The ornamental design for a concretepaverslab, as shown and described.
FIG. 1 is a top view of a concrete paver slab;.
FIG. 2 is one side view thereof, each of the other three side views being identical thereto; and,
FIG. 3 is a perspective view thereof viewed from above one corner, each of the other three perspective views above the other three corners being identical thereto.