Abstract: The invention relates to a method for the production of concrete pipes, particularly for wastewater lines, having a plastic inner pipe, wherein the concrete part is manufactured in a horizontal position in order to simplify the production process and reduce the costs thereof, and wherein the plastic inner pipe is maintained in a horizontal position in a trough, wherein the trough is further filled with flowable concrete to above the plastic pipe, and wherein the plastic pipe serves as an inner tray and remains in the concrete pipe after the concrete has cured, and to a concrete pipe system.

Abstract: Paving stones of concrete as well as artificial stone material are provided having a tread surface along the top thereof as well as upright sides which are located between corner points of the stone. The side surfaces are provided with serrations, wavy-shaped contours and irregular groove-ridges up to 8 mm deep retreating toward the stone interior along the upright side walls. Such irregular serrations, wavy-shape contours and irregular groove-ridges are adapted to interengage with corresponding configuration of adjoining stones to anchor the stones against any lateral shifting and displacement during travel of a vehicle in a curve or when making a turn as well as during application of brakes of the vehicle wich would result in a horizontal thrust being transmitted to the stones which otherwise would be caused to shift or dislocate from the smooth contour of the tread surfacing of the stones.