Horsehair vs. rebar in concrete

Regarding my earlier post about the cost of a concrete floor in a machine shed, I have another question: How do those of you who are familiar with both feel about adding "horsehair" fiber strands to concrete vs. using rebar and/or steel mesh? I'm looking at a 40x26 or larger slab floor in a pole shed. The heaviest weight on the floor would be a full-size pickup. All opinions appreciated.
 
If a crack develops using horse hair the hair will break. The purpose of using rebar is to keep the concrete from moving if a crack develops. Without rebar one piece of the slab can raise up above the other or just pull apart where there is a crater between the sections.
 
Rebar should be used under the slab for support,fiber holds the concrete together in place of wire mesh.Put rebar under the slab and use fiber its far better than wire mesh because its evenly distributed throughout the slab.
 
I had a shed with the fiberglass concrete in it. The shed was unheated. It was more than 10 years old when I left and had no breaks.
 
Rebar keeps big chunks of concrete in position after it cracks. Over the decades, concrete most always cracks....

Horsehair, aka fiberglass, keeps surface bits together, little bits from popping out. It doesn't really offer the big crack strength one needs. Also, some folks find it's tough to work on, the little hairs appear on the surface and poke a person. Lot prefer no fiberglass in their shop floor concrete.

Wire mesh is rarely installed right, it sags tot he bottom and is a worthless steel layer sitting between your gravel and concrete. If done right, it still will rust away quickly as cracks appear and salt hits the thin metal, and does not offer he strength that rebar does.

So, rebar is the answer......

Paul
 
We used fiberglass concrete on the patio of my mom's house - poured 4 to 6 inches deep. With only foot traffic it formed massive cracks in three places. Not a fan.
 
Fiber mesh is good enough for the big industrial floors we're pouring. Normally we're only putting 1/2" rebar on one foot centers in exterior concrete. Steel mesh is a thing of the past.
 
Check out the different kinds of fibers. When we pour slabs at foundries they almost always want "forta-fibers" in the mix at about 5 pounds per yard (that's a lot in my opinion).
Forta-fiber is different than regular fiber mesh.
 
I second this, no substitute for rebar. One place we poured a patio over an old patio, less then 10 years later we removed both for an addition. The slab we poured only had wire came right up, with the wire rusted off at every little crack. The old slab underneath had rebar, had to beat on it with an excavator to get it to break then cut the rebar to make smaller pieces.
 
Last time I checked horsehair is not an option. The are many fiber types available including steel chips. Best to discuss with your readi mix supplier. If you use fiber reinforcement you usually don?t need mesh or bars except for dowel rods at joints. Good luck.
 
Welded wire fabric should be what you need. It is for crack control and doesn't have anything to do with wheel loads.
 
good morning rossow, I had 1/2" rebar and fibre mesh instead of steel mesh in all the concrete poured in both my shops. the only cracking has been fine surface cracking in a few places. the fibre mesh allows the concrete to move without breaking. I would highly recommend it.
 

When I was working in the concrete business we had a saying. There are two types of concrete, cracked and concrete that's going to crack...
 
I have a couple pictures of work we performed a few years ago at a local lumber mill. The plans called for rebar and the spacing for the kiln. Compaction tests were performed and we could not continue until we had the proper results. Concrete was also tested and we didn't have to our it over so must of passed. We removed an old poured foundation and even though it had many large cracks the rebar held it together and I torched it apart. We used flat 5 x 10 mesh and rebar in most of the slabs we poured and all tied. The last picture is the completed building that they store the lumber in. We poured over 5000 yards for them in a few months time including walls flat work and columns. They added hardener fiber mesh to the mix for the kiln floor but still the acid from the wood eats at the concrete floor.
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Eldon that's what my boss always said! Classic example is the local interstate highway that was all done to state specs. They are always fixing cracks and repouring sections. Tons of salt and our 6 months of winter help too! lol
 
I read all the posts below,and one thing I was told/taught,keep the concrete wet for a week,to prevent cracking.In other words,the cure is very important to prevent cracking. No one else mentioned this,so I bring it up. I was told the fiber glass hair was strong,but the cure,keeping it wet,was more important than what reinforcement you had.Any comments ,thoughts? Mark.
 
Wet curing is an option, but most of the construction industry has gone to spray on / roll on cure. It accomplishes the same thing. Stress cracks will always happen. Cutting control joints is essential if your slab is larger than a 15' square.
 
Yes, it's a chemical reaction, they call it hydration and the important aspect of this is to not allow the concrete to "hydrate" too quickly, hence a "slow cure".

In this area, you will see burlap placed over the concrete after it's been finished and has hydrated enough to do so. Burlap protects the green finish and water sprinkler lines are spread out to keep the new slab wet until such time both can be removed.

A day like it is today is perfect for placing concrete, 30F this morning, no humidity and highs in the 50's to 60F today.

In hot weather, if the concrete hydrates rapidly, likely the finish will spall or just not hold up like it should. Eventually the aggregate will be exposed. Concrete has capillaries and when salt is used to de-ice in the winter, it will seep through the capillaries and react with reinforcing steel, sometimes expanding same 3x its diameter and spall the concrete around it.
 
yes keeping the concrete wet and above 40 degrees for the first week is very important. Also pour the concrete with the lowest slump possible to prevent shrinkage cracking and increase durability.
 
I have a 40x40 barn with a 20x40 apron. Fiber mesh, no problems. Poured 9 years ago, no cracks, I also had a plastic vapor barrier put underneath, I don?t get the condensation I used too. I think the vapor barrier slows down the cure, at least that?s what my concrete guys told me. I have kept multiple trucks, tractors, and it has held up very well. I think rebar is ok if you are talking really heavy loads, bulldozers, loaded semis, but for most stuff it is overkill. I think the Fiberglas is a direct replacement for steel mesh. Local concrete guys don?t use it anymore. I hired the whole thing out. I?ve done driveways and sidewalks, but doing a floor, keeping it flat, smooth, and sloped right is much harder. These guys did a great job, they spent a lot of time compacting the soil, and setting grade with a laser. I don?t have thing rusting like they used too, so very happy with the vapor barrier.
 
In mine the final load had the fiberglass in it and that went in the door area where it was needed the most. The other loads were straight concrete they did cut expansion joints in
 
spray on sealer works well if the concrete is not on a porous base--sand and gravel will suck the moisture out of the concrete so water is needed to keep the hydration action going. a moisture barrier under the slab really helps a lot to keep the moisture in the concrete. Remember concrete cures for 28 days to reach its specified strength so some moisture is needed to keep the curing going
 
(quoted from post at 09:36:08 04/22/18) We used fiberglass concrete on the patio of my mom's house - poured 4 to 6 inches deep. With only foot traffic it fot to preventrmed massive cracks in three places. Not a fan.

Sounds like whoever did your base prep wasn't any good.
 
This subject comes up on here and I always think the guys up north over do it. I am sure the extreme cold has something to do with it. Around these parts a full 4 in floor on good base with good 5 bag mix concrete is considered adequate for farm storage. This photo is of a sawmill shed I had poured 10+ years ago. We drive in with logs and park on it with tractors . So far no cracking. They did saw cross ways and long ways so each section is about 18X22. The concrete had the fiber added AT THE SITE. The guy that poured it said if it was added at the plant he thought it got wore out in the mixing. Not sure what that meant but I know the fiber was added to each load as they pulled in. Note if you are thinking about getting it don better do it . Concrete is going up just like steel. Jumped from $ 90 yd to $ 100 a yard last week here.
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It all depends on the base, but in N MN my opinion is if you don't put re-bar in it you are wasting the concrete! Wire mesh is better than nothing, but if you park a winter vehicle on it the road salt will seep down into the small cracks and rust off the wire mesh in time, then you have nothing. That's why the re-bar for modern bridge construction is kind of gold colored, it's corrosion resistant.
 
(quoted from post at 14:24:58 04/22/18)
(quoted from post at 09:36:08 04/22/18) We used fiberglass concrete on the patio of my mom's house - poured 4 to 6 inches deep. With only foot traffic it fot to preventrmed massive cracks in three places. Not a fan.

Sounds like whoever did your base prep wasn't any good.

Yeah, if the base isn’t compacted, and drain correctly, the concrete will crack because the voids and soft spots underneath. Kinda like painting, prep is 90% of a successful job.
 
I agree, it all starts with the base. If that isn't addressed properly, your eventually gonna have problems. When I did mine, I started with a well compacted gravel base. I then put a heavy mil plastic down for a vapor barrier. Although probably overkill, I had the concrete guys put in wire mesh(and it's in the concrete not laying underneath like a lot I've seen) and fiber. Once it was poured, they saw cut it and I kept it wet for 10days. It has been a year so far and not a crack.
 
Yes D, as in the summer time, newly poured bridge decks are covered in burlap, and use sprinkler systems, or soak hoses for x amount of time.
 
Sorta OT but one of my sisters owns a haybale house in Arizona. If they can make houses out of hay (for reinforcement) I guess they can make concrete reinforcement out of horse hay.

Thinking farther on this I recall a section of today's standards 4 lane urban roadway that had a well prepared, asphalt road bed under concrete poured with NO obvious reinforcing except for 2' to 3' pieces of rebar every 50' where they sawed the road essentially making blocks out of it. Possibly that was a "horse hair" reinforced road. It was US highway so there were the appropriate inspections made. Was done before I retired in '05 and no signs of any wear to date.

All the rest of the many 10's of miles of upgraded roads around here with the same road bed prep. are rebar reinforced.
 

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