This report gives an overview of the origin and properties of fly ash, its effect on the properties of portland-cement concrete, and the proper selection and use of fly ash in the production of portland-cement concrete and concrete products. The report contains information and recommendations concerning the selection and use of Class C and Class F fly ashes generally conforming to the requirements of ASTM C 618. Topics covered include a detailed description of the composition of fly ash, the physical and chemical effects of fly ash on properties of concrete, guidance on the handling and use of fly ash in concrete construction , use of fly ash in the production of concrete products and specialty concretes, and recommended procedures for quality assurance. Referenced documents give more information on each topic.