Civic body tests cold asphalt for city roads

MUMBAI: If the promise is as good as it seems, the city's roads may soon have a solution to constant wear-and-tear during the monsoons. The BMC is experimenting with a water-based asphalt technology for roads which is supposedly better than the hot-mix asphalt currently used.

As a pilot study, a 45 sq m stretch at Anik-Wadala road was coated with the new mixture on Friday. The cold-mix asphalt, which has been been tried in other countries and states, will be used on Mumbai's other roads if it stands the test of heavy rains and traffic.

Another busy junction where the mixture will be used on a trial basis is E Moses Rd, Worli. "We will have to see if the new product is suitable for Mumbai with its typical problem of water stagnation and heavy traffic.

The Standing Technical Advisory Committee (STAC) on roads will decide if the technology should be used in Mumbai. It will give its approval based on reports by IIT experts and civic officials," said J Bharbhaiya, officer on special duty, BMC's road department.

The cold mix comprises pebbles and carbonaceous shale and requires oxidation as against the crystallisation process in hot asphalt. "The reason asphalt roads come apart post-monsoon is that it can't withstand water. As against this, the cold mix in fact needs water to settle firmly.

Moreover, while hot-mix asphalt requires 6 to 10 hours to settle, in this case the patch hardens quickly making the road available to traffic movement as quickly as possible," said Jasbir Bhandari from the South African company Carboncer Pvt Ltd which is testing the product in Mumbai.

(IndiaTimes)

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Asphalt plants told to work on weekends

MUMBAI: Under immense pressure to fix the city's potholed roads and quickly, the civic body has urged private asphalt plant owners across the city to keep their businesses open even on weekends. Asphalt goes into a premix that is used to make roads and fill craters.

"We need a constant supply of the material, particularly during monsoon. We have asked owners to keep their plants open on weekends so that our work does not suffer," said a senior official from the civic roads department.

The Brihanmumbai Municipal Corporation (BMC) owns an asphalt plant in Worli, but it alone cannot meet the city's enormous needs. There are as many as 13 recognized private drum-mix plants and three batch-mix plants, all of which are outside city limits. They have a capacity to generate 100 metric tonnes of asphalt per hour.

The civic body uses hot and cold mixes to fix potholes. It claims to have already used 1,943.73 tonnes of bituminous macadam hot mix this year to repair craters spread across 1,370.8 km of roads. The remainder of the roads the BMC oversees are concretised. The hot mix was used during June and three weeks of July.

Since long, experts have recommended batch-mix asphalt plants over drum-mix plants, which mix coarse bitumen and metal aggregates on the basis of volume and not weight. The batch-mix technology is normally recognized as better because it guarantees proportionate and high quality volume of mix.

BMC data shows that since 2007 it has spent more than Rs 212 crore to fix potholes during the four monsoon months. However, despite trying both the traditional hot mix and cold mix methods, the civic body has been unable to ensure that contractors fix potholes in such a way that they do not recur. State PWD officials say they spend Rs 60 lakh a year to repair potholes on the eastern and western express highways.

(IndiaTimes)

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Motorists, beware of paver blocks used to 'fix' potholes

MUMBAI: Fixing potholes with paver blocks appears to be latest trend this monsoon, though experts rue that the practice defies engineering logic. Paver blocks come loose within two-three days, ensuring motorists a nightmarish ride, especially so during peak hours, they say.

These potholes resurface within a few days of the "damage-control exercise" as asphalt, concrete and paver blocks do not hold during rains.

An independent expert who works closely with the government said, "Paver blocks are a makeshift arrangement during heavy showers. Only if the repair team maintains them every other day, can this temporary arrangement work. If they come loose, mishaps are likely; they are even more dangerous for bikers." The one benefit, he said, is that paver blocks help stop a pothole from widening.

While a senior technocrat with the public works department (PWD) admitted that this method of fixing potholes may be illogical, he added that paver blocks are being chosen as a temporary measure in the "absence of an alternative".

TOI observed fixing of a pothole with paver blocks on Chheda Nagar flyover on Monday (see pic). This spot is maintained by Maharashtra State Road Development Corporation (MSRDC)'s contractor, Mumbai Entry Point Toll Ltd (MEP).

MEP chief executive officer Kiran Pangaonkar called this a temporary measure and assured that "as soon as we have a dry spell, we will fill all these potholes with bitumen and a proper hot mix by removing the paver blocks".

A senior MSRDC official defended the use of paver blocks by saying that the other cement-based fixing materials currently in the market are not cost-effective. The cost of fixing potholes with these materials would be equal to re-carpeting a major stretch of a road, he said.

"We think concretizing all roads and maintaining flyovers properly with high-quality asphalt are the only solutions. Government firms cannot afford new technology and materials to fix potholes."

(IndiaTimes)

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