Concrete is used at least partially in most structures made in the United States, from bridges to houses to dams. It is composed of a mixture of sand and rock and a paste consisting of cement and water.
The strength and durability of concrete is achieved by reaching the correct proportions of the ingredients. There should be 10 to 15 percent cement, 60 to 75 percent aggregates and 15 to 20 percent water. Air bubbles can make up to 8 percent of the composition.Learn more about Building Materials