The Hindu : Karnataka / Bangalore News : From trash to tar

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Tuesday, Sep 14, 2010
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Karnataka

Karnataka - Bangalore

From trash to tar

Priyadarshini Kumaresan

— FILE PHOTO: K. Murali Kumar

SMOOTHER RIDE:The HAL Airport Road in Bangalore is one of those that has benefited from the plastic-bitumin mix.

BANGALORE: Perhaps the most important among three ‘R's of plastic use — recycling — has twin benefits: it helps reduce our daily contribution of waste to landfills, while also creating some useful and innovative products.

Scientists at the Bangalore University paved the way to one such innovation. They used low-density (thin) polythene to make a potent mix that is today used in the construction of roads in the city.

Beginning from Kengal Hanumanthaiya Road in Richmond town and down the small bylanes here, many roads have benefited from the addition of plastic into the mix, according to BBMP sources.

Eureka moment

M.S. Amarnath of the Civil Engineering Department of Bangalore University, who was instrumental in the project, said: “This novel idea sprouted when we noticed that Kanakapura Road had many potholes that kept recurring despite repairs. So we thought of using waste plastic instead of the conventional method.” The team of researchers found that plastic waste not only improved the road quality but also brought down the material cost of road construction.

The scientists collected low density waste plastic which they then blended with bitumen (a mixture of organic liquids). As plastic is a polymer, this mix altered in its properties, enhancing its bond strength and resistance to wear-and-tear. The potholes were filled with the plastic and bitumen mix, which has shown remarkable results: five years later, there is no sign of erosion.

Fatigue testing

Prof. Amarnath explained: “Initially we filled the potholes with bitumen alone, but this did not show as much durability as it did when the plastic shreds were mixed in.” To further test the sustainability of roads, the team developed a fatigue testing mechanism which assessed the behaviour of roads when repeatedly exposed to loads. This test showed that out of the two mixes, the one with plastic lasted longer and showed more resistance than the one made only of bitumen.

Three stretches were tarred on a pilot-basis using this mixture: a road near the Bangalore University campus, a stretch near NH 48 and a small stretch of road near Maddur. The technology has since been transferred to the Bruhat Bangalore Mahanagara Palike (BBMP) which has supposedly used this technique on almost all of Bangalore's roads, including the Old Airport Road.

‘Implementation'

So why then is our commute still so bumpy and potholed? A researcher, who did not want to be named, held “the lack of positive implementation” responsible: “There should be a willingness to implement these methods, which should be properly used to get positive results. Arbitrary implementation without paying heed to quality will give way to improper roads.”

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