Coal fly ash is a coal combustion product that has numerous applications in highway construction. Fly ash has been used in roadways and interstate highways since the early 1950s. In 1974, the Federal Highway Administration issued an official notice which urged states to allow partial substitution of fly ash for cement whenever feasible. In addition, to encourage the use of fly ash the Environmental Protection Agency published federal procurement guidelines for cement and concrete containing fly ash. The present course provides basic technical information for highway engineers who want to learn about the advantages of fly ash as originally envisioned by the FHWA and the EPA and as borne out by the subsequent experience of other engineers involved in highway construction. This course is based on FHWA Report No. FHWA-IF-03-019, “Fly Ash Facts for Highway Engineers,” 2003.

Learning Objectives

• Origin and production of fly ash;
• Handling of fly ash;
• Physical and chemical characteristics;
• Environmental benefits;
• Environmental impacts;
• Portland cement concrete applications;
• Applications in stabilized base courses;
• Applications in flowable fills;
• Soil improvement using fly ash;
• Applications in asphalt pavement;
• Fly ash applications in grouts for pavement subsealing; and
• Additional developments in fly ash technology.