Abstract: The crushing tools are designed as rocker-like chisels having cutting edges. These chisels are pivotably supported at a frame such to pivot around a horizontal axis. These chisel-like crushing tools are operated by a piston-cylinder unit which extends almost vertically and is pivotably mounted to the box-shaped frame. Accordingly, the apparatus can be designed with a small width. Furthermore, the rocker-like design of the crushing tools allows due to the various lengths of the lever arms an increase of the forces without necessitating an exchanging of the piston-cylinder units. Furthermore, an adjusting of the apparatus to pillars of varying thickness is made merely by an exchanging of the crushing tools having dimensions of cutting edges which are selected in accordance with the prevailing distances between the reinforcing bars.