Field Performance Evaluation of Hydrated, Fly Ash Bases in the Atlanta District - Year 4

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C.K. Estakhri

Publication Date:

October 2000


Hydrated fly ash is produced by allowing a Class C powder fly ash (ASTM C 618) from coal power plants to cure with moisture. The hydrated (cured) fly ash becomes a stiff material that can be crushed to form a synthetic aggregate. When properly processed and compacted to optimum moisture content, the hydrated fly ash continues to gain strength after placement as a base material.|The Atlanta District has constructed six pavement sections since 1993 using hydrated fly ash as the flexible base material. This research project was initiated to evaluate and monitor performance and changes in material properties for these six pavements through the year 2001 and to evaluate a problem experienced during construction where the asphalt surface treatment did not bond well to the base.|Evaluation of pavement base performance was based on visual documentation, falling-weight deflectometer tests, ground-penetrating radar, and compressive strengths of field cores. This report is an interim report documenting the performance evaluations conducted in the spring of 2000. This report covers the fourth annual evaluation in a series of five.|Based on visual evaluations, FWD data, and compressive strengths of cores, the hydrated fly-ash test pavements are performing well, and none are exhibiting any significant signs of deterioration.

Report Number:



Hydrated Fly Ash, Coal Combustion By-products, Fly Ash, Stabilized Bases, Highway Construction

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