Thank you for the quick and good response MaxPax!
I had apparently confused spikexpander with expanderspik
It was expanderspik I meant in my question actually, but the first link answered it. Apparently, the expanderspik can handle only a tenth as much as the concrete screw, which makes sense.
The reason for my question is that I had never seen expanderspik before, but it said it was intended for attaching spikläkt for ceiling panels.
/P