S K Chaturvedi;M M Ali;A Pahuja;
<正>In India,the estimated generation of fly ash was of the order of 190 million tonnes in 2010-11,expected to reach 450 million tonnes by 2020-21 and 900 million tonnes by 2031-32,thus posing serious disposal and ecological problems in addition to occupying large tracts of scarce valuable land.Despite the development of a large number of technologies for utilization of flyash,its estimated use remains around 100 million tonnes only.Major problems in the utilization of flyash relate to its availability in wet state,quality variation and high capital and operational cost of storage,handling and transportation systems.The paper highlights the availability and physical,chemical and mineralogical characteristics of flyash,technological options available for its utilization,its activation and research and development work carried world wide at National Council for Cement and Building materials for promoting its use.Further, improvement in fly ash quality through processing by mechanical chemical and thermal routes will play a long role in enhancing the fly ash utilization potential,engineering properties of fly ash based cement,concrete and building materials besides mitigation of global warming.The results of mechanical activation by grinding and fractionation of storage mix non conforming fly ash indicated improvement in its quality in terms of lime reactivity,fineness,glass content,etc.The PPC blends prepared using such activated fly ashes showed that their performance conformed to Indian Standards Specifications IS:1489(part 1) 1991. Originality The investigations pertaining to activation of fly ashes not conforming to Indian Standard Specification IS:3812 was carried out with a view to make them usable in the manufacture of Portland Pozollana Cement.The investigations revealed that besides converting non conforming fly ash into conforming fly ash,the activation of non conforming fly ash resulted in increased lime reactivity and glass content also.
fly ash activation;;lime reactivity;;glass content;;GHG emission
To explore the background and basis of the node document