Roads with potholes have become nearly universal in India. In fact, it has become second nature for drivers to swerve through lanes to avoid potholes, which causes nearby vehicles to also panic.
Speaking in the Lok Sabha, Minister of State for Roads Mansuk Mandaviya said that 3,597 people had been killed and 25,000 injured in 2017 because of accidents caused by potholes alone. The Supreme Court responded to this in shock stating that more Indians have died due to potholes than by terrorist attacks.
In 2017, the budget for road safety increased by a whopping 100.4 per cent to Rs 5,217 crore. With this much money pouring into roadworks and safety, shouldn’t we see an increase in road quality?
Naturally, a significant reason for this lies in rampant corruption and the outright shoddy construction of roads. Though significant funds are released for roads every year, it sometimes feels like no road can last more than six months in the country.
To be fair, not all roads in India are embedded with potholes and cracks. There are good roads and bad roads although the ratio favours the latter. So what makes a good road–good?
Well, as a civil engineer, I wanted to look into why roads fail and in the process, share information apparently missing from our textbooks – or even road construction manuals.
Well, the answers lay in the roads themselves – how roads are constructed and how they are being maintained.
A road consists not only of a single layer of asphalt but multiple beds of different materials.
An ideal road consists of different strata or subgrades which have different-sized rocks, or as engineers like to call them, aggregates. The bigger aggregates are called coarse aggregates, while the smaller ones are called, you guessed it, fine aggregates.
Construction of the road starts off with an excavation three to four feet deep. There are three layers of foundation for the road – coarse aggregates on the bottom, finer aggregates on the top, with bitumen or asphalt topping it off.
Now, here are some problems due to which potholes emerge.
In most cases, roads fail due to a faulty foundation. And the aggregates are what the asphalt stands on. Due to the pace of construction, aggregates are not used in adequate quantities or sometimes, completely ignored.
This results in a breakdown of the top layer more quickly, which corrodes even quicker when there is water stagnation.
So why does this happen? The usual assumption is that money required for aggregates and manpower may have been pocketed somewhere else. And though that is not definitely proved in every case, in many others it is simple lack of knowledge.
Bitumen is a new type of asphalt that has replaced tar in recent years. The quality of the bitumen also plays an important role in extending the life of the road. And it also matters how it is laid.
Bitumen should always be laid with a slope on either side as shown in the image, so that water can easily run off to the drainage. Uneven roads can cause water stagnation which can lead to the corrosion of bitumen.
Like any other infrastructure, roads also need maintenance.
Let’s say that there is a crack in the road. When it grows, municipal workers fill it up with more bitumen to repair it. This process does more harm than good.
When cracks appear on the asphalt, it is because of a localised failure of the bitumen. When it is filled with more bitumen, the increased weight, along with its compaction, can cause even more damage.
Alternatively, what can be done is an identification of the local failure of bitumen, whereby the cracked part of the road is literally “cut” out and replaced with newer and better bitumen. This would prolong the life of the road and decrease the progress of cracks.
Further, regular maintenance is mandatory if you want buttery smooth roads.
With the second largest road network in the world, India is expanding its roadways in leaps and bounds. This seems to have led to a drop in quality, as compared to quantity.
And though these are pointers to inform us about why roads fail, I do recommend having utmost precaution while riding on roads with potholes, especially during the rains.
(Edited by Vinayak Hegde)