Here follows an engineer’s pet peeve.
Cement. Concrete. They’re the same thing, right? It’s the hard grey stuff that many buildings and slabs are made out of.
What you’re thinking of is concrete. Concrete is a mixture of a water, sand, aggregate (stone) and cement. Concrete takes advantage of chemistry to create a very hard, cohesive product that is extremely useful in construction.
Cement is a light grey powder which acts as a binder, joining together whatever comes into contact with it (stone and sand in the case of concrete).
So please stop saying that you fell over on the cement: that’d be a fairly soft landing compared to what you really fell on, which was concrete.