it's a sedum. I have the exact same one at my house, actually- starts out as rosettes, which over the course of the summer turn into something like a charm bracelet of little diamond-shaped leaves.

it will take some foot traffic (it squishes easily, but bounces back fast) and it's pretty much unpeturbed by anything but boggy conditions.

This sedum roots very very easily. I tossed some (I thought they were) dead ends into a corner for pick up later and they rooted and grew... now have a nice patch. I have most of mine in an old turkey feeder where they do quite nicely. The patch in the corner has grown quickly, but it doesn't seem invasive and it is easy to pull.

I received a bag of cuttings of this from a plant trade. I have now (2 years later) given it to the whole neighborhood. It grows like crazy, but it's roots are super shallow so it can be pulled out very easily. I am not sure about it by a path since it would break when you step on it, although there is so much it would grow right back. It also would have a tendancy to grow over the path itself as some of the pieces I have are at least 15-18 inches long.