The Karnataka State Pollution Control Board (KSPCB) will coordinate and spearhead a campaign along with steel, road, construction and other infrastructure industries, technologists and engineers to get the Indian Industry Standards (IS) code redrawn so that millions of tonnes of unused waste blast furnace slag can be converted into “a least-cost replacement” for natural sand.
It has been demonstrated that granulated blast furnace slag (GBFS), a by-product obtained during manufacture of iron in blast furnaces in the integrated steel plants, can effectively replace river sand.
Many developed countries have been successfully using GBFS as a replacement for sand in the construction industry and infrastructure projects for more than a decade now. GBFS products manufactured under suitable quality control conditions are compliant with various international standards.
They do not contain materials like chlorides, organic impurities, silt, clay and other marine materials which affect the quality and durability of concrete (cement), the common product to which slag sand has been limited in its use.
According to Vaman Acharya, KSPCB Chairperson, GBFS is piled up as waste on some 200-300 acres at steel plants in Karnataka.
“There is tremendous potential to turn it into a replacement for river sand and our initiative is to get beyond acceptance problems,” he said.
However, the country is still dragging its feet over making changes to the “orange book” that dictates what materials can be used for road and other construction projects, said S Girish, Vice President, GMR. “If they can include slag, it will make all the difference to protecting the environment.”
“We are willing to use GBFS, but the norms have to change. The key clause in the norms relates to the insistence on ‘natural material’ for road fill and this must be changed. Central Road Research Institute and such outifts should do the necessary tests and clear the use of GBFS materials,” he said.
S M R Prasad, Associate Vice President, JSW Steel, said, “We are looking for ways to help roads and construction people and are now capable of producing GBFS products according to their needs.
The labs in JSW have shown the superiority of GBFS products over natural sand and we can also help with the incorporation of appropriate norms in IS or state standards,” he said.