India is world’s second largest producer of steel and accounts for generation of around 19 million tonnes of steel slag per annum from various integrated steel plants as solid waste. Steel slag generation is expected to reach 60 million tonne by FY 2030 considering the ongoing capacity augmentation in Indian steel plants to produce 300 million tonnes of steel by FY 2030. Majority of steel slag after metal recovery ends as a waste dump or as land fill in and around the steel plants which occupy huge tracts of land and causes air, land and water pollution. CSIR-Central Road Research Institute (CRRI) under the major R&D project sponsored by Ministry of Steel along with four major steel industries namely M/s Tata Steel, ArcellorMittal Nippon Steel (AMNS) India Limited, JSW Steel and Rashtriya Ispat Nigam Limited, has developed technology for steel slag valorisation used for conversion of steel slag as road making aggregates.

Intrinsic challenges with steel slag utilization as road construction material such as vesicular structure of steel slag, volumetric expansion, corrosion potential due to metallic iron content, possibility of heavy metal & high pH Leachates and TUFA (Calcium carbonate precipitates) formation have been addressed through the customized steel slag specific, slag valorisation technology as road making aggregates.

Processed Electric Arc Furnace steel slag aggregates developed through customized Steel Slag Valorization technique of CSIR-CRRI, has been successfully utilized for construction of one-kilometer-long six lane bituminous “Steel Slag Road” connecting NH-6 to Hazira port at Surat, Gujarat. Around 1 lakh tonne of processed steel slag aggregates developed at AMNS steel plant, Hazira, Gujarat, under the technological guidance of CSIR-CRRI, has been successfully utilized in all layers of road as 100 % substitute of natural aggregates.

The heavy duty steel slag road is designed for 100 MSA (Million Standard Axle Repetition) design traffic for 20-year design life period and subjected on 1000 to 1200 commercial vehicles per day carrying 30 to 40 ton load for past two years. Owing to novel design composition and improved stiffness of pavement layers “Steel Slag Road” is built with 32% less thickness in comparison to conventional bituminous roads.

Steel Slag road for its novel technological features received many national and international acclaims and has been Inducted in India Book of Records and Asia book of Records as “First Steel Slag Road”. Former Minister of Steel, Govt. of India, Shri R.C.P Singh and Member NITI Aayog Dr. V.K.Saraswat after inspecting the steel slag road, appreciated CSIR-CRRI technology and recommended its further utilization for road construction in the country.

Satish Pandey, Principal Scientist, CSIR-CRRI
Project Leader, Steel Slag Road and Steel Slag Valorization R&D Project