Testing fiber reinforced concrete with an expert

[@nashsteve25]

I never thought anyone can make concrete videos so interesting.

[@TylerLey]

Thank you so much!

[@jeffrey1312]

I had a long and wide walkway poured with added fiberglass. It's been 15 years and it still has not cracked. Money well spent.

[@TylerLey]

Thanks for sharing! This type of information can help make others more confident.

[@USAFreedom4Ever]

@@TylerLey it would be cool to see fiberglass in your test. That’s what I hear more of than anything else as far as an additive. Also added cost on all of them would be great.

[@mhx6437]

@@TylerLey Hey, I wonder if it is sometimes a good idea to implement a mix of both rebar and fiber? Are there cases where it is beneficial?

[@Dadnatron]

As a consumer, I’d absolutely pay for fewer and smaller cracks. I’ve put in a little concrete on my own farm, and my slabs invariably do better over the long haul than when I hire out. I take my time, use good prep and compaction, superplaticizers, low water, slow, covered curing, and fibers. The last ‘professional’ concrete work I had done, the guy putting it in, told me at the very beginning, “there are 2 types of concrete… concrete that has cracked… and concrete which is yet to crack.” I took it as him preparing me for shitty slab. And he came through. It was cracked within 3 months.

[@TylerLey]

Those stories are tough to hear. I am glad you have had success when you did it yourself.

[@travisjazzbo3490]

Yeah. I don't trust concrete contractors to prep the surface well with strong compaction. They may do some, but never enough. Also, some don't use chairs for the rebar; they just try to lift it up as they pore. I don't trust that either.

[@elbuggo]

@@travisjazzbo3490 To me it looks like they are only rewarded or paid for the finishing. Sloppy compacting and preparations will typically not make them less money. Just get the concrete in there, make it look good, and all is well! Don't need no curing!

[@USAFreedom4Ever]

Yeah, I’m really sick of that comment two types of concrete. Basically too many guys out there with half a brain talking like they have a full brain.

[@Ariccio123]

​@@USAFreedom4EverNo, their brain is definitely full! Just full of concrete instead of neurons 😆

[@mikkoekstrom8109]

I make concrete tables and counter tops. I use plastic and basalt micro and macro fibers extensively. They are totally worth the extra expense. I've used them also in making concrete pavers. They allow considerable material and weight savings which turn into savings in labour and transport costs.

[@TylerLey]

Thanks so much for sharing!!!

[@philthisup]

How thick are your tables? I’m trying to make lightweight concrete panels (say 1” thick around 4’ x 8’ size) it’s only if we’re aesthetics on walls. I have an architect wants me to do this. I’d rather not use 1 inch thick concrete. Can be rather heavy. Thoughts?

[@mikkoekstrom8109]

@@philthisup I made a prototype that was about 12mm thick and was about 500mm by 1000mm. In stress testing it was strong enough to be a writing desk and you could use it as a support when getting up but it cracked when about 50kg of weight was put in the middle. In this configuration the support points for the table top were 150mm away from edges leaving a space of about 800mm by 500mm for your legs. What you propose (4' by 8') sounds feasible at thickness much less than 1". If the panels are strictly aesthetic and are well secured against a sturdy level wall, I think you could get away with a panel thickness as thin as 12mm so long as you use proper reinforcement. This table used a combination of basalt fibers of various sizes, basalt fiber mesh and basalt fiber rebar of a very thin diameter (between 4 and 6mm if remember correctly). While this technique makes the panels flexible (you can see visible bending without failure when force is applied) but careful handling of the panel will be necessary. Proper curing process must be observed and you need to carefully think before hand how you are going to attach the panels.

[@mikkoekstrom8109]

@@philthisup One more thing I forgot to say. I also use a special ultra high performance concrete (UHPC) mix which I make myself. I don't think any regular concrete mix can get you this thickness without failing. My mix uses extremely low W/C (~0.3) and silica fume along with other special added components. Use of superplasticizer is a must and to achieve proper mixing of the ingredients is extremely important. I also use high quality white cement as the binding agent because it has higher strength then the regular cement varieties sold in here. I then add pigments to achieve the desired color, usually black or dark gray.

[@philthisup]

@ Thanks for getting back to me

[@perryallan3524]

I hope that future testing includes SS rebar with SS fibers. That solves the long term rusting issue with steel.

[@TylerLey]

Keep watching! I think there are some cool things that we can do with this test.

[@mikemorgan5015]

There is a galvanized rebar supplier at the Port of Catoosa outside Tulsa, OK. Looks interesting. I can only imagine the cost of SS rebar and the problems bending cages with it. Hopefully Tyler will comment on that too.

[@perryallan3524]

@@mikemorgan5015 Galvanized and expoxy coated rebar has not worked out as well as it was thought. Every defect and the cut ends are ripe for very rapid rusting and corrosion. There are multiple grades of SS rebar and SS tie wire - and at least some of them can be bent. My understanding is that overall SS rebar typically adds 5-7% to the cost of a project. But totally stops rebar rusting and related concrete failure in the future. A lot of bridges are now being built exclusively with SS rebar and tie wire. Nuclear power plants as well (where they are hoping to run the new reactors for over 100 years).

[@mikemorgan5015]

@@perryallan3524 Cool! I knew about corrosion creeping extremely fast under epoxy coated rebar through nicks and defects. I can see the same with galvanized happening. Makes sense.

[@perryallan3524]

@@mikemorgan5015 My understanding is that while galvanization provides better protection than does epoxy as the adjacent zink will sacrifice itself until the rust defect overcomes it... but the long term results are the same as the rust keeps growing. One comment I heard (not sure how accurate) was that galvanization lasted about a decade longer than epoxy in most applications. Still not long life - and still failed concrete reinforcement. So there is perhaps a use for planned shorter life concrete. But, any concrete strucrure I plan on I feel should last hundreds of years - and I've been dreaming of thousand year+ concrete.

[@jacobdumars4515]

That's why some contractors burn off the fiber from the surface. They have a crew that knows how to finish the surface with high doses of fiber.

[@Bowie.]

I found your vids about fiber last year before I poured my first slab and I'm really thankful for the education bro. Very empowering.

[@TylerLey]

Thanks so much! I am glad it worked for you!

[@markstipulkoski1389]

Tyler. Please do videos on ICFs. ICFs provides a great environment for your precious concrete to cure. Throughout it's lifetime, ICFs reduce the temperature extremes that it will experience. There are academic papers that say laterally constraining concrete makes it stronger meaning less concrete needed.

[@ItZxDraW]

Please Videos on thin concrete surfaces! Testing how thin you can go on a concrete bench that holds a person would be very interesting. Love your videos, great channel!

[@michaelclark7602]

Well, I've been a general contractor for over 10 years, and we've had steel building foundations that were 6 inch thick slabs, 3 foot by 3 foot footers, double Mat. Rebar, one foot on center and fiber mesh concrete, and they still cracked

[@elbuggo]

I don't think rebar will eliminate cracking, but if you use more rebar, the cracks will be smaller.

[@SpaceCrete]

Nice testing! Almost always use fibers in slabs, but there is one more downside that causes high-end artistic contractors to avoid fibers. Lack of dispersion - that leads to small clumps at the surface. They don't show right away, but after acid etching or weathering, they do. Eventually leave surface pockets. This is at 1.5 to 2 lb per yard of fiberglass fibers (what the batch plant says - they think that 2 lb is way too high, and still did not stop all visible cracking). So, been testing PVA (PVOH), Basalt, Acrylic, and Aramid (Kevlar), and fibrillated PE minifibers for overlays. So far, so good. Medium/small combo works! Such as basalt/pva. Have had steel fibers puncture embedded PEX heat-system tubes (finisher stepping on it?), which was really really bad. You can see amazing results with strong-bonding synthetic fibers that work at lower doses (NOT nylon or maybe not polypropylene). Now prefer to keep it around 1 lb per yard, but of really effective material per pound. Still learning.

[@elbuggo]

What do you pay for 1 lb?

[@SpaceCrete]

@@elbuggo Retail is al over the place. Acrylic are the most reasonable. I use ICF brand (not the foam forms) - confusing! Combine 1/4" with 3/4" for nice result on thinner placements.

[@TylerLey]

@@SpaceCrete Thanks for the reply! It sounds like you are using microsynthetic fibers. I have not heard of the problems with the surface pockets, but that makes sense. I will have another video where I talk about testing microsynthetic fibers. They are best for plastic shrinkage cracking. I typically use them at 1lb/cy. Some of the best microsynthetic fibers work well at 0.5 lb/cy. This should help with balling.

[@NitroAuto77]

@nobreighner same issue here. 1.5" fibrillated microfibers at 1.5 lb/yd. Burnished finish. Anywhere fibers lay horizontal is a superficial weakspot or crater. Investigating different fiber that can be consolidated better or better techniques like vibrascreed or rollerbugs.

[@SpaceCrete]

@@TylerLey It was fiberglass (supposedly), the default choice from the batch plant. Just got some kevlar to test.

[@somedude-lc5dy]

Tyler, one consideration with the different fibers should be longevity. if poly fibers are great but fall apart after X time, while glass fibers never degrade, then that might be a consideration for a client.

[@jackdbur]

The latest is PET fibre recycled from pop bottles lasts for longer than you ever will! 😊

[@uandmeus5]

I poured my shop foundation with fiber reinforcement and no rebar except in the footers and so far so good. Burned the finish with no fibers being visible. The cost for fiber in Arizona is negligible. I won’t even think of doing a concrete pour without fiber. My next pour is 20’X40’ approach in to shop and plan on using fiberglass rebar and fiber reinforcement. Material manufacturers are using fibers in asphalt now as well.

[@haythamibraheem8323]

I wish you talk more about the applications of steel fiber reinforced concrete. In one of our projects, we proposed a value engineering solution to replace the rebar reinforced rafts with hybrid reinforcement (rebar + steel fibers ). But, we faced resistance from the project management consultant claiming that SFRC is only applicable for slab on ground.

[@TylerLey]

Thanks! This is a good idea for future videos. I talk about this a little in my video "5 proven strategies to make green concrete". I agree that more indepth discussion is needed. Unfortunately, there are not a lot of agreement on the best way to do this.

[@rs2024-s4u]

Why did you not include besalt fibres a natural stone product so adhesion is excellant and product thermally expands at same rate as the concrete and is 3-5 times stronger than steel. Second for me curing has been my preferred method for maximum crack reduction, If concrete is kept uniformally wet/hydrated and not allowed to dry from any surface unequally the internal stresses created during curing are eliminated and so are the primary causes of future cracking. Lastly you did not mention that fibreglass type fibres should never be mixed into concrete for more than 10-15 minutes prior to placing they will seperate into individule fibres and become useless. Further if one uses besalt rods and or besalt mesh stresses and adhesion issues between concrete and reinforcing materials is eliminated while eliminating future spalling entirely and getting a stronger crack free pour at same time. The 28 day wet curing does not cost much other than the time to cover concrete with visqueen or re-wet daily during 28 day cure, and finishing properties are not changed. Federal and state DOT have made wet curing (covering) a requirement for highway structrual members for decades and this has allowed/helped concrete supports to remain free from cracking for decades. Ray Stormont

[@nevertolatetoprepare2802]

Do you mean "basalt?"

[@rs2024-s4u]

@@nevertolatetoprepare2802 Typing skills 0 you're the first to bring this misspelling to my attention, Thanks, It took three months for someone to notice. Ray

[@muhibmishu9597]

Your videos are really educative and fun to watch, Sir. Inspired by them, I also researched fiber-reinforced concrete last year and was finally able to publish in a journal!

[@mikemaj8467]

@Tyler Lay You mention the percentage that cracking is reduced. I'm curious to know how maximum load was is compared with regular concrete as well as concrete slump testing results. Great video!

[@danvanf]

I have 50 yards of fiber reinforced concrete with no rebar in the slab installed in 2006. It has performed very well. I only have one unexpected crack. Finishing was not bad, part of it is slick the rest broom finish. It is cut in about 10' squares.

[@1965kiran]

loved it you simplify complex issues.

[@microscopicexplored8346]

I work in concrete structural design for 15 years. Most people do not realize, concrete is expected to crack. Normally it's not a big concern unless agressive salts can propagate through the gaps and cause rebar erosion.

[@robnowe5464]

YES! I would and will pay extra for the benefits of fibers including reducing crack sizes to < 0.4 mm

[@huckleberrysundry]

Great video. I've had good an bad experiences with adding fiber. The first (good): 6lb medium weight fiber/cy, 24' pad, 4" thick cut into 8' sections. Surface a bit hairy so I used a diamond cup flat wheel to level surface imperfections and remove the hairs. Ten years later no cracks and looks great. The second (bad): I failed to monitor the contractor who used micro fibers of some unknown dosage. He texured the surface using a broom which clumped the fibers and didn't make it easily fixed. Cracked after a few weeks, although the cracks aren't huge. Not particularly happy with the results. Lesson learned: Make your specifications clear to the contractor and then closely monitor what they are doing. If you don't do this, you have no control over the results.

[@truman4956]

Love the passion and knowledge

[@SashaXXY]

Wow! This is so much useful info! I'm not a pro -- I just have a ton of backyard projects that involve masonry in one way or another. I've been waiting for something like this. Thank you so much!

[@Latrocinium086]

What about using water reducers and plastiziers? Also how do the fibers distribute/settle under a vibrator, say in a foundation? Nice info, great video as usual!

[@TylerLey]

Thanks for the note! Water reducers are great. Depending on the dosage that you use, you may need to use a little higher dosage for a fiber reinforced concrete mix. If your mix is designed correctly then the fibers shouldn't settle. This is called segregation. This is really controlled by the aggregate distribution within the concrete mix. Watch my videos about the Tarantula Curve for more info on this.

[@Latrocinium086]

@@TylerLey is there a place to download your tension graphs for the different fibers? Or your associated paper? Personally I’m interested in seeing how the polypropylene fibers do.

[@criley2723]

Fibermesh helps to prevent cracks from forming, and rebar golds cracked pieces together. Regular rebar itself does nothing to prevent cracks, but it will keep concrete from heaving and separating once it does crack.

[@Nudnik1]

I use this fiber and retarder for years . Best way to prevent cracking. To much causes surface finish Polish issues though. Freeze thaw performance increased . I love fiber additives . I recall ACI requirements call for .003 of cross section area of steel minimum amount rebar or WWM . Add fiber plus minimum amount of steel on ground bearing slabs . Proper subsoil no organic clay and 98% compaction critical . Low slump low water possible also . Always put heavy plastic under slabs. Keep surface wet for days like bridge deck after sets up. Always!

[@TylerLey]

There are some good tips there. Thanks for sharing!

[@Nudnik1]

@@TylerLey Contractor since 1979 and Degree in Architecture NYIT. Enjoy your channel. Many who install concrete have no knowledge of such . Frustrating

[@michaelvrbanac6923]

I paid for fiber admixture. It works. Finishing is not much different unless there is a large amount of fiber.

[@stevewalker2028]

Thanks, really interesting. In UK we use a very fine chopped fiber for reinforcing concrete, each strand is hair-thin and maybe an inch long. It's something like glass fibre or Kevlar, if I recall. Very easy to mix, pour and finish, but I have no data on the reinforcing performance compared to other methods.

[@napster7825]

Fibers sound great. But how will the fibers affect the working parts of a concrete pump? Especially the steel ones?

[@gregmarsters2434]

Anything on effects for demolition? Does it impact effort/cost of cleanup? Does it have to be included in a disclosure about the property?

[@markrosenstand4796]

I brought in a ton of micro for all my slabs,freezing and cracks need to be controlled,so it worth it.

[@terencemerritt]

Wasn’t expecting this video to be this damn good 😂

[@russdabigguy3885]

...great content...what is your view of applying liquid sealer when the job is done?

[@86Ivar]

Tyler, I was visiting a powerplant that uncontrollable vibrational issues. These vibrations, 100-500 hz was cracking up the concrete. Would concrete fibers resist this?

[@behdadghadimi3087]

When and where are you going to add fibers? do you ask the provider,or add it by yourself in the truck while mixing?

[@Norbingel]

Do you have content on ferrocement or soil cement? I'm planning on building a monolithic thin shelled, ferrocement dome. Do I put the fiber on all layers (if it'll even do anything on thin concrete) or just the final ones?

[@pasqualesofia5886]

Thanks for the video. This is not new technology. Our family never pours a slab without fiber. Our first test was back in the 1980's. As far as expense, our last batch only cost $8 more per yard to add fiber. I would not call it cost, it's a requirement. Thanks again! Great video 😊

[@ScooterFXRS]

I do hope Tyler covers more fiber types. I suspected fiber was a good additive but with this opening video we could get more definition on how different types work. As another commented, "PVA; basalt and AR glass", these are what is commonly available that I could find.

[@TylerLey]

Thanks! The fibers in the video are examples of the types most commonly used in commercial concrete mixes today. In my new study, I hope to test other types. I will report back on what we find. Thanks for watching!

[@J_Strong]

I am not immersed in the concrete world, but I would have thought glass fibers used in GFRC would have been one of the most used fibers in concrete. I have been researching some lately and I see that there are two techniques in GFRC. Using upside down forms where you spray a non-fiber face coat then a GFRC backer coat and the formless design like they use in artificial rocks, caves, outdoor structures etc... Where they place the GFRC backer first on a structure (usually made of rebar wrapped with hardware cloth and burlap or an EPS foam core) to create the shape, then a non-fiber face coat is applied that can be carved or stamped. Please do an episode related to glass fiber, GFRC mixes.

[@zerg9523]

Howdy Prof, sorry to ask a question unrelated to the videos topic, but i didn’t really know who else to ask for a solid opinion. I recently got a look at someone installing a “bubble deck”, what is going on with that, i have nothing but questions… could you cover that one day please. Thank you.

[@ron4175]

Would like to see Galvanized rebar and GatorBar GFRP which can be cheaper than black bar at times. Would love to see helix and Hyperfiber and Dramix 5D, 4D, 3D compared. PRAH admixtures seal cracks and E5 Internal Curing is supposed to help a lot too.

[@trafficsignalman]

Curious as to which fiber performs best, and if it is steel, what is the negative effect or susceptibility of the steel to corrosion? Will the fiber segregate when vibrated? Great data, and looking forward to more research on this.

[@TylerLey]

All the fibers were helpful. The plastic fibers that were twisted with good anchorage at the end did surprisingly well. They did as well as the steel fibers. If you mix is designed correctly then the fibers will not segregate. This is mainly about aggregate distribution. I have videos that talk more about this. Thanks for watching!!!!

[@Latif_1994]

very insightful. Thank you for your video I am learning so much.

[@TylerLey]

Thanks for watching!

[@JuanLuísSerna-n4u]

Thanks for the video Tyler, do you know if there's any research with continuous fibers in concrete? Long strands of it alligned and placed where the forces are instead of little pieces allover?

[@Aleksander.Gaszka_Inzynier]

Great work, dr Ley. Are there any data regarding reduction of water permeability for concrete with fibers? If waterproofing membrane could be skipped in basement walls applications, it would definitely help to popularize them.

[@jackmclane1826]

What about woven fiber reinforcement mats as inlays. Like glass fiber mats to place into the wet concrete?

[@bkucinschi]

What do you think of Helix Steel as a replacement for rebar? It is used more and more in ICF construction. A friend of mine poured a 26x60 workshop of 4-inch core Fox Blocks ICF with no rebar. I plan a one-storey ICF house with 6 inch core blocks, and I want to use Helix Steel fibers. The local concrete mixers know about it and it comes in the truck ready to use on the construction site.

[@SSOMMERHOFF]

What about using plasticizers? You could increase the fiber doses without affecting the finishing or at the same dose reducing the water of the mix increasing the concrete strength.

[@unseenadventures8130]

As a concrete contractor I use fiber in every pour! It's more than worth the extra $7 per yard

[@MatthewPoppoff]

Tyler is out doing god's work! and yes, our standard in any concrete that has no specifications has fiber!

[@hartfordboothe7466]

I just poured a 44" x 8" x 260' erosion wall around a slab for my shop. I rented the forms, set them, and did the pour myself (boom pump hired for placement, and one friend to run the vibrator while I handled the hose). I used almost 26 cu yds. I had the plant add fiber. I don't know which kind or how much per yard. I will find out after watching this video, just so I know. But I do know that they only charged me $5/yd for the fiber. When dealing w contractors, asking for 4k PSI instead of 3k5 PSI or asking for fiber has universally gotten me, "that'll cost more". Yeah, no kidding...but they use it as leverage to inflate the cost. On the one job where I had a contractor use 4k PSI and fiber, it cost me $1,200 extra. After that, I found out that it was only $10/yd to go to 4k PSI and only $5/yd for the fiber. $15/yd more expensive. When concrete is costing $170/yd for "run of the mill" 3k5 PSI, who cares about $15/yd? Had I simply ordered the concrete myself, going to 4k PSI and fiber, would have only cost me about $500 extra, not the $1,200 the contractor charged me. The contractor got paid an additional $700+ of my money for doing nothing other than telling the plant to change the mix. FYI to those having concrete placed for them.

[@daniellec2172]

Some of the GFRC and specialty suppliers (this is in the context of interior applications I guess) recommend rolling the thin layers of concrete to flatten the fibers in the direction of tension. I assume this is only when you have very thin applications?

[@rossb4802]

Thank you for the info. I have used to much fiber in a couple projects just to see how much i could use. I would like to see some tests with the twisted SS fibers and basalt fiber. Mainly I am interested in fire and corrosion resistant fibers. Downloaded your document, thank you again

[@m00ndog3]

What is your take on ReforceTech's 'MiniBar' 'High performance composite macrofiber for concrete reinforcement' that seems to be leaning away from just preventing cracking and more towards replacing rebar? It even appears to be twisted like weedwacker line giving it tooth effect, seems like a great way to reduce carbon in projects.

[@TylerLey]

I have not tested it. I am big fan of replacing rebar with fibers for certain applications. You can see my video "5 proven strategies to make green concrete". You can reduce or replace rebar with any macrosynthetic or steel fiber but there is not a prescribed way to do this yet.

[@joshuahansen5486]

If you made the metal wires into something that looks like a chain link with an open space in it do you think they would naturally make it three-dimensional web of interconnected chain links

[@elihassan9009]

your videos are awesome! thanx for spreading the knowledge! I've been diving deep into the world of concrete for my radiant floors! I'm being told I'm crazy but I want to pour a 2" slab of fiber reinforced concrete over my 5/8ths radiant tubes (done with a 6" spread) Can fiber reinforced concrete be the secrete ingredient to obtain a 2 inch pour?

[@mochouinard]

For wall, I guess we really need the fiber to be going on a single direction. If metal fiber, couldn't we use a magnet system to align the fiber inside the wall. Could it be a system of loop fishing string, that is expanded using a vibration system once the concrete is poored in.

[@Chris-qo2sb]

brooo, i love your voice, you sound like saul goodman

[@BuildingCivilVideo]

Thanks for the update 👍🙏👷. More updates on this topic will be highly appreciated , especially on ways to avoid agglomeration of the fibers while mixing. Also please address the issue of corrosion of steel fibers in the cover concrete. Can placement in columns, beams and other members which do not require surface finishing like slab top, be an issue with fiber mixed concrete. Moreover how will fibers behave in Self Consolidating Concrete (aka SCC).

[@JELWwL6unE8V7iGB3]

In cooking, when you want to keep something you're adding from clumping up, one thing to do is make a paste, mixing it with a smaller amount of the main batter, which makes it harder for clumps to avoid the mixing process. Then, the paste is added to the main batch, and the new ingredient disperses fairly evenly.

[@BuildingCivilVideo]

@@JELWwL6unE8V7iGB3 Ok, i will try out your suggestion and observe the results. Thanks 👷👍🙏

[@JELWwL6unE8V7iGB3]

​@@BuildingCivilVideo I hope it helps.

[@TylerLey]

If you add the fibers with the aggregate then that helps a lot with clumping. Steel fibers will corrode in the cover concrete but they don't cause additional cracking. Plastic fibers don't have this issue. Fibers are great in columns, beams, etc. Most people don't use them there because they are not as concerned with cracking in those elements. SCC can be designed to use fibers but you have to be sure that the material does not segregate. There are lots of strategies to deal with this but I would require trial batching to see how they perform.

[@BuildingCivilVideo]

@@TylerLey Thanks for the prompt response. I have one more query, will adding fibres have any adverse impact on permeability of concrete? My query is based on wild imagination that the fibres may make a channel for transmission of liquids from surface to interior. A water penetration test may reveal useful details. I am a bit surprised that people don't bother about cracks in Columns and Beams, especially when they are structurally far more important than slabs. Anyways will be waiting for your forthcoming videos. 🙏👍👷

[@Maulakus]

Hey Dr. Ley! This is great info. Do you know if the fiber content effects the freeze/thaw durability? It seems like smaller cracks would mean less water infiltration into the concrete meaning less issues with freeze/thaw concerns. What do you think? Cost is also a major concern for public and private projects. Do you have a general idea of price increase per CY of concrete at the 4LB/CY dosage?

[@TylerLey]

I have not seen any data where fibers were shown to reduce freeze thaw damage but it would make sense to me that it would at least delay it. The cost of fibers depend on the dosage and the type. I have seen them from $6 to $12 per cubic yard. This is less than a 10% increase in cost but you should check with your local ready mix supplier.

[@Maulakus]

@@TylerLey Thanks!

[@tchornomud]

I'd be interested in prep underneath slabs. Aggregates, depth? maybe using plastic or styrofoam or none. Whats underneath seems just as important as slab itself.

[@Leonidimus59]

Would be good to know specific product names used in these tests. I have no idea what samples M3 and M4 are and what are their dimensions

[@TylerLey]

I can't give product names because I don't want to look like promoting one type over another. I am just reporting what I found.

[@ssmith2019]

Great Vid ! Gracias Amigo !

[@TylerLey]

Thank you!!!

[@alaskacanoe6837]

Reinforce using stainless pins At the .025 ratio How does that measure up in crack resistance ?

[@nicks1146]

Fibers to compare: PVA; basalt and AR glass. Some cellulose base would pull-in the nature lovers for more reach.

[@JELWwL6unE8V7iGB3]

I have been reading studies of fibers for use in cellular concrete. A lot of the studies that aren't pay walled are from China. PVA fibers with PVA admixture and basalt fibers with silica fume admixture seem to be two combinations that show some success.

[@TylerLey]

Hopefully, we can look at these once the new study has started!

[@sparksmcgee6641]

Steel

[@michaelpettit1263]

For both concrete roofs (critical rebar at the bottom of the foam I-beam molding) as well as ICF walls, which have a bazillion plastic tab ties penetrating the concrete, is there such a thing as a self-consolidating concrete mix that uses fibers as recommended here along with regular rebar and a water stopping crystalline admixture (something like Kryton or Xypex) to minimize the water intrusion via the capillary effect of the plastic tab ties? When pouring these structures, especially when making tanks, the cost of the mix is minor when compared with the cost of remediating rock pockets and water intrusion to the steel over time. You did another video where you showed a regular concrete L beam and a High Performance Concrete version of the same thing. I'm kind of looking for a sweet spot in between standard concrete and High Performance Concrete, but I'd like to reference good materials instead of doing trial and error.

[@jackdbur]

There is fibreglass rebar !

[@garysmith789]

Concrete reinforced fibers work great. Some fibers work better than most. We have a lot more experience with poly fibers on flat work. The amount of fibers in the concrete have certain issues with finishing but not insurmountable Steel fiber have cause issues with pumping and finishing.

[@chrisdaniel1339]

Tyler, will water reducers make the concrete have better workability and easier finishing with increased fiber dosages? What were each of the fibers in your tests, it looked like code numbers listed on the colorful bar graph?

[@fluxcapacitor1621]

I used Owens Corning concrete fibers in a table that I made and after 5 years there aren't even any small cracks.

[@TylerLey]

That is awesome!

[@steveadler4090]

Say you were doing a 26x53 slab for a basement with precast concrete walls on the basement and first floor and there were bedrooms and living room bath on the slab . And you don't have enough money to put in flooring . So you don't want cracks showing , whats best for that on a budget ? And is there some way to make it easier on your feet like not so hard ? That last part may be too much to ask.

[@aochider]

What effect does more rebar or wire mesh have on reducing cracks? For example, in the split beam test, what if you added a second piece of #3 rebar, would that also reduce crack size? I assume there is a limit to how much rebar you can add before you have issues (eg, voids), but I'm assuming that limit wasn't part of the split beam test.

[@TylerLey]

Yes! more rebar would also reduce the crack size. I ran the Split Beam test to just compare different types of fibers to one another. One cool idea would be to compare the crack reduction from 1 rebar, 2 rebar, and 3 rebar to the fiber performance. Thanks for bringing this up. We can add this to our testing.

[@MrHazlip]

I’ve read good things about helix micro rebar do you have any experience with their product?

[@TylerLey]

I have not tested it.

[@wheelerdealer2105]

Wet curing has made more difference in my projects than anything.I have to do that my self to get it done right.

[@elbuggo]

Interesting. Have you tried making a pond around the slab, and submerge the slab in water?

[@wheelerdealer2105]

@@elbuggo No.I cover it with canvas, soak it good and cover that with plastic. It stays wet a long time, have left it up to a month. The wet cured sections look better, and dry much faster after a rain ( not absorbing as much water i assume) And I have no cracks after two years :)

[@elbuggo]

@@wheelerdealer2105 Excellent! This is the method I was thinking about, from the 3rd world - if interested: Curing of Slab by Water Pounding Method /watch?v=usHf2BUOy5I

[@TylerLey]

@@wheelerdealer2105 Nice!!! Thanks for sharing!

[@Omenowl]

I have been looking at fiber reinforced concrete. How much extra does it cost is the real question. I am willing to accept 20% increase to cut down on the cracks. My real question is how does it work with self consolidating concrete?

[@criley2723]

Fiber is like 6 dollars a yard for a standard dose. Not expensive at all.

[@mikkoekstrom8109]

Both macro and micro fibers work with self consolidating concrete but you may have to adjust your water and plasticizer amounts.

[@travisclark5057]

Can I consult with you about foamed concrete formulas?

[@TylerLey]

Thanks for the note. I am not a foamed concrete expert and so I am probably not the best person to help with this.

[@travisclark5057]

​@@TylerLey Thanks for the reply. I would be curious to know if it is interesting you to at all.

[@lowercherty]

Do steel fibers rust and expand if exposed to water or salt water? How does this all work in freezing weather like Minnesota?

[@JELWwL6unE8V7iGB3]

If it matters, I think there's admixtures that help to prevent chlorides from causing reactions in rebar. I'm guessing that since the same chemistry is involved with the fibers, they might help similarly.

[@TylerLey]

Steel fibers will rust if they are exposed to salt water. This doesn't impact plastic fibers. Fibers are widely used in Minnesota for concrete overlays on highways. They do great in freezing environments.

[@JELWwL6unE8V7iGB3]

@@TylerLey Would admixtures designed to prevent chloride based damage to rebar also work on steel fibers?

[@robnowe5464]

What about just fibers with no rebar? What about GFRP in place of rebar or a bundle with both a #3 black bar and a #3 GFRP GatorBar ?

[@petergerdes1094]

Heard it's also good for bunkers that need to resist bunker busting weapons.

[@joshuahansen5486]

I think I remember this kind of cement being used in bunkers in Iraq to make them stronger I think it would be cool if we could figure out how to make a super concrete using these fibers what we've learned about Roman cement and fiberglass rebar and when it comes to the standardized testing if you could make a jig out of Parts you can get at a hardware store and then make a free online plan for it you could probably share the link to that in one of your videos

[@untitled6391]

Wouldn't the fibres make the concrete weaker?

[@daniellec2172]

What are real-life purchasable example materials of the different types of fibers? Where does fiberg;ass fit into these types? I was disappointed to go looking for the report which is only accessible by signing up for emails (ugh), to see that the "report" is just a summary of this video. The link to another study in that doc just goes to a dropbox that has a 404 error.

[@clcpakistan4151]

Mr. Tyler please make a video on graphene based concrete.

[@nicks1146]

Not all graphene is equal - would be great to see the same dosage of different graphene products compared.

[@clcpakistan4151]

@@nicks1146 can we use expandable graphene to enhance strength of concrete.

[@TylerLey]

@@nicks1146 Agreed! Maybe I will be able to work on this someday.

[@clcpakistan4151]

@@TylerLey I used just graphite powder in foam concrete and got immaculate results.

[@stangman50]

So if .25 percent is the sweet spot does that mean you’re using around 10lb per yard?

[@elbuggo]

I think 0.25% is 4 lbs per yard.

[@TylerLey]

Thanks @elbuggo ! Yes, 4lb/cy.

[@brainwater]

How does vibrating the concrete affect the fibers? Do plastic fibers float towards the top when vibrating, and do steel fibers sink? What happens when a DIY person runs the vibrator for 5 times as much as needed to get air pockets out?

[@Jakeunlimited]

I like the fiber! I don't like the parking lot i used to frequent that was poured with steel fibers that were loose all over the surface and in my tires.

[@TylerLey]

I get it!

[@Jakeunlimited]

@@TylerLey make a video on rebar placement in arches! I've always wondered about that.

[@thrasosthrasos7353]

Fibers made from steel will probably make a problem in the long term - they are closer to the surface than rebar and as consequence more prone to rust. Rust cause steel to expand and concrete will crack.

[@brucemurray2520]

Will use fiber!

[@TylerLey]

Great!

[@NitroAuto77]

Screed vs vibrascreed, jitterbug vs rollerbug etc?

[@TylerLey]

You can use any of these as long as you don't over do it. It also depends on the mix you use. You should adjust the mix depending on what strike off technique that you will use.

[@NitroAuto77]

@TylerLey heavy equipment shop floor, normally spec 5000psi, no air, HRWR, last one had wwr in it and 1.5" fibrilated fibers at 1.5lb/yd, would like to go with a more substantial product going forward but we would like less fiber protrusion at the top layer because just screeding floating and then getting on it with the machines doesn't knock the fibers down into the paste enough IMO. In fact I think you can end up with a weaker top layer (impact resistance) if you have fiber laying horizontal and burnt in with finishing blades as you end up with little to no cover on the top fibers. Next one we do we would like to investigate vibrascreed and maybe a rollerbug to get the fibers a bit more below the surface, within reason.

[@jackdbur]

​@@NitroAuto77Go lower on the long fibre & add some fine short 1/4 to 3/8 fibre ! Have used fibreglass & PET 1/4" shotcreteing you can get a nice finish

[@NitroAuto77]

@@jackdbur much appreciated!

[@anthony01571]

OUTSTANDING : o .....

[@TylerLey]

Thanks!

[@npsit1]

Alright chill out with the sound effects...

[@kalebbillig3472]

Maybe you need to add flow control chemical

[@MrDhalli6500]

The new World Trade center is made with UHPC (ultra high performance concrete) and has a tensile strength of 60,000 PSI. I trust this would be a little cost prohibitive for the average drive way or home foundation. Iran is in a high earth quake zone and they use a finer purer quartz and sand for their concrete.

[@kalebbillig3472]

Your graph shows s2 @ 1.5% being almost exactly the same finishing demand as no fibers… so wouldn’t that be the right choice? 13:10

[@ehsnils]

One concern I have is that the fibers will get worn down if they are in the mixer for too long.

[@benhall8172]

they go in right at the end just long enough to mix. Too long and they break down.

[@TylerLey]

I think this can be an issue with some glass fibers but it is not an issue with plastic or steel fibers.

[@Stevexnycautomotive]

How old is this technology method?. So it's not proven.

[@georgemichaels2325]

What about carbon fiber? What about carbon fiber rebar. Utilizing both at 7lbs.per Cubic yard ? Inquiring minds want to know.🤔

[@TylerLey]

No one makes commercial carbon fiber rebar or individual fibers for concrete at this time. I think this will happen in the future but it is too expensive right now.

[@Georgewilliamherbert]

@@TylerLey I have seen both carbon fiber strands and rebar online coming from China, but no good source information or credibility of specifications listed. Also basalt fiber, same online sources from China mostly (some from Russia), also no good source info etc. I'm not sure "I found it on Amazon" would pass building inspector approval...

[@steverone7623]

Three guarantees It’ll get hard It’s gonna crack Nobody is gonna steal it

[@benhall8172]

I cannot watch a single video of this guy, I cannot stand how the camera is right up his nostrils on every single video.

[@perryallan3524]

Says someone who obviously watches the videos....

[@GRUBB-MUDD]

Why dont u test w out rebar, test everything at 4 inches thick. Use wire mesh, use fiber and use rebar, also title it the residential concrete guidebook😂😂😂

[@elbuggo]

If you send him the money, he will!

[@TylerLey]

I think these are good questions. The people that fund me are primarily focused on bridge decks and so that is what I focused on. We are working on a version of the test that does not use rebar. Stay tuned!

[@GRUBB-MUDD]

@@TylerLey I wana bring u up on a live

[@GRUBB-MUDD]

@@TylerLey how do I contact tyler ley?

[@GRUBB-MUDD]

@@TylerLey cant wait!!!

[@MrDhalli6500]

Here's a link to Curious droids channel. this video is mostly about bunker busters but the technical stuff about new concrete tech is at the 10 min mark. Curious to know if you have heard about the research about concrete coming out of China and Iran? kzbin.info/www/bejne/aWSsl3aqYst0hc0