Any of you concrete guys have experience with the helix micro rebar? I'm getting ready to start my workshop. Planning on a monolithic pour and was wondering if I could use this for the whole thing. Is it as good as traditional rebar? Does it help with cracking of the slab? Any info would be appreciated.
I don't have any experience using it but it's
supposed to reduce cracking. If you are getting a permit, check your local codes to see if you need rebar. There are differences in opinion with respect to using rebar in a 4 inch slab, which is probably what you are pouring. I'll give you my half ass explanation and opinion and you can take it from there.
Concrete cracks due to shrinkage, drying too quickly while it cures, weather, settling or stress. Rebar will not prevent cracks for any of these reasons outside of stress b/c it will strengthen the slab. The concrete, without the rebar, should be strong enough to prevent stress cracks so some people believe there is no reason to add rebar.
Cracks caused by shrinkage can be limited by not adding a ton of water to the mix while you pour and not letting it dry to fast. Sometimes the conditions require you add more water - it's really hot outside, you don't have enough guys to finish timely or they bring you a shitty load. You can control the drying, to an extent, by soaking the slab every day after it's poured until it's fully cured, which takes 30 days.
You can't do much about the weather cracks aside from adding expansion joint where it's needed so when it expands it has room. Nothing much you can do about frost.
Settling is the biggest problem, especially with new construction. You can follow local codes with stone/compacting and it won't matter. If you are doing it on your own and you have time and patience, here is the best thing you can do: Excavate the area you are pouring and repeatedly floud the area before you add the stone. You can do this before or after you frame. Do it as many times as possible. Frame the pad, add your stone, and flood it again, over and over. Add more stone to get yourself to the depth you want and run a compactor over it while you drink a sixer.
The guys who argue rebar is unnecessary may not be completely wrong but I always use it. It may not prevent a crack but it may (usually will) prevent a crack from increasing in size over time and it's relatively cheap. That's enough for me. I don't know how much this helix shit costs but if it's expensive, I wouldn't use it for a slab.