Thursday, January 5th, 2012
Local and regional governments in India increasingly are laying down what the local media like to call plastic roads, which are in reality a mixture of recycled plastics and asphalt that doubles the life of the road surface, as well as increases local plastics recycling and decreases litter.
Just beginning to use the mixture is Chennai (formerly called Madras), a sprawling city of nearly 5 million people on India’s southeast coast. On January 4th, Mayor Saidai Duraisamy was out inspecting Chennai’s first repaving of roads with plastic-asphalt compound in the city’s bustling T Nagar area. It was a good day to be mayor: He was able to assure motorists of better quality roads and tell area residents they were in the process of becoming a litter-free zone.
Though fighting litter and increasing recycling are factors, converting road surfaces to plastic-bitumen, as asphalt is called in India, is primarily a response to the rapid deterioration of all-asphalt roads caused by Chennai’s weather. Summer highs in the area often surpass 120ºF, humidity is high, monsoon rains are heavy, cyclones are not uncommon, and on top of all that, the volume of vehicle traffic is increasing as the city continues to grow.
At about 10% by weight, the plastic portion of the compound is a mix of polybags, cups, and bottles. Recycled and powdered, the polymer is mixed into the asphalt where it becomes a flexible binding agent that helps the pavement resist high temperatures and keeps rainwater from penetrating. In the Chennai area a traditional all-asphalt road lasts four to five years before needing resurfacing; plastic-bitumen roads last up to ten years.
Although the plastic road costs slightly more than conventional straight asphalt, government leaders say the benefits greatly exceed the cost difference. Plastic-bitumen roads already are installed in other areas of India and more are planned. Chennai is one of
India’s leading industrial centers, notable for software and information technology, as well as for its large share of India’s automobile manufacturing sector.