Potholes — Prevention and Cure

By Ashwin Tombat
22 July 2019 21:42 IST

Last year, former Union Minister of State for Roads Mansuk Mandaviya told the Lok Sabha that 3,597 people had been killed and 25,000 injured in 2017, just from accidents caused by potholes. The Supreme Court of India noted that more Indians had died from potholes than by terrorist attacks.

Potholes are not merely a nuisance. They can injure and kill people.

Recently, the Corporation of the City of Panaji (CCP) boasted to the media that it had acquired two tonnes of special road bond material manufactured by Hindustan Petroleum (HP) at a cost of Rs25,000 per tonne to fill the state capital’s potholes.

This happened after a citizen covered a large pothole in the city with a basket and topped it with an empty beer bottle to caution two-wheeler riders about the hazard. Then Raj Vaidya of Hindu Pharmacy wrote a letter to the CCP demanding that it repair the potholes before a death or severe injury takes place.

The CCP got into action. But it should know that prevention is better than cure.

The most common cause of potholes is water penetrating in through cracks in a road’s surface and weakening its foundation. Less than an hour of heavy rain is enough to flood roads in our cities. If the CCP cleared the city’s storm drains properly before the rains, then there would be much less waterlogging and, consequently, less potholes.

The second thing that the CCP should know is that problems do not get solved merely by throwing money at them. There is a technique to pothole repair. First, the pothole must be cut into a square or rectangle shape. Then, all the loose debris must be removed and the pothole area must be cleaned. Last, the road bond material is put in and pressed down. If the pothole is deeper than 15cm, the application must be done in two coats.

If potholes are filled in an as-is-where-is manner — as shown in the photograph released by the CCP to the media prominently showing the mayor, former mayor and officials ‘supervising’ the repairs (above) — the potholes are bound to be back within a few days.

But I’m being too harsh on the CCP; it doesn’t build roads. The government’s Public Works Dept (PWD) and the Goa State Infrastructure Development Corporation (GSIDC) do. The problem is, even their fancy new roads like the four-lane Old Goa highway or the Dona Paula-Bambolim road have numerous stretches where water accumulates either along the roadside or the median. It looks like the engineers who designed these roads and supervised their construction didn’t pay enough attention to drainage.

The bitumen layers on any road should always be laid with a slope on either side, so that water can easily run off to the drainage. If the road has a median, it should have channels every few metres to allow rain water to pass through easily. Water stagnation is the principal cause for corrosion of bitumen.

Road repairs must be done scientifically. If a crack in the road is just filled with bitumen, it actually does more harm than good, because the increased weight causes more damage. Actually, the cracked part of the road must be cut out and replaced with newer and better bitumen. That’s the only way to decrease the progress of cracks.

Coming back to the CCP, ‘road bond material’ can be cheaper and better. Prof Prithvi Singh Kandhal, former associate director of the National Centre for Asphalt Technology (NCAT) at Auburn University in Alabama, USA, has developed a material known as MC-800 or, informally, ‘Kandhal Mix’. It is certified by the Indian Roads Congress (IRC:116-2014). The Jaipur Development Authority has been using it as a readymade pothole patching solution.

MC-800, which comprises 80 per cent bitumen and 20 per cent kerosene, costs only Rs6,000 to Rs10,000 per tonne (compared to HP’s Road Bond at Rs25,000). This unpatented technology is used widely in the US, but is mostly unknown in India. It has a shelf life of six months, is ‘idiot-proof’, durable and economical. Prof Kandhal claims that a pothole filled with his cold mix lasts for four years in Jaipur. Even if it lasts for one full year in Goa, that would be enough.

Blogger's Profile

Ashwin Tombat

Ashwin Tombat has been the Editor of Gomantak Times and Herald. Worked as an Associate Editor of national magazine Gentleman in Mumbai, before shifting to Goa. Loves sailing, also participates in Marathons. Has worked as an activist in students's union and trade unions in Maharashtra. Also an artist of Street Theatre during student days.

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