Two new road miller machines will scrape the old bituminous layer off city roads before a fresh coat of bitumen is laid.
The machines bought by the Calcutta Municipal Corporation (CMC) will be operational later this month or in early December.
Metro had reported in April that the road level in many parts of the city was gradually becoming higher than the houses along the road, leading to flooding of homes during the monsoon.
The CMC had two road millers, which were proving inadequate. The two new machines are likely to make it easier for the corporation to ensure that the top bituminous surface is scraped off before a fresh coat is laid.
“Each machine costs Rs 1 crore. The millers would be deployed from this week or the next,” a senior CMC official said.
The two new machines will be able to work on roads at least 10ft wide. The two existing machines cannot enter roads narrower than 12ft. “The millers can scrape off a two-inch thick bituminous coating at one go. Depending on the need, the machine can be repeatedly used on a stretch to scrape off a thicker coating,” the official said.
The bitumen is removed with cutters attached to a drum-like structure underneath the driver’s seat in a miller. Engineers said the millers would also help recycle the scraped-off bitumen.
Sangeeta, who heads the flexible pavement division at the New Delhi-headquartered Central Road Research Institute (CRRI), said the scraped-off bitumen can be used to create a new bituminous top layer of a road.
“A mixture of 70 per cent fresh bitumen and 30 per cent recycled bitumen (the bitumen obtained after scraping off old layer) can be used to give a new bitumen layer coat,” Sangeeta said. She said millers could also help level an undulating road surface.
Pothole repairs
The CMC has also bought two pothole-repairing machines.
A senior civic engineer said the machines would be able to fix a pothole in 30 minutes and vehicles would be able to move over the repaired portion without causing any damage. “This would help us repair potholes faster,” a civic official said.
