Dry Fly Ash Placement-Overcoming Unique Challenges and Streamlining Filed Operations
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Fossil plant owner/operators are currently anticipating that EPA will more strictly regulate disposal of coal combustion residuals (CCRs) in the near future. Many facilities that operated wet disposal ponds are in the process of converting to dry disposal practices and facing new operational challenges.

Dry fly ash has highly variable and time-dependent compaction characteristics due to pozzolanic and cementitious properties and the source of coal. Therefore establishing a compaction criterion, based on conventional soil mechanics using target relative compaction and moisture content, becomes challenging and often impractical from a construction perspective and increases the level of uncertainties in the construction quality assurance procedure. This paper presents a summary of field observations from actual dry fly ash placement operations at a fossil power plant, along with laboratory and field-scale testing of representative fly ash materials from the same fossil plant. Physical and engineering properties of dry fly ash relevant to construction quality control during disposal operations are discussed. The result of this study provides insight into the in situ density, stiffness, and strength properties of compacted dry fly ash with the ultimate goal of developing an alternative criterion and/or a method-based specification for fly ash placement. The findings of this study can lead into streamlining field operations, including placement, testing, and quality control, which could result in significant operational cost savings over the life of a fly ash disposal facility.

Publication Summary

  • Geosyntec Authors: Ali Ebrahimi, Sarah Fick, Cuneyt Gokmen, Mehmet Iscimen
  • All Authors: Ali Ebrahimi, Sarah B. Fick, Cuneyt Gokmen, Mehmet Iscimen, Rachel B. Combs, Vernon J. Dotson, Jr.
  • Title: Dry Fly Ash Placement-Overcoming Unique Challenges and Streamlining Filed Operations
  • Event or Publication: World of Coal Ash Conference 2013 Annual Conference
  • Practice Areas: Waste Containment Facility Planning and Design, Geotechnical and Geoenvironmental Engineering, Utility Industrial Ash and Scrubber Sludge Monofills
  • Date: 2013
  • Location: Lexington, KY