The Use of Bottom Ash in Highway Embankments, Subgrades, and Subbases

This research assessed those properties of power plant bottom ash likely to affect its use as highway fill or pavement material, based on laboratory investigation conducted on eleven Indiana bottom ashes. Laboratory tests included: chemical analysis, mineralogical study, microscopic examination of ash particles, specific gravity, grain size distribution, sulfate soundness, Los Angeles abrasion, permeability, shear strength, moisture-density relations, degradation under compaction, compressibility, and California bearing ratio. The various test values and properties were compared to- those of representative granular soils or appropriate specifications. These comparisons provide information necessary for judging the suitability of bottom ash in Indiana highway construction. The potential environmental effects of bottom ash utilization were evaluated by performing leaching tests outlined in the EP toxicity test and an Indiana leaching method. Chemical analysis of the leachates showed that bottom ash is nonhazardous, and its effects on the quality of ground water is minimal