MAXIMIZING WASTE UTILIZATION IN CEMENT AND CONCRETE FOR SUSTAINABLE DEVELOPMENT
Date : 17 Nov 2008
Location : New Delhi
Indian cement industry has been utilizing cementitious and pozzolanic by-products for manufacture of cement and concrete in a prudent and cost-effective manner. Seventy per cent of the cement produced in India at present is blended cement, as against 30% in 1999-2000, revealed deliberations at the two-day National Workshop on Maximizing Waste Utilization in Cement and Concrete for Sustainable Development here today. The Workshop is organized by National Council for Cement and Building Materials (NCB), jointly with the Cement Manufacturers’ Association (CMA), to discuss various issues for facilitating enhanced utilization of wastes in cement and concrete.
CMA Secretary General, Shri N A Viswanathan, I.A.S. (Retd) inaugurated the Workshop, which was presided over by NCB Director General, Shri M Vasudeva. CMA Advisor (Technical), Dr S P Ghosh delivered the Keynote Address. The Workshop, attended by over 100 experts from industries like pulp, paper, power, cement, concrete, construction and fertilizer, etc, is expected to contribute substantially in achieving the common goal of sustainable development of the cement and concrete industries, besides bridging a large gap in the generation of wastes on one hand and their utilization on the other.
In his Inaugural Address, Shri Viswanathan spoke at length on the huge amount of wastes generated by industrial, mining, agricultural and other activities vis-à-vis environmental degradation. “It is well established that there is tremendous scope for the utilization of various types of wastes in the manufacture of cement, with benefits in terms of conservation of natural resources, reduction in cost of production improvement in quality and prevention of environmental hazards including mitigation of Green House Gas Emissions, all of which serve the goal of sustainable development”, added Shri Vaswanathan.
Shri Vaswanathan informed that wastes such as Fly-Ash from thermal power plants, slags from metallurgical industries, red mud and spent pot lining from aluminium industries, sludges from different chemical industries, spent catalyst from petroleum industry, marble dust from marble industry, and chemical gypsum and phosphochalk from fertilizer industry, which pose serious disposal and ecological problems in addition to occupying large areas of valuable land, are now being used in various cement plants in India, as blending components and performance improvers in cements and also as raw mix components. “Looking at the technical advantages of blended cement and to enhance Fly-Ash utilization, minimum and maximum usage of Fly-Ash permitted in Portland Pozzolana cement have already been raised from 10% to 15% and from 25% to 35% respectively in the Indian Standards. Further, addition of Fly-Ash, slag, limestone, rice husk ash, metakaolin or silica fume to the tune of 5% is also now permitted in OPC as Performance Improver”, added Shri Viswanathan”
Delivering the Presidential Address, NCB Director General, Shri M Vasudeva said that the Workshop was aimed at bringing together the various waste-producing & utilizing industries and R&D organizations to deliberate on maximum utilization of wastes in production of value-added construction materials. The Workshop would focus more on technological innovations in all pertinent areas of waste utilization in cement and concrete, informed Shri Vasudeva. The Workshop, added Shri Vasudeva, would deliberate on contemporary issues like Use of industrial and other wastes as alternate raw materials and resources in cement manufacture; blended components or performance improvers in cement; Use of wastes in concrete mix, including ready mix concrete; Technologies for maximizing use of wastes in cement and concrete; etc.
Earlier, delivering the Keynote Address, CMA Advisor (Technical), Dr S P Ghosh, said that cement manufacturers across the world have already been utilizing a variety of wastes including Calcareous Component (limestone, marble, marl, etc) – Lime sludge from paper, sugar, fertilizer industries; Press mud from sugar industry, sugar cane trash; Argillaceous Component (clay, shale, etc) – Pottery waste, waste porcelain, crockery moulds; Silica Component (sand, sandstone) – Foundry sand, mould sands; Iron Component (Iron ore, laterite, bauxite, etc) – Red mud, mill scales, iron filings, scrap iron. “Recycling of industrial wastes and by-products started gaining rapid momentum only during the last decade. Besides cost reduction in manufacture through substitution of scarce non-renewable resource and fuel without compromising the product quality (in fact, it leads to enhancement in many cases), such substitution has a larger global dimension viewed in the light of serving both national and international goals of environmental protection and minimizing GHG emission”, concluded Dr Ghosh.