Nah, it's not an Oklohoma thing, or an Oklahoma one, for that matter. I do it the same way in Texas, Arkansas, Kansas, Missouri... The work that I do is designed by architects and engineers, most of whom do things more or less to industry accepted norms. Often, the work we do is intended to last for a very long time, so we do things to a little higher standard than you see in the average house. Face it, most houses are pretty much absolute crap, from a quality standpoint. The average buyer doesn't know the difference; the purchase price is all they see. Most of us in the commercial or industrial construction business wouldn't touch the housing market with a ten foot pole...

Curbs that are poured by a curb machine, in a housing edition, don't have rebar. The curbs I build, which are poured by hand, do have rebar. Overkill? It depends upon how long you want it to last.

Here's the deal. Disregarding temperature changes, if concrete were placed on a perfect base that would not move in any direction upon the application of a load, you wouldn't need rebar. Sadly, we live in the real world and the dirt that Mr. Webb will have underneath his "curb" will not be compacted very well. Thus, rebar is quite useful.

And, did I mention, it's CHEAP?

JR

Well, form my egr perspective, simply telling someone, who's never done this before, to "put rebar in it" does them no good. ...it just complicates the matter. ...if crack avoidance is a big concern, saying ""put rebar in it" misses the week spots. (interface with existing)

And then, there's the whole Q of what will a length of #4 rebar, laid down the center, really going to do for such a thin section? Sure, if it cracks, the cracks will stay thin, but I don't see the rebar as providing much tensile stiffness (due to the short cross-section/neutral axis) ...a tube of wire mesh would be much better.

Furthermore, since he (or the city) might decide that the newbie first pour/finish is less than desirable, leaving the rebar OUT will make an easier job of jack-hammering it out.

Randy, maybe consider sections of 'curb stone' ...since you will be putting pavers up against it anyway. ...granite curb-stone might be cool. (most rock places have it)

FWIW, this is the best advice I saw on this thread. Further, Island is correct in that a newbie is going to be pretty clueless, probably, on where to place reinforcing. And finally, Island is also correct on the finishing matter. Finishing concrete looks easy, but some skill is involved. The last thing you want is to have the concete delivered and not have the personnel on hand to put a finish on it before it cures.

It's not rocket science, but you have to have a minimum bit of knowledge of what you're doing. And again, as I say, depending on the size of the pour, you might need finishers on hand.

With all due respect to the guys who think concrete can be used with no rebar, my personal belief is that this is ALWAYS a mistake. Well, except for mailbox posts and similar. Never......ever.....pour a slab without reinforcing. Perhaps in Southern California your earth is perma-dry compacted soil. My observation is that the ground moves. Seriously. It moves. It is moving all the time.

Yeah, if you sprinkle sugar water (cola) on the surface, the surface wont harden, (wash off) and you'll have exposed aggregate (sand/pebbles)

I expect that someone here can give better details on that.

See:

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Then consider staining it. Apart from the color change you get in cured concrete, the environment takes a toll. Around here, the major staining agent is acorns. They fall, cars run over them, they get wet and then they create a brown stain.

JR

I agree with you all the way. But, there's a difference between industrial commerical construction and a little patch of concrete in front of some guy's house. I am a custom remod. concractor who, like you, built above and beyond general building codes. Do you really need to blue print, balance and have JE piston custom make a set of pistons for 20 year old Hundai Motor when you rebuild it so you can drive it to work? I am sure it is a better built and it will out last a new Hundai many times, but at what cost?

I have done the curb (4'x10') in front of my parent's house ten years ago with a buggy I mention above without rebars, and no city permit on a saturday. They drive over it daily. No cracks, nothing. But then, I am in Socal, so no crazy temp change and almost no water beside the sprinkler system.

That's what I would do. Goog luck

Jeff

You know, I guess what I was trying to get across was this: Randy probably doesn't have anything to compact the subgrade with, apart from his feet. He can rent equipment to do the job, but that costs money and requires a pickup truck to haul it in, which he may not own. He lives in a wet climate. His soil type is unknown to me. Rebar is cheap insurance.

Given the aggravation of mixing umpteen bags of "instant concrete" in a wheelbarrow with a shovel (he has no mixer, I assume) and knowing how long it will take, I'm concerned that he'll be able to mix it, place it and finish it before it gets out of hand. Maybe he has thirty kids that can help, I don't know. Me, I'd pick up the phone and order it. Maybe he could use up the rest of his minimum order on a sidewalk, tool shed slab, or whatever else he may want to add to his house, now or in the future.

Some things aren't worth doing to save a buck. Mixing a bunch of concrete by hand is one of them, at least for me.

JR

Boy, I sure hope he's using ready-mixed concrete from a supplier vs. mixing and placing his own with bags. Self mix is a recipe for disaster and do-it-all-over again for a first timer.

I'm on the yes vote for rebar, depending on the conditions (is the street network in your area well graded and not showing signs of settlement) and what your cross section is. Rebar is indeed cheap, easy to place (stirrups are available from whomever you get the rebar from) and is not going to harm anything even if you do it completely wrong (not likely). Our Village code requirement where I work (Village Engineering Division) is two #4 bars throughout, contraction joints sawcut every 15 ft. and 60 ft. spacing on expansion joints.

So, yes, people do use it and it is worthwhile from a long term maintenance standpoint in a rather bad freeze-thaw region like Chicagoland. Place it in the bottom 1/3rd of the curb section, where the possibility of tension is located in the cross section. Obviously to dowel it into the adjoining curb, you need to utilize shorter bars in the existing curb, and then wire tie the long bars that span the curb trench into the short bars you have doweled into the existing curb.

But honestly, of most importance IMO is the curb section. Our curb & gutter spec is a 9 in. front depth and 10-1/2 in. back depth (where the gutter has an actual "back" on it) and an 18 in. minimum width. Most often a 9 in. "depressed" curb (basically a gutter only) in our area will experience cracking at heavily trafficked intersection crossings, so we ensure a heavy cross section at those locations. There a minimum 12 in. depth and 24 inch width is desired. In a residential setting, proper depth is the most important. So don't skimp there.

You can age the surface fairly easily. Lightly sprinkle some dirt on it.......... Not kidding. What do you think is happening with age? Fine dirt particles find their way into the pores of the concrete and stick to it. You'd just be initializing that process with a light, uniform sprinkling of dirt.

And to end this babbling of mine, without question the MOST important thing is to stay off of it for as long as possible. Drive around it if you can for as long as you can. Nothing F's up our rehab work better than impatient residents who absolutely have to get back into their driveway shortly after the curb is placed. Then they wonder why their curb is a piece of crap in the years soon after street rehab project is gone......

It takes so long to mix up batches that the placed stuff starts to cure before you mix the next batch. Different batches are mixed to different consistencies. Working the "new" batch into the "placed" stuff only works while the "placed" stuff is still workable. Concrete doesn't dry like a mudpie. It cures. A chemical reaction takes place, making it warm to the touch. That curing process is unstoppable. You can add water until you are blue in the face and it will still cure. It's pretty frustrating when you realize you're not done mixing and placing and finishing but the mud is starting to cure already. You get that "I'm screwed" feeling. The best plan is to fully prep the site first (break out and haul away the old stuff, set up your forms, shoot your grade, etc. Be completely ready and have some helpers on site when the truck arrives.

hmmm...the conc pump guys all carry bags of sugar with them. in an emergency, they dump it in, recirculated the material and dump it all out. i have been told it halts the curing process. never seen that firedrill, so i cannot verify.

my neighbor hired a contractor to install a walkway around the home. the crew showed up, and then a flatbed 10-wheeler..with pallets of redi-mix. i was very sceptical that it would even work, but they got it all done. two small mixers, and wheelbarrows! those dudes were freaky strong. running dumping finishing. no cracks yet.

Concrete placing is definitely not as easy as it looks. Not necessarily hard, just some experience is helpful.

Super is correct about how concrete sets-up. It's not the drying, it's the reaction going on with the portland cement (if that's the type of cement in the mix). You can place concrete underwater and it will cure and fully harden- i've found "lab samples" (concrete truck washout and excess dumping) in stormwater ponds and sewers to prove it! Concrete is kind of a living thing in that it's constantly curing, LONG after it's been placed

Point being is if you're not mixing consistently, you can end up with a crumbly mix (too little water to thoroughly complete the reaction) or a mix that takes long to cure (not necessarily a bad thing). That's where experience comes in, to judge how your mix is behaving and add water or admixtures to steer it in the desired direction. Bottom line, concrete mix is a science in and of itself. However less critical applications like curbs, sidewalks, general flatwork, etc. are not a big deal due to the low liability. Bridges, dams, buildings, etc. are another story!

And that's just the mixing issues. Placing and finishing is a whole 'nother story. Working the mix too much weakens the curing process on account of it breaking the bonds created by the reaction, plus disturbance of the air content of the mix. People who finish the crap out of the placed concrete can sometimes pull too much of the paste to the surface and segregate the aggregate from the paste. Without that aggregate, you lose some strength and can invite surface deterioration- spalling.