ABSTRACT
This chapter discusses concrete strength and air content variability due to variations of fly ash in a single source.
A 2012 NRMCA survey (Obla et al. 2012) reported that fly ash was used in 60% of all ready mixed concrete placed in the United States. It is the most widely used SCM in the United States and constitutes 15% of all cementitious content used in ready mixed concrete. Due to sustainability and performance benefits, the use of fly ash continues to grow. Fly ash is an industrial by-product produced due to coal burning in an electric power utility. Electric utilities are primarily focused on optimizing power generation and are not concerned with fly ash quality or variability. Fly ash properties may change, depending on type and origin of coal used, blends of coal used, changes in the burner, and other factors.
