"The Phase II research involved the following four objectives: optimize a preconditioning (hydration) step to control heat release problems encountered with the use of SB material; optimize the PFA:SB blend in order to maximize compressive strength, while maintaining an acceptable workability; optimize the coarse aggregate content to provide maximum strength gains and acceptable workability; and test the optimum mix for heat release and expansion characteristics, compressive strength, modulus of elasticity, permeability, and setting time. Each of these objectives was addressed by means of an experimental study or task. These include Preconditioning Studies, PFA/Spent Bed Optimization Studies, Coarse Aggregate Optimization Studies, and Characteristics of Optimum Mix."