what's the difference between concrete and cement, and what are they used for?
Cement is heat treated limestone. More properly called Portland Cement, after the guy who perfected the technique. Tho this stuff has been around for a very long time, used extensively by Roman Empire. The heating of the limestome drives off the water and allows a chemical reaction to take place when water is added. It gives off heat when curing. Concrete is cement with added stuff, aggragate and is used for many things. Most often seen as driveways and walls. Depending on what you add to it it can be used to make boats too.
Most people use concrete for pouring things like patios, foundations, driveways, they are basically made up of the same ingredients, the difference is what you mix them with. You would mix concrete with gravel, cement would be mixed with sand. Cement is usually used as a grout, for example, the mortar that holds bricks together on a brick home, and cement is easier to smooth, but a lot less durable.
Cement is a binder, a substance which sets and hardens independently. Concrete consists of cement and usually sand and some form of aggragate in various proportions.(with water)depending on the job to be done..
Concrete is a composite structure of sand, gravel, possibly some larger rocks, and cement. Cement is basically a water activated adhesive that is used for gluing rocks and sand to each other. To get a feel for how this works, without mixing up concrete and cement, first try and tear through ten sheets of computer paper, then pour out a puddle of white glue onto wax paper and let it dry over night then try to bend and tear it, then use a paint brush to evenly spread white glue onto paper and press together ten layers of the same paper you tried to rip before, cover with wax paper and lay several books on it overnight so it can dry then try and rip the glued paper. What you will find is that the glued paper is much stronger than either of the two ingredients by themselves, and if you use just the right amount of glue it will be stronger than the sum of the parts. In the same way, the Aggregate (Sand, Gravel and rocks) act as the structure that the load rests on, while the cement is the glue that keeps the aggregate from shifting. Many people think that cement dries to become hard, but that is inaccurate, a chemical reaction takes place between the water and the cement powder that causes the powder to turn into a solid mass, then any excess water that was not used in the chemical reaction evaporates from the concrete.
