Is it true that with fiber concrete you do not have to put in any rebar or wire when you pour a garage floor?

I seen a house done with rebar, and Fibercrete. It had major cracking. I was dissapointed, after hearing how miraculous it was. I hope it was just installed incorrectly.
I like things that work, and if it does, I would use it.

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Originally Posted by larrys1835

is it true that with fiber concrete you do not have to put in any rebar or wire when you pour a garage floor?

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If the job actually requires rebar (like for a house footing) than I would not exclude it. I would personally use the rebar and exclude the fibre mesh for a footing. I believe if your garage floor is going to be like most others it needs some reinforcement because you are talking parking a heavy car or SUV on it. The standard 4" garage floor needs a little boost. 6 X 6 steel floor mesh reinforcing has just got to have more potential for holding floor checks together than any fancy plastic goose down in my book. I have done concrete flatwork as an occupation and will never be convinced otherwise. I will also say that I have worked with both methhods in the past. Obviously, to the contractor using the fibres is much simpler than taking the time to include 6 x 6 steel. I am not surprised by it's rapid growth in marketability and use but skeptical of all those claims regarding comparative strength with steel.

Good luck with the floor.

bs5

I had a 30x50 garage built and the contractor talked me into using the fibre concrete without rebar for the floor. It was done with a 6 inch thick pour. I have cracks all over the place. I was really disappointed.

The installer did cut expansion joints a day after the pour--but I still had a lot of cracks. It could have beed a temperature issue because it did get below freezing the night of the pour.

When I did my 1200 sq ft garage addition, the footings and stem walls obviously required rebar to comply with code. The floor was a separete pour 4 to 5 inches thick with saw cuts a day later instead of expansion joints. I have no wire mesh in the floor, just 3000 psi concrete with fiber-mesh. It has been down for three years, and I can find no cracks. The new driveway leading to it was also done with 3000 psi concrete with fiber-mesh, and has no cracks. My neighbor had a driveway done without fiber-mesh, and cracks appeared the very next day. I don't know that much about concrete, but the fiber-mesh worked fine for me. Maybe I just had a real good cement guy. I live in AZ, without snow and ice, if that makes any difference.

Dr D, glad it worked, It may be the Installer.

Just to make a point. The purpose of either steel or fiber reinforcing can never be to absolutely prevent a concrete floor from cracking. The purpose of reinforcing is better described as to try to contain or hold the concrete together. I think of concrete about the same way I would think of an 800 lb. gorilla. If it wants to crack somewhere, it's just going to happen.

We can help minimize cracking of concrete much better I believe if we manage such properties as water retention while it cures. Vapor barriers over top and below concrete in an effort to slow down hydration of the concrete. Wetting the base prior to a pour. We should also provide proper granular fill. It should be compacted mechanically (if needed)beneath our pours, managing tempertures as curing takes place and recognizing it's highly likely at some point this large floor will crack. Send it a message by sawing or tooling a joint in vulnerable places. (like cuts to drain openings or to an inside corner as soon after the pour as possible. Most certainly, those of us who live in the South enjoy warmer temps and can have a more certain opportunity to avoid cracking because of frost movement to and fro which occurs as the ground freezes in the North.

Bs5

Bullshooter hit the nail on the head. While my slab was poured over a layer of ABC, that had been properly wetted the night before; and the pour was done in mid-January (AZ). My neighbor had his driveway poured on a day when the temperature hit close to 100. He had no ABC, and the soil was bone dry. Another case of operator error.

I believe that my cement guy (a good friend) said that he preferred not using the wire mesh because over time it would rust away to nothing. I cannot ask him about this because he died at age 42 in September of 06 of a heat stroke while working at his frantic pace in the AZ heat. He was 6' 5", and a man of steel. This shows that rapid dehydration is not good for concrete or people.

Lighting nut - Stated that the temp, fell into the freezing mode night of his pour, ( NO WONDER HE HAD CRACKES!! things like this won't happen if you take the PROPER precautions. If during the pour the mix sat in truck, takes awhile to pour it out , The concrete becomes what is called "hot", IF too much water was put into the mix. These are some of the causes that will cause concrete to crack,breakup Ect Ect, I HAVE SEEN FIBERMESH CONCRETE THAT I POURED AND FINISHED, SEVERAL YEARS AGO Using THE FIBERMESH MIXAND Couldn't SEE ANY CRACKS, ect> etc. IN THE CONCRETE . If CONCRETE DOES NOT STAY WET DURNING FIRST 24 HRS. IT WILLCRACK AND BREAK UP, MOST SO IN TEMPS. 80 AND ABOVE.::::: gOOD LUCK AND godbless,;;; F.B.E.

When i was making flat-Slabs for a 8 story building im making 8 mounths ago i had the same problem witth cracks . the slab being 500 square meter had some crackings the day after . i used super plastiziesers for lowering the water cement ratio but didnt get any result . but watering and keeping the slab wet was working . i coated it just after it poured by felt and got amazing results .

I am a superintendent of a large general contracting firm building mostyl ground ups and malls. I have used fiber extensively in restaurant ground ups and have not used rebar reinforcement for my parking lots. Conditions and preparation are key to success in minimizing cracks and damage.

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Originally Posted by larrys1835

is it true that with fiber concrete you do not have to put in any rebar or wire when you pour a garage floor?

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That is what I was told--but I ended up with cracks all over the place even though expansion lines were cut into the floor.

I would use Mesh at the VERY least. Sounds like it needs to be watered after pour.

I was told by my Grandfather was still doing small projects into his 90's that ANTIFREEZE can be added to concrete. With this, it could be poured in the winter.

I have not been able to find much info about how much is used. However, I would like to try it with propolyene glycol as it is non-toxic.

I have also heard that concrete with antifreeze last longer. (The antifreeze effect obviously not going away)

I had a 40x20 patio concrete floor installed a couple of weeks ago. The small concrete fibers are sticking out of the surface. How could this be addressed? I was thinking of applying a solid color sealer. Please advise.