Steel Slag Road: Transforming Waste to Wealth for Green Infrastructure Development

With codified standards, proper processing protocols, and collaborations amongst the stakeholders, steel slag can become a mainstream construction aggregate, transforming millions of tonnes of waste into a national resource.

India, the world’s second-largest steel producer, generates about 19 million tonnes of steel slag annually, projected to reach 60 million tonnes by 2030. Traditionally, air-cooled steel slag is stockpiled near plants, occupying land and creating air, water, and soil pollution. Given its abundance, steel slag offers immense potential as an alternative to natural aggregates in road construction. However, intrinsic challenges such as volumetric expansion, vesicular structure, and potential leaching have restricted its large-scale use.

To address these issues, CSIR–CRRI, supported by the Ministry of Steel and in collaboration with major steel industries, namely, AM/NS India, Tata Steel, JSW Steel, and RINL, have developed a tailored valorisation process to convert raw slag into safe and durable road aggregates. This initiative is a significant step towards India’s waste-to-wealth and circular economy vision.

Case Studies

Processed EAF, CONARC and BOF steel slag aggregates developed through customized steel slag valorization techniques were successfully utilized for the construction of steel slag road sections in Gujarat, Maharashtra, and Arunachal Pradesh, respectively.