Asphalt [1]

In its natural state, asphalt is a solid, dark-colored bituminous substance that can be found in the earth, like coal, at various locations around the world. From a chemical standpoint, asphalt is classified as a hydrocarbon. Much of the asphalt used in the United States is derived as a by-product from crude oil [2] during the cracking process. 

When mixed with gravel or crushed rock, asphalt is used as a paving product.