, 30, etc years? It wouldn't matter until a once every 20 or 30 years earthquake happens and then your basement wall reinforcement fails.
I spent a bit of time researching this... positives: + higher tensile strength, +lighter , +corrosion resistance, +lower-install-costs; negatives: -fire resistance very low, -no-ductility, -low-shear-resistance, -higher-cost-of-material, -not-site-bendable.
Questions: bond strength vs black bar.
Isn’t rust an ever-present property of steel rebar, due to the moisture intrinsic to concrete?
It needs water and air to really rust. So if it is covered properly, it isnt rusting
What about using both steel and fiberglass? Steel for the corner bends, and fiberglass for the straight runs?
I'd say about 65% of the stuff shown on this channel makes me think I should consider that - this was a big swing and a miss as a consumer - it might be interesting for a builder though.
This would be a perfect product for pumicecrete walls and roof
Would be interesting to see fiberglass reinforced concrete as a mixture.
I know some people in Switzerland were playing with this where they added, like little fiberglass threads inside of the concrete mix, allowing you to pour the concrete as though it is reinforced without actually having to do the work of the reinforcing. The other benefit is that it becomes a homogenous material. It truly is reinforced throughout the entire assembly.
That product is widely available and used in low-strength applications like patios and front walks. I don't know how well it really works, though.
It does add homogenous tensile strength and reduces cracking but it's not a substitute for rebar when you need force distributed across the length of a beam or slab. On larger pours it can also cause the fibers to be unevenly distributed as a factor of fluid dynamics.
@@Suavocado602 thank you for the answer there, that makes sense, it would be hard to create a close to homogenic mixture with such different materials.
That said , concrete by default is aggregate and cement and stays pretty well mixed, by virtue of the rotating cementtruck drum.
I guess I’m curious why this is all that different? Given large particles tendency to rise and different densities, etc. working well in concrete already?
@@FreekHoekstra the issue I'm referring to has more to do with the alignment of the fibers that change as it flows. That said, high performance fiber reinforced concrete has come a long way in the past decade. Iran made some very durable bunkers using the material so maybe it's been solved by now.
Search - - - steel fiber reinforced concrete
Questions:
1. How does the cost compare to steel rebar?
2. Can you mix and match rebar types in the same build (assuming it's accounted for in the design)? E.g. Using fiberglass for straight sections, using steel for bent ones.
3. Being only 25% less weight than steel doesn't sound right - are you sure it's not 25% of steel weight instead?
1. Generally speaking, the cost of MST BAR is very comparable to steel rebar. The price of steel rebar is known to fluctuate significantly, whereas the price of MST BAR holds quite consistently. An ICF building for example, often will see an approx. 15% reduction in rebar price when compared to steel rebar cost.
2. Yes, using both MST BAR and steel rebar in the same wall is acceptable. There is no chemical reaction between the steel and MST BAR in concrete. Obviously, to avoid corrosion, we recommend using only MST BAR.
3. Yes, the weight of MST BAR is 75% LESS THAN the weight of steel rebar. This was misspoken during the video clip you are correct.
It totally makes sense. The only issue I see is that buildings are torn down for one reason or another. At job sites I see piles of materials for recycling. A pile of concrete chunks here and a pile of mangled rebar there. When it comes time for crunching concrete laden with fiber-reinforced polymer bars will there be any issues? Does it even need to be separated? Perhaps some buildings are torn down due to spauling. So maybe fewer demolitions will need to happen.
When recycling concrete which has been reinforced with MST BAR there is no need to separate the MST BAR from the concrete. Everything can be ground together back to its original state of sand and stone.
They call me steel rebar because my pullout strength is weak
On the recycling aspect, I have a local concrete recycler that charges extra for concrete with rebar, I wonder if this fiberglass rebar would feed through the machine in comparison to steel.
When recycling concrete which has been reinforced with MST BAR there is no need to separate the MST BAR from the concrete. Everything can be ground together back to its original state of sand and stone.
The final recycled product would prob benefit from the polymer and glass tbh. It's like glass fiber reinforced concrete along with polymer modified concrete
Curious as to mingling GFRP and steel. Lots of comments about the sheer strength questions on GFRP but also curious about job site changes when concrete delivery is imminent.
Mingling MST BAR with steel rebar is acceptable.
basalt rebar seems more interesting as an alternative, steel rebar most important quality in the market place is its ability to be made from recycled steel and be recycled again in the future
I will not trust fiber rebar for a simple reason: the fail mode is always going to be a catastrophic failure (engineeirng terms used quite a bit in mechanical/material science engineering for a sudden and unobservable failure) in fiber rebar. Fraying can be an issue, fatigue related surface-bonding between fiber and resin can be an issue. However, I will trust fiber in concrete since their thermal expansion constant is almost identical which will increase quite a bit of surface strength and gives concrete more self-healing cabilities.
I will use ASTM2205 duplex or some other grade duplex stainless steel as rebar: they are much easier to handle in some salty/marine environment (Duplex behaves well under load and Chloride environment .... to be honest, Duplex behaves well in many environments and it has been used quite a bit in offshore drudger/oiler). They have proved their worth in the UAE and Shenzhen which are both hot and humid (especially the latter is humid as hell and the one using it is the largest insurance company in China). Stainless steel can be prone to catastrophic failure, but Duplex behaves much more like their ferric cousins
would like to see that actually
@@MultiYlinA la that carbon fiber submarine…
@@jon4715 I dont get why people still think X-FRP is some magic spell for everything ... I can see the use in cars or aeroplanes (even aeroplanes are used in great cautions which added quite a bit of ground crew works to ensure the CFRP ... I bet A350 is a much better planes after 10 years of service ... the CFRP head is rather stupid)... and I dont think buildings should have a planned obsolete like cars or planes.
Cost is important if you can't use it on every job it's not worth it . Working with fiberglass, you need ppe gloves , masks, respirators, cutting shields , and long sleeves .
what about the difference in thermal expansion. steel and concretes mostly match
MST BAR has almost the same expansion as concrete in longitudinal direction. Moreover, MST BAR maintains its very high bond strength to concrete through temperature fluctuations. Simply put, MST BAR performs very well under these conditions. This is one reason why many municipalities are regularly specifying MST BAR for infrastructure, highway and bridge projects.
how does this compare to Helix microrebar?
Good question
MST BAR would be more comparable to steel rebar for use and installation. MST BAR could and has been used alongside a product like this if required.
@@g2buildingproducts But it's still a big bar versus micro rebar which is tiny little fragments that form a binder on a micro level.
@@rockys7726 Very true. This is why, any product used must be engineered for proper application in any given use case.
Any data available for use in ICF construction?
Why would the data be different for ICF versus any other application? The mechanical properties are independent of application.
@@D2O2 because GRFP can be smaller in diameter, which MAY allow you to use a 6" ICF block instead of an 8", which is normally not a good idea because it's hard to fit your hands in to tie the bar.
I’m in SE WY and last year, it was not approved in foundation walls or ICF walls. Not sure why but as the engineer mentioned, it does not have good sheer strength and not recommended for connecting sidewalk/driveway to house. Hood that helps
@@LukeFinley-d4c the mention of shear strength is what had me wondering - thanks!
Seems like a big deal. All concrete eventually cracks and exposes the rebar to eventual rust (if not actively maintained). Wonder if this could extend the lifespan of reinforced concrete beyond a couple hundred years or so, though I worry about the longevity of those polymer bonds.
Yes, MST BAR, fiberglass rebar holds the advantage that corrosion does not affect the reinforcement when exposed to cracking or moisture. For this reason many salt water areas, break walls, bridges and other standard applications enjoy lower maintenance and longer lifespan on the concrete MST BAR is reinforcing. MST BAR will outlast the concrete!
As you don't mention it, I guess thermal expansion and conductivity are not of concern in Texas? Otherwise, fiberglass rebar having a thermal coefficient that is much close to that of concrete and being less thermally conductive are advantages in rest of the world.
MST BAR has almost the same expansion as concrete in longitudinal direction. Moreover, MST BAR maintains its very high bond strength to concrete through temperature fluctuations. Simply put, MST BAR performs very well under these conditions. This is one reason why many municipalities are regularly specifying MST BAR for infrastructure, highway and bridge projects
I'm curious about breathing the fibers. When we do fiberglass insulation we have the same cactus in the hands feeling if not wearing gloves. We also make sure we are wearing masks.
I hope this isn't going to be an asbestos-like problem in later years when people have to do demolition.
MST BAR does not release fibers. It has a different molecular structure than fiberglass insulation. Cutting MST BAR produces round dust particles similar to cutting stone or wood. Although there is no specific health risk in cutting MST BAR, personal protective equipment (PPE) should always be worn.
If this becomes the industry standard where does the glass come from? I’ve heard that sand supplies for concrete are dwindling. Is that true? If so, what about the sand used for glass?
We are of the belief that there is plenty of sand available on the earth to support our industry requirements indefinitely.
What about the difference between adding fiberglass fiber to your concrete mix vs fiberglass rebar?
MST BAR is comparable to steel rebar for installation procedures. This product is a different category with different installation procedures and requirements. Our understanding is, some form of reinforcing bar would be required to go along with the fiberglass fibers.
Nice to see it in Amerika....But in my eyes you did not adres one of the main plus points of this material.....ea its non conductive ness....
About 15 + years ago when i was stil in construction and i worked as a cad designer at a structural design company i came across this type of product and they had a presentation at the company i worked at .....
I was working at that time making plans for a new hospital wing here in Holland where we had to make an M.R.I room....
And normally these rooms are like bunkers because of the magnetic interference etc etc causing lights to flash etc when not built to standaards.....
Wel i asked them if this would help and you guessed it it does.....
We could make the walls of that room a lot thiner etc etc....
It was as far as that company here said the first to use it for that purpose Although they were using it at that time in Tramway Foundations on bridges to also not let signal current leak out which was causing fals red signals to trip.....
So yes another great benefit you need to consider for this material.....my client was certainly happy as far as we know it worked and did the job....it saved a lot of hassle and money for them....
Just wanted to let you know
What I would love to see this product used in bridge decks. Can't tell you the number of times I've seen bridge decks being rehabilitated by removing the brocken an up heaved concrete, cleaning the rebar and pouring more concrete. To use this on current decks it would require more work but the future savings would be worth it.
In our area, the cost is basically identical. Some of the gfrp bars are for horizontal applications only.
I'm a bit surprised about the mention of concrete sprawling and rust on a sidewalk. In Canada, many sidewalks don't even have rebar in them. They just don't need it to do the job that they are expected to do, and mind you, we do run sidewalk plows on them during winter. A 10 centimeter thick slab with compacted stone under it is more than strong enough in most cases. We've got a fair bit of clay in our soil, and despite that, we generally don't have much of any problems with our sidewalks.
there's a lot of softer soil in the US, as well as not having mountains and stone quarries everywhere.
Sprawling? The word being discussed is spalling not sprawling.
Does it expand thermally in the same ratio compared to steel rebar? one of the nice things about concrete plus steel rebar is that they kinda shrink and expand in the same ratio under thermal loads
MST BAR has almost the same expansion as concrete in longitudinal direction. Moreover, MST BAR maintains its very high bond strength to concrete through temperature fluctuations. Simply put, MST BAR performs very well under these conditions. This is one reason why many municipalities are regularly specifying MST BAR for infrastructure, highway and bridge projects.
How are you bending it
He said at the factory, nothing on site
Any shapes (hoops, stirrups, bends) are formed in the manufacturing process. As the warm materials come out of the pultrusion machinery, they go directly into a jig for forming to the required specifications. Because they are formed in a jig, each piece is identical. There is no variation in the shape or angle of the bend.
Biggest downside is you can’t bend it on the job site… that’s all
What about the fibres upon cutting, are those fibres as abrasive & damaging as Asbestos?
MST BAR does have the carcinogenic characteristics that Asbestos has. Cutting MST BAR produces round dust particles similar to cutting stone or wood. Although there is no specific health risk in cutting MST BAR, personal protective equipment (PPE) should always be worn.
Rebar should have bends in it, you can’t bend fiberglass rebar, no good.
You can bend fiberglass, you are thinking of carbonfiber...
We only use rebar when joining old to new, plus an expansion joint to prevent the inherent damage from new joined to old. Maybe glass highway mesh? How do you make hoops for ladders and sono tubes? Are the laps the same as with metal? Are they tied with wire ties vs. welded?
All shapes are made in the factory when the polymer is ' plastic '.
Any shapes (hoops, stirrups, bends) are formed during the manufacturing process. MST BAR is manufactured to spec using custom jigs for forming. Because they are formed in a jig, each piece is identical. There is no variation in the shape or angle of the bend. We also avoid any breakage during production that may be experienced using steel.
Laps are the same as with steel rebar. MST BAR can be tied with wire ties or zip ties but cannot be welded.
The thing about recycling steel rebar is that it's likely going to be stuck in concrete for 50+ years. If you were ripping it up every decade, the recycling value would cut hard into the GFRB's reduced carbon advantage but if both are going to be in use for the better part of a century before either is going to ripped out then it's kind of a moot point. Besides, the advancements that have been made in the last decade toward successfully recycling fiberglass wind turbine blades are any indication, you should have no issues recycling the glass rebar when it comes time to do so.
Basalt fiber!!!
If you are doing a project and want it to last a 100 years, you don't want steel rebar. I have inspected many buildings and concrete rot is real on buildings past 50 years.
No bending on site sucks.
Did Matt mention anything about the Fiberglass rebar's compression strength? We know it performs well in other areas besides shear. Curious to hear if the compression strength of the fiberglass has a similar or even better testing result as the steel. Its stiffness properties when used in a vertical manner would make me a little concerned.
Basalt rebar also - less beach sand, more rock..
Hint GFRP IS FibreGlass Polymer/Crosslinked Plastic, Composite - loves calling it Polymer, I go with Plastic (it means the same thing - trolls the "academics")
Yeah the discount on the product is the same as cash. So, sponsor by any other name.
getting it for free, being paid to use it or giving a discount to bring it inline with the cost of steel to offer a comparison are each different things. Thanks to Matt for being on the up and up.
@@atyt11 I think he's legally obligated to be "on the up and up". I'm sure he and his sponsor would love to be able to omit that detail. The law is there to help mitigate the kind of exploitation Matt's business is based on.
Fiberglass rebar would be good for swimming pools
Yes, MST BAR is fantastic for swimming pools and is rapidly being adopted by the pool industry.
I believe even cured concrete is always considered electrically conductive because the water content never goes to zero?
I thought the epoxy coated rebar was very bad? Because any break in the coating would allow moisture to spread by capillary action and cause unseen oxidation of the steel?
Since any steel rebar is exposed to this concrete moisture content for the life of the structure. Isn't the formation of expanding rust (iron oxide) inevitable for most structures with steel rebar reinforcement? Obviously salt water exposure probably accelerates this process. Especially after spalling or cracking is observed.
Most of the beautiful historic bridges over the rivers on the coastal Oregon highway have had accelerated damage from this problem. I believe there are extensive and expensive remediation and monitoring programs addressing this issue ongoing.
Conducted by my Alma Mater, Oregon State University. Go Beavers.
I've lived in NW Texas for 30+ years. We don't see high humidity here at all. But cement here still has a finite life.
I saw a short video about how Roman concrete still stands in Europe. Because of better design of, even very large, masonry structures. I don't remember any details about how the concrete/mortar was different. However, it sure has stood the test of time.
I think it's a very bad idea in many applications. Steel wil flex but fiberglass rod will shatter. Long term, I think the idea sucks bigly.
Can't you deform this stuff with a torch?
Deforming MST BAR with a torch (i.e. to make bends on site) is not an option. Bends are made only during the manufacturing process. Some choose to use MST BAR straight bar and mix in their own on site bent steel stirrups.
Worker safety: Particle release on demolition, so wet the material to minimize particles becoming airborne. Though once materials dry, if exposed to air, particles can become airborne.
Will this bar require a higher density bar array due to lower shear strength?
No more rust removal before the pour? I like that.
The stuff made from remelted lava works well, but it is hard to find.
6:12 “ Sidewalk “ spalling & de laminations. DURABLE, reinforced concrete 👍
There are obvious pluses and minus' for both products but I don't think that GRP rebar is a wonder material, its just another option. You only have to look at the way fibre reinforced concrete has not taken over the market as was originally expected. I see two downsides for GRP rebar:
1) The fact that it cannot be bent on site or at the suppliers, any bent rebar has to be specially moulded, which is OK for major works or those of a very simple nature but you can bet that it causes a real headache for the sites as a special order has to be placed just for the one length that you are short and you can also guess that delivery may be extended. This compares with on site bending of a piece of steel rebar that you probably bought from the merchants an hour ago.
2) In UK we use a considerable amount of weld mesh reinforcement, particularly for floor slabs and clearly that option is not available in GRP.
Cost diff? Great content thank you as ever!
Generally speaking, the cost of MST BAR is very comparable to steel rebar. The price of steel rebar is known to fluctuate significantly and is quite different dependant on geography, whereas the price of MST BAR holds quite consistently. Many builders report savings on both materials along with high labor cost savings when using MST BAR.
One difference is that the steel rebar can be used as an effective grounding system is some cases, where the fiberglass rebar can't be.
I think the industry is moving away from the epoxy coated rebar now because they found that when the epoxy gets nicked (like it inevitably does), water gets under the epoxy and then is effectively trapped inside and the deterioration begins. I’ve used a fair amount of galvanized rebar on jobs exposed to harsh environmental conditions. I haven’t been around long enough to know if it surpasses the standard 100 year expected lifespan of standard rebar 🤷♂
I can see this being less expensive on a large job just because it's easier on the workers (easier to move around the site, less tired, less mistakes).
But, the part I'm wondering about is temperature related expansion and shrinkage. I don't know if it's true, but I've heard that steel rebar expands and shrinks by the same amount as concrete, reducing damage to both materials due to changes in temperature causing them to expand and shrink by different amounts. For me, this makes me wonder how well this holds up in areas where the temperature can be 0 degrees F in the Winter and 115 degrees F in the Summer?
You don’t need to use rebar at all if you just use fiber reinforcement but not the garbage that the concrete companies try to push on u. For every yard of concrete throw in like 5 -6 Oz of chopped fiberglass fibers, doesn’t sound like a lot but it is like a lot a lot. Then throw in some concrete solidified like s2000 and your concrete will not ever crack apart. Tell the driver to spin that on high for like 5 minutes and those little fibers will mix through the concrete and it will bond together so tight it’ll be harder then engender quartz.
Bamboo is stronger. namely Bamboo Veneer Composite (BVC) and Bamboo Strand Composite (BSC)
I appreciate that you did not do the annoying intro on this video, that’s a really great improvement. Now you just have to get rid of the squeaky voice outro and I can start watching and liking all your videos. Sorry Matt, but the accentuated voices you typically make on the intro and outro are no bueno. It gets hard for me to watch what would otherwise be great videos.
“Not sponsored, but they did give me a discount”. Well isn’t that a kind of sponsorship?
I can confirm fiber glass or pink bar is better. Anytime I’m breaking concrete with steel rebar, the concrete just sheds off. In fact a weak point during the demolition process
Basalt bar I believe is better than steel and fiberglass.
I was always taught you want reinforced concrete to fail inelastically so it doesn’t snap/fail with no warning. Sounds like this can’t do that.
Well if price will not get down then use of it is small.. after all If cost is up to 50% more than normal steel..well not likely ..it doesn't wight so much..nobody cares..if you build your own house you do it once and you are done and if not you could order two 3 more ppl to help you and it is still cheaper..
It has benefits on other side..yes and big ones ..but only if your base is not properly designed with no water in mind..after all that is what will kill your steel ..water..not time as such..
Pro tip from my dad when i was getting into the trades(plumbing) never get good at concrete. Or they'll want you to do concrete....
Between not rusting, and probably being closer to the thermal expansion rate of average concrete mixes, it should be superior all around.
Modern concrete admixtures are so good, that it basically makes the steel last long enough to make it more attractive th fiberglass. Fiberglass has been added to concrete for years as fiberstrand, or toughstrand. the biggest problem after this is, you cant bend fiberglass bar, so i assume you have to special order any pieces that arent straight. since its creation decades ago, numerous other reinforcement methods have been put on the market. instead of tough strand you can get a stainless steel strand additive. lastly, concrete was perfected in the 50s and 60s, i can show you concrete structures that were built in the salt water in the 50s, that are still fine today. not a rust stain in sight, and zero spalling. Its just that a lot of people do not know how to do concrete properly near saltwater
Concerning the yield strength, this is a negative. Using a reinforcement in beams that has high yield values will leave to catastrophic collapse rather than noticeable cracks that can be investigated and repaired. That being said for low rise structures this product will do well but Ill stick to steel on my high rise.
I've always wondered about steel rebar........so old bridges are really sketchy
I was thinking about buying some but where I live the cost was more than double that of steel. The fact that it didn't bend made me concerned about the strength at the corners too so I went with heavy trusty steel. I do look forward to seeing cheaper fiberglass rebar in the future though.
One place that that weight must add up is in high rises though. Are high rise buildings using this more to reduce their weight as they go up and just using steel where bends are needed?
I would love to see you bend fiberglass rebar. End of story, just keep using regular rebar.🎉
Concrete will spall all day long without any rebar in it, so it's not accurate to automatically attribute spalling to the steel rebar. People act like shear strength isn't a factor in walls for instance, I like some benefits of fiberglass, but I personally feel better about a steel grid resisting lateral movement in a wall.
Looks like we will still get impalement injuries. Seriously, the no bend thing is a killer. I would think at least it would end up used in combination.
😂 leave it to the experts engineers to decide to use a heavier grade bar than the maker recommends. Reminds me of the early adopter of fiberglass boat manufacturers who used real thick laminated fiberglass to build the hull and then someone else figured out that fiberglass was so strong that a thick layer was not needed.
Fibreglass glass and glass fibre are the exact same thing.
The magic of rebar and concrete is they both have exactly the same coefficient of expansion…
You said it was not the same as fiberglass and justified that by describing it in a way that perfectly matches fiberglass.
Without getting too technical "fiberglass" to the general public is the sheet goods you can buy in a Bunnings or the like to fix your boat or car. In industry there are many many variations of GFRP for many purposes. One would need a full data sheet to really know exactly what is being spec'd here.
The greatest benefit I see over steel is the issues with steel Spalding around homes exposed to saltwater... Huge benefits how do you cut it?
So salt water won't ever corrode the rebar even when you have incompetent installation?
I guess you can fabricate the odd stirup or fabricated piece out of steel rebar when you have a need.
saw someone get a splinter of it in his belly, No pulling it out they cut a core around it..