Concrete and cement are often confused with each other. Think of Cement as glue with sand. More specifically, it’s a hydraulic product that sets and hardens when it chemically reacts with water. It’s kind of considered the glue that holds everything together. Concrete then, is cement that has some form of aggregate, like gravel or crushed stone, in it. Pretty much everything you see, from sidewalks to pool patios to house foundations, is concrete.