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Abstract
Enormous amounts of coal fly ash produced by the utilities industry create a significant disposal problem. The abundance of fly ash along with its self‐hardening properties led the Louisiana Department of Transportation and Development (LA DOTD) to use fly ash as a soil stabilizer for road bases. However, the LA DOTD is primarily concerned with the strength of the material and has not studied its leaching characteristics.
During this study, a total of three samples, a 30 percent lignite fly ash/soil mixture, lignite fly ash, and soil, were leached following the EPA multiple extraction procedure and analyzed by Inductively Coupled Argon Plasma Spectrometry (ICAP). Results indicate that little change in leachate quality of lignite fly ash was caused by the soil stabilization process. The insignificant change is attributed to the low cation exchange capacity of the soil. ICAP analysis revealed that heavy metal concentrations were within RCRA and Public Drinking Water standards.
road bases [3,10]. However, the majority of the fly ash stabilization projects implemented by various highway departments have been devoted more to the measurement of strength and durability of the material rather than to its possible environmental impact [2]. The leaching potential from fly ash structures must be determined in order to evaluate the possibility that heavy metals from the ash could migrate to groundwater systems and possibly contaminate drinking water sources. Therefore, the quality of leachate from fly ash must be well‐evaluated before using large amounts of it in engineering structures. The primary objective of this research was to determine the influence of the stabilization process on the leachate quality of lignite fly ash when this pozzolan is used as a road base material.