Concrete, as in sand, cement and gravel?? Darn hard to draw on concrete because of the gravel but stucco, mortar or a fine hypertufa mix you can draw on. You apply smooth and let set up then you can carve...carefully. Make sure you use arcylic fortifier in your water. Helps the new cement mix stick to the old mix.
I've attached a link to a true fresco web site using plaster

Here is a link that might be useful: fresco on plaster

Thanks Billie ann,
I'll look for some arcylic fortifier and add it to my water.
~Deb~

Oops and make sure you soak the pieces of broken concrete in water prior to adhereing the hypertufa. Think damp concrete. Helps the two pieces stick together and the old won't suck the water out of the new. Billie

Thanks Billie
Will do. I'll let you know how it works out.
~Deb~

Sorry, was thinking of this post and the other one about adhereing hypertufa to broken pieces of concrete, that's why I said broken but wetting the old concrete applies to anytime you apply new cement product to old. Billie

Yes, it can be done. The ones I've seen personally were by artists George Little and David Lewis. See link below.

Sue

Here is a link that might be useful: Little & Lewis painted fragments