The Hindu 26.08.2009
Guidelines issued for ‘plastic roads’
S. Annamalai
| Ministry for using plastic waste for rural roads |
MADURAI: The road has been cleared for productive use of waste plastic. The National Rural Roads Development Agency of the Ministry of Rural Development has come out with guidelines for laying rural roads using waste plastic. They are based on the recommendations of R. Vasudevan, Dean, Thiagarajar College of Engineering (TCE), Madurai, and Central Road Research Institute.
The TCE has patented a technology to coat aggregate with waste plastic while laying roads. Roads using waste plastic have been laid at several places in Tamil Nadu and other States, especially in Mumbai, since 2002 and the results have been positive. In Mumbai, the ‘plastic roads’ have weathered consecutive monsoons.
Studies satisfactory
The Ministry’s guidelines say that the performance studies carried out on the roads (using waste plastic) constructed in Tamil Nadu indicated “satisfactory performance with good skid resistance, good texture value, stronger and less amount of progressive unevenness over a period of time.” The experiments of the CRRI also indicated better stability value, indicating higher strength, less flow and more air voids.
The guidelines recommend the use of poly films with thickness up to 60 micron, hard and soft foams and laminated polymer with thickness of up to 60 micron. However, poly vinyl chloride sheets (flex sheets) should not be used. The process of coating aggregate with molten (waste) plastic does not require any machinery. No toxic gas evolves in the process. Dr. Vasudevan says that there is no need to go in search of waste plastic as it is abundantly available anywhere.
Cost factor
The Ministry has pointed out that though the cost goes up by Rs. 2,500 per tonne for modifying bitumen with shredded waste plastic, the increase in cost is compensated by lesser bitumen use, better performance and environmental conservation.
Almost five per cent of municipal solid waste consists of plastic in different forms. Plastic waste creates water stagnation and associated hygiene problems. In order to prevent the ill effects, the Ministry of Rural Development has recommended use of waste plastic in construction of rural roads. The specifications relate to types of plastic that can be used to lay roads and method of road laying.