As an extension of the application of plastic waste in road construction, recycling of existing roads to improve network in rural areas has been mooted. The idea, according to R. Vasudevan, Dean, Thiagarajar College of Engineering, whose Department of Chemistry has a patent for use of aggregate coated with plastic waste in laying roads, is to minimise cost and also improve rural road network.
At present, new roads are laid over the existing roads, thereby increasing their height. In residential areas, enhancement of the height of the road leads to water stagnation. Many residential colonies have houses that have gone below road level due to stacking of layers of road over the years. Dr. Vasudevan says that the old road can be removed using earth movers for use elsewhere. The process involved is coating the used aggregate with plastic waste while being heated and relaying it. In the case of urban roads and highways, there may be a need to add bitumen to reinforce strength. It may not be required in the case of rural areas, where wear and tear is less.
Recycling of roads will have many advantages for local bodies, especially panchayats. Use of plastic waste will help in solid waste management; improve the stability of roads; bring down periodic spending on relaying and maintenance and result in substantial saving. The old highways and urban roads can be used for relaying in rural areas.
Above all, regular recycling will save hillocks, the source of aggregate for road laying, says Dr. Vasudevan. Repeated destruction of hillocks for stone mining will alter the geological balance of a region. It will also mean about 50 per cent of reduction in bitumen use.
The National Rural Roads Development Agency of Union Ministry of Rural Development, in its ‘Guidelines for the use of plastic waste in rural roads construction,' states that “plastic roads are found to perform better compared to those constructed with conventional bitumen. Further, it has been found that such roads were not subjected to stripping when (they) come in contact with water.” The advantages of laying roads using aggregate coated with plastic waste listed in the guidelines include enhanced strength; better resistance to water; no stripping and no potholes; increased binding and load withstanding property; reduction in bitumen consumption and no maintenance cost.
Dr. Vasudevan explains that road recycling using plastic waste will also minimise emission of carbon dioxide into the atmosphere to a great extent.
