Environmental impacts of using bitumen in roads

While essential for infrastructure, the use of bitumen has several environmental impacts:

1. Greenhouse Gas Emissions: Bitumen is a byproduct of crude oil, a fossil fuel.Its production is energy-intensive and releases significant amounts of carbon dioxide (CO2).Furthermore, heating bitumen to high temperatures for hot-mix asphalt application also consumes energy and releases fumes.
2. Air Pollution (VOCs): The use of cutback bitumen releases a high volume of Volatile Organic Compounds (VOCs) into the atmosphere, which contribute to the formation of smog.
3. Leaching of Pollutants: Bitumen contains Polycyclic Aromatic Hydrocarbons (PAHs), some of which can be toxic.Over time, these can leach into the soil and groundwater.
4. Urban Heat Island Effect: Dark asphalt surfaces absorb a high amount of solar radiation, increasing the ambient temperature in cities and contributing to the heat island effect.
5. Resource Depletion: As a non-renewable resource derived from crude oil, its supply is finite.

Mitigation Efforts: Modern techniques like Warm-Mix Asphalt (WMA), cold-applied bitumen emulsions, and the use of Recycled Asphalt Pavement (RAP) are being adopted to reduce these environmental impacts.