Abstract: The continuously extruding curb forming machine for roads, for example, may be equipped with a downwardly moving sharpened blade for use in the insertion of an expansion joint piece at appropriate intervals into the curb without stopping the operation of the machine while the expansion joint piece is inserted. The expansion joint piece may be well known felt material for this purpose and the inserting blade has a template attached thereto the surface of which conforms to the surface of the curb and thus to the surface of the expansion joint piece. As the blade moves into the partially cured concrete, the template forces the joint piece into the same concrete.