You can do something very similar with concrete mix and aragonite sand. Do a Google search on "aragocrete." I can't point you to the site cause it would violate the rules here, but search on that term and you'll find it.
I've got about 50 lbs of it in my currently-cycling tank. Mine turned out really, really ugly because it was my first attempt and my first try at anything generally tanks, but it does at least add to the rock volume in the tank You have to cure it in freshwater for several weeks so it won't spike your pH, but apparently it works quite well. I'll post some pics later if I can.