Road repairs ahead of Puja are scheduled to start in a few weeks in Calcutta, and engineers anticipate that they may have to undertake several rounds of repairs this year because of an early Durga Puja, when rain is most likely to continue.
An official of the Kolkata Municipal Corporation (KMC) stated that they were aware of the possibility of rain during Durga Puja, but this would not deter plans for road repairs. Sashthi falls on September 27.
Metro has been reporting the bad conditions of roads across the city and its suburbs. Over a dozen roads, including some of the key arteries, including EM Bypass, VIP Road, Park Circus Connector, Belgharia Expressway, Diamond Harbour Road, and BT Road, are dotted with potholes, some deep enough to stall vehicular movement.
In Calcutta, damaged roads are repaired with a layer of bitumen, and potholes are filled before the Puja festival to ensure smooth roads during the festive season.
“We are already filling up potholes now as part of our road repairs programme, but some of these may wear off by the end of September. If required, we will fill the potholes again with bituminous mixture,” said the official.
“Fresh potholes may emerge before September ends. We will fix them also. We know we may have to conduct several rounds of repairs this year before Puja,” said the official.
“For a patch repair to sustain for a few months, we need at least two days for the bed to dry before pouring bituminous hot mix on the potholes or the worn off road. The way it is raining this monsoon, we are hardly getting that time. Therefore, there is a risk of the potholes forming again after repairs,” said an official.
Sources in the KMC said there will be teams who will repair stretches of roads overnight during the Puja days, if so required.
“We are also trying innovations in the way potholes are repaired so that they can be more durable,” said the official.
Several engineers of the KMC’s road department and the roads and bridges wing of Kolkata Metropolitan Development Authority (KMDA) said truckloads of bitumen and stone chips have been kept ready for the repairs.
“These are patchwork repairs. We don’t have the time to undertake a thorough repair. The top layer of the roads will be cleaned once the area is dry and filled with bituminous mix,” a senior engineer of KMC’s roads department said.
But these would not last if a spell of heavy showers precedes Bengal’s biggest festival, several engineers said.
Some of the reasons they mentioned are:
- A patchwork repair of a road surface often means a quick fix of the potholes and allowing traffic to move within a few hours. Since the bituminous mix doesn’t get enough time to strengthen, the repaired top surface remains vulnerable to abrasions when vehicles move.
- Patchwork repairs done in a hurry often do not take into consideration the condition of the subsoil or the layer below the surface of the pothole. These layers usually remain wet. After a round of repair, when it rains again, water seeps through and hits the subsoil. The soil layer loses strength, and a subsidence follows.
- Despite best efforts, the stone chips used for patchwork repairs during the monsoon do not remain completely dry. The presence of moisture, even in small amounts, ensures that the bituminous mix is not at its optimum level. Fissures and pores that remain allow water seepage through the repair spot when it rains again.
“The cuing time for a dense mix of bitumen should be at least two days. Since that is not possible during patchwork repairs, the mix used to repair the potholes doesn’t gather enough strength,” said a senior engineer of the KMDA.
According to several KMC engineers, in mid-July, stretches of several roads were repaired after Kolkata Police demanded restoration of these thoroughfares at the earliest. Within a week, some of these repairs had worn off amid continuous showers.
“Pavered blocks work best in stretches where water tends to accumulate every year due to the undulating ground surface. The other alternative is using mastic asphalt. But these are costly options and hence mostly shunned,” said a senior KMDA official overseeing repair of bridges and roads.
Others said one of the vital aspects of road repair that often remains neglected is ensuring proper drainage of water along the channels adjoining roads. On several stretches of EM Bypass and Park Circus Connector, the drains often fail to clear the water that accumulates on these roads.
“Water is bad for bitumen. When it accumulates, the bitumen layer starts to wear off. We need to have a good drainage mechanism along the throughfares so that rainwater can easily pass,” the official said.