# Rebar in Driveway Slab



## jakejorgenson (Mar 17, 2009)

Do you put rebar in a driveway? How thick do you pour it? We are not required to do this here in our area, but I wanted to know what you guys think and what the pros and cons of this are. We usually put it in our patios against the house and dowel them in to prevent falling if the ground settles or heaving in the winter when it freezes. Isn't the sub-base the most important part, and proper compaction?

On another note, how do you guys do your sub-base/compaction? Plans around here just call for 4" of gravel. It is an area that gets a lot of snow and ice in the winter.

Thanks.


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## mudpad (Dec 26, 2008)

jakejorgenson said:


> Do you put rebar in a driveway? How thick do you pour it? We are not required to do this here in our area, but I wanted to know what you guys think and what the pros and cons of this are. We usually put it in our patios against the house and dowel them in to prevent falling if the ground settles or heaving in the winter when it freezes. Isn't the sub-base the most important part, and proper compaction?
> 
> On another note, how do you guys do your sub-base/compaction? Plans around here just call for 4" of gravel. It is an area that gets a lot of snow and ice in the winter.
> 
> Thanks.


Yes the subgrade is the most important, not the 4" of stone but whats under the stone. You have to get down to a good clay soil, no organics, roots etc. You cant just throw 4" of stone on topsoil. 

Rebar shouldnt be required, just wire mesh or fiber mesh if you want to go that route.


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## ScipioAfricanus (Sep 13, 2008)

Around here I usually spec out 4" crete at 300 PSI with 4" sand on 4"of 3/4" gravel compacted. If the customer wants I will include 10 ga. wire mesh (6") squares. or whatever else they want that seems like over kill. The sand and gravel are mostly required here though. Even though there is no snow or frost heave to worry about.

Andy.


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## bhock (Feb 17, 2009)

Here in Northeast Wyoming we are not required to have rebar in anything that is not structural.
I do use a #4 rebar mesh 16" OC for driveways, and 6x6 concrete mesh for patios, just makes me feel better. 
I also pin to structure where possible 2 ft OC with #5. All slabs are poured around 4" thick
For subbase we use item 4, aka roadbase usually 4" where possible I compact with skidsteer and plate packer, or just plate packer.
Minimum 2-3 runs with packer.


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## bhock (Feb 17, 2009)

And to add, as mentioned above, this is all dependent on the soil beneath the pour.


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## mudpad (Dec 26, 2008)

ScipioAfricanus said:


> Around here I usually spec out 4" crete at 300 PSI with 4" sand on 4"of 3/4" gravel compacted. If the customer wants I will include 10 ga. wire mesh (6") squares. or whatever else they want that seems like over kill. The sand and gravel are mostly required here though. Even though there is no snow or frost heave to worry about.
> 
> Andy.


The subgrade that is underneath that sand, stone and concrete is still the most important factor. Specially if your concrete is 300 psi. (i'm sure you meant 3000):laughing:


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## WarnerConstInc. (Jan 30, 2008)

we always put bar in them and poured most 5" thick.

I think we used pea gravel for our stone base, been a while since I had the unfortunate pleasure of pouring concrete.


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## mudpad (Dec 26, 2008)

WarnerConstInc. said:


> we always put bar in them and poured most 5" thick.
> 
> I think we used pea gravel for our stone base, been a while since I had the unfortunate pleasure of pouring concrete.


Pouring concrete is one of the things I still enjoy. Probably cause all I gotta do is sign the concrete tickets. Still, it's like the reward at the end of a lot of hard work and headaches. (Unless something blows out, then it's just another headache.


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## WarnerConstInc. (Jan 30, 2008)

mudpad said:


> Pouring concrete is one of the things I still enjoy. Probably cause all I gotta do is sign the concrete tickets. Still, it's like the reward at the end of a lot of hard work and headaches. (Unless something blows out, then it's just another headache.


It always turns into a cussing and hollering match around here though.:whistling:laughing:

I liked finishing it, I don't like carrying 9' wall forms.


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## mudpad (Dec 26, 2008)

WarnerConstInc. said:


> It always turns into a cussing and hollering match around here though.:whistling:laughing:
> 
> I liked finishing it, I don't like carrying 9' wall forms.


I rather enjoy cussing and hollering, as long as it doesnt turn into an a$$ whipping.


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## tgeb (Feb 9, 2006)

On driveways:
Minimum 4" crushed run stone (what we call CR-6), compacted.
Minimum 5" thick, 4,000 psi concrete with air and fiber.
Welded wire mesh, compromised below the location of control joints.
Hand tool joints, or machine (saw) cut within 24 hrs.


But that's just how we do it.


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## dayexco (Mar 4, 2006)

in my 57 years, i've yet to pour/finish ONE yard of concrete for people to drive on, walk on...in that same time frame, i've probably seen 1000's of yards poured. i've always been impressed when i see mesh in concrete, on how quickly it gets pushed down to the bottom of the pour by everybody standing on it. and years later when i pull it to demo it...how well that mesh looks at the bottom of the slab laying on the gravel


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## tgeb (Feb 9, 2006)

That is true Gene, It takes dilligence to make sure the guys pull the wire up as they work the pour, and is the reason we'll put fiber in the mix as well.

I too have demoed plenty of slabs with the wire rusting out and laying on the dirt.


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## superseal (Feb 4, 2009)

Most areas around me require 4" 3/4 stone x 4" for public walkways, X 6" for aprons and drives. No mesh required and fiber is frequently used :jester:

One local large township is now requiring aprons to be 6" of 3/4" stone x 6" concrete with double wire mat  and...2 cont. #5 bar in the depressed curb :blink:


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## jakejorgenson (Mar 17, 2009)

All they require here is 4" of concrete over compacted backfill. Most plans I get show 4" of draining gravel under the fill. I'm assuming this is for a place for the water to drain under the slab and not get as much frost heave but I'm not sure on that.

We typically do a 4" slab without rebar in most areas, using 4000 psi mix with air for our exterior slabs. If we are already at 4000 psi strength of the concrete, what is the benefit of the rebar anyway? How does it strengthen the concrete? Does it help it last longer?


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## concretemasonry (Dec 1, 2006)

jake -

The high concrete strength does little to increase the flexural strength of the slab.

Around here you cannot buy concrete for a driveway unless it is 4000 psi(min.), air entrained and 3" slump (not sloppy). It is all for durability and definition of liability if there is a problem.

Joints are usually sawed and fibers added for micro-cracking.

You can always find a guy to dump concrete, finish it and walk away, but that does not build a business or reputation even if you can find someone dumb/cheap enough to sell the wrong concrete.

Obviously, you need a compacted base and decent sub-base, unless you over-do the base thickness and compaction to bridge over the muck.


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## Willie T (Jan 29, 2009)

ScipioAfricanus said:


> Around here I usually spec out 4" *crete at 300 PSI* with 4" sand on 4"of 3/4" gravel compacted. If the customer wants I will include 10 ga. wire mesh (6") squares. or whatever else they want that seems like over kill. The sand and gravel are mostly required here though. Even though there is no snow or frost heave to worry about.
> 
> Andy.


Yeah, that 300 PSI concrete is tough to work with. It just doesn't want to hold anything more than a moped. :clap:


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## cleveman (Dec 28, 2007)

Superseal answered correctly. Ding ding ding ding.

You want the part of the driveway in the roadway to be able to withstand heavy traffic. If you are a concrete guy looking for work, all you have to do is get in a dump truck and start pulling up, fully loaded, into people's driveways. You can just go ahead a bust up the concrete into the sidewalk, where the right of way stops.

This is why the concrete there needs to be 6" thick.

After that, it is only for the homeowner. Normal traffic. Heaviest thing will be a UPS truck or a moving van. There you go 4" thick.

I believe in the fiber, no rebar. But you can talk me into a thicker perimeter with rebar in the perimeter.

Of course you need a 4" compacted rock base underneath, and the sub-base should be stable.

Laugh if you like, but I like to put plastic underneath and spray seal the concrete or cover it with plastic after the pour.

Cut every 8'. When in doubt, cut. Tooling is fine also, better in fact.


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