There is already vanilla concrete, you just added a recipe-less version of your concrete with the block variants.

Wait a minute, you already had recipes
but they don't show up in JEI

so add ponders to prevent confused people like me from making a new issue

Concrete is poured, that's why it has no "recipe." Concrete mix is made, then you can transport to the concrete molds and pump directly into the mold "tank." They connect and set to form concrete. Rebar vs regular concrete is just the type of mold. You can technically create "concrete" by simply pouring the liquid our of an open pipe and letting it set, then breaking the resulting block.

Some people have broken textures for them, I haven't seen that, and the molds are SUPER laggy if there's more than 60 or so. They destroy RAM and video performance, but shouldn't crash anything. Lag completely vanishes once a mold column has concrete poured in it.