Introduction
Asphalt, or bitumen, is an essential component to the global economy. As one of the top road construction materials, it has enabled the development and global connectivity of the transportation infrastructure, thus playing a vital role in sustaining and expanding the economies of all countries worldwide.
History
Asphalt has been around for thousands of years, and was used by the ancient Greeks and Egyptians to form roads and even limited pavements. It wasnt until the 19th Century, however, that its use as a road material was common and popular. This was primarily due to the rise of the macadam method of road construction—a process that involved rolling a mix of small aggregate and asphalt onto the prepared ground. The macadam method was chosen due to its cost-effectiveness and relative durability.
Chemical Make-Up
Asphalt is a bituminous cementitious material that is made up of a variety of organic and inorganic materials. The primary component of asphalt is bitumen, which is an oily, highly viscous hydrocarbon mixture. Bitumen is extracted from petroleum sources and is composed of 85 to 100 percent carbon and 0 to 15 percent hydrogen. The other components of asphalt include mineral matter, such as quartz, feldspar, clays, and iron oxides.
Uses
Asphalt is used primarily for road construction and for waterproofing materials. As a road material, asphalt is mixed with a variety of aggregates and then applied in a thick layer to the road bed. It is durable, cost-effective, and can be easily catered to different weather and climatic conditions. In addition, asphalts waterproofing qualities make it an ideal sealant for roofing materials and damp proofing materials.
Environmental Impact
Due to its hydrocarbon component, asphalt is considered to be a high-emission material and can have negative impacts on the environment. Asphalt is a major contributor to ground-level ozone concentrations, which have been linked to health effects such as respiratory problems, cardiovascular issues, and reproductive disorders. In addition, asphalt production and use can lead to water and air pollution.
Conclusion
Asphalt is an essential component to the global economy as it enables the development and global connectivity of the transportation infrastructure. It is composed of 85 to 100 percent bitumen, an oily, highly viscous hydrocarbon mixture, as well as mineral matter and other inorganic components. Asphalt is mainly used for road construction and waterproofing purposes, and its high-emission component has resulted in a number of environmental problems.
