Cement is an ingredient of concrete and it is made to bind to other products. For example, often cement is used when people lay bricks. Concrete is a product made by mixing cement, water, sand, and pebbles or crushed rocks. Much of the Romans building revolution came from their improvement of mortar, such as their use of concrete. They used concrete on many of their buildings but covered it up with slabs of polished marble and granite, because the concrete was visually unappealing. The Romans produced concrete by mixing lime, sand, small rocks, and rubble.
