it can't be reused because of the heat exposureor also a building that has been torn down
The concrete can be used for fill to raise the level of the ground at the edge of a slope to provide more level ground.
Concrete from demolished buildings can be used for erosion control provided it is not contaminated with toxic or other environmentally negative materials. It can also be used as faux stone if broken into pieces of the correct size and stained to look like stone. One of our neighbors has a large retaining wall made from this type of reclaimed concrete.
I think you are confusing cement with concrete. Sometimes crushed concrete is used as a base material for roads, or as ballast in gabion baskets. Cement is the very fine dusty material that reacts with water to make concrete. It's generally not used without aggregate (i.e. sand, stones).
