Textural Alterations in Coal Fly Ash due to Alkali Activation
Publication: Journal of Materials in Civil Engineering
Volume 28, Issue 11
Abstract
Over the years, coal fly ash has been used as a backfill material in embankments, mines, roads and around pipelines. Recently, there has been a growing interest in its alkali activation for synthesis of both geopolymers and highly porous minerals known as zeolites. These end products find applications as cement admixtures, molecular sieves, and for contaminant depuration in aqueous media. In this regard, the textural characteristics, viz, particle size, pore size, and pore structure distribution characteristics of alkali activated fly ashes elucidate their potential as porous additives to cement and concrete, reactive media in permeable reactive barriers, and sorbents for contaminant removal. With this in view, this study investigates the particle size and pore structure modifications occurring in calcium hydroxide–based activation of coal fly ash. Furthermore, the morphological features also show the effect of alkali interaction on the reduction in larger sized particles and on the steady growth in smaller-sized crystals.
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Acknowledgments
The authors acknowledge the IRCC Central Facility, IIT Bombay for utilization of Cryo-FEGSEM during the course of this study.
References
Arjunan, P., Silsbee, M. R., and Roy, D. M. (2001a). “Chemical activation of low calcium fly ash. Part 1: Identification of suitable activators and their dosage.” Proc., 2001 Int. Ash Utilisation Symp., Vol. 105, Center for Applied Energy Research, Univ. of Kentucky, Lexington, KY.
Arjunan, P., Silsbee, M. R., and Roy, D. M. (2001b). “Chemical activation of low calcium fly ash. Part II: Effect of mineralogical composition on alkali activation.” Proc., 2001 Int. Ash Utilization Symp., Vol. 106, Center for Applied Energy Research, Univ. of Kentucky, Lexington, KY.
Arulrajah, A., Kua, T., Phetchuay, C., Horpibulsuk, S., Mahghoolpilehrood, F., and Disfani, M. (2015). “Spent coffee grounds—Fly ash geopolymer used as an embankment structural fill material.” J. Mater. Civ. Eng., 04015197.
ASTM. (2006). “Standard test method for specific gravity of soil solids by gas pycnometer.” ASTM D5550, West Conshohocken, PA.
Bandura, L., Franus, M., Józefaciuk, G., and Franus, W. (2015). “Synthetic zeolites from fly ash as effective mineral sorbents for land-based petroleum spills cleanup.” Fuel, 147, 100–107.
Chatterjee, A. (2011). “Indian fly ashes: Their characteristics and potential for mechanochemical activation for enhanced usability.” J. Mater. Civ. Eng., 783–788.
Criado, M., Fernández-Jiménez, A., and Palomo, A. (2010). “Alkali activation of fly ash. Part III: Effect of curing conditions on reaction and its graphical description.” Fuel, 89(11), 3185–3192.
Cristelo, N., Glendinning, S., Fernandes, L., and Pinto, A. T. (2012a). “Effect of calcium content on soil stabilisation with alkaline activation.” Constr. Build. Mater., 29, 167–174.
Cristelo, N., Glendinning, S., Miranda, T., Oliveira, D., and Silva, R. (2012b). “Soil stabilisation using alkaline activation of fly ash for self compacting rammed earth construction.” Constr. Build. Mater., 36, 727–735.
Delle Site, A. (2001). “Factors affecting sorption of organic compounds in natural sorbent/water systems and sorption coefficients for selected pollutants. A review.” J. Phys. Chem. Ref. Data, 30(1), 187–439.
Feng, J., Zhang, R., Gong, L., Li, Y., Cao, W., and Cheng, X. (2015). “Development of porous fly ash-based geopolymer with low thermal conductivity.” Mater. Des., 65, 529–533.
Fernández-Jiménez, A., Palomo, A., and Criado, M. (2005). “Microstructure development of alkali-activated fly ash cement: A descriptive model.” Cem. Concr. Res., 35(6), 1204–1209.
Fernández-Jiménez, A., Palomo, A., Sobrados, I., and Sanz, J. (2006). “The role played by the reactive alumina content in the alkaline activation of fly ashes.” Micropor. Mesopor. Mat., 91(1), 111–119.
Grace, H. P. (1956). “Structure and performance of filter media. I. The internal structure of filter media.” AIChE J., 2(3), 307–315.
Jun, Y., and Oh, J. E. (2015). “Microstructural characterization of alkali-activation of six korean class F fly ashes with different geopolymeric reactivity and their zeolitic precursors with various mixture designs.” KSCE J. Civ. Eng., 1–12.
Khale, D., and Chaudhary, R. (2007). “Mechanism of geopolymerization and factors influencing its development: A review.” J. Mater. Sci., 42(3), 729–746.
Kolay, P. K., Singh, D. N., and Murti, M. V. R. (2001). “Synthesis of zeolites from lagoon ash.” Fuel, 80(5), 739–745.
Koshy, N., Jha, B., Kadali, S., and Singh, D. N. (2015a). “Synthesis and characterization of Ca and Na zeolites (non-pozzolanic materials) obtained from fly ash- interaction.” Mater. Perform. Charact., 4(1), 1–16.
Koshy, N., Singh, D. N., Jha, B., Kadali, S., and Patil, J. (2015b). “Characterization of Na and Ca zeolites synthesized by various hydrothermal treatments of fly ash.” Adv. Civ. Eng. Mater., 4(1), 131–143.
Murayama, N., Tanabe, M., Yamamoto, H., and Shibata, J. (2003). “Reaction, mechanism and application of various zeolite syntheses from coal fly ash.” Mater. Trans., 44(12), 2475–2480.
Palomo, A., Grutzeck, M. W., and Blanco, M. T. (1999). “Alkali-activated fly ashes: A cement for the future.” Cem. Concr. Res., 29(8), 1323–1329.
Pangdaeng, S., Phoo-Ngernkham, T., Sata, V., and Chindaprasirt, P. (2014). “Influence of curing conditions on properties of high calcium fly ash geopolymer containing portland cement as additive.” Mater. Des., 53, 269–274.
Peled, A., Castro, J., and Weiss, W. J. (2013). “Atomic force and lateral force microscopy (AFM and LFM) examinations of cement and cement hydration products.” Cem. Concr. Comp., 36, 48–55.
Radlińska, A., Yost, J., and Salera, M. (2013). “Material properties of structurally viable alkali-activated fly ash concrete.” J. Mater. Civ. Eng., 1456–1464.
Rujiwatra, A., Phueadpho, M., and Grudpan, K. (2005). “Selective synthesis of zeolitic phillipsite and hibschite hydrogarnet from lignite ash employing calcium hydroxide under mild conditions.” J. Phys. Chem. Solids, 66(6), 1085–1090.
Schürenkamp, D., Bleck, M., and Oumeraci, H. (2012). “Granular filter design for scour protection at offshore structures.” Proc., 6th Int. Conf. on Scour and Erosion, La Société Hydrotechnique de France, Paris, 27–31.
Sing, K. (2001). “The use of nitrogen adsorption for the characterisation of porous materials.” Colloid. Surf. A., 187, 3–9.
Sing, K. S. (1985). “Reporting physisorption data for gas/solid systems with special reference to the determination of surface area and porosity (Recommendations 1984).” Pure Appl. Chem., 57(4), 603–619.
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© 2016 American Society of Civil Engineers.
History
Received: Nov 8, 2015
Accepted: Mar 7, 2016
Published online: Jun 3, 2016
Published in print: Nov 1, 2016
Discussion open until: Nov 3, 2016
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