Stabilizing Soft Fine-Grained Soils with Fly Ash
Publication: Journal of Materials in Civil Engineering
Volume 18, Issue 2
Abstract
The objective of this study was to evaluate the effectiveness of self-cementing fly ashes derived from combustion of sub-bituminous coal at electric power plants for stabilization of soft fine-grained soils. California bearing ratio (CBR) and resilient modulus tests were conducted on mixtures prepared with seven soft fine-grained soils (six inorganic soils and one organic soil) and four fly ashes. The soils were selected to represent a relatively broad range of plasticity, with plasticity indices ranging between 15 and 38. Two of the fly ashes are high quality Class C ashes (per ASTM C 618) that are normally used in Portland cement concrete. The other ashes are off-specification ashes, meaning they do not meet the Class C or Class F criteria in ASTM C 618. Tests were conducted on soils and soil–fly ash mixtures prepared at optimum water content (a standardized condition), 7% wet of optimum water content (representative of the typical in situ condition in Wisconsin), and 9–18% wet of optimum water content (representative of a very wet in situ condition). Addition of fly ash resulted in appreciable increases in the CBR and of the inorganic soils. For water contents 7% wet of optimum, CBRs of the soils alone ranged between 1 and 5. Addition of 10% fly ash resulted in CBRs ranging between 8 and 17 and 18% fly ash resulted in CBRs between 15 and 31. Similarly, of the soil alone ranged between 3 and 15 MPa at 7% wet of optimum, whereas addition of 10% fly ash resulted in between 12 and 60 MPa and 18% fly ash resulted in between 51 and 106 MPa. In contrast, except for one fly ash, addition of fly ash generally had little effect on CBR or of the organic soil.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
Financial support for this study was provided by the DOEU.S. Department of Energy through the Combustion Byproducts Recycling Consortium, the University of Wisconsin-Madison Consortium for Fly Ash Use in Geotechnical Applications (funded by Mineral Solutions, Inc., Alliant Energy Corporation, and Xcel Energy Services, Inc.), and the Wisconsin Department of Transportation (WisDOT). The opinions and conclusions described in the paper are those of the writers and do not necessarily reflect the opinions or policies of the sponsors. Mr. Fred Gustin is acknowledged for his efforts in initiating this research effort.
References
Acosta, H., Edil, T., and Benson, C. (2003). “Soil stabilization and drying using fly ash.” Geo Engineering Rep. No. 03-03, Dept. of Civil and Environmental Engineering, Univ. of Wisconsin-Madison, Madison, Wis.
American Association of State Highway and Transportation Officials (AASHTO). (1993). Guide for design of pavement structures. Washington, D.C.
American Coal Ash Association (ACAA). (1999). Soil and pavement base stabilization with self-cementing coal fly ash, Alexandria, Va.
American Coal Ash Association (ACAA). (2000). ACAA’s CCPs production use and survey. Alexandria, Va.
Axelsson, K., Johansson, S., and Andersson, R. (2002). “Stabilization of organic soils by cement and Pozzolanic reactions—Feasibility study.” Swedish Deep Stabilization Research Center Rep. No. 3, Swedish Geotechnical Institute, Linkoping, Sweden.
Bin-Shafique, S., Edil, T., Benson, C., and Senol, A. (2004). “Incorporating a fly ash stabilized layer into pavement design—Case study.” Geotechnical engineering, Institution of Civil Engineers, London, Vol. 157, No. GE4, 239–249.
Bowles, J. E. (1992). Engineering properties of soils and their measurement, McGraw-Hill, New York.
Cokca, E. (2001). “Use of class C fly ashes for the stabilization of an expansive soil.” J. Geotech. Geoenviron. Eng., 127(7), 568–573.
Edil, T., Benson, C., Bin-Shafique, S., Tanyu, B., Kim, W., and Senol, A. (2002). “Field evaluation of construction alternatives for roadway over soft subgrade.” Transportation Research Record 1786, Transportation Research Board, Washington, D.C., 36–48.
Ferguson, G. (1993). “Use of self-cementing fly ashes as a soil stabilization agent.” Fly ash for soil improvement, Geotechnical Special Publication No. 36, ASCE, New York, 1–14.
Fredlund, D., and Wong, P. (1977). “Relation between resilient modulus and stress conditions for cohesive subgrade soils.” Transportation Research Record 642, Transportation Research Board, Washington, D.C., 73–81.
Hampton, M. B., and Edil, T. B. (1998). “Strength gain of organic ground with cement-type binders.” Soil improvement for big digs, Geotechnical Special Publication No. 81, A. Maher and D. Yang, eds., ASCE, New York, 135–148.
Heukelom, W., and Foster, C. (1960). “Dynamic testing of pavements.” J. Soil Mech. Found. Div., 86(1), 1–28.
Holtz, R., and Kovacs, W. (1980). An introduction to geotechnical engineering, Prentice-Hall, Englewood Cliffs, N.J.
Janz, M., and Johansson, S. (2002). “The functions of different binding agents in deep stabilization.” Swedish Deep Stabilization Research Center Rep. No. 9, Swedish Geotechnical Institute, Linkoping, Sweden.
Kaniraj, S., and Havanagi, V. (1999). “Compressive strength of cement stabilized fly ash-soil mixtures.” Cem. Concr. Res., 29(5), 673–677.
Kaniraj, S., and Havanagi, V. (2001). “Behavior of cement-stabilized fiber-reinforced fly ash-soil mixtures.” J. Geotech. Geoenviron. Eng., 127(7), 574–584.
Lee, W., Bohra, N., Altschaeffl, A., and White, T. D. (1997). “Resilient modulus of cohesive soils.” J. Geotech. Geoenviron. Eng., 123(2), 131–136.
Misra, A. (1998). “Stabilization characteristics of clays using class C fly ash.” Transportation Research Record 1161, Transportation Research Board, Washington, D.C., 46–54.
Muhanna, A., and Rahman, M. (1999). “Resilient Modulus Measurements of Fine Grained Subgrade Soils.” Transportation Research Record 1687, Transportation Research Board, Washington, D.C., 3–12.
Nicholson, P. G., and Kashyap, V. (1993). “Flyash stabilization of tropical Hawaiian soils.” Fly Ash for Soil Improvement, Geotechnical Special Publication No. 36, ASCE, New York, 15–29.
Nicholson, P., Kashyap, V., and Fuji, C. (1994). “Lime and fly ash admixture improvement of tropical Hawaiian soils.” Transportation Research Record 1440, National Research Council, Washington, D.C., 71–78.
Pandian, N., and Krishna, K. (2003). “The pozzolanic effect of fly ash on the California bearing ratio behavior of black cotton soil.” J. Testing and Evaluation, ASTM, Vol. 31, No. 6, 479–485.
Powell, W., Potter, J., Mayhew, H., and Nunn, M. (1984). The structural design of bituminous roads, TRRL Laboratory Report 1132, Transportation and Road Research Laboratory, Crowthorne, Berkshire, U.K., 62.
Sawangsuriya, A., and Edil, T. B. (2005). “Evaluating stiffness and strength of pavement materials, geotechnical engineering.” Geotechnical Engineering, Institution of Civil Engineers, London, Vol. 158, No. GE4, 217–230.
Tremblay, H., Duchesne, J., Locat, J., and Leroueil, S. (2002). “Influence of the nature of organic compounds on fine soil stabilization with cement.” Can. Geotech. J., Vol. 39, 535–546.
Trzebiatowski, B., Edil, T., and Benson, C. (2004). “Case study of subgrade stabilization using fly ash: State Highway 32.” Recycled Materials in geotechs, GSP No. 127, A. Aydilek and J. Wartman, eds., ASCE, Reston, Va., 123–136.
Turner, J. P. (1997). “Evaluation of western coal fly ashes for stabilization of low-volume roads.” Testing Soil Mixed with Waste or Recycled Materials, STP 1275, ASTM International, West Conshohocken, Pa., 157–171.
Information & Authors
Information
Published In
Journal of Materials in Civil Engineering
Volume 18 • Issue 2 • April 2006
Pages: 283 - 294
Copyright
© 2006 ASCE.
History
Received: Feb 15, 2005
Accepted: Jul 29, 2005
Published online: Apr 1, 2006
Published in print: Apr 2006
Notes
Note. Associate Editor: Hilary I. Inyang
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.