Field Performance Evaluation of Hydrated, Fly Ash Bases in the Atlanta District - Year 3 (7-2966-3)

Hydrated fly ash is produced by allowing powder fly ash (Class C) 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 1999. This report covers the third annual evaluation in a series of five.|All of the test pavements are continuing to perform well at this time. Laboratory and field testing data indicate that the pavement bases are not exhibiting any significant sign of deterioration.