How is Asphalt Made?

Most of us are familiar with asphalt. We see it used on our roadways, as the cover for jogging paths, and often the material of choice for parking lots. Here are a few facts about how it is made, as well as some examples of the different types used today.

While we often refer to the road covering we know as asphalt, the fact of the matter is that the substance would be more accurately referred to as an asphalt compound. Asphalt itself is a hydrocarbon mixture that is heated until it has the consistency of tar. Depending on the amount of heating, it may take on a relatively solid state, or become the consistency of a thick liquid. With some uses, such as in road building, the semisolid form is mixed in with other elements such as crushed stone, sand, or gravel to make up the compound that is used to provide cover on highways and city streets.

The hydrocarbon material that is used to create asphalt is actually derived from the waste material left over after the manufacture of gasoline, kerosene and diesel fuels. Essentially, it is a by-product of the residue that is left behind after the more desirable components of crude oil and petroleum have been harvested. One of these by-products, bitumen, is sometimes referred to as asphalt oil.

Along with being derived from petroleums and being an essential binding element in the cover used for roadways, asphalt has been used to patch or cover a worn roadway, such as a city street. In addition, when heated to a high temperature, it forms the basis for the creation of asphalt roofing and shingles, which have been used for years to make roofs of homes more secure and water repellent. Heating the material to the proper temperature and then adding in cement to the mixture also makes asphalt concrete.

There are some recycling programs that are now using asphalt along with rubber chips made from old tires to create materials for sidewalks and walls, similar to the way concrete has been used for years. The binding capabilities of this material are probably the most important aspect of the substance, along with the fact that once applied, it takes a long time to wear away.

Interestingly enough, the word asphalt has some Greek origins, with a rough translation of the term being to prevent something from falling down or collapsing. Certainly, asphaltenes that have been used for our roadways prevents the collapse of the roadway system from daily use, as well as protecting the roofs of many structures from collapsing due to the weather conditions. Asphalt caulking has been used in times past to repair leaks in boats and ships, and while the use of shingles made from it is on the decline, they are still the roof covering of choice for many homeowners.