The 'pour' looks a bit rough around the edges, but yes I have heard of people framing up CNC tables & other machines & then casting/filling with inert concrete like materials. Sometimes just in key areas like the frame or legs, sometimes integrated & encapsulating the components. Its relatively cheap & adds rigidity & vibration dampening. From what I've read, I think epoxy/aggregate mixtures are favored & offers more advantages. It has less potential shrinkage over cement cure, better boding to dis-similar materials, you can stage the pour & you can mess with the mixture recipe with a bit more latitude. I've done some RC molds using this technique where stability & dimensional accuracy is important. Having said that, there are new mixtures of cement being used for decorative counters etc. where they modify the additives to try & balance out shrinkage (like tooling plasters).