Asphalt and bitumen may appear similar on the surface, but they are distinct materials with unique compositions, production processes, and applications. With its load-bearing capacity and durability, Asphalt remains the top choice for road construction. Whereas bitumen excels in applications requiring waterproofing and adhesion.
What is Asphalt?
Asphalt is a black, sticky liquid that is mixed with gravel, crushed rock, sand, and slag. A binder is used to make a cohesive mixture. This is the most widely used material for roads and pavement.
What is Bitumen?
Bitumen is a mixture of dense, sticky, viscous organic liquids composed mainly of polycyclic aromatic hydrocarbons and obtained naturally by the distillation of crude oil. It is a complex colloidal system whose chemical properties depend on the properties of the crude oil from which it is obtained.
Bitumen is a black or dark (viscous, non-volatile liquid , semi-solid or solid), amorphous, cementitious material that can be found in various forms as hard, slightly friable bitumen in rock asphalt and as softer, more viscous material found in tar sands and asphalt ‘lakes’. Bitumen derived from oil, called petroleum bitumen commonly referred to as bitumen or asphalt. Pure bitumen is a colloidal dispersion of microscopic asphalt particles (dispersion phase). It is a semi-solid hydrocarbon product formed by the removal of the lighter fractions (such as liquefied petroleum gas, gasoline, and diesel) from heavy crude oil during the refining process. As such, it is correctly referred to as refined bitumen.
Differences between Bitumen and Asphalt
The most apparent difference is the physical state of these materials. Asphalt is a mixture of bitumen, aggregates, and fillers and is solid at room temperature. Bitumen, on the other hand, is a semi-solid or highly viscous liquid at room temperature.
Asphalt is laid and compacted as a hot, semi-solid mixture, while bitumen is applied in various forms, such as hot bitumen, bitumen emulsions or cold bitumen compounds, depending on the application.
- Bitumen is used to bind the road material together by spraying on it and then covered with aggregate whereas asphalt is premix bitumen, aggregate, and sand mixture which applied on the surface through a paving machine as of required thickness.
Advantages and Disadvantages of Bitumen and Asphalt
Asphalt is by far the most popular construction product that people use for roads and resurfacing. It is because of the several benefits it offers. Asphalt causes minimal noise because of the smooth surfacing it offers. Also, it results in lesser wear and tear in tyres; is energy efficient and reduces friction between the tyres and the car resulting in more fuel economy and lesser carbon dioxide emission. Furthermore, this construction product offers a longer lifespan of the road more than 20 years. However, its installation is more expensive as compared to a bitumen laying process. On the flip side, while using asphalt you will need a well-prepared surface for installation and extreme hot temperatures can make the asphalt go soft.
On the other hand, bitumen is a cheaper construction product when it comes to installation and can be recycled. However, the loose rocks on a bitumen paved road or pavement can cause more wear and tear in tyres. It is also not as durable as asphalt. The biggest challenge while working with bitumen is that it can cause pollution to soil and groundwater. Bitumen works best for roads where you do not expect heavy traffic.