15 years after its invention by BMC engineer, civic body to implement UTWT method for repairing Mumbai's roads

Indian Express

01-05-2025

The Brihanmumbai Municipal Corporation (BMC) on Wednesday informed that it will increasingly adopt the Ultra-Thin White Topping (UTWT) method of road repair.
The UTWT methodology was invented by a BMC engineer in 2010, but it has not been implemented regularly in Mumbai till now.
The UTWT is a technology under which a thin layer of concrete is laid over the top layer of asphalt roads, following which, it is left to cure. The concrete layer is usually 60 mm-150 mm thick, and the curing period takes a maximum of seven days, following which the road is opened for vehicular movement. Unlike the regular concretising method, which involves the excavation of roads in their entirety, the implementation of UTWT doesn't involve the excavation of roads.
Abhijit Bangar, Additional Municipal Commissioner (Projects), said, 'We are planning to implement this methodology on existing asphalt roads of Mumbai that are not yet concretised. Initially, we will start with roads that are less than 12 metres wide, which comparatively record lesser traffic volume. Later, we will augment the implementation of this module on wider roads.'
At present, the BMC is concretising 700 km of roads through the regular method at an estimated cost of Rs 17,000 crore, making the per kilometre cost of road concretisation approximately Rs 24 crore.
Bangar said that implementing UTWT for every 1 km of road would cost between Rs 1.7 crore and Rs 2 crore, excluding the GST.
'This is a tried and tested methodology which has given good results in the past. Many civic bodies have implemented it, and we are confident about its benefits. One of the primary reasons why we are opting for this methodology is that it costs less time. The road gets ready for traffic movement within just seven days, and it doesn't require any excavation on the surface,' Bangar said.
The UTWT method was developed by BMC road engineer, Vishal Thombare, in 2010, when he was pursuing his PhD from the Indian Institute of Technology-Bombay. At present, Thombare is an executive engineer in the civic body's road and traffic department. The UTWT method has been adopted by the Thane Municipal Corporation as well as the Nagpur Municipal Corporation. In 2022, Thombare presented the methodology to the National Rural Infrastructure Development Agency (NRIDA) to make durable roads in Bihar and Tripura under the Pradhan Mantri Gram Sadak Yojana (PMGSY).
Speaking to The Indian Express, Thombare said the technology was not implemented in Mumbai owing to certain limitations.
'The primary constraint is of utility channels like gas lines, internet cables and telephone wires that run below the road surfaces. Even if we had implemented UTWT earlier, then digging of roads would have been required for laying and maintenance of new and existing utilities, and frequent digging of roads would nullify the entire objective of applying this methodology. Now, we have created dedicated ducts for utilities on the side strip of roads for which digging of the main carriageway of the road wouldn't be required,' Thombare said.
He also said that in Mumbai, UTWT was implemented on a select few minor roads in the Fort and Mulund areas on a pilot basis. He said that to date, these roads don't record potholes. He also said that under this methodology, the minimum lifespan of a road stands at 25 years.
'The UTWT was designed by studying the concrete behaviour and how concrete behaves under certain temperature changes. We reduce the cement quantity by recycling products like micro silica. This also leads to a decline in carbon emissions and in the future may also give us the benefit of earning carbon credit,' said Thombare.