Waste materials can be used for laying roads
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With rising construction cost and demand from various sectors for conventional building materials, a move is afoot to use waste material for laying roads.
The Central Road Research Institute (CRRI) has gained expertise in use of agricultural, municipal, construction and demolition wastes, metallurgical industry waste and by-products, quarry waste, pulverised fuel ash, diamond mine waste and paper industry waste.
During tests, roads constructed with these wastes were found to be at par with, if not better than, the ones traditionally laid with soil, stone aggregates, sand, bitumen and cement.
Though the Indian Road Congress has standardised most of the CRRI specifications, these have not been put to use by the road construction industry as yet.
To carry forward the initiative, the CRRI has been directed to prepare a database on availability of waste and marginal materials to optimise their use in construction of highways.
In a joint paper, CRRI senior principal scientist R.K. Swami and senior technical officer Uma Arun noted that while the effort would help in addressing waste disposal and conserving natural resources, the problem was availability of waste materials close to the construction project. The inhibiting factor was transportation. Large haulage would have its impact on environment and fuel costs and would outweigh the benefits of waste removal, they said. This explains the government effort at preparing a database on availability of waste and marginal materials to assess the cost of substituting these for natural materials and find means of making them economical
The Indian Centre for Plastics in the Environment (ICPE) has been promoting the use of plastic waste to construct asphalt roads.
A few trial roads have been paved successfully by combining waste plastic with bitumen.
“It has been decided by the local municipalities where demo roads were constructed, after observing their performance in the monsoon, that all municipality roads would be built using the waste plastic in the future,” said Sourabh Khemani, co-chairman of Indplas’12, held Oct. 5-8 in Calcutta.
“Soon the use of waste plastic will be added in the States Public Works Department list, so that all new tenders for road-laying in [Calcutta] would add the use of waste plastic,” he added.
So far, trial roads made by using plastics have remained intact after the rainy season and are saving money. About 8-15 percent of the bitumen normally used is replaced with waste plastic from thin polyethylene and polypropylene carryout bags that are not regularly recycled and are considered low-end waste.
The Calcutta-based Indian Plastics Federation also has been involved in the project.