Prefabricated superimposed recycled lump concrete slab and construction method thereof

A prefabricated concrete slab, adapted to be integrated with post-casting concrete layer at a surface of the slab, the prefabricated concrete slab comprising a fresh concrete, a plurality of demolished concrete lumps and a reinforcement fabric at a lower part of the slab, the demolished concrete lumps are mixed with the fresh concrete, gaps between the demolished concrete lumps are filled with the fresh concrete, a ratio of a horizontal projected area of the demolished concrete lumps protruding from the fresh concrete to a surface area of the fresh concrete is no less than 1:3, a protruding height is no more than 25 mm, and the protruding height is limited by assembling molds;

• the assembling molds comprise casting molds and a height-controlling cover plate, reinforcement-locating slots are reserved on side molds of the casting molds, and a vertical position of the height-controlling cover plate is determined by using screws, position-controlling nuts and gaskets of different thicknesses, which are located at four corners of the casting molds, wherein a post-casting concrete layer is adapted to cover the slab, and the demolished concrete lumps are not exposed from the post-casting concrete layer.