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Chatterjee A.K.,Conmat Technologies Private Ltd
Journal of Materials in Civil Engineering | Year: 2011

In India, the generation of electricity is overwhelmingly dependent on the combustion of high-ash coal. The present availability of fly ash has already exceeded 130 million tons, and its generation is likely to reach 170 million tons by 2011-2012. Although the present gainful use of fly ash is close to 50% of the quantity generated, a countrywide directive has been established to effectively use the entire quantity generated in 2011-2012. This objective can be met only if one looks for newer avenues of bulk use that have not been tried successfully. To achieve this target, several technological endeavours are in progress in India to enhance the quality and reactivity of fly ashes through mechanochemical activation. The regular and experimental technologies of comminution and size classification have not resulted in producing submicrocrystalline or nanocrystalline particles from the crystalline fly ashes; and hence, no quantum jumps in their reactivity have been realized. Therefore, the need for converting the fly ash grains to submicrocrystalline particles is critical if the performance of fly ashes has to approach that of silica fume or silica gel. © 2011 American Society of Civil Engineers. Source


Chatterjee A.K.,Conmat Technologies Private Ltd
Kuei Suan Jen Hsueh Pao/Journal of the Chinese Ceramic Society | Year: 2015

There are numerous evidences to show that if concrete can make use of materials with nano-size (<100 nm) at least in one direction in small but optimal proportions, its properties can be selectively improved and modified to an extent that could not have been otherwise possible. The nanosilica, nano-carbonate, nano-carbon tubes and fibres are receiving increasing attention in modifying concrete properties. The titania nano-particles in coating can capture and decompose organic and inorganic air pollutants and make the exposed concrete surfaces "self cleaning". Steel reinforcement can be made corrosion-resistant with the help of nanotechnology and nanomaterials. On the whole, the application of nanotechnology to concrete construction has the potential of minimizing matter (an aggregate of energy and mass) consumed during the whole life cycle "from cradle to grave", minimizing negative environmental impacts and finally ensuring a comfort of using. Notwithstanding the great promise of nanomaterials and nanotechnologies in concrete construction, the long-term safety aspects of these novel materials are poorly understood, particularly with respect to their toxicological liabilities. With increased attention on health hazards, there has been a need to develop new methods of toxicity profiling, safer manufacturing procedures, and application of "greener" nanomaterials to concrete construction. The present paper is an attempt to review if the construction industry will eventually be a strong beneficiary of nanotechnology with substantial sustainability impact. © 2015, Chinese Ceramic Society. All right reserved. Source


Chatterjee A.K.,Conmat Technologies Private Ltd
2nd International Conference on Sustainable Construction Materials and Technologies | Year: 2010

In India, the generation of electricity is overwhelmingly dependent on combustion of high-ash coal, the present availability of fly ash has already exceeded 130 million tonnes and its generation is likely to touch 170 million tonnes by 2011-12. Although the present utilization of fly ash is close to 50% of the quantity generated, the directive is to effectively utilize the entire quantity that would be generated by the year 2011-12. This objective can only be met, if one looks for newer avenues of bulk utilization. In order to achieve this target several technological endeavours are being made to enhance the quality and reactivity of fly ashes through mechano-chemical activation. This paper addresses the issues pertaining to the intrinsic quality parameters of the Indian fly ashes, potential of chemical activation, feasibility of adopting the newer milling systems such as vibration and attrition milling, etc. Finally, the need for converting the fly ash grains to submicrocrystalline particles and, thereby, significantly altering their properties and behaviour has been touched upon. Source


Chatterjee A.K.,Conmat Technologies Private Ltd
Concrete Repair, Rehabilitation and Retrofitting III - Proceedings of the 3rd International Conference on Concrete Repair, Rehabilitation and Retrofitting, ICCRRR 2012 | Year: 2012

Repair, restoration and renewal are unavoidable measures in extending the service life of concrete structures. The materials used, to start with, were based on Portland Cement in the form of mortars, concrete, shotcrete, etc. Because of their intrinsic deficiencies in many instances of actual repairs, there has been a preferred shift towards total or partial substitution of Portland Cement with polymeric or monomeric binders. In the process a significant departure is observed from the demands of green chemistry and associated sustainability requirements. This article is an attempt to highlight this issue along with the emerging corrective strategies to synergize the repairs systems with green chemistry. © 2012 Taylor & Francis Group. Source


Chatterjee A.K.,Conmat Technologies Private Ltd
RILEM Bookseries | Year: 2015

Out of the three major clay mineral groups, viz, kaolin, smectite and palygorskite – attapulgite, the cement science primarily focuses on the first group to be used on calcination as a pozzolanic admixture. The general understanding is that the dehydroxylation of dehydrated kaolinite in the temperature range of 550 – 650 °C apparently yields an x-ray amorphous alumino-silicate phase which provides the pozzolanic property to clay. There is not much of information on how the highly crystalline kaolinite loses its long-range order in the lattice on account of dehydroxylation. Little data are available on the effect of cation exchange capacity on pozzolanicity. Further, in EN-197-1 the usability of a calcined clay as a pozzolana has been linked with the presence of minimum 25 per cent reactive silica in it. The test methods for determining the pozzolanic property of calcined clays are still in the realm of arbitrariness. The present paper is a brief crystallo-chemical disquisition of the above issues, based on the characterization of six different Indian clay samples. © RILEM 2015. Source

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