Abstract: A method and an apparatus for the manufacture of concrete pipes (2) made of an outer layer and having an inner layer of greater density in surface structure is described. The inner layer is applied by an applicator in a mould (1) having both outer (3) and inner (4) mould parts. The applicator is formed by an inner mould part or core (4) or by an applicator unit in immediate connection with the core (4). The applicator applies the inner layer simultaneously or immediately following vibration of the concrete forming the pipe. The inner layer is applied during movement of the inner mould part or core (4) in its longitudinal direction, the core having one or more supply openings (14) provided along the circumference of the core (4) at the upper end of the core (4) for supplying a further material of greater density to form the inner layer.

Abstract: A method and an apparatus for the manufacture of concrete pipes (2) made of an outer layer and having an inner layer of greater density in surface structure is described. The inner layer is applied by an applicator in a mould (1) having both outer (3) and inner (4) mould parts. The applicator is formed by an inner mould part or core (4) or by an applicator unit in immediate connection with the core (4). The applicator applies the inner layer simultaneously or immediately following vibration of the concrete forming the pipe. The inner layer is applied during movement of the inner mould part or core (4) in its longitudinal direction, the core having one or more supply openings (14) provided along the circumference of the core (4) at the upper end of the core (4) for supplying a further material of greater density to form the inner layer.