Concrete and Cement are often thought of as the same product but actually Cement is just one part of Concrete.
Concrete is a mixture of Aggregates and Binders (Rocks and Cement).
Depending on your needs you can use larger or more aggregate to get a harder product or you can use smaller aggregate to allow the mix to flow.
This difference is easy to understand when you compare the tough but formable sandy mixture that is shot onto Swimming Pools and the much stronger …