How should I join sections of concrete sidewalk poured in stages?

Question

I am pouring a sidewalk that will span roughly 60 feet from the front to the back of my house. I am intrigued by dry-pouring it but my construction background is steering me to doing it the right way and wet pouring it.

I would like to pour the sidewalk in 6' sections to make the project easier for me to manage by myself.

What is the best practice for connecting the sidewalk between each pour? is it really necessary to add expansion strip every 6'? And if so, should I also dowel the pours together with rebar in addition to the expansion strip?

If I am only pouring in 6' sections, do I need to tool in control joints as well?

This sidewalk is for foot traffic only and I live in Colorado where the climate is naturally drier.

Answer 1

You will only need expansion joints at immovable objects, foundations, other slabs that it will intersect with. If the sidewalk is really long, you may want to add one every 40 ft or so, 20 ft if there is a large differential in summer/winter temps.

These can be scheduled to coincide with the control joints, whether they are struck in with a control joint tool or cut in with a diamond wheel after it has set up but don't wait too long. I have seen the cutting done as soon as it is hard enough to walk on. This makes a fine line, but needs to be done right to keep it straight, or it will be bad.

If you choose the control joint tool method, presumably you will have an edger too. Use the edger on either side of the control joint, should you have one in mid run, besides where they are at walls or other slabs.

It is typical to cut in control joints at the least every 10'. I have seen it done on residential sidewalks much more often than that. 3ft apart at the smallest to 5 ft apart as another, so it is whatever you choose. I would prefer the 3' plus dimension so it will keep in check any possible cracking.

The most important thing to allow the control joints to do what the do best is, insure the thickness of the concrete is uniform. No pipe creating a thin area or gravel base heaped to allow a thin spot for it to crack other than where the control joints are.

Many a sidewalk I seen poured didn't have reinforcing. You can add 6"X6" mesh or rebar if you choose, continuous to the control joints. Keep all reinforcing 2" off all forms and control joints. If you feel you need to connect the control joint halves, so to speak you can set rebar in the first pour through the drilled expansion joint, and set small diameter PVC pipe or snug garden hose cut offs over the exposed ends with tape to seal the ends and pour that into the next slab, that way the sleeve will allow the expansion and contraction to move freely.

Answer 2

Control joints at 6 foot intervals is fine. That's fairly typical for residential and commercial sidewalks.

Expansion joints with flexible fillers are only needed every 18-24 feet (3-4 sections, in your case), depending on thickness. The rest are simply crack control joints. If your sidewalk is not constrained on either end, two spaced evenly are enough. If it's constrained by building foundations or other concrete, also put them at the ends. (If you're in an extreme heat region, add one or two more for safety.)

You'd extend whatever reinforcement you're using (bar, mesh) beyond each pour so it's properly lapped in the next section. How far that lap should be depends on the type of reinforcement. A common strategy is to use a half-height form set to the top of the pour so you can extend the reinforcement underneath. It's not a big deal if some mud sloughs underneath.