Abstract: A concrete mixer and the like adapted to be attached to the lifting system of a tractor or other vehicle. This mixer comprises a bucket having a cylindrical drum shape, the lateral wall of which is provided with an aperture having a maximum opening of one quarter of a circle. A shaft is mounted in the cylindrical drum along the longitudinal axis thereof and carries radial arms having mixing blades secured to their outer end. Drive means can rotate the shaft in either of the two opposite directions; that is in an unloading direction and in a mixing direction. The bucket is mounted on bearings to pivotally attach it to the lifting system and to pivot it between the unloading position in which the aperture faces downward and the loading and mixing position in which the aperture faces upward.