Refer to table. A thrust block is required for a 45 degree elbow in class 150 psi in a 12″ water main. How much concrete will be required for this fitting in sand & gravel?

Refer to table. A thrust block is required for a 45 degree elbow in class 150 psi in a 12″ water main. How much concrete will be required for this fitting in sand & gravel?