What is the difference between cement and concrete ?

Although the terms cement and concrete often are used interchangeably  , cement is actually and ingredient of concrete . Concrete is basically a mixture of aggregates and paste . The aggregates are sand or gravel or crushed stone ; the paste is water and portland cement . Concrete gets stronger as it get older . Portland cement is not a brand name , but the generic term for the type of cement used in virtually all concrete , just as stainless is a type of steel and sterling a type of silver . Cement comprises from 10 to 15 percent of the concrete mix , by volume . Through a process called hydration , the cement and water harden and bind the aggregates into a rocklike mass . This hardening process continues for years meaning that concrete gets stronger as it gets older .