I think that the "concrete" you are referring to is a product by DAP called weldbond or weldwood . . . someone else around here will be able to tell you more precisely, but I believe it is actually a plastic polymer product rather than a concrete.
Another option that is relatively easy to pull off with good results is the Great Stuff background with a substrate siliconed in place. Check out Black Jungle for a step-by-step for the process.
Good luck,
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Homer W. Faucett III, esq.
Purveyor of Trivialities and Fine Nonsense