While Chief Minister Basavaraj Bommai has set a deadline of January 15 to get all potholes in Bengaluru filled up, there are some important points that need to be stressed, not just to fill potholes but to ensure that potholes do not recur.
If the authorities work to ensure quality roads without potholes, cracks or ruts, and want to make it convenient for motorists to use them, all it requires is a little application of mind and technology, because roads are not a permanent phenomenon.
At the outset, let me cite some of the good roads in India and in Karnataka, like the Grand Trunk (GT) Road, which linked Calcutta with Peshawar, but which, at present, stretches from Amritsar to Kolkata; the Bengalur-Mysuru stretch of NH-275 and the Vidhana Soudha frontage road. All these roads are constructed using cement concrete for long life without sacrificing on quality in construction and supervision.
Black top, or bitumen roads, are designed for 10 to 12 years, but their life is restricted to not more than 2 to 3 years due to rain water penetrating various layers. White top, or cement concrete roads, are planned and designed for long life without much maintenance, except attending to weak spots at joints. White topping, or thin white topping of 10 cm, can give life of more than 10 years without maintenance, but perfect drainage systems must be in place.
Here, it must be noted that water is considered a dangerous enemy of black-topped (bitumen) roads and a friend of white-topped (cement concrete) ones. Hence, water must not be allowed to stay on the surface of black-topped roads as stripping of bitumen aggregates takes place, subsequently leading to potholes on the roads. This has become a regular affair in urban areas of the state even as these potholes are filled unscientifically for reasons known best to the authorities.
But in either type of roads, storm water must be drained well with longitudinal and transverse road gradients based on rainfall intensity of the region. Also, for both pavements, the sub-base has to be sufficiently strong. Due to the failure of this requirement as well as not cleaning drains frequently or before rainy seasons, the roads generally fail. Higher transverse slopes are also equally the cause for failure of roads.
There should not be any compromise in the quality and quantity of material to be used as well as good quality control stipulated in the code of practice while designing and constructing roads. Finally, although skill is required for laying roads, supervision and quality inspection is a must during and after construction.
If these are supervised properly and inspected effectively, we will certainly have seen the last of the much familiar periodic failures of roads in our cities. That has been the secret of roads in Mumbai, Goa and other areas which experience heavy rainfall, which can be replicated in Karnataka too for our major and arterial roads.
Prof M N Sreehari,
Road Infrastructure Expert, Adviser & Consultant