Year of Publication


Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation




Civil Engineering

First Advisor

Dr.. Michael E. Kalinski


For this study, the main material to be investigated is Class F fly ash that originates from the combustion of Appalachian coal. Alone, fly ash exhibits poor strength properties and is susceptible to liquefaction when subject to dynamic loading. This research is focused on investigating the effect of adding materials that would otherwise be considered as waste products to the fly ash. Materials to be considered include crumb rubber, shredded carpet and shredded paper. The benefits from this research are twofold. First, provide a method to stabilize fly ash. For large masses of fly ash such as those found at power plants and landfills, improved strength of the fly ash will make the mass safer and more reliable with respect to stability. Second, provide a use for waste materials that would otherwise be stockpiled or disposed of in landfills at a significant cost, which in turn will minimize the environmental impact. Using this approach, materials will be added to fly ash rather than using fly ash as an additive, which will increase the rate of fly ash usage and more directly address the issue the large volumes of fly ash that are being produced today.

To perform this research, representative samples of Class F fly ash were tested to characterize the physical properties of the materials. Later, this Class F fly ash was mixed with specific percentage of three waste materials to evaluate the behavior and performance of the fly ash admixture. Using these reconstituted specimens, a suite of laboratory tests to assess the static and cyclic strength properties of each specimen was performed, as well as the dynamic properties of the specimens. The expectations were to develop correlations between mixture ratios and the various measured properties, and to identify mixture ratios that will optimize the strength characteristics of the specimens.

In the end, crumb rubber was found to be the best additive to improve the properties of Class F fly ash compared to the other waste materials used. This conclusion can be used by power plant facilities to increase the safety factor against liquefaction at their impoundment facilities.

Digital Object Identifier (DOI)