I'm building a shed this coming spring, and I'm considering my options for the floor. I've heard a lot of people using the fiber reinforced concrete, and then NOT using wiremesh.

I talked with a guy who is an ex-concrete plant owner, and he indicated that the fiber reinforced only helps during the curing, and there's not a lot of residual strength once the concrete has cured.

Does anyone have any good data on one or the other? Does anyone have any data on on which is cheaper, or is it about a wash?

Darrin

I'm not a concrete expert, but I believe the fiber reinforcement does add quite a bit of strength. Send a PM over to "fingers" and ask him, he used to be a contractor.

not much difference in price. The only advantage to using fiber is that it is continous throughout the concrete, where the mesh can be walked down during placement of slab rendering it useless. If you need some more info Pm me and I can get you some specs.

Depending on the fibre, it is about the same strength increase as #10 mesh in a 5" slab. However, the failure modes are different between the two types of reenforcing. Fibre works well for slab on grade and monolithic subgrade pours while the mesh is better for suspended slabs and walls. Fibre enhances surface toughness.

On money jobs, I use both for driveways, but only fibre for sidewalks. For the weekend warrior, go fibre.

This site has a bunch of helpful info. why's, where's and how-to stuff.

http://www.concretenetwork.com/concrete/slabs/index.html

Depending on the type of Synthetic fibers you are using whether its a micro fiber or a structal fiber, the micro fiber is reduce plastic shriking of any concrete, a structual fiber is a replacement for wire mesh. We use micro fiber (aka fibermesh) in flatwork to help prevent cracks from forming while the concrete is still in a plastic state, fibermesh also helps increase resistance to abraison, impact, and reduce permeability. The purpose of Wiremesh is to control cracking after the concrete has cracked, it does nothing to prevent cracking. Wiremesh also to be effective needs to be place between the middle and the top of the slab, Usually it ends up on the bottom compleatly useless.
One does not replace the other and really should be used together.

Structal fiber, which we us in precast manufacturing, replace wiremesh, these fibers are much more expenisve but solve the problem of the wire mesh movin to the surface during casting. These fiibers are not normaly used in flatwork.

Another, but very expensive option is Steel Fibers, These replace rebar and wiremesh, the best and most effective, and the most expensive. and really not need in a grarage appliction.

ZR1150 said almost exactly what my ex-concrete guy told me. Makes a lot of sense.

I have also poured enough concrete to know that the mesh is ALWAYS at the bottom. You try to pull it up as you go, but pretty soon you've forgotten all about it, and then you start pulling it up again. Not to mention the fact, that even if you have it on cradles, it still gets mashed to the ground when you step on it while you're screeding.

Even with all this being said, I like the idea of using the fiber and no mesh. I hate wiremesh. If I can go with the fiber crete, I'm thinking that I'll do two pours, each 21' x 72'. I can put rebar between the the two halves so that they don't move in relationship to one another. Of course me pouring this much hinges on whether or not I can get a power screed. I'm not even going to attempt this without one of them.

Darrin

sounds like you got it together Darin. One thing you might want to check on is "key joints". This will enable you to have a good solid joint between the two and it also has holes in it for rebar. In addition it will give you a form on one side to stop your pour. Most concrete supply places stock it and it comes in 4 inch or 6 inch heights. Good luck.

sounds like you got it together Darin. One thing you might want to check on is "key joints". This will enable you to have a good solid joint between the two and it also has holes in it for rebar. In addition it will give you a form on one side to stop your pour. Most concrete supply places stock it and it comes in 4 inch or 6 inch heights. Good luck.

Durabeast,

I'd never heard of, or seen these before. I checked them out, and that is a really slick deal. Can you actually use that to "ride" the power screed on? That would make a DANG strong joint...

Darrin

When Dad poured the floor in half of his shed about 20 years ago, the fiber was the new and greatest thing. It didn't hold up too badly, but hasn't performed as well as it would have with mesh (at least according to the local concrete guru). Of course it is highly likely fiber technology has advanced much in the interim. Last weekend we poured the floor on the other side of the wall, finally, and didn't use fiber this time.

That was the first time I had been around a powered screed and if you have much to pour I highly recommend it. We rented it for 45 bucks for the day and it was worth all that and then some. After using it once, I'm not sure how we ever did it without one.

...

That was the first time I had been around a powered screed and if you have much to pour I highly recommend it. We rented it for 45 bucks for the day and it was worth all that and then some. After using it once, I'm not sure how we ever did it without one.

I'm NOT doing it without one. I saw one used on a job that I was helping at, but I've actually never used one myself...

Darrin

Darin-
You should be able to run the power screed on it fine. Just make sure that you use plenty of the stakes to give it good support.

Do you mean a power trowle or power screed, a screed is a 2x4 of wood or magnisum used to level the wet concrete, a power screed is to level two patchs, made with a screed(long and narrow six feet apart and parallel) usually with a guy raking out the high spots. The power trowle is used when the you can walk on the concrete leaving marks but not sinking in. This "burns" the surface sealing it.( but is it very important to let all the bleed water come up and evaporate off and not trowle it into the surface, this weakens the surface by increasing the water cement ratio at the surface, this casuses the surface to dust, if you trowle before the bleed water comes up, and seal the surface to early,this will cause a weak layer about a 1/16" under the surface and after the first frezze thaw cycle the surface will peel off, and you cant fix it. the key is not to rush it.

By the way, IMO, when you order your concrete use, at least 4500psi with 6% air entrainment, flyash and micro fibermesh.

4500psi is IMO the minimum to use for a garage, 5000psi is lots.

6% air entrainment is a chemical added to protect from frezze/thaw cycle.

Flyash helps reduce permability and makes a "tighter" surface and floor.

The fibermesh will reduce plastic shrinkage, help is resist impact and abrasion( important in a "garage" floor).

Feel free to ask any other questions.;)

Do you mean a power trowle or power screed ....

I don't technically know what the thing is called, but it's a device that you use to screed off the concrete, and it's powered. There's different styles. Some have a gas motor and a truss like system that spans large distances, and they just shake/vibrate a screed board to level off the concrete, or there's some that you actually attach to a 2 x4 that have a motor that just vibrates the whole 2 x 4, and then you just pull it by hand...

Darrin

My bad, your right, Most people don't know or have seen a power screed in action, the best option if you can rent one, your floor will thank you for it. Most have a hard time justifing a power trowle, they figure a float finish is enough, not.


I don't technically know what the thing is called, but it's a device that you use to screed off the concrete, and it's powered. There's different styles. Some have a gas motor and a truss like system that spans large distances, and they just shake/vibrate a screed board to level off the concrete, or there's some that you actually attach to a 2 x4 that have a motor that just vibrates the whole 2 x 4, and then you just pull it by hand...

Darrin

.... Most have a hard time justifing a power trowle, they figure a float finish is enough, not.

I think that we might actually have access to a power trowel to use, if we wanted one. The only problem is that the only person in my family that knows how to run one is my dad, and he can't do it. I don't that I want to learn on my own project. :D

Darrin

Some of the fiber reinforced concrete that I have seen did not finish well due to the fibers floating to the surface during finishing.
Depending on the surface that you want, you should ask the concrete supplier which type of fiber that they recommend with which surface. A super slick surface lends itself to sweeping and cleanup but can be slippery and cause falls. While a broomed surface is tough to clean, but is less susceptible to slipping.
One other thing to consider for an interior floor is a moisture barrier between the concrete and the sub-base. This will help prevent floor "sweating".

Good Luck with your Project,

Britt

Navion is right, it will be "fuzzy" for a while until they wear off. Youcan still obtain a slick finish with it though. We do it on our commercial buildings all the time. As to the trowel machine, if you haven't used one before they are a little tricky. THe main thing is don't get on it too soon.

Picking the brain (02 durabeast).
I am wanting to pour a driveway to back my TT up into the backyard from the street, over 60 ft and to store it on the same drive. It will be right next to the house and my question is this. The house is originally a pier and beam foundation with concrete base. There is also a add-on room with a regular slab foundation. I don't want the driveway to separate and have a big gap between the house and the drive, so am I safe to dowel the entire foundation? I am worried about the new drive settling and cracking the pier foundation.
What to do?

Also, is it imperative to use the wire mesh in a driveway or will fiber be good for my situation too?

Don't attach your drivway to your house! Any movment due to any cause could crack you foundation. As long as you have proper compation of the sub grade, your driveway won't move.

Rebar- when placed properly, it will help resist cracking and seperaton of control joints.

Wiremesh- when placed properly, it will control cracks after they happen.

Fibermesh- helps prevent cracking when concrete is still wet.

Fact: All concrete will crack, that is why control joints (saw cuts) are nessary. All the water put into the concrete to mix it, comes out, when it does the concrete will shrink and crack.

"Haulin", ZR1100 has good advice. I would not personally attach my driveway to my house. If you have a sufficient subgrade it should do fine. I would divide the slab up into 150 sqft pads. PUt proper expansion joints in and you should be fine. As to fiber or mesh, Being that you are going to park a fairly large TT for extended periods in one place. This means a constant load on the slab, I would at least pour it 4" thick with mesh and 4000 psi concrete. Also since it is outdoors make sure you tell the Concrete company that you want "air entrainment." THis will help the slab during really hot and really cold cycles. THe air gives it room to expand and contract. Good luck!

Up here we have a lot of frost going in and out, My standard recomendation to my customers for driveways is a 4500psi 6-8% air and 6" thick. Can't fight mother nature but we try :D

NOt much deep frost her in west TN! But thicker doesen't ever hurt, if you have the cash.