Durability of base course construction using lime stabilized fly ash and flue gas desulfurization sludge by-product
- Dravo Lime Co., Pittsburgh, PA (United States)
- American Electric Power Service Corp., Columbus, OH (United States). Geo/Hydro/Site Section
Fourteen coal-fired power plants in the Ohio Valley totaling 13,500 MW`s use the magnesium-enhanced lime flue gas desulfurization (FGD) scrubbing process. The discharge of these scrubbers is an aqueous slurry of water containing magnesium and calcium sulfites, and solid particles of calcium sulfite and calcium sulfate. Most of these plants dewater the FGD sludge and mix the 35--45% solids cake with coal fly ash and/or bottom ash and pulverized quicklime to cause a cementitious chemical reaction. This type of pozzolanic and hydration reaction can be described as lime reacting with alumina from the fly ash which in turn react with the calcium sulfite and sulfate FGD waste to form ettringite minerals. With a proper mix design and compaction, the resulting material can be used in a beneficial application as a roller compacted FGD base course (RCFGD) for pavement construction. The mix design procedure for RCFGD is described; it includes extra fly ash and lime materials than that used for landfill disposal to yield additional strength and durability. RCFGD was produced in a portable pug mill and placed trying several at a 10,000 sq. ft. cattle feedlot. Mix design criteria and factors affecting strength and durability are discussed. Results of unconfined compression tests as well as of durability tests are reviewed.
- OSTI ID:
- 504722
- Report Number(s):
- CONF-960954-; TRN: IM9733%%137
- Resource Relation:
- Conference: 13. annual international Pittsburgh coal conference, Pittsburgh, PA (United States), 3-7 Sep 1996; Other Information: PBD: 1996; Related Information: Is Part Of Thirteenth annual international Pittsburgh coal conference: Proceedings. Volume 1; Chiang, S.H. [ed.]; PB: 786 p.
- Country of Publication:
- United States
- Language:
- English
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