Waste to worth for green highways

With more than 6.6 million kilometres of roads, India already has the second-largest road network in the world after the United States—and more are being built. The government is projecting the construction of around 40 kilometres of national highways daily, while municipal, district, and rural road networks continue expanding as the country grows economically.

- Soumya Chatterjee

However, building and maintaining infrastructure on such a massive scale has a significant environmental cost—from quarrying stone aggregates to the energy used in bitumen production and transport. To reduce costs and the carbon footprint, the road sector is witnessing a material transition—turning industrial, municipal, and farm waste into usable construction materials.

Masood Mallick, chairman of the CII National Committee on Waste to Worth Technologies, underscored the importance of these initiatives and suggested that the widespread use of waste in the road sector should be expanded into other areas. “India, with 17-18% of the global population on just 2.4% of the global land area, faces critical import dependence for materials like crude oil and critical minerals, has no room to repeat the wasteful ‘take, make, throw’ Western model.”

He said with virgin materials contributing roughly 40% of total carbon footprint, embracing frugality, reuse, and recycling is central to India's economic, resource, and climate security.

Roads from industrial waste

In Raigarh, Chhattisgarh, a two-kilometre, six-lane road leading to the Jindal Steel Plant—one of India’s largest integrated steel facilities—is being rebuilt using steel slag, a byproduct of steel-making. The project, technically supported by CRRI, is among India’s most advanced industrial waste utilisation efforts and follows successful pilots in Hazira and Mundra ports in Gujarat.

The Hazira port road—built in May 2022 using processed slag from Arcelor Mittal Nippon Steel—showed that steel slag can replace natural aggregates in all pavement layers. According to CRRI and the Ministry of Steel, substituting steel slag for quarried stone can cut aggregate extraction by nearly 40%, reduce carbon emissions by about 30%, and divert over 22 million tonnes of slag generated annually from landfills into productive use.