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Chris

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I searched but didn't find any particular thread about concrete in general. Hoping someone with a little more experience than me can give some pointers.

These are the few major questions that get asked that I would like to touch on.

What is the proper way to cure concrete?

Do I need mesh or rebar and why?

What mix do I use for what?


I have done quite a bit of structural concrete in my time and have asked many of my subs these questions, I will refrain my answers until after I hear what others have to say.
 
What is the proper way to cure concrete?
depends on the weather and conditions

Do I need mesh or rebar and why?
for strength

What mix do I use for what?
depends on what your doing
 
Lets say you are pouring in about 90-100 degree heat, low humidity and it is for an RV pad and patio.
 
1 - burlap & a garden hose, curing compound, lawn sprinkler

2 - nothing in a 4" slab - no mesh, no rebar, no fiber,,, mesh adds strength ONLY when the conc's in tension ( curing - 'green' ),,, once its cured, no help at all,,, rebar adds FLEXURAL strength - that's it why its used in bridges, etc, not runways or highways,,, added compressive weight comes from design mix & water/cement ratio

we generally use 3,500psi - winter we'll add a little calcium for rapid cure + air & in summer wtr reducer & plasticizer
 
Mesh does help with change in temperature from one season to the next.Also if installed properly,when your concrete cracks, which it will,helps keep the two pieces on the same plane.It ties them together and keeps one piece from sinking lower than the other.It also aids in keeping the crack from getting larger.
When pouring concrete with mesh it's important to try and get it to the center of the slab to be most effective.Use your come along to pull it up into the concrete as you pour.
 
Mesh does help with change in temperature from one season to the next.Also if installed properly,when your concrete cracks, which it will,helps keep the two pieces on the same plane.It ties them together and keeps one piece from sinking lower than the other.It also aids in keeping the crack from getting larger.
When pouring concrete with mesh it's important to try and get it to the center of the slab to be most effective.Use your come along to pull it up into the concrete as you pour.

We build house on mountainsides and mountainsides move and when they do driveways crack. To counter that everyone puts rebar in the drive way and I have fun asking the dumb questioin why.
The answer is always just what you said, it will keep it on the same plane.
I think you will agree if you have frost heaving it, nothing will keep one side down.
If the fill under it has settled and you expect the plane to stay in place, you are expecting it to be a bridge, there is no way you have enough steel or concrete to hold up especially in a driveway.
Consider too, that now that there is a crack that allows water and air to get to the rebar the rebar will rust and grow over time and break it's way out of the concrete.

After that fun little discussion the guys usually go back to tieing steel.
 
Neal:You are correct but it does help and some help is better than none at all.In central IL with the varied seasons we get it also helps the concrete from cracking to a point.This is why rebar on the bottom of slabs and wire mesh are also referred to as temperature steel.
 
Rebar is the best call for areas of bad weather or sloped driveways. Typically, we use mesh for your normal driveway. WE ALWAYS raise the metal during the pour to get it off the ground. Have even seen guys use "hats" or "adobes" to assure proper placement in the pour.

Here is a fun primer on doing a driveway. Notice the guy does lift the mesh during the pour.

[ame]https://www.youtube.com/watch?v=xUgiHghs8vs[/ame]
 
That type of bull float when you twist the handle it flips the float. Some have short chains some have levers. They both work about the same. Some pros like the chain type as they are quick to fix if they get stuck.


Sent from my iPhone using Home Repair
 
I was intrigued on how many cigarettes the edging guy smoked on that job.

I did think that was a great video to show all the steps. My broom finishing was always straight on my jobs, but I may have to try the zig zag method if I ever help anyone with concrete again.
 
My biggest problem with any cement is getting the mix right. When I start to mix, I can't believe there is enough water in the pot. And if I add, it often comes out too wet.
 
welded-wire mesh adds no strength to cured conc,,, it does add strength while the fresh mud's in 'tension' (initial cure) but, after that, all it does is make tearing out the damaged work a large pita,,, not to mention aci doesn't recommend any steel/mesh in slabs less than 4" thick,,, better you should worry about a properly installed joint pattern,,, impo, fiber is only good IF you own the fiber plant & want a bigger boat,,, the benefits of fiber & steel are vastly overrated in my view altho they're much easier to use than the aforementioned jnt pattern,,, steel rebar adds FLEXURAL strength but NOT compressive strength nor does it add to the tension strength,,, hope this clears up steel & fiber in conc - they do have their place but generally aren't needed, spec'd, or used in h/o diy work
 

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