Since the process of initiation and growth of cracks which lead to fracture in concrete must surely be influenced by the various components in the mixture (as well as state of stress, curing conditions, moisture content, etc.), it would be desireable to verify that the proposed testing standards are suitable for a wide range of key mix parameters. Concomitantly, the influence of different mix parameters on fracture properties including the shape of the crack front and process zone also may be determined. The successful completion of this work will provide further evidence that fracture mechanics is a viable and useful tool for the characterization of the behavior of cementitious materials subjected to stress and for the development of design formulas for shear strength, bond strength, deflection response and crack width of reinforced concrete structures in which size and brittleness effects can be considered explicitly.