pouring sidewalks; reinforcement?

[rogdan]

Its been years since I helped anyone with any concrete work and I keep getting conflicting advice. I am building 3' and 4' wide side walks framed with 2x4 lumber and don't know how to reinforce the concrete. Some say to use reinforcement rod but not what size or how to space it, some say the reinforcing wire or just any old fence wire will do and some even say to not worry about reinforcing concrete for just side walks. I am mixing the concrete myself with a mixer to work around my free time and expect to mix 3-2-1 stone, sand and portland.
Any advice would be greatly appreciated, I am in zone agricultural 5-6 if that has any relevance.

 

[Jarrett]

For a sidewalk I would use reinforcing wire. That should suffice. Down here, that's all that's used in slabs, even for buildings, except maybe for commercial buildings.

 

[Highbeam]

In western washington we use no reinforcement in the sidewalks. 4" of concrete above 4" of compacted 5/8- crushed rock.

3-2-1 is a great method and one they taught us in school to use when you have just the ingredients.

 

[Dhill]

Reinforcing the concrete is not necessary, but it's a good idea. For that application, I would recommend putting some kind of mesh wire (chicken wire would work well). Re-bar I think would be over kill. The idea is that you don't want the walkway to crack, and the more stuff you have in there to solidify the pour, the better. You may be able to find scrap wire pieces laying around to use. When I poured the slab for my shed, I used some old field fence pieces and mesh wire. Just be careful to not let the wire stick above the finished surface, and be sure to have something beneath it to keep it from sinking to the bottom when you pour the mix. Ideally, the reinforcing material should be suspended in the middle of the concrete. Of course, there are other considerations that effect the need for reinforcement such as ground shifting and moisture content of the soil. Good luck.

 

[EddieWalker]

Here in East Texas, the new subdivisions don't use anything in there sidewalks. Just a good base adn 2x4's for framing.

On my own projects, I like to put two sticks of 3/8 rebar in there. Nothing fancy, just someithing to help hold it all together.

Wire is a pain to deal with on pads. For a sidewalk, it would really add allot of extra work to a job with minimal returns. Another thing to remember about wire is that it has to be in the middle of the pour to do anything. Most of the time, part of it is on the bottom of the pour. Sometimes almost all of it is!!!

I read an article about using wire mesh in pads. They did some sample pours, then went back after they had dried to test for strength and wire location. In the places that the wire was in the middle of the pour, it was stronger than rebar. I forget what sized rebar they were talking about or the spacing. But what was really interesting is that in every case, part of the wire was at the bottom of the pour. And this was on a special test pour to do it right. The pros can't keep the wire in the center of a pour, and neither can I.

Eddie

 

[scott_vt]

Afternoon Rogdan,
In the limited amount of concrete work that I have done I have used the wire mesh with very good results. The drawback as Eddie has just mentioned is that its a pain to work with. What I bought came in 6' wide rolls and 50 or 100' long. Not easy to manuever that stuff around But the results were good.

 

[RobertN]

The pros can't keep the wire in the center of a pour, and neither can I.
Eddie

That's where you use the little concrete blocks with the tie wire in them. The little concrete clock spaces the rebar or mesh about 1.5 above the base level. They're another step and expense though.

Out here, I've seen people use fiber reinforcement. It looks like batt's of fiberglass insulation that they throw in the mix. When the concrete is done, it looks a little "hairy" on the surface, although that wear off quickly. I have no idea how it compares to rebar or wire mesh though.

 

[rogdan]

I think I will look for some old fencing around the farm to use, might as well save a few bucks and help the clean up. Thanks for the responses

 

[RobJ]

That's where you use the little concrete blocks with the tie wire in them. The little concrete clock spaces the rebar or mesh about 1.5 above the base level. They're another step and expense though.

They are called chairs, some in metal and some in plastic, different shapes and sizes.

Also if you use a cement kumalong it has a hook on the back to be used to pull the wire back to the middle.

Oh and if you use the rolled wire mesh, be sure you TRUST the person on the free end. Trust as in when you ask them to step on the end that they will STAY there(and are heavy enough!!). I think the end will spring back to the roll at mach 2.3.

 

[EddieWalker]

The chairs are for rebar. They used to be pretty common in the cemtent blocks, but now it seems all I see are the little plastic pyramid shaped ones. They are dirt cheap and easy to use.

If you put them on wire mesh, they will hold the wire up in that location, but the wire will still bend. I guess if you used enough of them it would work, but I've never seen it done, nor do I know if too many chairs will affect the integrity of the pour.

For a sidewalk, keep it simple and either use nothing, or just a few stick of rebar. No need to make it any harder than you have to.

Eddie