Swelling Characteristic of Bentonite on Pelletization and Properties of Fly Ash Aggregates
Publication: Journal of Materials in Civil Engineering
Volume 21, Issue 10
Abstract
Earlier studies have established that aggregates could be produced from fly ash through pelletization, which has the advantages of reducing (1) environmental pollution and (2) consumption of depleting natural aggregates. Though cement, lime, and bentonite were used for improving the properties of fly ash aggregates, limited studies have been reported on the effect of binders on the pelletization process of fly ash. This paper discusses the relative performance of bentonite with two different swelling characteristics on the pelletization of fly ash. The variation of factors and its optimum level on the overall pelletization efficiency, efficiency of producing three individual size fractions, ten percent fines value, and water absorption were determined through a statistically designed experiment using response surface methodology. The maximum pelletization efficiency of fly ash aggregate was achieved with lower dosage level of high swelling bentonite. Higher factor levels facilitate enhanced ball growth, i.e., produce aggregate size fraction greater than 10 mm. Similarly, the maximum ten percent fines value and minimum water absorption result at the maximum level of the factors studied. The optimal level of factors for a given aggregate size fraction was almost similar, independent of swelling characteristics of bentonite, except for the variation in bentonite and moisture contents.
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References
ASTM. (1998a). “Standard specification for fly ash and raw or calcined natural pozzolan for use as a mineral admixture in portland cement concrete.” C 618, West Conshohocken, Pa.
ASTM. (1998b). “Standard specification for lightweight aggregates for structural concrete.” C 330, West Conshohocken, Pa.
Baykal, G., and Doven, A. G. (2000). “Utilization of fly ash by pelletization process; theory, application areas and research results.” Resour. Conserv. Recycl., 30, 59–77.
Bijen, J. M. (1986). “Manufacturing processes of artificial lightweight aggregates from fly ash.” Cem. Concr. Compos., 8, 191–199.
British Standards Institution (BSI). (1990). “Methods for determination of aggregate crushing value.” BS 812-110:1990, London.
Cheeseman, C. R., Makinde, A., and Bethanis, S. (2005). “Properties of lightweight aggregate produced by rapid sintering of incinerator bottom ash.” Resour. Conserv. Recycl., 43, 147–162.
Grim, R. E. (1968). Clay mineralogy, McGraw-Hill, New York.
Harikrishnan, K. I., and Ramamurthy, K. (2006). “Influence of pelletization process on the properties of fly ash aggregates.” Waste Manage., 26(8), 846–852.
Jaroslav, S., and Ruzickova, Z. (1988). Pelletization of fines, Elsevier Science, New York.
Kawatra, S. K., and Ripke, S. J. (2001). “Developing and understanding the bentonite fiber forming mechanism.” Minerals Eng., 14(6), 647–659.
Manikandan, R., and Ramamurthy, K. (2007). “Influence of fineness of fly ash on the aggregate pelletization process.” Cem. Concr. Compos., 29, 456–464.
Montgomery, D. C. (2001). Design and analysis of experiments, Wiley, New York.
Neville, A. M. (2000). Properties of concrete, Longman, UK, London.
Ramamurthy, K., and Harikrishnan, K. I. (2006). “Influence of binders on properties of sintered fly ash aggregate.” Cem. Concr. Compos., 28, 33–38.
SAS; release 8.02. (2000). SAS Institute Inc., Cary, N.C.
Tangtermsirikul, S., and Wijeyewickrema, A. C. (2000). “Strength evaluation of aggregate made from fly ash.” ScienceAsia, 26, 237–241.
Tay, J. H., Show, K. Y., and Hong, S. Y. (2000). “Reuse of industrial sludge as pelletized aggregate for concrete.” J. Environ. Eng., 126(3), 279–287.
Teplitskiy, A., Gee, R., and Kourmaev, R. (2005). “Application of physical-chemical properties of bentonite utilized in construction, as viewed through the TRIZ prism.” TRIZ Journal, ⟨www.trizjournal.com/archives/2005/10/05.pdf⟩.
Wainwright, P. J., and Cresswell, D. J. F. (2001). “Synthetic aggregates from combustion ashes using an innovative rotary kiln.” Waste Manage., 21, 241–246.
Yang, C. C. (1997). “Approximate elastic moduli of lightweight aggregate.” Cem. Concr. Res., 27, 1021–1030.
Yoo, J. G., and Jo, Y. M. (2003). “Finding the optimum binder for fly ash pelletization.” Fuel Process. Technol., 81, 173–186.
Information & Authors
Information
Published In
Journal of Materials in Civil Engineering
Volume 21 • Issue 10 • October 2009
Pages: 578 - 586
Copyright
© 2009 ASCE.
History
Received: Feb 12, 2008
Accepted: Apr 13, 2009
Published online: Sep 15, 2009
Published in print: Oct 2009
Notes
Note. Associate Editor: T. G. Sitharam
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