I recently saw a concrete parking lot being made. This was after hours, so no one was around to ask. They had the forms made, and had rebar placed about every 2 feet in both directions. Under the rebar they had small plastic "stands" to keep it off the ground.
What are these things called, and where does someone buy them? Also, what did they use before they made these plastic things? I plan to pour a pad of concrete in front of my garage soon, and think rebar should be used, but I was just going to use rocks under the rebar. Actually the thought was to buy some of those cheap patio blocks, which are about 1.5 inches thick and bust them up into pieces for this. That way the rebar would all be about the same space off the ground, and those patio blocks are pretty low cost. Possibly cheaper than those plastic things.
On the other hand, I was wondering if using that metal mesh material which is sold in rolls would work just as well as rebar and which would be cheaper to buy.
Any concrete experts out here?