State agency offers ‘permanent’ solution

April 8, 2008

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A perpetual or permanent road is a long-life bituminous road that needs no maintenance, is of superior quality and ideal for heavy-traffic corridors

Bangalore: Bumpy rides on Indian roads may soon be a thing of the past, if the Central Road Research Institute, or CRRI, has its way. The institute is compiling a report on its research on introducing perpetual roads— that last as long as 30 years without cracking—in the country.

Perpetual roads are hugely popular in the US and China.

“Perpetual roads are the future for important roadways like the national and state highways where maintenance is a huge concern and need to be refurbished because of high traffic volume,” said Sunil Bose, deputy director of pavements at CRRI, which has just completed laboratory tests on perpetual roads in India.

Once the report is complete by July, the New Delhi-based institute wants to collaborate with the National Highways Authority of India, or NHAI, and run a pilot project on a stretch of the National Highways Development Project (NHDP).

A perpetual or permanent road is a long-life bituminous road that needs no maintenance, is of superior quality and ideal for heavy-traffic corridors such as the national highways, said Bose. It has three layers: a wear-resistant top layer, an intermediate layer and a fatigue-resistant base layer, he said.

In India, important roads are overloaded with traffic and therefore suffer harsh weathering, leading to cracks and potholes. Entire structures have to be rebuilt every four-five years at high cost. According to NHAI data, India’s 66,590km of national highways, for example, constitute 2% of its road network but carry 40% of the traffic.

Nirmaljeet Singh, technical member at NHAI, said despite good construction, NHDP roads invariably deteriorate due to the heavy traffic and have to be relaid every five years.

Road experts say that in perpetual roads, the layer of bitumen, a petroleum product that is used to lay roads, is 25-30% thicker than the usual 900mm, and of better quality, giving the roads a stronger cover.

“We are open to such research but it needs to be tested and seen whether it suits our roads and can be effectively maintained in the long run,” said Singh.

These roads are also less expensive in the long term, says CRRI. Bose said that while the cost of building 1km of any NHDP road is around Rs4.2 crore, a perpetual road would cost 25% more. However, these roads would last much longer, recovering the additional costs.

“Perpetual roads are a boon for the economy because goods are delivered on time and there is less fuel wastage because of reduced obstruction in traffic movement. And once you construct these roads, they don’t deteriorate,” said B.B. Pandey, emeritus professor of civil engineering at the Indian Institute of Technology, Kharagpur.

Source: www.livemint.com