Our mission is to provide pothole-free roads to the citizens of Mumbai with good quality concrete.

Dr. Vishal Thombare
Executive Engineer (Roads), Brihanmumbai Municipal Corporation (BMC)

How do you view India’s progress in roads sector?

India has a lot of potential when road sector is concerned. In India, basically we build three types of roads, asphalt roads or bituminous roads, concrete roads and white topping. In the last many decades, we used to build only asphalt roads. Now things have been changed due to various reasons of increased traffic, more heavy vehicles on road, changing soil conditions, etc. Concrete roads help to get rid of all these kinds of distresses. Even our honourable minister Nitin Gadkari always emphasised on cement concrete roads because they have a number of advantages. One is long life of the road, second is free of potholes, and third is no water penetration so that they are not damaged due to water. I am not against asphalt roads as they also have their own advantages in many ways. But where rainfall is more and in pothole prone area, we should go with either concrete roads or white topping.

What are the major road developments happening in Mumbai? Which are the key projects?

In Mumbai, we have taken up a mass programme of converting all existing roads to concrete roads. We have invited four mega tenders for concrete roads in two phases. Phase one has already been started while Phase 2 will be started from this October. The main aim is to have pothole-free Mumbai.

As the Mumbai coastal road is now operational for traffic, another coastal road is coming up in western suburb. We have invited tenders in six packages under EPC contract. So, the contractors are free to design, build with any technology that is approved by the authority. The construction of Goregaon-Mulund Link Road (GMLR) is already under progress. There are some flyovers and two tunnels coming up on this project. Currently, the coastal road tunnel is the largest with a diameter of 12.9 m. But the GMLR tunnel will be bigger with 15-meter diameter. Once it is operational, this will be the largest diameter tunnel for road transportation. GMLR will be one of the iconic projects of Mumbai connecting eastern and western suburbs of Mumbai.

With all these projects under implementation, the connectivity of Mumbai will be enhanced significantly. The main aim of these projects is to decongest Mumbai. We are trying to use the best materials available and the latest technology so that the construction time is reduced. We are going to use more and more machinery in the construction of concrete roads so that more accuracy and quality control can be achieved.

Maintenance plays an important role in the life of roads. What are the technologies used by BMC in the maintenance of roads in Mumbai?

In the maintenance of roads, we use the methods of ultrathin white topping and thin white topping. When the road is fairly good with minor damages, we use these solutions. As per design, we can construct the rehabilitation technique and once we do ultrathin white topping or thin white topping, the life of the existing layer will prolong to another 25 years. It is similar to concrete with the thickness 100-150 mm and the time taken for construction is also very less.

How is the white topping technology gaining traction in the maintenance of roads?

There are many advantages of using ultrathin white topping and thin white topping technologies. Basically, when we construct a road, we have to excavate everything, put different layers and on the top, they have to put either PQC quality pavement concrete or asphalt concrete. But in this case, we are utilising the residual strength of the road because a number of times traffic plying on the roads, the strength of the subbase of the road is further consolidated. We are using compaction for the top layer. In this technology, we are not excavating anything, but just milling the top surface of the existing road and after milling we are putting asphalt as per mix design in 100-150 mm thickness and fixing concrete. In this technology, we can open traffic within 3-7 days. Even at some portions we have opened the road to traffic within 72 hours. Good plasticisers and chemical admixtures are now available in the market. So, we can design the concrete mix according to our requirement to open the road to traffic within a particular period. Theoretically we can open the road for traffic after 24 hours. By using curing compounds during the production of concrete, the need for further curing after laying the concrete can be avoided.

Nowadays, a new technology of panel concrete concept is evolving faster. In this method, concrete panels are casted in the casting yard just like segmental concrete which we are being used for construction of flyovers. The cemented concrete panels casted in the casting yard, transported to the site and placed on the uniform surface, and the road is ready to use. Very soon this technology will come to Mumbai also. We have done this on an experimental basis and now we will be implementing on BMC sites.

Any other new emerging technologies coming up in road construction or maintenance?

In maintenance, nowadays we are using geopolymer concrete. In this, we are not using cement, but some additives. If you use concrete for repair work, it requires its own time for curing, but if we use geopolymer concrete for repair or filling potholes, it gets hardened within 15-20 minutes. So, within half an hour we can open the road to traffic. This year we are using this as an experimental method on eastern express highway and on western express highway. Currently, we are using geopolymer concrete on concrete roads for potholes.

How do you visualise the transformation of roads in Mumbai?

In the next five years, maximum roads in Mumbai will be paved with concrete. So maximum roads will be either concrete or ultrathin white topping and thin white topping. After that the roads will be pothole free so that it will be a smooth ride for the citizens of Mumbai.

What is your mission 2025 for Mumbai roads?

Our mission is to provide pothole-free roads to the citizens of Mumbai with good quality concrete. The new emerging technologies will be part of the concrete pavements. Along with roads, we are also doing beautification along the roads. We are not just constructing road but we are beautifying the entire area along the road so that there will be a smooth and happy ride for the citizens. We are improving the entire area by beautifying the surroundings along with the roads. Very soon, you will see a Vibrant Mumbai!