I was able to create this using Flowify. The sidewalk is done on a flat surface and the expansion joints was basically a 2x6 using Profile Builder (you can create your own) which I then arrayed using copy along path. Then grouped all those and exploded them within said group and then just subtracted it from the sidewalk. Then Flowify.
It's not exactly real world flat work but it would be close enough for a rendering. You would have to divide the site layout into rectangle since you need the 4 points for Flowify.
I haven't tried it yet but you can also stamp the topo with Sandbox and then either push-pull manually or use Fredo's Joint Push pull and then apply materials as required. I like to have the sidewalk grouped to apply beveled edges in Thea Render.
After you Flowify the sidewalk you'll have to lower it by about 3 inches because otherwise the sidewalk will project 6 inches from the surface of the topography.
I also subracted the sidewalk outline in the topography.
