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原文传递 Utilization Of Western Coal Fly Ash In Construction Of Highways In The Midwest

题名：	Utilization Of Western Coal Fly Ash In Construction Of Highways In The Midwest
作者：	Anil Misra
关键词：	Class C Fly Ash. Soil Stabilization Sub-grade- Improvement, Fly Ash Leaching Behavior.
摘要：	Coal burning utilities in the Midwest using sub-bituminous coal from Wyoming typically produce fly ash, which, because of its high calcium oxide content, may be classified as Class C fly ash. These ashes are characterized by their self-cementing property and, therefore, they can be used greatly improve soil strength. This research project focused upon the design, construction and environmental issues pertaining to utilization of Class C fly ash for soil stabilization. The compaction and strength development behaviors of clay soils stabilized with fly ash obtained from Kansas City Power and Light were investigated. Laboratory evaluations required to obtain efficient fly ash addition rates and compaction procedure were devised. In this report we present examples of laboratory evaluations for eight different clay soils. Four of these are natural clays obtained from the vicinity of Kansas City. The other four clays were prepared in the laboratory by blending a small proportion of bentonite with kaolinite. These laboratory clays have properties that are easily duplicated, and thus provide standard clays for evaluating efficacy of a particular ash. It is found that compaction delay is an important factor controlling soil stabilization. It is also found that the stabilization characteristics depend significantly upon soil plasticity. Finally, it is observed that long-term performance of fly ash stabilized soil depends upon the curing method and shrinkage crack development. Therefore, construction guidelines best suited for Class C fly ash soil stabilization are outlined. Environmental issues related to utilization of Class C fly ash for soil stabilization are also examined. The related federal and state regulations are presented. The leaching behavior and potential laboratory leaching tests for Class C fly ash are discussed. It is noted that. Class C fly ash, generally, leaches only very small quantities of ccntaminants of concern. Nevertheless, leaching behavior of each ash must be examined on a case-by-case basis in relation to the background water quality. Standards must be established for these leaching tests with respect to the leaching fluids that best represent the fluids in nature, such as, simulated groundwater or rainwater leachates. These issues are discussed in relation to the federal and state regulations.
报告类型：	科技报告