Abstract
Fillers added to asphalt concrete mixes have long been used as stiffening, extending, or otherwise void-filling materials, dependingon their type and particle size. Fly ash, a by-product of the coal-burning process for power generation, is a filler that can serve oneor more of the above-mentioned functions. The role of fly ash in asphalt concrete mixes has been investigated. Three sizes of fly ash (coarse, medium, and fine) were used. The effect of these fly ash sizes on the resilient modulus, rutting potential, and water resistance of these mixes was investigated. It was found that the medium-sizefly ash was the best size for an asphalt extender. This paper appears in transportation research record no. 1323, Asphalt mix materials1991