Dead end for asphalt cover

TT, Calcutta: The Bengal government has banned mastic asphalt in building or repairing roads in Calcutta and other urban centres after it emerged that the surfacing material is often used to cover up low-quality stretches.

The decision was conveyed by chief secretary Malay De to the Calcutta Municipal Corporation, Calcutta Metropolitan Development Authority, the public works department and other agencies during a meeting of the state road safety council on Friday.

"No major city in developed countries uses mastic asphalt for urban roads. The material is not used even on national highways. Use of mastic asphalt has several hazards and the state government wants to get rid of these," the chief secretary was quoted as saying at the meeting.

Mastic asphalt roads are common in Calcutta, Salt Lake, Siliguri and Burdwan.

The use of the material, laid over bituminous layers to ensure durability, has increased in recent years to give roads a flawless look, sources said.

Chief secretary De listed some of the reasons why the government wanted to do away with the material. He said he had himself found rides in Calcutta bumpy as mastic asphalt was laid on low-quality roads, the sources said.

Also, use of mastic asphalt causes pollution as it increases friction when cars ply on such roads, burning more fuel. Such stretches are prone to accidents when the top layer of mastic asphalt wears away, exposing the stones.

"The roads in major cities abroad are made of bitumen or concrete. We should start constructing either bituminous or concrete roads. This will improve ride quality in Calcutta and other towns across the state," the chief secretary was quoted as saying.

But some engineers said in a city like Calcutta, where water-logging was a serious problem, bituminous roads would wear out faster if mastic asphalt was not used.

The chief secretary then suggested concrete roads.

The engineers disagreed again, saying as utility services such as power cables run beneath the roads in Calcutta, concrete was not a proper alternative.

Dey then asked the engineers to work out a plan to shift utility services to the side of pavements and lay concrete roads on the rest.

"The plan has worked on Diamond Harbour Road, where utility services have been shifted to one side and a concrete road laid on the major part," said a PWD engineer.