This investigation was performed to evaluate the long-term performance of concrete pavements made with high volumes of Class F and Class C fly ash (FA). Six different mixtures - three mixtures with Class C fly ash with up to 70° cement replacement and three mixtures with Class F fly ash with up to 67% cement replacement-were used. Long-term performance tests for all mixtures were conducted for compressive strength, resistance to chloride-ion penetration, and density using core specimens from in-place pavements. Results revealed a greater pozzolanic strength contribution of Class F fly ash relative to Class C fly ash. Generally, the concrete mixtures containing Class F fly ash exhibited higher resistance to chloride-ion penetration relative to mixtures containing Class C fly ash. Compressive strengths of core specimens taken from in-place pavements ranged from 45 to 57 MPa (6500 to 8200 psi). The highest long-term compressive strength was achieved for the high-volume fly ash mixture incorporating 67% Class F fly ash at the age of 7 years. Visual observations revealed that the pavement sections containing high volumes of Class F fly ash (35 to 67% FA) concrete performed well in the field with only minor surface scaling. All other pavement sections have experienced very little surface damage due to the scaling.