In the last decade jordan has given serious consideration to theuse of oil shale as an alternative energy source. Such use will be accompanied by the production of a large amount of oil shale ash. Possible areas of application for this byproduct are under investigation, including its possible use with asphalt concrete mixes under different environmental conditions. Many researchers have indicated that it is possible for a mineral filler (fly ash, dust, etc.) To act as an asphalt extender or substitute binder for paving construction. The main objective of this study was to evaluate quantitatively the use of oil shale ash as a partial substitute for the asphalt binder in bituminous paving mixtures under normal conditions as well as under freezing and thawing conditions. Oil shale ash was added to the asphalt concrete mix at optimum asphalt content. Five ash levels, ranging from 0 to 20% by volume of asphalt, were used in the study. Foreach level marshall and indirect tensile tests were performed underboth normal and freeze-thaw conditions. The test results indicated that the substitution of ash up to 10% by volume of asphalt would improve the performance of mixtures under both conditions. Such ash inclusion resulted in paving mixtures with higher marshall stability, greater tensile strength, a larger stiffness modulus, and higher resistance to freeze-thaw damage in coparison with mixtures without ash. This paper appears in transportation research record no. 1228, Asphalt mixtures and asphalt chemistry.
Abstract