The words asphalt and bitumen are often mistakenly used to define the same thing. Asphalt is a composite of aggregates, sand, and bitumen; where bitumen acts as a liquid binding material that holds asphalt together. To make things simple, we can relatively say asphalt is concrete (mixture) while bitumen is cement (binder) for pavements. A pavement surface sealed only with bitumen is also common though, which is done by setting up a layer of bitumen and topping it with aggregates. This process is then repeated to create a two coated seal.
So, what are the other differences between Bitumen and Asphalt?
Differences between Asphalt and Bitumen
Followings are the differences between bitumen and asphalt.
| Asphalt | Bitumen |
|---|---|
| Asphalt pavements are durable; with a layer depth of 25-40 mm and life span of 20+ years. | Bitumen pavements are less durable; with a layer depth of 10-20 mm and lifespan of 5-10 years. |
| Surface made of asphalt is smoother and more skid-resistant, ensuring the driver’s safety and minimal noise. | The loose fragments on bitumen pavements make the driving experience noisier and can wear down tires, consequently causing safety issues. |
| Reduced friction between tire and car; meaning better fuel economy and minimization of carbon dioxide emission. | Higher frictional resistance of a bitumen pavement means less efficiency in energy utilization. |
| Asphalt is an impermeable material, thus the pavements do not leach. Therefore, they have a lesser chance of infiltrating and polluting the groundwater | Exposure to bitumen leaching may cause deterioration of soil and groundwater quality. |
| Less sensitive to temperature compared to bitumen pavements. Negative impacts are seen only in extremely high or low temperature. | Pavements are susceptible to high temperature, which can make it slick and soft. |
| Installation is comparatively costlier. | Cheap to install compared to asphalt. |
| Cost effective. An asphalt surface doesn’t require regular maintenance like bitumen surface, rather a routine check periodically is enough. | They require regular maintenance, especially when resurfacing a pavement with greater traffic volume. So not cost effective in the long run. |