Meaning of Asphalt
Asphalt is a thick brown or black substance derived from the same crude oil that produces kerosene, gasoline, and vinyl.
It is literally scraped off the bottom of the barrel after all other petroleum-based products have been refined or processed. This substance is at least 80% carbon, which explains its deep black color. Sulfur is another ingredient found in tar-like asphalt, as well as some trace minerals.
It is primarily used as a roof sealer and a durable surface for roads, airport runways, playgrounds, and parking lots.
Sulfur is found in asphalt.
Tar from crude oil is usually mixed with sand or gravel (often called aggregate) to form the finished product we call asphalt.
The black tar forms a strong adhesive bond with the aggregate, making it durable. When used in road construction, asphalt is typically poured onto a bed of heavier aggregate in a heated state, then pressed into place by an extremely heavy steam roller.
Once it cools to room temperature, it becomes durable enough for automobile traffic. Asphalt can harden further over the years, but still retains enough flexibility to adapt to natural variations in the road bed.
Parking lots and driveways are often covered in asphalt.
Asphalt is also a popular roof sealant. When heated, it can be pumped to the roof of a new building and poured into place.
While still flexible, roofers can spread an even layer to form a nearly impenetrable barrier between the building and the elements. Over time, the aggregate may come out of the tar, but the overall integrity is comparable to other roofing methods.
Asphalt supports the weight of cars very well, providing a durable road surface.
Because asphalt supports the weight of automobiles very well, it has become a very popular material for the construction of parking lots. The material can be applied quickly to a prepared surface, meaning a parking lot can be graded, poured and painted with little delay.
Patching it is usually a matter of bringing new material to the affected area and pressing it against the cracks or potholes. This makes asphalt preferable to more permanent materials like concrete. Repair crews can fix most problems without blocking traffic or removing entire sections of road.
However, asphalt has some drawbacks as a building material. Sulfur fumes released during the heating process can be dangerous to workers and unpleasant to bystanders. Traffic and constant exposure to the elements can cause the surface to wear faster than anticipated.
Because the ground beneath the asphalt can freeze and thaw repeatedly, roads made from it are susceptible to cracking and pothole formation. But for overall durability and low production costs, this material is hard to beat for many projects.
At most, asphalt rock contains around 15% asphalt, while the rest is made up of the stone in which it is lodged.