Although the terms cement and concrete are often used interchangeably, cement is actually an ingredient in concrete.
Concrete is basically a mixture of paste and aggregates. The aggregates are crushed stone or sand and gravel; the paste is made of water and Portland cement. Concrete material happens to get stronger as it gets older. Portland cement is not the name of a particular brand of cement; it’s the generic term for the type of cement utilized in almost all concrete (ex: stainless is a type of steel and sterling is a type of silver).
Pervious concrete, also known as "green concrete," is a choice that helps combat building code issues with storm water run-off.
Cement is composed of 10 to 15 percent of the concrete mix, by volume. Then through a process called hydration, the cement and water harden and bring together the aggregates into a rocklike form. This developing and hardening process continues for years, again meaning that concrete gets stronger as it gets older.