The word "cement" derives from the Latin, caementum, which means rough stone. The word concrete derives from the Latin, concretus, which means grown together, or hardened. The two are often confused but are different.
Cement is a mineral product primarily made up of limestone heated to the point of melting, although other mineral elements such as shale or clay may account for some amount of the composition. Once cooled into a powder, it is typically mixed with water to undergo a chemical reaction that results in hardening. If the powder is mixed with water and other ingredients such as stone or gravel, it is technically called concrete. Therefore, to be accurate, cement is an ingredient of concrete, though the terms are often used as identical in meaning. In fact, the cement ingredient is what accounts for most of the binding properties of concrete.
Natural cement products refers to the melted limestone already described, however, the most common type of cement products used today is called Portland cement -- the name deriving from being similar in color to stone quarried from the Isle of Portland off the coast of England -- and is stronger than natural cement. This is because it is made with the added ingredients of silica, alumina, iron oxide and gypsum and is technically classified as hydraulic cement. As a result, this type of cement product sets faster, remains water resistant, and binds more strongly.
There are other types of cement products enjoying increasing usage and are properly called polymer concrete products. These products contains much of the same ingredients as Portland cement but also include the addition of certain polymer resins -- and sometimes other aggregates --in order to enhance desired physical properties such as resistance to temperature. Depending upon the nature of the mix, various forms of concrete products are available such as grout, stucco and mortar. For example, when cement is mixed with sand and water it is called mortar, which is used as a paste between bricks or stones. Ultimately, whatever the final mix of ingredients, concrete or cement products are used to join or form.
Concrete and cement products are easily recognized as primary ingredients in roads, bridges, sidewalks, foundational walls and brick or stone structures but there are many more categories of use especially since the advent of polymer cement products. These include building materials such as blocks, pipes, and pre-cast slabs, but also art sculptures, movie sets, and miscellaneous items as diverse as drinking fountains, ash urns, tables, benches, mailboxes, planters and trash receptacles.
