Summary: The main objective of this research was to evaluate the effect of partial replacement of fine aggregate by fly and bottom ash, on selected physical properties of asphalt concrete mixtures. Specific objectives of this research included: 1) Study the effect of fly and bottom ash on the indirect tensile strengths (dry and wet) and tensile strength ratios of asphalt concrete mixtures. 2) Study the effect of hydrated lime on various asphaltic mixtures containing coal ash under wet and dry conditions. 3) Determine whether significant differences existed among the two coal ash sources as observed by indirect tensile strengths and tensile strength ratios. 4) Determine whether different coal ash percentages produced any significant differences among mean values of indirect tensile strengths and tensile strength ratios. 5) Study the effect of coal ash as detected by indirect strengths and tensile strength ratios among Marshall specimens prepared with three different aggregate sources.